Alternative Prostate Cancer Treatments

How does a man decide on the best treatment option for prostate cancer?

Dr. Gregory Echt is a radiation oncologist, a doctor who specializes in using radiation to treat cancer. He and his team offer the most highly sophisticated methods of radiation therapy available in the United States, equal to that found in major medical center and academic settings. These include prostate seed implantation, high dose radiation implants, and external beam radiation with image-guided and intensity-modulated (IGRT and IMRT) capabilities.

Dr. Echt has treated prostate cancer in more than 2,500 men, including urologists and other radiation oncologists, with seed implantation, which is also referred to as brachytherapy.

Radiation therapy offers options for safely and effectively treating prostate cancer and many other cancers. Goals of radiation therapy include curing cancer, controlling cancer growth, or relief of cancer symptoms including pain. Radiation therapy damages cancer cells in such a way that cancer cells cannot reproduce. When damaged cancer cells die, the body naturally eliminates them. Radiation affects normal cells, but they are able to recover from the treatment in a way that cancer cells cannot.

Choosing a treatment option involves the patient, his family, and one or more doctors. Cancer grade and stage, the man’s age and health, and his values and feelings about the potential benefits and harms of each treatment option should be considered.

Prostate Cancer Treatment Options

Prostate Seed Implantation (Brachytherapy or Internal Radiation): Tiny radioactive pellets or seeds are placed in or near the prostate cancer tumor. Cancer cells are killed by the energy given off as the low dose rate radioactive material decays or breaks down over a period of several weeks or months, leaving no radioactive material in the prostate gland. The procedure takes about one hour, then the patient walks out of the clinic and is driven home by a friend or family member. Most patients are back to a normal routine within a day or two. Fifteen years of data are available on this method of treatment. It is has proven to be an excellent option for treating prostate cancer. More...

High Dose Radiation Therapy (HDR or Temporary Brachytherapy): HDR is another form of internal radiation. This therapy involves placing radioactive seeds temporarily in the prostate. These seeds contain more radioactive material than those used in traditional prostate seed implants. The procedure involves a hospital stay during which a template is fitted to the area to be treated. The patient is treated with seed placement two or three times initially, then two weeks later the treatment is repeated. More...

External beam radiation: External beam radiation therapy generally involves treatments at a radiation facility once a day, Monday through Friday for seven to eight weeks. The treatments cause no pain and each session lasts a few minutes. The primary target is the prostate gland itself. Dr. Echt offers intensity-modulated radiation therapy (IMRT), image-guided radiation therapy (IGRT), and 3D conformal radiation therapy. These treatments use the same technology found in major medical and academic settings. More...

Combination therapy of seed implant and external beam radiation therapy: Patients with advanced stage prostate cancer have a high risk of the disease spreading outside the prostate. In these cases, external beam therapy may be needed in addition to seed implants or HDR treatment. More...

Hormonal Therapy: In many cases, if the cancerous tumor is large, hormonal therapy may be started at the time of radiation therapy and continued for several years. Hormonal therapy is treatment that adds, blocks, or removes hormones in order to slow or stop the growth of certain cancers.

Quality Assurance

Whether a patient undergoes a traditional seed implant, HDR treatment, external beam treatment, or combined therapy, significant work is done to make sure the treatment is completed properly. The process that is set up is called quality assurance.

Each type of treatment requires trained staff and high quality equipment with an ongoing verification of periodic inspections, calibrations, and updates. Physicists specializing in medical application of radiation review every patient treatment. They also conduct the ongoing tests of all equipment used in planning and delivery of radiation treatments.

For traditional prostate seed implants, a CATScan is acquired about one month after the procedure and the images are used to determine the precise location of each seed within the prostate. Thc radiation dose distribution is calculated and the results are reviewed with the radiation oncologist. For external beam treatments using Intensity Modulated Radiation Therapy (IMRT) each treatment field is test run and compared to the intended pattern before treatments begin. For HDR treatments, independent cross checks of the radiation source positions and dwell times is verified prior to treatment.

Each treatment modality involves a team including a nurse, radiation therapists, and physicist in addition to the physician. Each team member is licensed by the state and ongoing training and continuing education is provided to keep up to date with the latest advances in treatment techniques. The goal of each is to provide a safe, effective treatment.

Prostate Seed Implantation or Brachytherapy

Dr. Gregory Echt focuses on prostate seed implantation as the preferred method of treatment for prostate cancer. It is the fastest growing method of treating prostate cancer in the United States. Dr. Echt has performed this procedure on more than 2,500 men over his 17 years in practice.

Criteria necessary for a patient to be considered for seed implantation alone (monotherapy):

• Prostate gland cannot be too large.
• A PSA result of less than 10, depending on the patient’s specific case (see Testing for Prostate Cancer)
• Gleason score of 6 or less, depending on the patient’s specific case (see Grading and Staging Prostate Cancer)
• If it is likely that cancer has spread outside the prostate gland, external beam radiation may also be required.

Advantages of seed implants:

• The procedure takes about one hour, then the patient walks out of the clinic and is driven home by a friend or family member. Most patients are back to a normal routine within a day or two.
• Fifteen years of data are available on this method of treatment. It has proven to be an excellent option for treating prostate cancer. In numerous medical studies, seed implantation equals or exceeds the cure rate of surgery to remove the prostate.
• Treatment is generally painless, as the patient is given a mild anesthetic.
• Recovery is much quicker and has fewer complications because the procedure does not require major surgery.
• Rates of sexual problems such as erectile dysfunction (ED) and urinary problems are very low. According to the American Cancer Society, a major study (CaPSURE), rates brachytherapy as having the lowest rate of sexual dysfunction of any treatment, even after five years.

Disadvantages:

• Most men temporarily experience occasional urinary urgency and frequency, and/or a weak urinary stream. Less than 5% of men may find they are temporarily unable to urinate, with the need for insertion of a catheter to relieve this problem. Medication can be prescribed for these issues.
• PSA is a blood test that indicates the possibility of prostate cancer. Following seed implantation, the PSA may decline for as long as several years before reaching its lowest point. The patient’s urologist and/or Dr. Echt follow the PSA closely.
• Sexual problems such as erectile dysfunction (ED) occur in approximately 20% to 30% of patients. This probability is lower in younger patients.
  Medication such as Viagra can be used to successfully treat 70% to 75% of men with this problem.

How does Prostate Seed Implantation work?

Prostate seed implantation, or brachytherapy, is a procedure to place radioactive rice-sized "seeds" into the cancerous prostate. The goal of the treatment is to kill cancer cells with radiation while preserving healthy tissue. Doctors use the tiny radioactive seeds to target the tumor and to control the area exposed to radiation.

It is the fastest growing method of treating prostate cancer in the United States. After the area is anesthesitized with drugs or substances that cause loss of feeling or awareness, the seeds are injected into the prostate through the skin with a needle in the area between the scrotum and anus. Seeds can be left in place permanently; in which case they give off radiation for weeks or months, and are not removed once the radiation is gone.

Ultrasound and sophisticated computer programs help guide the placement of the radioactive seeds. Ultrasound is a procedure in which high-energy sound waves are bounced off internal tissues or organs and make echoes. The echo patterns are shown on the screen of an ultrasound machine, forming a picture of body tissues called a sonogram. Using the most advanced technology available, the doctor is able to target cancerous areas of the prostate with higher doses of radiation. Typically the entire gland is treated because cancer is likely to be found in more than one area of the prostate gland.

Images of the prostate are taken and transferred to the treatment planning computer. The computer evaluates the exact position of the prostate and generates a three-dimensional plan that dictates the precise placement of the seeds to provide exactly the amount of radiation needed to cover 100% of the prostate gland while minimizing the exposure of healthy tissue such those in the urinary tract and rectum.

The procedure takes about one hour, then the patient walks out of the clinic and is driven home by a friend or family member. Most patients are back to a normal routine within a day or two. Radiation exposure to other people is minimal, so restrictions are recommended only if the patient is returning to a setting where a newborn child or pregnant woman is present.

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High-dose Rate (HDR) Brachytherapy

High-dose rate brachytherapy (HDR or Temporary brachytherapy) is a newer form of brachytherapy involving seeds that are placed temporarily in the prostate gland. These seeds stay in place for less than an hour and contain higher intensity radioactive material than traditional prostate seed implants.

Using sophisticated computer and radiologic techniques, the patient is fitted with a template that holds tiny tubes, also called catheters, in place. The catheters are placed within the prostate and pelvis, with a length of the catheter remaining outside the body for connection to the high dose radiation machine. The fitting of the template and catheters is done in the operating room, followed by an overnight stay in hospital. The catheters and the template remain in place for one to two days during each treatment. A series of radiation treatments, usually three, are given the day after the fitting of the template. A computer-controlled device pushes highly radioactive seeds into the tubes one by one and controls the length of time each seed remains in place, thus controlling the radiation dose in different areas of the prostate. A higher dose can be targeted at the tumor, with a lower dose given in the areas near the urinary tract and rectum. The tubes are then removed and no radioactive material is left in the prostate gland. The patient returns in two weeks and the same treatment is repeated. The treatment is relatively pain-free.

Criteria necessary for a patient to be considered for HDR brachytherapy:

• Most prostate cancer patients are candidates for HDR brachytherapy, if so desired.

Advantages of HDR brachytherapy:

• Treatment requires only minor surgery, therefore there are fewer surgery-related complications.
• Treatment is generally painless, as the patient is given a mild anesthetic.
• Recovery is much quicker because the procedure does not require major surgery.
• Radiation dosage can be modified after the catheters are in place to dispense radiation.
• Impotence and incontinence rates, or urinary problems, are very low. According to the American Cancer Society, a major study (CaPSURE) rates brachytherapy as having the lowest rate of sexual dysfunction of any treatment, even after 5 years.

Disadvantages:

• HDR treatment is demanding on the patient as he goes through multiple steps including template fitting, catheter placement, and radiation treatment. The template and catheters remain in place in the genital area during the entire nearly 24 hour process.
• This treatment is inconvenient for patients in terms of time because it requires an overnight stay in the hospital for template fitting and a second day for treatment. In addition, two weeks after the initial treatment, the patient must return for another template fitting, including an overnight stay in the hospital, and a second day of treatment.
• The patient may experience pelvic discomfort for several weeks after treatment due to the dose intensity. This can be treated with over-the-counter medication.

Effect of low dose-rate prostate brachytherapy on the sexual health of men with optimal sexual function before treatment: analysis at >= 7 years of follow-up

Jamie A. Cesaretti, Johnny Kao, Nelson N. Stone* and Richard G. Stock

Departments of Radiation Oncology and *Urology, Mount Sinai School of Medicine, New York, NY, USA
Accepted for publication 16 February 2007
This work was presented at 47th annual ASTRO annual meeting in October 2005.

SEXUAL FUNCTION OF MEN 7 YEARS AFTER LOW-DOSE PROSTATE BRACHYTHERAPY

Patient and tumour characteristics are outlined in Table 1. Brachytherapy was administered via the real-time transperineal approach using TRUS to direct the placement of each radioactive source within the prostate [13]. The implant characteristics are shown in Table 2. The prescription dose for 125 I-implants was 160 Gy, corrected for the TG-43 recommendation [14]. The prescription dose of 103 Pd-implants was 124 Gy for a full implant and 100 Gy for partial implants, following the National Institute of Standards and Technology 1999 recommendations [15]. Patients treated with partial implants received supplemental EBRT of 45 Gy to 59.4 Gy [16]. Patients returned at ˜ 4 weeks after the implant for detailed CT-based dosimetric analysis; EBRT was begun 8 weeks after the implantation. The follow-up included a DRE and serial PSA measurements. Biochemical failure was defined using the American Society for Therapeutic Radiation and Oncology consensus definition [17]. To accurately assess ED after brachytherapy, for the entire group, patients treated with salvage hormone therapy were included in the study.

All patients had a detailed history taken and a physical examination before implantation, followed by a directed history and physical examination at 6-month intervals afterward. ED was assessed using the Mount Sinai EF (MSEF) physician-assigned scoring system, i.e. 0, complete inability to have erections; 1, able to have erections but insufficient for intercourse; 2, can have erections sufficient for intercourse but considered suboptimal; and 3, optimal EF. The derivation and relevance of this scoring system were described previously [18,19]; a score of 0 or 1 was considered as ED. Beginning in June 2000, the validated International Index of Erectile Function (IIEF-5) was used as a complementary method to better quantify late ED [20], with a score of >= 16 on the IIEF- 5 defining adequate EF; a score of 16 was found to result in good EF in a group of 124 men given sildenafil in a randomized clinical trial of men who had a baseline mean IIEF-5 score of 7.7 [21]. In addition, investigators from the Cleveland Clinic found that a score of >= 16 on the IIEF-5, using the ‘medicated urethral system for erection’ after RP, predicted continued sexual activity, whereas a lower score predicted the discontinuation of erectile attempts using this treatment [22]. Because of the relatively recent use of the IIEF-5, the present analysis did not allow a

CESARETTI ETAL

prospective evaluation in the present patients and the last completed form was used for the study. All patients included in the study were entered based on guidelines approved by the Mount Sinai Medical School institutional review board. The results were analysed using standard statistical software, with differences in proportions tested using the chi-square statistic, and difference in means with Student’s t -test, with a two-sided P <= 0.05 considered to indicate statistical significance in all tests. RESULTS The median (range) follow-up of the 223 patient was 8 (7–14) years; those with a longer follow-up appeared to be in a more favourable prognostic category, with a statistically lower Gleason sum of 2–6 in 77% ( P = 0.03). There was a trend to better baseline EF at implantation among patients with >= 7 years of follow-up, with 131 of 223 (58.7%) having normal EF, vs 179 of 363 (49%) ( P = 0.02; Table 1). The incidence of diabetes, hypertension, smoking and use of adjuvant hormone therapy, distribution of isotopes used for treatment, and EBRT dose were evenly distributed between both the patients followed for >= 7 years and those lost to follow-up and not assessed for EF. Of the 131 patients with an optimal MSEF score (of >= 3), 42 (32%) developed ED; the mean age at implantation of these men was 67 (57–78) years, vs 63 (50–78) years (P < 0.001) for those who maintained EF. Patients who were 50–59 years old when implanted had an potency rate of 92%, based on an MSEF score of >= 2, or 64% for an IIEF-5 of >= 16, at >= 7 years of follow-up; those aged 60–69 years had a 64% potency rate by MSEF score and 27% by the IIEF-5. Relatively elderly patients, implanted when aged 70–79 years, all of whom are now > 76 years old, had a MSEF score of >= 2 in 58% and a IIEF-5 of >= 16 in 19% (Fig. 1). There was no difference between the development of ED based on the isotope used. Of the 131 men with normal EF before implantation, 60% were treated with 125 I-monotherapy, 33% with 103 Pdmonotherapy and 7% with a combined partial 103 Pd-implant and supplemental EBRT. Patients treated with a full 125 I-implant had a 71% (56/79) potency rate, while those treated with a full 103 Pd-implant had a 63% (27/43)

potency rate, as evaluated by the MSEF score ( P = 0.36) (Table 3). The treatment strategy, which incorporated EBRT and the partial 103 Pd-implant with 9 months of hormone therapy, maintained EF in three of the nine men. Of interest, among patients treated with 125 I- or 103 Pd-implants alone, no D90-related dose relationship was associated with the onset of ED. As expected, PSA failure was a strong predictor of ED among the present patients because of the use of either intermittent or continuous hormone therapy. Of the 131 patients, 23 had PSA failure and 15 (65%) of these developed ED; by contrast, 27 of 108 (25%) who had no PSA failure developed ED (P < 0.001). Of patients who reported maintained EF after >= 7 years of follow-up 45/89 (51%) were currently using aids for EF, while six of 42 (14%) of those with erections insufficient for intercourse were using and aid for EF (P < 0.001; Table 4. Of these 51 patients, 44 (86%) were using either a phosphodiesterase type 5 (PDE-5) inhibitor, yohimbine (two, 4%) or alprostadil (five, 10%) at the final followup. The mean age at implantation of those using the aid was 63 years, vs 66 years in those not doing so ( P = 0.06). In addition, there was a trend to significance between the association of adjuvant hormone use, at 29 (57%) vs 33 (41%), and the use of an erectile aid at the final follow-up ( P = 0.08). Also, most men using an aid (45/51, 88%) claimed to have a good response to their chosen therapy. DISCUSSION Brachytherapy and/or EBRT appear to maintain higher rates of EF than RP, even though patients treated with radiation are a mean of 6–8 years older [23,24]. The reports that describe promising rates of preservation of EF after surgery focus on the subgroup of men aged 50–59 years and with intact sexual function before bilateral nerve-sparing RP done by high-volume surgeons [25,26]. In the present study we showed that comparably young and potent men treated with brachytherapy have a 92% likelihood of maintained sexual function at >= 7 years after completing treatment, using a similar type of physician-assigned measure. Based on this finding it is reasonable to conclude, to an even greater extent, that the same physiological redundancy which allows for preservation of EF in the younger man after

FIG. 1. The percentage of patients with an MSEF score of 2 or 3 and IIEF-5 score of >= 16 after >= 7 years of follow-up, and who had normal EF before brachytherapy. RP is also accessible to the young patient after radiotherapy. Among men with no prostate cancer and aged > 70 years the incidence of moderate to complete ED is about half [11]. This, in addition to the dramatic influence of age in this series, strongly suggests that ED after treatment for prostate cancer is multifactorial, with a strong dependence on both age and sexual motivation. In addition, it appears that younger patients are adequately treated with the current aids available for ED as it develops over the years after brachytherapy. Therefore, it is reasonable to hypothesise that the practice of supplying all patients treated with brachytherapy for prostate cancer with prophylactic PDE-5 inhibitors is not necessary in younger men. In the formulation of future trials to test prophylactic PDE-5 inhibitors, efforts should be made to target the more elderly patients who do not appear to benefit to the same extent as the younger patients from ondemand PDE-5 inhibitors when ED develops later in the follow-up. The EF data were analysed by using both the patient-reported IIEF-5 and the physicianreported MSEF, which is based on the scale used in the Massachusetts Men’s Aging study. While patient reported data are preferable, the IIEF-5 was only validated in 1999 [20]. Therefore, long-term data before and after treatment using only the IIEF-5, with an extended follow-up, was not possible in the present patients. However, in the present study, a significant percentage of patients classified as potent using the MSEF scale were classified as having ED based on an IIEF-5 score of <= 16; the IIEF-5 was validated in patients without prostate cancer, who

SEXUAL FUNCTION OF MEN 7 YEAR SAFTER LOW - DOSEPRO STATE BRACHYTHERAPY

presented only for consideration of erectogenic therapy; therefore a dramatic discordance between an IIEF-5 score and a physician-assigned score occurs in the less sexually motivated patient who is still physiologically able to have erections [20]. Also, there has been a ‘stage migration’ in EF in recent reports of sexual health after interventions for prostate cancer, due to the widespread adoption of oral PDE-5 inhibitors for patients with true or expected ED after therapy. Recent reports in urological oncology have begun to characterize patients using erectile aids as ‘not having ED’. A recent example from investigators at the Cleveland Clinic showed that after a bilateral nerve sparing RP the preservation of EF was 76% with sildenafil [27]. This is in contrast to the historical experience, where only 10–30% of patients maintain EF after RP when assessed using patient-reported questionnaires [8,10,23,24]. To compare series, this less purist approach might become the only practical way to compare the outcomes of treatment for ED among therapeutic methods as the understanding of erectile function advances. In addition, it is reasonable to anticipate that use of these heavily promoted medications will continue to be adopted by a growing segment of men with historically adequate EF. The implication is that maintaining the tenet that a definition of ED must be contingent upon erectogenic therapy will lead to a widening discordance in the future between any given patient’s sexual performance and their physician’s assessment of the effect of a treatment on his sexual function.

In conclusion, there is a very significant age effect mediating the development of ED in men after completing brachytherapy. The prevalence of the use of erectile aids is very high amongst younger men and its efficacy appears to be consistent even after >= 7 years of follow-up evaluation. In addition, young men (aged 50–59 years) fare particularly well in terms of maintained EF.

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External Beam Radiation Therapy

External beam radiation therapy interferes with a cell’s ability to reproduce by damaging the DNA within the cell. Normal prostate cells can repair radiation damage much more effectively than prostate cancer cells. Thus, smaller hits of radiation over a period of time allow noncancerous tissue to repair itself after radiation. Most cancer cells cannot recover from radiation, even when it is given in small doses.
External beam radiation therapy is given via a highly complex piece of equipment called a linear accelerator. Treatments are given once a day, Monday through Friday for seven or eight weeks.

Dr. Gregory Echt and his team offer the most highly sophisticated methods of radiation therapy available in the United States, equal to that found in major medical center and academic settings, including:

Image-guided radiation therapy (IGRT) is recognized as the finest technology available in radiation oncology at this time. This technology allows the radiation beam to be altered depending upon day-to-day movement of the prostate gland. It is used in combination with intensity- modulated radiation therapy (IMRT) described below.

Intensity-modulated radiation therapy (IMRT) is a state-of-the-art technology that has raised the bar in radiation therapy nationwide. IMRT combines extremely precise tumor imaging techniques with equipment to deliver hundreds of thin beams of radiation to the exact tumor location in three-dimensional patterns from any angle.

Targeting radiation to the tumor allows delivery of the maximum dose of radiation needed to the cancer, while sparing healthy tissues. The precision afforded by IMRT allows doctors to deliver radiation to tumors that have been traditionally not possible to treat with radiation because of proximity to critical organs. Higher radiation doses are delivered safely and side effects from a course of radiation therapy are fewer. Results are precise control of radiation delivery, declining complication rates, and fewer side effects.

Research has indicated that higher doses of radiation cancer treatments result in higher rates of curing cancer:

How does a patient receive external beam radiation?

External beam radiation therapy generally involves treatments once a day, Monday through Friday for seven or eight weeks. The treatments are given while the patient lies on a table with the linear accelerator moving around the patient, distributing radiation. The treatments cause no pain and each session lasts just a few minutes. The primary target is the prostate gland itself. In addition, the seminal vesicles and lymph nodes(see description below) may be treated with radiation, since they are a relatively common site of cancer spread.
The seminal vesicles are glands at the base of the bladder and connected to the prostate gland that provide nutrients for the semen the fluid that is released through the penis during an orgasm. The lymph nodes are rounded masses of lymphatic tissue that store white blood cells. White blood cells help the body fight infection and other diseases.

Criteria necessary for a patient to be considered for external beam radiation:

• Good option for men opposed to or who cannot endure surgery or anesthesia for seed implant or HDR.
• Men with locally advanced stage prostate cancer, the type that has likely spread beyond the prostate gland but is confined to the pelvis, may find external beam radiation is the best option.
• Not easily tolerated by men with conditions of the rectum or colon such as inflammatory bowel disease.

Advantages of external beam radiation:

• Does not involve anesthesia or surgical recovery time
• No pain during treatment
• Only takes a few minutes each day
• Immediate side effects are mild and usually do not limit daily activities
• Risk of urinary incontinence is very low compared to surgery
• Often are fewer temporary urinary symptoms than with seed implantation
• With newer techniques, available at Dr. Echt’s radiation therapy centers, long-term side effects may be fewer. Higher-energy radiation beams can be more precisely focused with IMRT and IGRT technology. This advanced technology allows a radiation oncologist to tailor treatment to the anatomy of the individual patient.

Disadvantages of external beam radiation:

• Inconvenient for the patient because treatment is daily for five weeks or more. Patients in rural areas may find traditional seed implants or HDR implants much more convenient.
• From 30% to 40% of men treated with external beam radiation therapy become impotent, also called erectile dysfunction (ED). According to the American Cancer Society, impotence usually does not occur right after radiation therapy but gradually develops over a year or more. Radiation patients often respond to medication such as Viagra.
• Because the radiation beam passes through normal tissues such as the rectum, the bladder, and the intestines, on its way to the prostate, it damages some healthy cells. Radiation to the rectum and intestines may cause inflammation that results in some temporary discomfort during bowel movements and possibly diarrhea. These symptoms are successfully treated with over-the-counter medications and typically disappear over a few months.
• Radiation-induced fatigue may occur, but usually clears up when treatment is completed.
• Long-term studies have shown that outcomes are better for men who chose seed implantation therapy rather than external beam radiation. This is because the external beam radiation dose is lower and not as intense as that delivered with traditional seed implants or HDR therapy.
• External beam radiation can also cause short-term problems including proctitis (inflammation of the rectum) with occasional mild rectal bleeding that can be easily treated. Bowel problems such as diarrhea may occur and cystitis (inflammation of the bladder) may lead to irritation during urination. These symptoms typically disappear over a few months with over-the-counter medications.

Studies show that Seed Implants are more favorable controlling PSA and better than IMRT Therapy alone for prostate cancer treatment:

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PROTON BEAM RADIATION THERAPY

Proton therapy is a type of particle therapy which utilizes a beam of protons to radiate diseased tissue. Proton therapy is a type of external beam radiation therapy. It works by aiming ionizing particles into the targeted tumor. Just as with photons, these particles damage the DNA of the cells, ultimately leading to cell death. Due to the relatively large mass, protons have less scatter into the surrounding tissue. The proton beam stays fairly focused on the tumor shape without much damage to surrounding tissues. Protons of a given energy penetrate a certain range with no proton scatter beyond that distance. The does delivered to the tissue is maximum over the last few millimeters of the particle’s range which is called the Bragg peak. The death depends on the energy to which the particles were accelerated. Tissue situated before the Bragg peak received reduced doses, and those after the Bragg peak receive no dose.

Proton beam has a radiobiologic effectiveness equivalent to that of photons. The amount of cell death is the same. Proton beam radiation therapy is delivered in a fractionated manner just as conventional external beam radiation therapy is done. Regarding management of prostate cancer, there is no evidence that proton beam gives a better outcome than conventional external beam radiation therapy or brachytherapy. When a patient is treated with proton beam radiation therapy there is scatter dose delivered through the tissues in front of the target. Outcome data for proton beam therapy preliminarily is equivalent, not superior to brachytherapy or IMRT based external beam radiation therapy. As prostate cancer is a common type of malignancy, proton beam programs are being adopted to treat prostate cancer. Many practitioners believe, however, that the optimal use of a proton beam is for treating lesions such as a choroidal malignant melanoma, an optic glioma, a retinoblastoma, a brain stem glioma, or possibly a rhabdomyosarcoma in a youth. Proton beam therapy can also be beneficial for intervention in those with spinal cord tumors. One could understand how utilizing a proton beam to treat a soft tissue component of a rhabdomyosarcoma in a youth could potentially deliver high doses of radiation into a tumor and minimize dose to the bone, thus decreasing the possibility of causing the epiphyseal plate to close prematurely and stunting growth in the individual. Due to the diminished exit dose with the proton beam accelerator, there can be a benefit of less secondary malignancies in pediatric populations treated in such a manner.

There are a handful of proton beam facilities around the country. Proton beam centers cost approximately 25 million to 100 million dollars to create. A course of proton beam therapy may cost 10 times what a seed implant would cost with no improvement in locoregional control probabilities or cure with very similar side effect profiles. Being treated with a proton beam based intervention takes approximately eight weeks for prostate cancer and requires immobilization properties frequently utilizing a balloon in the rectum for positioning prior to each treatment. The probability of locoregional recurrence after proton beam therapy is equivalent to that of a linear accelerator based application with photon energies.

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Combination of Seed Implant/HDR and External Beam Radiation

Depending on the patient’s specific case and various risk factors, Dr. Echt may recommend a combination of external beam radiation with either traditional seed implantation or HDR treatment. In combination therapy, external beam radiation treatments are usually given once a day, Monday through Friday for a period of five weeks. Please refer to the above section for the advantages and disadvantages of external beam radiation.

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Robotic Surgery

We are hearing more and more about robotic surgery these days. What is the significance of that? Clearly, surgery is an option of management for many patients with prostate cancer. It does have its pros and cons as with any type of intervention used to cure patients of cancer. A radical prostatectomy is a very tricky operation. A big part of any surgery is being able to feel what you are doing. With a robot you can’t feel. Surgeons try to make up for it with excellent magnification so there are advantages. But there is still a problem with robotic prostatectomy with cancer at the margins which means not getting out all the cancer. It may well be that it is as much experience as anything else. It is the surgeon behind the robot, not the robot.