Carcinoma of the prostate: results of radical radiotherapy (1970-1985)

La Radioterapia Nel Trattamento Del Carcinoma Della Prostata: Indicazioni, Evoluzione Tecnologica e Approcci Integrati

Prostate cancer is a heterogeneous, indolent or sometimes aggressive tumor. Treatment options are various and without proved superiority. Radiotherapy (RT) plays a key role in the disease history. Technological evolution with Intensity Modulate Radiation Therapy (IMRT) and Image Guided Radiation Therapy (IGRT) allowed improvement, with significant results on local control and survival. Hypofractionation, Stereotactic Body RT (SBRT) and new brachytherapy approachs are still under investigation, with promising opportunities. Adjuvant vs salvage postoperative RT, hormone association, prophylactic pelvic irradiation are still under debate, but guidelines express overlapping indications.

Multidisciplinary managements will be the future for care optimization, providing the best tool for holistic and informed patients' choice.

[Hypofractionated radiotherapy in prostate cancer]

Radiotherapy plays a central role in the management of localized prostate cancer, but the total duration of treatment of nearly 2 months poses not only problems of fatigue related to repetitive transports, especially for older patients, but also increases the overall cost of treatment including linear accelerators occupancy and patient transportation. To address this problem, various teams have developed hypofractionated radiotherapy protocols seeking to maintain the same efficacy and toxicity while reducing the total duration of treatment. These hypofractionated protocols require recent techniques such as image-guided radiation therapy (IGRT) and intensity-modulated radiation therapy (IMRT). Single centre series have validated the feasibility of "light" hypofractionation schemes at doses per fraction less than 6 Gy Similarly, different teams have shown the possibility of stereotactic irradiation for delivering "severe" hypofractionation schemes at doses greater than 6 Gy per fraction. Whatever the dose per fraction, the current clinical data support the conclusion that hypofractionated radiotherapy does not increase mid-term toxicity and could even improve biochemical control. Studies with the objective of demonstrating non-inferiority are expected to definitively validate the role of hypofractionated irradiation in the treatment of prostate cancer.

Hypofractionated external-beam radiation therapy (HEBRT) versus conventional external-beam radiation (CEBRT) in patients with localized prostate cancer: a systematic review and meta-analysis

BACKGROUND

The purpose of this work was to conduct a systematic review and meta-analysis of all randomized controlled trials comparing the efficacy and side effect profile of hypofractionated versus conventional external-beam radiation therapy for prostate cancer.

METHODS

Several databases were searched, including Medline, EmBase, LiLACS, and Central. The endpoints were freedom from biochemical failure and side effects. We performed a meta-analysis of the published data. The results are expressed as the hazard ratio (HR) or risk ratio (RR), with the corresponding 95% confidence interval (CI).

RESULTS

The final analysis included nine trials comprising 2702 patients. Freedom from biochemical failure was reported in only three studies and was similar in patients who received hypofractionated or conventional radiotherapy (fixed effect, HR 1.03, 95% CI 0.88-1.20; P = 0.75), with heterogeneity [χ(2) = 15.32, df = 2 (P = 0.0005); I2 = 87%]. The incidence of acute adverse gastrointestinal events was higher in the hypofractionated group (fixed effect, RR 2.02, 95% CI 1.45-2.81; P < 0.0001). We also found moderate heterogeneity on this analysis [χ(2) = 7.47, df = 5 (P = 0.19); I2 = 33%]. Acute genitourinary toxicity was similar among the groups (fixed effect, RR 1.19, 95% CI 0.95-1.49; P = 0.13), with moderate heterogeneity [χ(2) = 5.83, df = 4 (P = 0.21); I2 = 31%]. The incidence of all late adverse events was the same in both groups (fixed effect, gastrointestinal toxicity, RR 1.17, 95% CI 0.79-1.72, P = 0.44; and acute genitourinary toxicity, RR 1.16, 95% CI 0.80-1.68, P = 0.44).

CONCLUSION

Hypofractionated radiotherapy in localized prostate cancer was not superior to conventional radiotherapy and showed higher acute gastrointestinal toxicity in this meta-analysis. Because the number of published studies is still small, future assessments should be conducted to clarify better the true role of hypofractionated radiotherapy in patients with prostate cancer.

Systematic review of hypofractionated radiation therapy for prostate cancer

Prostate cancer is the second most prevalent solid tumor diagnosed in men in the United States and Western Europe. Conventionally fractionated external beam radiation therapy (1.8-2.0 Gy/fraction) is an established treatment modality for men in all disease risk groups. Emerging evidence from experimental and clinical studies suggests that the α/β ratio for prostate cancer may be as low as 1.5 Gy, which has prompted investigators around the world to explore moderately hypofractionated radiation therapy (2.1-3.5 Gy/fraction). We review the impetus behind moderate hypofractionation and the current clinical evidence supporting moderate hypofractionated radiation therapy for prostate cancer. Although hypofractionated radiation therapy has many theoretical advantages, there is no clear evidence from prospective, randomized, controlled trials showing that hypofractionated schedules have improved outcomes or lower toxicity than conventionally fractionated regimens. Currently, hypofractionated schedules should only be used in the context of clinical trials. High dose rate brachytherapy and stereotactic body radiation therapy (fraction size 3.5 Gy and greater) are alternative approaches to hypofractionation, but are beyond the scope of this report.

Stereotactic body radiation therapy for prostate cancer: is the technology ready to be the standard of care?

Prostate cancer is the second most prevalent solid tumor diagnosed in men in the United States and Western Europe. Stereotactic body radiation therapy (SBRT) is touted as a superior type of external beam radiation therapy (EBRT) for the treatment of various tumors. SBRT developed from the theory that high doses of radiation from brachytherapy implant seeds could be recapitulated from advanced technology of radiation treatment planning and delivery. Moreover, SBRT has been theorized to be advantageous compared to other RT techniques because it has a treatment course shorter than that of conventionally fractionated EBRT (a single session, five days per week, for about two weeks vs. eight weeks), is non-invasive, is more effective at killing tumor cells, and is less likely to cause damage to normal tissue. In areas of the US and Europe where there is limited access to RT centers, SBRT is frequently being used to treat prostate cancer, even though long-term data about its efficacy and safety are not well established. We review the impetus behind SBRT and the current clinical evidence supporting its use for prostate cancer, thus providing oncologists and primary care physicians with an understanding of the continually evolving field of prostate radiation therapy. Studies of SBRT provide encouraging results of biochemical control and late toxicity. However, they are limited by a number of factors, including short follow-up, exclusion of intermediate- and high-risk patients, and relatively small number of patients treated. Currently, SBRT regimens should only be used in the context of clinical trials.

Hypofractionation for prostate cancer

Hypofractionation for prostate cancer was originally carried out in the pursuit of efficiency and convenience but has now attracted greatly renewed interest based upon a hypothesis that prostate cancers have a higher sensitivity to fraction size, reflected in a low alpha/beta ratio, than do late responding organs at risk such as the rectum or bladder. Tumor control and acceptable toxicity outcomes from several hypofractionation or brachytherapy analyses do in fact support an alpha/beta ratio for prostate cancer that is low, perhaps even lower that that for the normal organs that ordinarily constrain the delivery of radiation therapy. However, many of these studies lack sufficient patient numbers and follow-up, are clouded by dose inhomogeneity issues in the case of brachytherapy, or delivered effective doses that were too low by contemporary standards. Thus, the clinical efficacy of the approach has yet to be fully validated. However, a number of newer prospective trials, some randomized, are underway or have reached accrual but await sufficient follow-up for analysis. These studies, which cover a wide range of doses per fraction, should ultimately be capable of validating the utility of prostate hypofractionation and the models that predict its effects. With hypofractionation's significant potential for therapeutic gain, cost savings, and improved patient convenience, the future management of localized prostate cancer could be profoundly altered in the process.

Rationale, conduct, and outcome using hypofractionated radiotherapy in prostate cancer

Hypofractionated radiation therapy for prostate cancer has become of increasing interest with the recognition of a potential improvement in therapeutic ratio with treatments delivered in larger-sized fractions. In addition, the associated reduction in fraction number produces attractive cost and patient convenience advantages as well. A still limited but growing number of hypofractionation trials have reported acceptable short-term levels of toxicity and biochemical control, but most have insufficient follow-up to ensure the long-term safety and efficacy of this approach. This situation will improve as many currently active trials mature, particularly several high-value randomized trials. In contrast, extreme hypofractionation, with schedules delivering only on the order of 5 fractions, is truly in its infancy for prostate cancer, with extremely limited tolerance and efficacy information currently available. Several uncertainties in the radiobiology of hypofractionation mitigate for an organized, cautious investigational approach. The fractionation response (alpha/beta ratio) of prostate cancers and, for that matter, late-responding normal tissues, has yet to be rigorously defined. Additionally, the linear-quadratic (LQ) model used in the design of hypofractionation schedules is subject to its own uncertainties, particularly with respect to the upper limit of fraction sizes for which it remains valid. Contemporary dose-escalated radiation therapy is already highly effective, making it imperative that ongoing and future studies of hypofractionation be performed in carefully designed, randomized clinical trials. Clinical validation permitting, the adaptation of hypofractionation as a standard of care could profoundly influence future management of localized prostate cancer.

Hypofractionated intensity modulated irradiation for localized prostate cancer, results from a phase I/II feasibility study

BACKGROUND

To assess acute (primary endpoint) and late toxicity, quality of life (QOL), biochemical or clinical failure (secondary endpoints) of a hypofractionated IMRT schedule for prostate cancer (PC).

METHODS

38 men with localized PC received 66 Gy (2.64 Gy) to prostate,2 Gy to seminal vesicles (50 Gy total) using IMRT.Acute toxicity was evaluated weekly during radiotherapy (RT), at 1-3 months afterwards using RTOG acute scoring system. Late side effects were scored at 6, 9, 12, 16, 20, 24 and 36 months after RT using RTOG/EORTC criteria.Quality of life was assessed by EORTC-C30 questionnaire and PR25 prostate module. Biochemical failure was defined using ASTRO consensus and nadir+2 definition, clinical failure as local, regional or distant relapse.

RESULTS

None experienced grade III-IV toxicity. 10% had no acute genito-urinary (GU) toxicity, 63% grade I; 26% grade II. Maximum acute gastrointestinal (GI) scores 0, I, II were 37%, 47% and 16%. Maximal acute toxicity was reached weeks 4-5 and resolved within 4 weeks after RT in 82%.Grade II rectal bleeding needing coagulation had a peak incidence of 18% at 16 months after RT but is 0% at 24-36 months. One developed a urethral stricture at 2 years (grade II late GU toxicity) successfully dilated until now. QOL urinary symptom scores reached a peak incidence 1 month after RT but normalized 6 months later. Bowel symptom scores before, at 1-6 months showed similar values but rose slowly 2-3 years after RT. Nadir of sexual symptom scores was reached 1-6 months after RT but improved 2-3 years later as well as physical, cognitive and role functional scales.Emotional, social functional scales were lowest before RT when diagnosis was given but improved later. Two years after RT global health status normalized.

CONCLUSION

This hypofractionated IMRT schedule for PC using 25 fractions of 2.64 Gy did not result in severe acute side effects. Until now late urethral, rectal toxicities seemed acceptable as well as failure rates. Detailed analysis of QOL questionnaires resulted in the same conclusion.

Evidence-based radiation oncology: Definitive, adjuvant and salvage radiotherapy for non-metastatic prostate cancer

The standard treatment options based on the risk category (stage, Gleason score, PSA) for localized prostate cancer include surgery, radiotherapy and watchful waiting. The literature does not provide clear-cut evidence for the superiority of surgery over radiotherapy, whereas both approaches differ in their side effects. The definitive external beam irradiation is frequently employed in stage T1b-T1c, T2 and T3 tumors. There is a pretty strong evidence that intermediate- and high-risk patients benefit from dose escalation. The latter requires reduction of the irradiated normal tissue (using 3-dimensional conformal approach, intensity modulated radiotherapy, image-guided radiotherapy, etc.). Recent data suggest that prostate cancer may benefit from hypofractionation due to relatively low alpha/beta ratio; these findings warrant confirmation though. The role of whole pelvis irradiation is still controversial. Numerous randomized trials demonstrated a clinical benefit in terms of biochemical control, local and distant control, and overall survival from the addition of androgen suppression to external beam radiotherapy in intermediate- and high-risk patients. These studies typically included locally advanced (T3-T4) and poor-prognosis (Gleason score >7 and/or PSA >20 ng/mL) tumors and employed neoadjuvant/concomitant/adjuvant androgen suppression rather than only adjuvant setting. The ongoing trials will hopefully further define the role of endocrine treatment in more favorable risk patients and in the setting of the dose escalated radiotherapy. Brachytherapy (BRT) with permanent implants may be offered to low-risk patients (cT1-T2a, Gleason score <7, or 3+4, PSA <or=10 ng/mL), with prostate volume of <or=50 ml, no previous transurethral prostate resection and a good urinary function. Some recent data suggest a benefit from combining external beam irradiation and BRT for intermediate-risk patients. EBRT after radical prostatectomy improves disease-free survival and biochemical and local control rates in patients with positive surgical margins or pT3 tumors. Salvage radiotherapy may be considered at the time of biochemical failure in previously non-irradiated patients.

Radiation therapy in prostate cancer

Adenocarcinoma of the prostate is one of the most frequently diagnosed cancers of men in the Western hemisphere and is second only to lung cancer for male cancer mortality. Most patients are diagnosed in the early/clinically localized stage, which can be treated curatively with radiation therapy alone. Innovative methods such as brachytherapy, three-dimensional conformal radiotherapy (3D-CRT), and IMRT (intensity modulated radiotherapy) are able to deliver very high tumoricidal doses to the diseased prostate, with minimal side effects to the surrounding tissue. Radiation therapy combined with hormonal treatment can be curative in locally advanced disease. Radiation therapy is also very effective in alleviating symptoms of metastatic prostate cancer (bone metastases, spinal cord compression, and bladder outlet obstruction).

Use of Individual Fraction Size Data from 3756 Patients to Directly Determine the α/β Ratio of Prostate Cancer

PURPOSE

To examine the effect of fraction size and total dose of radiation on recurrence of localized prostate cancer.

METHODS AND MATERIALS

A total of 3756 patients treated with radiation monotherapy at three institutions were analyzed, including 185 high-dose-rate brachytherapy (HDRB) boost patients. The 5th to 95th centiles of external beam radiotherapy (EBRT) fraction sizes and doses were 1.8 to 2.86 Gy, and 57.4 to 77.4 Gy, respectively, and HDRB fractional doses were between 5.5 and 12 Gy, totaling 147 unique fractionation schedules. Failure was defined by one biochemical (nadir + 2 ng/ml) and two advanced disease endpoints. The alpha/beta ratios were estimated via a proportional hazards model stratified by risk severity and institution.

RESULTS

The alpha/beta ratio using biochemical recurrence was 3.7 Gy (95% confidence interval [95% CI], 1.1, infinity Gy) for EBRT-only cases and 2.6 Gy (95% CI, 0.9, 4.8 Gy) after the addition of HDRB data. This estimate was highly dependent on an HDRB homogeneity correction factor (120% HDRB dose increase; alpha/beta ratio 4.5 Gy, 95% CI 1.6, 8.7 Gy). A 5-Gy increase in total dose reduced the hazard of failure by 16% (95% CI 11, 21%, p < 0.0001), and had more impact as follow-up matured (p < 0.0003). The clinically advanced endpoints concurred with the biochemical failure results, albeit with less precision.

CONCLUSIONS

This study supports the concept that the alpha/beta ratio of prostate cancer is low, although considerable uncertainty remains in the estimated value. Outcome data from EBRT studies using substantially higher doses per fraction are needed to show increased precision in these estimates.

Hypofractionated versus conventionally fractionated radiation therapy for prostate carcinoma: Updated results of a phase III randomized trial

PURPOSE

The aim of this study was to compare the toxicity and efficacy of radiation therapy (RT) for localized carcinoma of the prostate, using a hypofractionated (55 Gy/20 fractions/4 weeks) vs. a conventionally fractionated (64 Gy/32 fractions/6.5 weeks) dose schedule.

METHODS AND MATERIALS

A total of 217 patients were randomized to either the hypofractionated (108 patients) or the conventional (109 patients) dose schedule, with planning with two-dimensional (2D) CT scan planning methodology in the majority of cases. All patients were followed for a median of 48 (6-108) months. Gastrointestinal (GI) and genitourinary (GU) toxicity was evaluated before RT and after its completion using modified late effects of normal tissue-subjective, objective, management, analytic (LENT-SOMA) scales and the European Organization for Research and Treatment of Cancer sexual function questionnaire. Efficacy of RT based on clinical, radiologic, and prostate-specific antigen data were also evaluated at baseline and after RT.

RESULTS

Gastrointestinal and GU toxicity persisted 5 years after RT and did not differ between the two dose schedules other than in regard to urgency of defecation. However, 1-month GI toxicity was not only worse in patients with the hypofractionated RT schedule but also adversely affected daily activities. Nadir prostate-specific antigen values occurred at a median of 18.0 (3.0-54.0) months after RT. A total of 76 biochemical relapses, with or without clinical relapses, have occurred since; of these, 37 were in the hypofractionated and 39 in the conventional schedule. The 5-year biochemical +/- clinical relapse-free and overall survival was 55.9% and 85.3% respectively for all patients, and did not differ between the two schedules.

CONCLUSIONS

Radiation therapy for prostate carcinoma causes persistent GI toxicity that is largely independent of the two dose schedules. The hypofractionated schedule is equivalent in efficacy to the conventional schedule.

Dosimetry and preliminary acute toxicity in the first 100 men treated for prostate cancer on a randomized hypofractionation dose escalation trial

PURPOSE

The alpha/beta ratio for prostate cancer is postulated to be between 1 and 3, giving rise to the hypothesis that there may be a therapeutic advantage to hypofractionation. The dosimetry and acute toxicity are described in the first 100 men enrolled in a randomized trial.

PATIENTS AND METHODS

The trial compares 76 Gy in 38 fractions (Arm I) to 70.2 Gy in 26 fractions (Arm II) using intensity modulated radiotherapy. The planning target volume (PTV) margins in Arms I and II were 5 mm and 3 mm posteriorly and 8 mm and 7 mm in all other dimensions. The PTV D95% was at least the prescription dose.

RESULTS

The mean PTV doses for Arms I and II were 81.1 and 73.8 Gy. There were no differences in overall maximum acute gastrointestinal (GI) or genitourinary (GU) toxicity acutely. However, there was a slight but significant increase in Arm II GI toxicity during Weeks 2, 3, and 4. In multivariate analyses, only the combined rectal DVH parameter of V65 Gy/V50 Gy was significant for GI toxicity and the bladder volume for GU toxicity.

CONCLUSION

Hypofractionation at 2.7 Gy per fraction to 70.2 Gy was well tolerated acutely using the planning conditions described.

Randomized Trial Comparing Two Fractionation Schedules for Patients With Localized Prostate Cancer

Purpose

The optimal radiation dose fractionation schedule for localized prostate cancer is unclear. This study was designed to compare two dose fractionation schemes (a shorter 4-week radiation schedule v a longer 6.5-week schedule).

Patients and Methods

Patients with early-stage (T1 or T2) prostate cancer were randomly assigned to 66 Gy in 33 fractions over 45 days (long arm) or 52.5 Gy in 20 fractions over 28 days (short arm). The study was designed as a noninferiority investigation with a predefined tolerance of −7.5%. The primary outcome was a composite of biochemical or clinical failure (BCF). Secondary outcomes included presence of tumor on prostate biopsy at 2 years, survival, and toxicity.

Results

From March 1995 to December 1998, 936 men were randomly assigned to treatment; 470 were assigned to the long arm, and 466 were assigned to the short arm. The median follow-up time was 5.7 years. At 5 years, the BCF probability was 52.95% in the long arm and 59.95% in the short arm (difference = −7.0%; 90% CI, −12.6% to −1.4%), favoring the long arm. No difference in 2-year postradiotherapy biopsy or in overall survival was detected between the arms. Acute toxicity was found to be slightly higher in the short arm (11.4%) compared with the long arm (7%; difference = −4.4%; 95% CI, −8.1% to −0.6%); however, late toxicity was similarly low in both arms (3.2%).

Conclusion

Given the results, we cannot exclude the possibility that the chosen hypofractionated radiation regimen may be inferior to the standard regimen. Further evaluation involving higher dose hypofractionated radiation regimens in contemporary radiation settings is necessary.

Lack of benefit from a short course of androgen deprivation for unfavorable prostate cancer patients treated with an accelerated hypofractionated regime

PURPOSE

High-dose radiotherapy, delivered in an accelerated hypofractionated course, was utilized to treat prostate cancer. Therapy consisted of external beam radiotherapy (EBRT) and transrectal ultrasound (TRUS)-guided conformally modulated high-dose rate (HDR) brachytherapy. The purpose of this report is (1) to assess long-term comparative outcomes from three trials using similar accelerated hypofractionated regimes; and (2) to examine the long-term survival impact of a short course of < or =6 months adjuvant/concurrent androgen deprivation when a very high radiation dose was delivered.

METHODS AND MATERIALS

Between 1986 and 2000, 1,260 patients were treated at three institutions with pelvic EBRT (36-50 Gy) integrated with HDR prostate brachytherapy. The total dose including brachytherapy was given over 5 weeks. The biologic equivalent EBRT dose ranged between 90 and 123 Gy (median, 102 Gy) using an alpha /beta of 1.2. Patient eligibility criteria included a pretreatment prostate-specific antigen > or =10, Gleason score > or =7, or clinical stage > or =T2b. A total of 1,260 patients were treated, and 934 meet the criteria. Kiel University Hospital treated 198 patients; William Beaumont Hospital, 315; and California Endocurietherapy Cancer Center, 459 patients. Brachytherapy dose regimes were somewhat different between centers and the dose was escalated from 5.5 x 3 to 15 Gy x 2 Gy. Patients were divided for analysis between the 406 who received up to 6 months of androgen deprivation therapy and the 528 patients who did not. All patients had a minimum follow-up of 18 months (3 times the exposure to androgen deprivation therapy). The American Society for Therapeutic Radiology and Oncology biochemical failure definition was used.

RESULTS

Mean age was 69 years. Median follow-up time was 4.4 years (range, 1.5-14.5); 4 years for androgen deprivation therapy patients and 4.9 for radiation alone. There was no difference at 5 and 8 years in overall survival, cause-specific survival, or biochemical control among the three institutions. The corresponding 8-year rates with and without androgen deprivation therapy were biochemical control 85% and 81%; overall survival 83% and 78%; cause-specific survival 89% and 94%; and metastatic rates of 16.6% and 7.3%. A multivariate analysis revealed androgen deprivation therapy did not predict for biochemical failure for either the entire group or the subset of 177 patients harboring all three poor prognostic factors. Moreover, adding androgen deprivation therapy strongly correlated with higher rates of both metastasis (p = 0.09; hazard ratio, 2.08) and cancer-related deaths (p = 0.02, hazard ratio 3.25). These negative results for the most unfavorable group led us to question if androgen deprivation therapy might have a deleterious impact through delay in delivery of the potentially curative radiation or whether there may be a biologic basis by fixing the cycling cells in G0.

CONCLUSIONS

Accelerated hypofractionated pelvic EBRT integrated with TRUS-guided conformally modulated HDR administered to 1,260 patients in three institutions was an excellent method of delivering very high radiation dose to the prostate in 5 weeks. Similar high overall, cause-specific, and biochemical no evidence of disease survival rates achieved show that prostate HDR can be successfully delivered in academic and community settings. At 8 years, the addition of a course of < or =6 months of neoadjuvant/concurrent androgen deprivation therapy to a very high radiation dose did not confer a therapeutic advantage but added side effects and cost. Furthermore, for the most unfavorable group, there was a higher rate of distant metastasis and more prostate cancer-related deaths. We question the value of a short course of androgen deprivation therapy when used with high-dose radiation.

Intensity-modulated radiotherapy for adenocarcinoma of the prostate: A point of view

Adenocarcinoma of the prostate (CaP) is treated by surgery or irradiation, or both, with the type of treatment determined largely by local resources and referral patterns. Although the techniques employed by surgeons and radiation oncologists have improved and the morbidities associated with each have declined, for neither are they negligible. Epidemiologic data suggest that between 81% and 85% of men with CaP die of other causes, and a recent survey of untreated men arrived at a similar figure of 83%. Clinical reports, based upon postoperative tumor volume and grade, show that at least 5% of prostatectomies are unnecessary but the extent to which the other 95% benefit from this procedure is unclear. Some sense of these benefits is provided by a randomized, prospective clinical trial that compared prostatectomy with watchful waiting, and found only a 6% gain in overall survival after 8 years. These data call into question the promotion of highly complex and expensive radiation therapy equipment for the treatment of CaP when the prospects for increased life expectancies are at best small and unlikely to be distinguishable from results achieved by surgery, conventional external beam, or radioactive-seed implants.

Anorectal dysfunction increases with time following radiation therapy for carcinoma of the prostate

OBJECTIVES

To characterize the prevalence and pathophysiology of anorectal dysfunction up to 2 yr following radiation therapy (RT) for localized carcinoma of the prostate.

METHODS

Thirty-eight patients, median age 68 (range 60-82) yr with localized prostate carcinoma randomly assigned to one of two radiation dose schedules, underwent evaluation of the following variables of anorectal function before RT, as well as 4-6 wk and 1 and 2 yr after its completion: (1) symptoms, (2) anorectal motility, (3) anorectal sensory function, and (4) anal sphincteric morphology.

RESULTS

There was a persistent increase in anorectal symptoms after RT. At 2 yr, bowel frequency, urgency, and fecal incontinence were increased in 50%, 47%, and 26% of patients, respectively. After RT, there were progressive reductions of (1) basal anal pressures, (2) anal pressures in response to squeeze and increased intra-abdominal pressure, (3) rectal compliance, and (4) rectal volumes associated with sensory perception and the desire to defecate. The thickness of the external anal sphincter increased with time after RT. No difference was observed between the patients in the two radiation dose schedules.

CONCLUSIONS

Anorectal dysfunction following RT for prostate carcinoma is an underestimated cause of morbidity, which progresses with time. The prevalence and pathophysiology of anorectal dysfunction is similar after treatment with two commonly used radiation dose schedules.

Do older men benefit from curative therapy of localized prostate cancer?

PURPOSE

Prior decision-analytic models are based on outdated or suboptimal efficacy, patient preference, and comorbidity data. We estimated life expectancy (LE) and quality-adjusted life expectancy (QALE) associated with available treatments for localized prostate cancer in men aged >/= 65 years, adjusting for Gleason score, patient preferences, and comorbidity.

METHODS

We evaluated three treatments, using a decision-analytic Markov model: radical prostatectomy (RP), external beam radiotherapy (EBRT), and watchful waiting (WW). Rates of treatment complications and pretreatment incontinence and impotence were derived from published studies. We estimated treatment efficacy using three data sources: cancer registry cohort data, pooled case series, and modern radiotherapy studies. Utilities were obtained from 141 prostate cancer patients and from published studies.

RESULTS

For men with well-differentiated tumors and few comorbidities, potentially curative therapy (RP or EBRT) prolonged LE up to age 75 years but did not improve QALE at any age. For moderately differentiated cancers, potentially curative therapy resulted in LE and QALE gains up to age 75 years. For poorly differentiated disease, potentially curative therapy resulted in LE and QALE gains up to age 80 years. Benefits of potentially curative therapy were restricted to men with no worse than mild comorbidity. When cohort and pooled case series data were used, RP was preferred over EBRT in all groups but was comparable to modern radiotherapy.

CONCLUSION

Potentially curative therapy results in significantly improved LE and QALE for older men with few comorbidities and moderately or poorly differentiated localized prostate cancer. Age should not be a barrier to treatment in this group.

Radiotherapy for t3 prostate cancer

Throughout the past decade, significant improvements in optimizing the management of T3 prostate cancer have been made. Phase III randomized studies have demonstrated the superiority of combined hormone therapy and radiation therapy over radiation therapy alone. Radiotherapy dose escalation using conformal techniques has improved local control and lowered toxicity. These advances have changed the approach to treatment of T3 prostate cancer from that directed at palliation of symptoms to earlier interventions directed at prolongation of survival. The contemporary role of radiation therapy in clinical T3 prostate cancer in the context of other treatment options is reviewed in this article.

Evidence for efficacy without increased toxicity of hypofractionated radiotherapy for prostate carcinoma: early results of a Phase III randomized trial

PURPOSE

We performed a randomized trial to compare the GI and urogenital toxicity of radiotherapy (RT) for localized (confined to the organ), early-stage (T1-T2N0M0, TNM classification) carcinoma of the prostate, using a conventional (64 Gy in 32 fractions within 6.5 weeks) vs. a hypofractionated (55 Gy in 20 fractions within 4 weeks) schedule and to determine the efficacy of the respective treatment schedules.

METHODS AND MATERIALS

This report is based on an interim analysis of the first 120 consecutive patients in this Phase III trial after a median follow-up of 43.5 months (range 23-62). RT planning was based on two-dimensional CT data, and the treatment was delivered using a three- or four-field 6-23-MV photon technique. GI and urogenital toxicity (symptom questionnaires incorporating the subjective elements of the late effects of normal tissues-subjective, objective, management, analytic classification of late effects and the European Organization for Research and Treatment of Cancer sexual function questionnaire) were evaluated before RT and 1 month, 1 year, and 2 years after RT completion. The efficacy of RT was assessed clinically (digital rectal examination and radiologic imaging) and biochemically (prostate-specific antigen assay) at baseline, and every 3 months for 2 years after RT and every 6 months subsequently.

RESULTS

RT, whether conventional or hypofractionated, resulted in an increase in all six symptom categories used to characterize GI toxicity and in four of five symptom categories used to document urinary morbidity 1 month after therapy completion. Sexual dysfunction (based on limited data), which existed in more than one-third of patients before RT, also increased to just more than one-half of patients 1 month after RT. The increase in urinary toxicity after RT was not sustained (diurnal urinary frequency had decreased significantly at 2 years). In contrast, all six symptom categories of GI toxicity remained increased 1 year after RT. Four of the six GI symptom categories (rectal pain, mucous discharge, urgency of defecation, and rectal bleeding) were still increased at 2 years compared with baseline. Except for a slightly greater percentage of patients experiencing mild rectal bleeding at 2 years among those who received hypofractionated RT, no differences were noted in toxicity between the conventional and hypofractionated RT schedule. The mean prostate-specific antigen level was 14.0 +/- 1.0 ng/mL at baseline and declined to a nadir of 1.3 +/- 0.2 ng/mL at a median of 16.8 months (range 0.8-28.3) after RT completion. However, it then rose in 17 patients (8 in the hypofractionated and 9 in the conventional treatment group). Only 8 of these 17 patients were found to have signs of clinical relapse (5 local, 1 regional lymph node, and 2 systemic [bony metastases]) after histopathologic and radiologic reassessment). The remaining 9 patients had biochemical relapse only (defined as three consecutive rises in prostate-specific antigen after nadir). The 4-year biochemical relapse-free survival rate was 85.8% for all patients and did not differ significantly between the two radiation dose schedules (86.2% for the hypofractionated and 85.5% for the conventional fractionation group).

CONCLUSION

RT for prostate carcinoma, using a three- or four-field 6-23-MV photon technique without posterior shielding of the lateral fields, is an underestimated cause of persistent GI morbidity. The incidence of clinically significant GI and urogenital toxicity after conventional and hypofractionated RT appears to be similar. Hypofractionated RT for carcinoma of the prostate seems just as effective as conventional RT after a median follow-up approaching 4 years.

Prostate cancer

It is a paradigm in cancer treatment that early detection and treatment improves survival. However, although screening measures lead to a higher rate of detection, for small bulk localised prostate cancer it remains unclear whether early detection and early treatment will lead to an overall decrease in mortality. The management options include surveillance, radiotherapy, and radical prostatectomy but there is no evidence base to evaluate the benefits of each approach. Advanced prostate cancer is managed by hormonal therapy. There have been major changes in treatment over the last two decades with the use of more humane treatment and developments in both chemotherapy and radiation. In this article we review the natural history and management of prostate cancer.

Does age influence the behaviour of localized prostate cancer?

OBJECTIVE

To assess, in a meta-analysis of published studies, whether age influences the behaviour of localized prostate cancer.

METHODS

The Medline database was searched from 1966 to 2000 to identify studies analysing the outcome of localized prostate cancer by age, using disease-specific outcome measures, and having controlled for the established prognostic factors of grade, T stage and, where available, serum prostate-specific antigen (PSA) level.

RESULTS

In all, 34 studies were identified, which included a total of 27 551 patients. The incomplete and heterogeneous nature of the reports precluded any quantitative overview. The findings of these reports are described and methodological shortcomings discussed.

CONCLUSION

The evidence suggests that young age was an adverse prognostic factor in some series of radiation therapy before the advent of PSA assays, when men typically presented clinically with locally advanced disease, but that age has no significant prognostic effect in contemporary series of localized prostate cancer. Possible explanations for this difference are discussed, together with implications for further studies.

Direct evidence that prostate tumors show high sensitivity to fractionation (low alpha/beta ratio), similar to late-responding normal tissue

PURPOSE

A direct approach to the question of whether prostate tumors have an atypically high sensitivity to fractionation (low alpha/beta ratio), more typical of the surrounding late-responding normal tissue.

METHODS AND MATERIALS

Earlier estimates of alpha/beta for prostate cancer have relied on comparing results from external beam radiotherapy (EBRT) and brachytherapy, an approach with significant pitfalls due to the many differences between the treatments. To circumvent this, we analyze recent data from a single EBRT + high-dose-rate (HDR) brachytherapy protocol, in which the brachytherapy was given in either 2 or 3 implants, and at various doses. For the analysis, standard models of tumor cure based on Poisson statistics were used in conjunction with the linear-quadratic formalism. Biochemical control at 3 years was the clinical endpoint. Patients were matched between the 3 HDR vs. 2 HDR implants by clinical stage, pretreatment prostate-specific antigen (PSA), Gleason score, length of follow-up, and age.

RESULTS

The estimated value of alpha/beta from the current analysis of 1.2 Gy (95% CI: 0.03, 4.1 Gy) is consistent with previous estimates for prostate tumor control. This alpha/beta value is considerably less than typical values for tumors (> or =8 Gy), and more comparable to values in surrounding late-responding normal tissues.

CONCLUSIONS

This analysis provides strong supporting evidence that alpha/beta values for prostate tumor control are atypically low, as indicated by previous analyses and radiobiological considerations. If true, hypofractionation or HDR regimens for prostate radiotherapy (with appropriate doses) should produce tumor control and late sequelae that are at least as good or even better than currently achieved, with the added possibility that early sequelae may be reduced.

Chronic effects of therapeutic irradiation for localized prostatic carcinoma on anorectal function

PURPOSE

To evaluate prospectively the prevalence and pathophysiology of anorectal dysfunction following radiation therapy (RTH) for localized carcinoma of the prostate.

METHODS AND MATERIALS

The following parameters of anorectal function were evaluated in each of 35 patients (aged 55-82 years) with localized prostatic carcinoma treated with RTH either to a dose of 55 Gy/20 fractions/4 weeks (18 patients) or 64 Gy/32 fractions/6.5 weeks (17 patients), before RTH and 4-6 weeks and at a mean (+/- SD) of 1.4 (+/- 0.2) years after its completion: (1) anorectal symptoms (questionnaire), (2) anorectal pressures at rest and in response to voluntary squeeze and increases in intra-abdominal pressure (multiport anorectal manometry), (3) rectal sensation (balloon distension) and (4) anal sphincteric morphology (endoanal ultrasound).

RESULTS

All but 1 patient completed three series of measurements. RTH had no effect on anal sphincteric morphology. The increase in frequency of defecation and fecal urgency and incontinence scores previously reported in the patients 4-6 weeks after RTH were sustained 1 year later (p < 0.001, p < 0.001, and p < 0.05, cf. baseline, respectively). At this time, 56% (19 of 34), 50% (17 of 34) and 26% (9 of 34) of the patients had increased frequency of defecation, fecal urgency, and incontinence, respectively. Decreases in anal sphincteric pressures at rest and in response to voluntary squeeze recorded in the patients 4-6 weeks after RTH were not sustained 1 year later but the volumes of rectal distension associated with perception of the stimulus and desire to defecate were lower compared with baseline volumes (p < 0.01 and p < 0.05, respectively), reflecting heightened rectal sensitivity in the patients. There was no difference in measurements between the two radiation dose regimens. Univariate logistical regression analysis was performed on patients who had experienced increased symptom scores or decreases in recorded motor and sensory manometric parameters at 1 year, cf. baseline. The predictor variables used included individual patient tumor and treatment characteristics as well as individual patient symptom scores and parameters of anorectal motor and sensory function at baseline and 4-6 weeks after RTH. The results of the univariate logistical regression analysis showed that (1) frequency of defecation at 4-6 weeks and (2) rectal volumes at baseline both for (a) perception (p < 0.001) and (b) desire to defecate (p < 0.001), predicted significantly for the patients who had symptoms and signs of anorectal dysfunction at 1 year. Individual patient tumor and treatment-related variables tested, in contrast, had no predictive significance.

CONCLUSIONS

Anorectal symptoms following RTH for prostatic carcinoma are common and persist at least until 1 year after its completion and are associated with objective evidence of heightened rectal sensitivity.

[Stage pT3 prostatic cancer after radical prostatectomy. Results in progression and survival]

PURPOSE

To analyse progression and survival after radical prostatectomy in patients with stage pT3 carcinoma of the prostate.

MATERIAL AND METHODS

Between 1986 and November 1998, we performed 372 radical prostatectomies, 74 of which were pT3N0 (19.8%), 43 pT3a and 31 pT3b (TNM 97).

RESULTS

In patients with pathological stage pT3, we found any progression in 24 patients (32%), 8 in pT3a, and 16 in pT3b. In 10 of 24 pT3, there was local relapse or distant metastases. About the freedom from biochemical relapse survival rate, we found statistically differences between pT3a and pT3b (p < 0.0001). In pT3a patients, we found no differences between PSA levels > 20 ng/ml, versus < 20 (p = 0.415), and statistically differences between pathological Gleason 6 or greater, versus < 6 (p = 0.048). However, we found no differences when we used both criteria (PSA and Gleason) (p = 0.195).

CONCLUSIONS

We support for early adjuvant hormonal therapy in pT3b patients. In pT3a, the hormonotherapy may be used if appears biochemical failure, specially with adverse prognostic factors (PSA and Gleason).

Effect of CT-based treatment planning on portal field size and outcome in radiation treatment of localized prostate cancer

The portal field sizes of 361 consecutive patients treated with curative radiotherapy for localized prostate cancer were measured. The introduction of CT-based information resulted in a significant increase of field sizes, leading to an almost doubling of the treated volume, some increase in late rectal toxicity, but also in local control.

Cancer surveillance series: interpreting trends in prostate cancer--part II: Cause of death misclassification and the recent rise and fall in prostate cancer mortality

BACKGROUND

The rise and fall of prostate cancer mortality correspond closely to the rise and fall of newly diagnosed cases. To understand this phenomenon, we explored the role that screening, treatment, iatrogenic (i.e., treatment-induced) deaths, and attribution bias (incorrect labeling of death from other causes as death from prostate cancer) have played in recent mortality trends.

METHODS

Join point regression is utilized to assess the recent rise and fall in mortality and the relationship of total U.S. trends to those areas served by the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Cancer Registry Program. Incidence-based mortality (IBM) is estimated with the use of prostate cancer data from the SEER Program to partition (from overall prostate cancer mortality trends) the contribution of cases diagnosed since the widespread use of prostate-specific antigen (PSA) testing starting in 1987. IBM is also used to examine the contribution of stage at diagnosis to the recent prostate cancer mortality trends.

RESULTS

IBM for cases diagnosed since 1987 rose above the pre-1987 secular (i.e., background) trend, peaked in the early 1990s, and almost returned to the secular trend by 1994. This rise and fall of IBM track with the pool of prevalent cases diagnosed within the prior 2 years. IBM for cases diagnosed with metastatic disease fell starting in 1991, while IBM for those diagnosed with localized/regional disease was relatively flat.

CONCLUSIONS

The rise and fall in prostate cancer mortality observed since the introduction of PSA testing in the general population are consistent with a hypothesis that a fixed percent of the rising and falling pool of recently diagnosed patients who die of other causes may be mislabeled as dying of prostate cancer. The decline in IBM for distant stage disease and flat IBM trends for localized/regional disease provide some evidence of improved prognosis for screen-detected cases, although alternative interpretations are possible.

Pion conformal radiation of prostate cancer: results of a randomized study

PURPOSE

To compare the efficacy of pion radiation therapy with conventional external beam photon therapy, for the treatment of locally advanced stage T3/4, N0, M0 adenocarcinoma of the prostate.

METHODS AND MATERIALS

Two hundred seventeen eligible patients were randomly allocated to either photon or pion therapy. No adjuvant hormone therapy was used.

RESULTS

Median follow-up was 42 months (range 2-90). Acute bladder toxicity was worse in the pion arm, p = 0.2, but other acute toxicity did not differ. Late grade 2 toxicity was significantly less in the pion arm (29% at 5 years versus 48%, p = 0.002), but late grade 3 or 4 toxicity did not differ. Clinical local control was not significantly different between treatment arms (64% after 5 years with photons, 56% with pions, p = 0.6). Cause-specific and overall survival also did not differ (p = 0.7). There was a significant delay in time to first failure in the photon arm, largely as a result of decreased biochemical relapse, p = 0.01. A multivariate analysis is presented.

CONCLUSION

Pion therapy was well tolerated, with increased acute toxicity and significantly decreased late tissue injury. This contrasts with the late toxicity observed with higher LET particle therapy such as neutron therapy. No improvement in local control with pion therapy was observed.

The Role of Radiotherapy in the Treatment of Carcinoma of the Prostate: A Survey of Clinical Practices in Lombardy, Italy, by the Airo-Lombardia Cooperative Group

Aims and background

We report the results of a survey performed in 1994 by the AIRO-Lombardia Cooperative Group, on the clinical patterns of radiation treatment for prostatic carcinoma in Lombardy, Italy, involving all radiotherapy centers serving an overall local population of about 8,800,000 people.

Methods

A questionnaire was sent to all 13 radiotherapy centers throughout Lombardy, asking for demographic and treatment details concerning the local population of patients with a localized (T1-4, N0-1, M0) carcinoma of the prostate treated with radiotherapy; 12 centers responded, making the basis for the present report.

Results

Analysis of collected data showed that in Lombardy: a) approximately 400 patients per year are irradiated for a localized carcinoma of the prostate, accounting for less than 30% of the total expected number of patients with this disease presentation; b) a complete staging (with PSA, transrectal ultrasonography, abdomino-pelvic CT or MRI scan and total-body bone scan) is performed in over 95% of patients before initiating radiotherapy; c) significant differences exist between radiotherapy centers as regards treatment planning and delivery.

Conclusions

An urgent need exists for implementing procedures aimed at standardizing radiotherapy procedures within Lombardy.

Fast neutrons in prostatic adenocarcinomas: worldwide clinical experience

Primary tumor control remains a major problem in the treatment of locally advanced prostate carcinoma. Clinical local failure rates approach 30-40% and may be significantly higher when results of prostatic biopsy or prostate-specific antigen (PSA) levels are considered. The low growth rate and cycling fraction of prostate adenocarcinoma suggest potential therapeutic advantage for the high linear energy transfer (LET) of neutrons. The Radiation Therapy Oncology Group (RTOG) performed a multi-institutional randomized trial (RTOG 77-04) comparing mixed beam (neutron plus photon) irradiation to conventional photon irradiation for the treatment of locally advanced prostate cancer. A subsequent trial by the Neutron Therapy Collaborative Working Group (NTCWG 85-23) compared pure neutron irradiation to standard photon irradiation. Both randomized trials demonstrate significant improvement in locoregional control with neutron irradiation compared to conventional photon irradiation in the treatment of locally advanced prostate carcinoma. To date, only the mixed beam trial has shown a significant survival benefit. Future analysis of the larger NTCWG trial at the 10-year point should confirm whether or not improved locoregional control translates into a survival advantage. These findings have significant implications for all local treatment strategies including dose-escalated conformal photon irradiation, prostate implantation, and neutron radiation. Given the large numbers of patients afflicted with this disease, a positive survival advantage for neutrons or mixed beam therapy would provide a strong incentive for the development of economically feasible clinical neutron facilities.

Four-week arc radiotherapy for B2-C prostate cancer: the need for prospective evaluation of short fractionation schemes

A retrospective review of 173 men with clinical stage B2-C prostate cancer treated by small-volume arc radiotherapy to 5200 cGy in 16 fractions over 4 weeks was undertaken. At 5 years, clinical local failure rates were 14% for stage B2 and 18% for stage C. Five-year survival rates were 81 and 61%, respectively. No discernible differences were detected between a policy of encompassing the planning target volume by the 90% or 95% isodose. The limitations of this retrospective evidence and that of the literature are discussed. In the context of resource limitations affecting radiation oncology, prospective assessment of this technique is required to determine the true outcome.

Long-term results of retropubic permanent 125iodine implantation of the prostate for clinically localized prostatic cancer

PURPOSE

The historical series of retropubic prostate radioactive source implantation from the Memorial Sloan-Kettering Cancer Center has served as the framework for the current transperineal implant approaches used in the treatment of localized prostatic cancer. We report the final assessment of the 15-year outcome.

MATERIALS AND METHODS

Between March 1970 and December 1987, 1,078 patients with biopsy proved adenocarcinoma of the prostate were treated at our cancer center with permanent implantation of 125iodine via a retropubic approach. In addition, all patients underwent bilateral pelvic lymphadenectomy before implantation. The clinical stages of disease were B1 in 234 patients (22%), B2 in 472 (44%), B3 in 145 (14%) and C in 227 (20%). Of the patients 733 (68%) had pathologically negative lymph nodes, whereas 345 (32%) had positive lymph nodes at lymph node dissection. Median followup was 11 years.

RESULTS

Multivariate analysis identified nodal involvement, high grade disease, clinical stage B3/C and implant doses less than 140 Gy, as independent predictors of local relapse. Independent predictors of distant metastases included nodal involvement, stage B3/C disease and poorly differentiated histological status. The local recurrence-free survival rates for patients with negative nodes at 5, 10 and 15 years were 69, 44 and 24%, respectively. The distant metastases-free survival rates at 5, 10 and 15 years for patients with negative lymph nodes were 59, 36 and 21%, respectively.

CONCLUSIONS

125Iodine implantation of the prostate via the retropubic approach was associated with a greater than expected incidence of local relapse at 15 years. Technical limitations of the retropubic technique resulting in suboptimal distribution of the isotope within the prostate are believed to be the explanation for the inferior local control outcome. Although long-term results are not yet available, the 5-year results of the computer optimized transperineal prostate implantation suggest that improved implant techniques will translate into a greater likelihood of tumor control.

Primary radiation therapy in the treatment of localized prostatic cancer

Prostatic carcinoma is one of the leading causes of male cancer deaths. However, the routine diagnostic and therapeutic strategies have not yet been established. Although the outcome of surgical and radiotherapeutical approaches has frequently been reported to be comparable, the profile of side effects is different. This could offer the basis for selecting the treatment of choice in individual cases. During the last decade the radiotherapeutical technique has markedly improved, in part due to the achievements in the field of computer assisted tomography planning and conformal technique; the outcome of side-effects has decreased with concurrent increase in the rate of local control. The prescribing, recording and reporting of irradiation have also recently developed, as well as the staging of the disease. Therefore we consider it timely to review progress in this subject and to emphasize the role of radiotherapy in the treatment of localized prostatic cancer.

Radiotherapy of prostate cancer: established results and new developments

Radical radiotherapy has been established as an effective modality for eradicating localised prostate cancer. No satisfactory comparisons have been made with patients treated by total prostatectomy, but in surgically staged patients with negative lymph nodes survival after radiotherapy exceeds that of an aged matched population, cancer deaths occurring in only 6-15% of patients and 85% remaining free of local recurrence after 10 years. Results are predictably less satisfactory in surgically unstaged cases and for more advanced localised presentations. Nevertheless, radical radiotherapy achieves local control of disease in the majority of patients. Improved local control may be obtained by increasing radiation dose but at the expense of increased radiation-induced side-effects. Conformal radiotherapy and combined modality treatment with the neoadjuvant or adjuvant androgen deprivation show considerable promise as novel methods to improve the therapeutic ratio, and prospective randomised studies are underway to test these approaches.

Prostate cancer

Prostate cancer is the most common noncutaneous malignancy diagnosed in American men, and in 1994 it will pass lung cancer as the most common cancer diagnosed in the United States, with an estimated 200,000 new cases. The molecular biology of prostate carcinogenesis is rapidly advancing, and it is clear that, to a degree, prostate cancer is a heritable disease. The use of serum prostate-specific antigen (PSA) as a screening tool has been widely accepted by the medical community, although the evidence to support the efficacy of screening is not yet available. The curative approaches to organ-confined, clinically localized prostate cancer include radiation therapy, radical prostatectomy, and close observation in selected patients. The absence of well-designed clinical trials contributes to the confusion surrounding which curative treatment is the best option in individual patients. The standard approach to patients with evidence of extracapsular spread without distant metastases has been external-beam radiotherapy, although the results with radiation therapy alone in these patients has left considerable room for improvement. Innovative combined-modality approaches are currently being investigated at a number of institutions for these poor-prognosis patients. Three-dimensional conformal radiation therapy is currently being investigated at multiple institutions and offers some hope for improved results. The treatment of metastatic disease remains hormonal manipulation, although the exact nature of optimal androgen deprivation is currently a matter of considerable debate. In patients with hormone-refractory disease newer regimens using novel chemotherapy regimens offer some promise.

A multivariable analysis of clinical factors predicting for pathological features associated with local failure after radical prostatectomy for prostate cancer

PURPOSE

A multivariate analysis is used to determine the predictive value of pretreatment clinical indicators on pathologic features associated with local failure after radical prostatectomy in patients with prostate cancer.

METHODS AND MATERIALS

A retrospective review of the pathologic findings of 235 patients with adenocarcinoma of the prostate treated between 1990 and 1993 with a radical retropubic prostatectomy was performed. The preoperative clinical data including the serum prostate specific antigen, clinical stage, Gleason sum, and endorectal magnetic resonance scan findings are used to identify patients prior to definitive treatment who would be at high risk for having pathologic features associated with local failure at radical prostatectomy. Outcome prediction curves are constructed from a logistic regression multivariate analysis displaying the probability of pathologic involvement of the seminal vesicle, extracapsular disease, or positive surgical margins as a function of the preoperative prostate specific antigen and Gleason sum for the cases when the endorectal magnetic resonance scan is positive, negative, or not included in the multivariate analysis.

RESULTS

Factors identified on multivariate analysis as significant predictors of seminal vesicle invasion include endorectal magnetic resonance scan findings (p < 0.0001), and preoperative prostate specific antigen (p = 0.017). Endorectal magnetic resonance scan findings (p = 0.0016), preoperative prostate specific antigen (p = 0.0002), and Gleason sum (p < 0.0001) were significant predictors of extracapsular extension and preoperative prostate specific antigen (p < 0.0001) and Gleason sum (p = 0.03) were significant predictors of disease extending to the margins of resection. Clinical stage was not a significant predictor (p > 0.05) of pathologic features associated with local failure on multivariate analysis. As a single modality, endorectal surface coil magnetic resonance imaging was accurate 93%, 69%, and 72% of the time for predicting seminal vesicle invasion, transcapsular disease, and final pathologic stage, respectively. Failure to recognize microscopic penetration of the capsule found at the time of pathologic evaluation in a prostate gland with a grossly intact capsule accounts for the majority (70%) of the staging inaccuracies.

CONCLUSIONS

The use of the endorectal surface coil magnetic resonance scan findings in conjunction with both the serum prostate specific antigen and Gleason sum improves the clinical accuracy of predicting those patients at high risk for clinically unsuspected extraprostatic disease. In particular, for the subgroup of patients with moderately elevated prostate specific antigen (> 10-20 ng/mL) and intermediate grade clinically organ confined prostate cancer [Gleason sum: 5-7] where the specificity of these tests to predict for occult extraprostatic disease is suboptimal, the additional information obtained from the endorectal coil magnetic resonance scan allows the physician to definitively subgroup these patients into low and high risk for seminal vesicle invasion or transcapsular disease.

The influence of transurethral resection of prostate on prognosis of patients with adenocarcinoma of the prostate treated by radical radiotherapy

Results of 999 patients with carcinoma of the prostate treated with radical radiotherapy were evaluated to assess the impact of pre-treatment transurethral resection of the prostate. (TURP). A total of 427 patients had a needle biopsy and 541 patients had a TURP. In 31 patients the diagnostic procedure could not be ascertained. In patients with stage T1/T2 disease (411) no adverse effect on prognosis was observed following TURP compared with needle biopsy. In patients with stage T3/T4 disease (534) a significantly higher distant relapse rate and cause-specific mortality were observed after TURP but overall survival was similar after TURP and needle biopsy. A significant correlation was observed between the probability of TURP and poorly differentiated cancers. Multivariate analysis which evaluated the influence of age, T stage, histologic differentiation and TURP did not demonstrate diagnostic TURP to be a significant independent prognostic variate for patients with prostate cancer managed by radical radiotherapy.

Photon versus fast neutron external beam radiotherapy in the treatment of locally advanced prostate cancer: results of a randomized prospective trial

PURPOSE

To evaluate the effectiveness of fast neutron radiation therapy in treatment of locally advanced carcinomas of the prostate.

METHODS AND MATERIALS

From April 1986 to October 1990, 178 patients were entered on a prospective, multi-institutional randomized study of the NCI-sponsored Neutron Therapy Collaborative Working Group. This trial compared external beam photon irradiation (7000-7020 cGy) with external beam neutron irradiation (2040 ncGy) for patients with high-grade T2 or T3-4, N0-1, M0 adenocarcinomas of the prostate. Eighty-nine patients were randomized to each treatment. Six patients were subsequently judged to be ineligible, leaving 85 photon and 87 neutron randomized patients eligible for analysis.

RESULTS

With a follow-up time ranging from 40 to 86 months (68 months median follow-up) the 5-year actuarial clinical local-regional failure rate for patients treated with neutrons was 11%, vs. 32% for photons (p < 0.01). Incorporating the results of routine posttreatment prostate biopsies, the resulting "histological" local-regional tumor failure rates were 13% for neutrons vs. 32% for photons (p = 0.01). To date, actuarial survival and cause-specific survival rates are statistically indistinguishable for the two patient cohorts, with 32% of the neutron-treated patient deaths and 41% of the photon-treated patient deaths caused by prostate cancer (p = n.s.). Prostate specific antigen (PSA) values were elevated in 17% of neutron-treated patients and 45% of photon-treated patients at 5 years (p < 0.001). Severe late complications of treatment were higher for the neutron-treated patients (11% vs. 3%), and were inversely correlated with the degree of neutron beam shaping available at the participating institutions. Neutron treatment delivery utilizing a fully rotational gantry and multileaf collimator did not result in an increase in severe late effects when compared to photon treatment.

CONCLUSION

High energy fast neutron radiotherapy is safe and effective when adequate beam delivery systems and collimation are available, and it is significantly superior to external beam photon radiotherapy in the local-regional treatment of large prostate tumors.