A ten year follow-up of 682 patients treated for prostate cancer with radiation therapy in the United States

Long-term biochemical results after high-dose-rate intensity modulated brachytherapy with external beam radiotherapy for high risk prostate cancer

Background

Biochemical control from series in which radical prostatectomy is performed for patients with unfavorable prostate cancer and/or low dose external beam radiation therapy are given remains suboptimal.

The treatment regimen of HDR brachytherapy and external beam radiotherapy is a safe and very effective treatment for patients with high risk localized prostate cancer with excellent biochemical control and low toxicity.

Biochemical outcome after high-dose-rate intensity modulated brachytherapy with external beam radiotherapy: 12 years of experience

Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Biochemical control from series in which radical prostatectomy is performed for patients with unfavorable prostate cancer and/or low dose external beam radiation therapy are given remains suboptimal. The treatment regimen of HDR brachytherapy and external beam radiotherapy is a safe and very effective treatment for patients with high risk localized prostate cancer with excellent biochemical control and low toxicity.

OBJECTIVE

• To investigate the long-term oncological outcome, during the PSA era, of patients with prostate cancer who were treated using high-dose-rate (HDR) brachy therapy (BT) combined with external beam radiation therapy (EBRT).

PATIENTS AND METHODS

• From June 1998 to April 2007, 313 patients with localized prostate cancer were treated with 46 Gy of EBRT to the pelvis with a HDR-BT boost. • The mean (median) follow-up was 71 (68) months. • Toxicity was reported according to the Common Toxicity Criteria for Adverse Event, V.4.

RESULTS

• The 10-year actuarial biochemical control was 100% for patients with no high-risk criteria, 88% for patients with two intermediate-risk criteria, 91% with one high-risk criterion and 79% for patients with two to three high-risk criteria (P= 0.004). • The 10-year cancer-specific survival was 97% (standard deviation ± 1%). • The multivariate Cox regression analyses identified, Gleason score and T stage as independent prognostic factors for biochemical failure. • Gleason score was the only factor to significantly affect distant metastases. • Grade ≥ 3 late toxicity was not detected.

CONCLUSION

• The 10-year results confirm the feasibility and effectiveness of EBRT with conformal HDR-BT boost for patients with localised prostate cancer.

Stereotactic body radiotherapy as boost for organ-confined prostate cancer

Stereotactic body radiotherapy (SBRT) boost following external beam radiation therapy (EBRT) for advanced localized prostate cancer may reduce toxicity while escalating the dose. We present preliminary biochemical control and urinary, rectal and sexual toxicities for 73 patients treated with SBRT as a boost to EBRT. Forty-one intermediate- and 32 high-risk localized prostate cancer patients received 45 Gy EBRT with SBRT boost. Twenty-eight patients (38.3%) received a total SBRT boost dose of 18 Gy (3 fractions of 6 Gy), 28 patients (38.3%) received 19.5 Gy (3 fractions of 6.5 Gy), and 17 patients (23.2%) received 21 Gy (3 fractions of 7 Gy). Toxicity was assessed using the Radiation Therapy Oncology Group urinary and rectal toxicity scale. Biochemical failure was assessed using the Phoenix definition. The median follow-up was 33 months (range, 22 - 43 months). Less than 7% Grade II and no higher grade acute toxicities occurred. To date, one Grade III and no Grade IV late toxicities occurred. For the 97% of patients with 24 months minimum follow-up, 71.8% achieved a PSA nadir threshold of 0.5 ng/mL. Three intermediate-risk and seven high-risk biochemical failures occurred; one high-risk patient died of his cancer. Three-year actuarial biochemical control rates were 89.5% and 77.7% for intermediate- and high-risk patients, respectively. SBRT boost for prostate cancer treatment is safe and feasible with minimal acute toxicity. At 33 months late toxicity and biochemical control are promising. Long-term durability of these findings remains to be established.

High-dose-rate brachytherapy boost for prostate cancer: comparison of two different fractionation schemes

PURPOSE

This is a retrospective study comparing our experience with high-dose-rate (HDR) brachytherapy boost for prostate cancer, using two different fractionation schemes, 600 cGy × 3 fractions (patient group 1) and 950 cGy × 2 fractions (patient group 2).

METHODS AND MATERIALS

A total of 165 patients were treated for prostate cancer using external beam radiation therapy up to a dose of 45 Gy, followed by an HDR brachytherapy prostate radiation boost. Between July 1997 and Nov 1999, 64 patients were treated with an HDR boost of 600 cGy × 3 fractions; and between June 2000 and Nov 2005, 101 patients were treated with an HDR boost of 950 cGy × 2 fractions. All but 9 patients had at least one of the following risk features: pretreatment prostate-specific antigen (PSA) level >10, a Gleason score ≥7, and/or clinical stage T3 disease.

RESULTS

Median follow-up was 105 months for group 1 and 43 months for group 2. Patients in group 2 had a greater number of high-risk features than group 1 (p = 0.02). Adjusted for comparable follow-up, there was no difference in biochemical no-evidence-of-disease (bNED) rate between the two fractionation scheme approaches, with 5-year Kaplan-Meier estimates of 93.5% in group 1 and 87.3% in group 2 (p = 0.19). The 5-year estimates of progression-free survival were 86% for group 1 and 83% for group 2 (p = 0.53). Among high-risk patients, there were no differences in bNED or PFS rate due to fractionation.

CONCLUSIONS

Results were excellent for both groups. Adjusted for comparable follow-up, no differences were found between groups.

High-dose-rate intensity modulated brachytherapy with external-beam radiotherapy improves local and biochemical control in patients with high-risk prostate cancer

Purpose Our aim was to report the 8-year outcome of local dose escalation using high-dose-rate conformal brachytherapy combined with external irradiation for patients with high-risk prostate cancer. Material and methods From June 1998 to June 2007, 134 patients with high-risk localized prostate cancer were prospectively enrolled in the study. The median follow-up was 45 months (12-107). Only patients considered as having high-risk criteria were accepted [prostate-specific antigen (PSA) > or =20 ng/ml and/or Gleason >7 and/or stage > or =T3a or two intermediate-risk criteria: PSA 11-19 ng/ml, Gleason 7, stage T2b-c]. The total dose applied by external beam radiotherapy was 46 Gy in 200-cGy daily fractions. High-dose-rate brachytherapy was performed at the end of weeks 1 and 3 of the 5-week radiotherapy course. The doses administered in each application was 1,150 cGy. Any patient free of clinical or biochemical evidence of disease was termed b-NED. Actuarial rates of outcome were calculated by Kaplan. Meier analysis and compared using the log-rank test. Cox regression models were used to establish prognostic factors of the measures of outcome. Results Mean follow-up for the entire group was 45 months (range 12-107). The overall survival (OS) according to Kaplan-Meier estimates was 85% (+/-5) at 5 and 8 years. The 5 and 8 years for biochemical control were 80% (+/-4%) and 73% (+/-7%), respectively, whereas for failure in tumor-free survival (TFS), they were 82% (+/-3) at 5 and 8 years, respectively. The 8-year cause-specific mortality was 10% (+/-4%). The multivariate Cox regression analyses identified the number of poor prognostic factors as independent for biochemical failure. Our report includes only patients considered as high risk, and the 8-year b-NED survival rate was 83% for patients with two intermediate-risk criteria, 78% for patients with one poor prognostic factor, 56% for two and 35% for all three (p = 0.001). There were no urethral strictures and/or urinary incontinence. Gastrointestinal toxicity grade 2 was 7.5%. Conclusions The 8-year results confirm the feasibility and effectiveness of external-beam radiation therapy with conformal high-dose-rate brachytherapy boost for patients with high-risk tumor. The late toxicity rates were low, corroborating the excellent dose conformity.

15-year prospective follow-up of patient-reported outcomes of late bowel toxicity after external beam radiotherapy for localized prostate cancer. A comparison with age-matched controls

We have previously described patient-reported outcomes of late side effects induced by conventional external beam radiotherapy (EBRT), 4 and 8 years after treatment, in 181 patients with localized prostate cancer compared with 141 age-matched controls. In the present study, we compare bowel side effects 15 years after EBRT with the same controls, and with the results of our previous 4-year and 8-year follow-ups. Of the 181 patients and 141 controls at the 4-year follow-up, 45 patients (25%) and 79 controls (56%) were still alive at the 15-year follow-up. Bowel symptoms were assessed using the symptom-specific questionnaire Prostate Cancer Symptom Scale (PCSS), which was sent to these 45 patients and 79 age-matched controls with a mean follow-up time of 15 years (162-197 months) after EBRT. The answer frequency was 64% in the patient group and 52% in the control group. The mean age was 78 years in both groups. At the 15-year follow-up, 39% of the patients and 84% of the controls reported no bowel problems (p < 0.001), while 16% of the patients and 0% of the controls reported "Quite a few/many" problems with mucus in the stools (p < 0.001). "Quite a bit/much" stool leakage was reported by 20% of the patients at the 15-year follow-up, in comparison to 4% of the patients at the 4-year follow-up (ns). The proportion of patients reporting late bowel symptoms was unchanged 15 years after EBRT in comparison to the 4-year follow-up. Increased bowel symptoms were seen in patients in comparison to the age-matched controls.

[The hormone refractory prostate cancer - a challenge for the internal specialist]

Prostate cancer is the second-leading cause of cancer-related death among men and the seventh most common cause of death in the United States overall. As prostatic carcinoma is a slowly growing cancer depending on the tumor burden, use of PSA results in early cancer detection. pT2 tumors can be cured with low morbidity by radical prostatectomy. Five years after operation only few patients will experience further PSA recurrences. Adjuvant radiation therapy is effective in about half of patients with pT3 tumors in case of PSA recurrence. Most prostate cancers are androgen-dependent, meaning that they respond to androgen-ablation therapy. However, these tumors eventually become androgen-independent and grow despite androgen ablation. Since androgens are essential to the survival of prostate cells, a major question is how a prostate cell survives after androgen-ablation therapy. The mechanisms by which a prostate cancer cell survives after androgen-ablation therapy are conflicting. Specific targeting of genes involved in such pathways may further increase the chance of inventing new therapeutic options. So far, chemotherapy with docetaxel has been proved to prolong survival time and minimize cancer induced side effects in patients with hormone refractory prostate cancer.

Combined modality treatment with high-dose-rate brachytherapy boost for locally advanced prostate cancer

PURPOSE

This is a retrospective review of our experience using high-dose-rate (HDR) brachytherapy boost for prostate cancer.

METHODS AND MATERIALS

During the study period, we recommended external beam radiotherapy (45 Gy) and HDR boost (18 Gy in three fractions) combined with hormonal therapy (HT) for 2 months before and during radiotherapy to patients with at least one of the following risk features: pretreatment prostate-specific antigen>10, Gleason score (GS)>or=7, and clinical T3 disease. Additional HT for 2 years after radiotherapy was recommended for patients with GS>7. To patients whose risk of positive nodes exceeded 15%, we recommended whole pelvic radiotherapy. We administered HDR via single implant, and all fractions were given within 24h.

RESULTS

This report is based on our initial 64 patients treated with HDR boost. The median follow-up was 50 months (range 25-68 months). The 4-year estimates of overall and disease-free survival were 98% and 92%, respectively. One patient experienced late grade 4 gastrointestinal toxicity.

CONCLUSIONS

HDR brachytherapy is an effective means of delivering conformal prostate radiotherapy, and may be used with whole pelvic radiotherapy and HT.

FAILURE AFTER PRIMARY RADIATION OR SURGERY FOR PROSTATE CANCER: DIFFERENCES IN RESPONSE TO ANDROGEN ABLATION

PURPOSE

Androgen ablation is the standard treatment for recurrent and metastatic prostate cancer. Surprisingly few studies have documented the specific results for local and distant failure in patients treated primarily with radiation or radical prostatectomy. We report the long-term outcome of a series of those patients.

MATERIALS AND METHODS

We followed until death 94 patients in whom primary radiation therapy failed and 67 in whom radical prostatectomy failed. All patients received androgen ablation.

RESULTS

Statistically (p = 0.04) more patients in the radiation group (78%) died of prostate cancer than in the radical prostatectomy group (63%). Of the radiation group with local failure alone 63%, died of prostate cancer at a median of 5.03 years. Of the surgery group with isolated local failure 50% died of cancer at a median of 9.83 years. Of the patients treated with radiation with distant metastasis 93% died of cancer with a median time to death of 2.34 years. Of the patients treated with surgery 69% died of prostate cancer at a median of 3.27 years. The differences in survival between the 2 groups was significant.

CONCLUSIONS

This study is unique in providing followup until death of patients treated with radical prostatectomy and radiation who had clinical failure and were treated with androgen ablation. Compelling is the finding that survival after androgen ablation after surgical failure is superior to that for radiation. If confirmed, this would be a significant consideration for future studies of patients in whom primary therapy fails.

Characterization of rectal normal tissue complication probability after high-dose external beam radiotherapy for prostate cancer

PURPOSE

Conformal radiotherapy (RT) has allowed radiation dose escalation to improve the outcome of prostate cancer. With higher doses, concern exists that rectal injury may increase. This study analyzed the utility and limitations of the widely used Lyman-Kutcher- Burman (LKB) normal tissue complication probability model in projecting the hazards of rectal complication with high-dose RT.

METHODS AND MATERIALS

A total of 128 patients were included in this study. These patients were treated with three-dimensional conformal RT alone at the University of Texas M.D. Anderson Cancer Center between 1992 and 1999. Patients were treated to 46 Gy with a four-field box technique followed by a six-field arrangement to boost the total dose to 78 Gy. All doses were delivered at 2 Gy/fraction to the isocenter. The minimal follow-up was 2 years. The end point for analysis was Grade 2 or worse rectal bleeding by 2 years. The LKB model was fitted to the data using the maximal likelihood method.

RESULTS

Of the 128 patients, 29 experienced Grade 2 or worse rectal bleeding by 2 years. For the entire cohort, the parameters obtained from the fit of the LKB model were as follows: the volume factor was n = 3.91 (95% confidence interval [CI] 0.031 to infinity ), dose associated with 50% chance of complication for uniform whole rectal irradiation [TD50(1)] was 53.6 Gy (95% CI 50.0-75.1), and a determinant of the steepness of the dose-response curve, (m), was 0.156 (95% CI 0.036-0.271). A statistically significant difference was found in the rate of postradiation rectal bleeding in patients with hemorrhoids vs. those without hemorrhoids. The parameters obtained for the patients without hemorrhoids were as follows: n = 0.746 (95% CI 0.026 to infinity ), TD50(1) 56.7 Gy (95% CI 49.9-75.2), and m 0.092 (95% CI 0.019-0.189).

CONCLUSION

Our analysis suggests a dose response for rectal bleeding probability along with a volume effect. We found that the LKB model might have limited utility in determining a large volume effect. We further suggest that LKB model should be used with caution in clinical practice.

External beam radiotherapy in elderly patients with clinically localized prostate adenocarcinoma: age is not a problem

The files of 183 elderly patients aged >70 years, with localized prostate cancer (T1-3, N0-X, M0), treated with radical external radiation therapy (ERT) from January 1992 to December 2001 at the Radiotherapy Department of the Istituto Nazionale Tumori of Milan, were reviewed. Median age was 75 years. ERT represented the sole treatment for 73 patients (39.9%); in 110 cases (60.1%) hormonal therapy (HT) was associated with neoadjuvant intent. Five-year overall, disease-specific and biochemical NED (bNED) survival rates were 90.2, 93.7 and 63.2%, respectively. A subset of 23 patients aged 80 years and over were analyzed and compared to 160 men aged 70-79 years. Acute toxicity and late complications were analyzed in the two groups of patients according to the RTOG scoring system. Only 10 patients (5.4%) showed grades 2-3 (G2-3) late sequelae. The results obtained in this single-institute series highlight the pivotal role of ERT in the management of clinically localized prostate cancer in the elderly.

Comparison between two iodine-125 brachytherapy implant techniques: pre-planning and intra-operative by various dosimetry quality indicators

PURPOSE

To prospectively compare two widely used seed implant techniques: pre-planning and intra-operative planning, based on 1 month post-implant CT-based evaluation.

METHODS

We report results of a detailed 1 month post-operative dosimetric evaluation and comparison between 142 consecutive men with prostate adenocarcinoma treated by the pre-planning methodology and 214 men treated with the real-time, intra-operative seed implant method.

RESULTS

Baseline parameters patient's age, Gleason score, clinical stage, and gland volume were similar in both groups (p>0.05). Length of physicist time and operating room team time were more than double in the pre-planned group compared to the intra-operative one (205 vs 100 min). Based on day 30 post-implant CT, for patients treated with the pre-planning method, mean V90, V100 and V150 (percent prostate volume receiving 90, 100 and 150% of the prescribed dose) were 67.5, 58.35 and 21.5%, respectively, while for the intra-operative group they were 97.9, 95.2 and 45%, respectively (p<0.01). Mean D90, expressed as percent of target matched peripheral dose (minimal dose covering 90% of the gland volume) was 53% for the pre-planned group and 114% for the intra-operative group of men (p<0.01). Short-term morbidity was minimal in both groups and did not correlate with the technique employed.

CONCLUSIONS

This large-scale comparison of implant adequacy favours real-time intra-operative method. While all dosimetric parameters are significantly better with this method, no increased early morbidity was noted. Longer-term PSA-based clinical outcome should substantiate our contention of the superiority of the intra-operative method when compared to the pre-planning one.

Iodine-125 brachytherapy for localized prostate cancer and urinary morbidity: a prospective comparison of two seed implant methods-preplanning and intraoperative planning

OBJECTIVES

To compare morbidity between two currently used iodine-125 seed implantation techniques for the treatment of localized prostate cancer.

METHODS

Iodine-125 brachytherapy was used in 300 consecutive men with localized prostate cancer. Two seed implant techniques were used: preplanning, using preloaded needles, and intraoperative planning, using a Mick applicator. A comparison was made between the groups for urinary morbidity. The International Prostate Symptom Score was assessed prospectively among all patients. Computed tomography-based implant quality parameters were correlated with lower urinary system morbidity.

RESULTS

The median follow-up was 30 months. In both treatment groups, the International Prostate Symptom Score increased significantly for about 9 to 12 months and returned to baseline thereafter. The International Prostate Symptom Scores reached a higher level and remained at a higher level for a longer period in the intraoperative group. Although the differences were statistically significant, they were of mild clinical importance. Overall, the incidence of acute retention and the need for surgery was very low in both groups (2% and 1%, respectively). No differences were noted between the two groups. Significantly better computed tomography-based implant dosimetry parameters were noted with the intraoperative method. A positive correlation (P < 0.001) was found between the dosimetry parameters and symptom severity.

CONCLUSIONS

This prospective study reports the first large-scale comparison of urologic outcomes after two different seed implant techniques. Both were associated with very low urinary retention rates or other grade 3 or greater urologic morbidity. Almost all men had worse urinary symptoms for the first 6 to 9 months, regardless of the seed implant technique used. Patients treated with the intraoperative method demonstrated toxicity for a longer duration. Because of the much better gland isodose coverage and greater doses delivered in the intraoperative seed implantation, we favor this method.

Conformal high dose rate brachytherapy improves biochemical control and cause specific survival in patients with prostate cancer and poor prognostic factors

PURPOSE

To improve outcome for patients with prostate cancer with poor prognostic factors higher than conventional radiation doses are required. To achieve this outcome a brachytherapy boost was given. We report the results of the first high dose rate dose-escalation brachytherapy trial.

MATERIALS AND METHODS

Between 1991 and 2000, 207 patients were prospectively enrolled in a dose escalation trial including pelvic radiotherapy and conformal high dose rate prostate brachytherapy boost. The dose was increased from 5.5 to 11.5 Gy. per implant. Patient eligibility for the study included pretreatment prostate specific antigen 10 or greater, Gleason 7 or greater or clinical stage T2b or higher. No patient received hormonal therapy. The American Society for Therapeutic Radiology and Oncology consensus panel definition of biochemical failure was applied.

RESULTS

Median patient age was 69 years. Mean followup was 4.7 years (range 0.6 to 10.4). The 5-year actuarial biochemical control rate was 74%. The 5-year biochemical control was 85% for 1 poor prognostic factor, 75% for 2 and 50% for all 3 (p = 0.001). On Cox regression multivariate analysis lower brachytherapy dose, and higher Gleason and nadir value were associated with biochemical failure. The 5-year actuarial overall survival was 92%, cause specific survival 98% and disease-free survival 68%. The 5-year actuarial rates of complications were 8% and 0% for grades 3 and 4 genitourinary, and 0.5% and 0.5% for grades 3 and 4 gastrointestinal, respectively. The 5-year actuarial impotence rate was 51%.

CONCLUSIONS

For patients with poor prognostic factors external beam radiation therapy with conformal high dose rate brachytherapy boost improved biochemical control, resulting in a high cause specific survival rate with low toxicity. Another important advantage is that the patient is not radioactive after the high dose rate implant.

Early clinical experience with anatomy-based inverse planning dose optimization for high-dose-rate boost of the prostate

PURPOSE

To present an exhaustive dosimetric comparison between three geometric optimization methods and our inverse-planning simulated annealing (IPSA) algorithm, with two different prescriptions for high-dose-rate (HDR) boost of the prostate. The objective of this analysis was to quantify the dosimetric advantages of the IPSA algorithm compared with more standard geometric optimizations.

METHODS AND MATERIALS

Between September 1999 and June 2001, 34 patients were treated to a dose of 40-44 Gy by external pelvic fields, followed by an HDR boost of 18 Gy in 3 fractions. The first 4 patients were treated with HDR using geometric optimization, and anatomy-based inverse-planning dose optimization was used for the remaining 30 patients. We retrospectively used the data from these 30 patients to create HDR dose distributions according to five different dose optimization protocols, including our IPSA algorithm. The various geometric optimization procedures differed in the way the dwell positions were activated and plan normalization was performed. Dose-volume histograms from all these plans were analyzed and multiple implant quality indexes extracted.

RESULTS

The IPSA algorithm provided better clinical tumor volume prescription dose coverage than did the geometric optimizations. The average prostate volume receiving 100% of the prescribed dose (V100) was 96.3% and 94.5% for IPSA with two different prescriptions compared with 92.1%, 92.6%, and 88.8% for the three geometric optimization schemes. The average urethra V150 value was 0.0% and 0.7% for IPSA with two different prescriptions, and the three geometric optimization protocols generated average values of 22.9%, 33.9%, and 38.8%. The bladder and rectal dose-volume histograms were similar, although the latest version of the IPSA algorithm slightly decreases the dose to these organs at risk because of organ-specific dose constraints included in the objective function.

CONCLUSION

We found that planning an HDR prostate boost could be performed in a fast, secure, and effective manner with the IPSA algorithm. We demonstrated that our inverse-planning algorithm produces superior HDR plans than more conventional geometric optimizations for adenocarcinoma of the prostate. The organs at risk protection included in the objective function is a major feature of the algorithm and should allow us to escalate the HDR dose to the prostate without increasing undesirable side effects.

Dose escalation using conformal high-dose-rate brachytherapy improves outcome in unfavorable prostate cancer

PURPOSE

To overcome radioresistance for patients with unfavorable prostate cancer, a prospective trial of pelvic external beam irradiation (EBRT) interdigitated with dose-escalating conformal high-dose-rate (HDR) prostate brachytherapy was performed.

METHODS AND MATERIALS

Between November 1991 and August 2000, 207 patients were treated with 46 Gy pelvic EBRT and increasing HDR brachytherapy boost doses (5.50-11.5 Gy/fraction) during 5 weeks. The eligibility criteria were pretreatment prostate-specific antigen level >or=10.0 ng/mL, Gleason score >or=7, or clinical Stage T2b or higher. Patients were divided into 2 dose levels, low-dose biologically effective dose <93 Gy (58 patients) and high-dose biologically effective dose >93 Gy (149 patients). No patient received hormones. We used the American Society for Therapeutic Radiology and Oncology definition for biochemical failure.

RESULTS

The median age was 69 years. The mean follow-up for the group was 4.4 years, and for the low and high-dose levels, it was 7.0 and 3.4 years, respectively. The actuarial 5-year biochemical control rate was 74%, and the overall, cause-specific, and disease-free survival rate was 92%, 98%, and 68%, respectively. The 5-year biochemical control rate for the low-dose group was 52%; the rate for the high-dose group was 87% (p <0.001). Improvement occurred in the cause-specific survival in favor of the brachytherapy high-dose level (p = 0.014). On multivariate analysis, a low-dose level, higher Gleason score, and higher nadir value were associated with increased biochemical failure. The Radiation Therapy Oncology Group Grade 3 gastrointestinal/genitourinary complications ranged from 0.5% to 9%. The actuarial 5-year impotency rate was 51%.

CONCLUSION

Pelvic EBRT interdigitated with transrectal ultrasound-guided real-time conformal HDR prostate brachytherapy boost is both a precise dose delivery system and a very effective treatment for unfavorable prostate cancer. We demonstrated an incremental beneficial effect on biochemical control and cause-specific survival with higher doses. These results, coupled with the low risk of complications, the advantage of not being radioactive after implantation, and the real-time interactive planning, define a new standard for treatment.

Prospective evaluation of urinary and intestinal side effects after BeamCath stereotactic dose-escalated radiotherapy of prostate cancer

BACKGROUND

New data suggest that a higher radiation dose will improve outcome in treatment of localized prostate cancer. External beam radiotherapy (EBRT) may on the other hand induce disturbances in the patient's urinary and intestinal function. Since 1997, 195 patients have been treated with a stereotactic boost of 4-8 Gy added to conventional 70 Gy EBRT. Late side effects were prospectively evaluated 3 years after dose-escalated EBRT.

METHODS

Urinary and intestinal problems were prospectively evaluated with a validated self-assessment questionnaire, the Prostate Cancer Symptom Scale (PCSS). Two hundred and eighty-seven patients completed the questionnaire at the 1 year follow-up, and 153 at 3 years after treatment. Pre-treatment mean age was 66 years. One hundred and sixty-eight patients were treated with the conformal technique and 195 were treated with the dose-escalated stereotactic BeamCath technique. Mean total dose in the conformal group (< or =70 Gy) was 66 Gy (60.8-70.4 Gy). The dose-escalated group consists of three dose levels, 74 Gy (n = 68), 76 Gy (n = 74), and 78 Gy (n = 53).

RESULTS

Analyzing the whole population 3 years after treatment, urgency and starting problems decreased in comparison to pre-treatment. A minor increase in urinary incontinence was reported 3 years after treatment in comparison to pre-treatment. No increases in other urinary symptoms were reported. Intestinal symptoms were slightly increased during the follow-up period in comparison to pre-treatment. Dose escalation with stereotactic EBRT (74-78 Gy) did not increase gastrointestinal or genitourinary late side effects at 1 year or 3 years in comparison to doses < or =70 Gy.

CONCLUSIONS

The stereotactic BeamCath EBRT technique facilitates safe dose escalation of patients with prostate cancer.

Quantification of late complications after radiation therapy

BACKGROUND

An increasing number of patients survive cancer after having received radiation therapy. Therefore, the occurrence of late normal tissue complications among long-term survivors is of particular concern.

METHODS

Sixty-three patients treated by radical surgery and irradiation for rectal carcinoma were subjected to an unconventional sandwich therapy. Preoperative irradiation was given in four fractions of 5 Gy each applied within 2 or 3 days; postoperative irradiation consisted mostly of 15 x 2 Gy (range, 20-40 Gy). A considerable proportion of these patients developed severe late complications (Radiother Oncol 53 (1999) 177). The data allowed a detailed analysis of complication kinetics, leading to a new model which was tested using data from the literature.

RESULTS

Data on late complications were obtained for eight different organs with a follow-up of up to 10 years. For the various organs, the percentage of patients being free from late complications, plotted as a function of time after start of radiation therapy, was adequately described by exponential regression. From the fit, the parameter p(a) was obtained, which is the percentage of patients at risk in a given year of developing a complication in a given organ during that year. The rate p(a) remained about constant with time. Following sandwich therapy, the annual incidence of complications in the bladder, ileum, lymphatic and soft tissue, and ureters was about the same (p(a)=10-14%/year), whereas complications in bone or dermis occurred at lower rates (4.7 or 7.5%/year, respectively).

DISCUSSION

Numerous data sets collected from published reports were analyzed in the same way. Many of the data sets studied were from patients in a series where there was a high incidence of late effects. Three types of kinetics for the occurrence of late effects after radiotherapy were identified: Type 1, purely exponential kinetics; Type 2, exponential kinetics, the slope of which decreased exponentially with time; Type 3, curves composed of two components, a fast initial decline followed by an exponential decrease. For each kind of kinetics, provided that the dose distribution is not too heterogeneous, the incidence of late effects appears to occur at exponential or approximately exponential kinetics, even many years after treatment. This implies that a random process might be involved in the occurrence of late radiation sequelae.

CONCLUSIONS

There might be a lifelong risk of developing late complications, of which patients and clinicians should be aware. It appears worthwhile to try to identify, in follow-up examinations of patients after radiation therapy, what kind of processes might be involved in triggering subclinical residual injury to develop into a clinically manifest late effect.

The 1989 patterns of care study for prostate cancer: five-year outcomes

PURPOSE

Five-year results from the 1989 patterns of care study (PCS) for prostate cancer are now ready for analysis. The PCS was initiated to determine national averages for treatments and examine outcomes prospectively; the 1989 prostate study is the first to have collected pre- and post-treatment serum PSA data.

METHODS AND MATERIALS

Six hundred patients treated with radiotherapy with curative intent for prostate cancer at 71 separate institutions in the year 1989 made up the study population. Three hundred ninety-one cases were fully analyzable. Pretreatment patient and tumor characteristics were as follows: of the 391 analyzable, 255 had pretreatment PSA values obtained, and 245 had a Gleason's sum (GS) reported. Three hundred fifty-eight were Caucasian, 24 African-American, and 3 Hispanic (also 6 unknown). One hundred three patients had PSA < 10, 60 had PSA 10-19, and 92 presented with PSA >20. Ninety-seven patients were from Radiation Therapy Oncology Group (RTOG), Community Cancer Centers (CCC), or teaching institutions; 141 patients were from other hospital-based, nonteaching institutions; and 153 were from freestanding radiation oncology facilities. Seventy-one patients were T1, 203 T2, and 100 T3/4. Twenty-four out of 391 patients also received neoadjuvant hormone therapy. Survival curves were constructed using Kaplan-Meier methods, and differences between groups were tested for significance using the log-rank test. For cumulative incidence curves, Gray's test was used to investigate failure distributions between groups. The variables entering Cox model for multivariate analysis included age, race, T stage, pretreatment PSA, and GS. A patient was considered a PSA failure if the treating radiation oncologist reported it as such.

RESULTS

With a median follow-up of 5.7 years, the 5-year biochemical no evidence of disease (bNED) and overall survival were 56% and 79% respectively for Stage T1, 52% and 81% for T2, and 36% and 63% for Stages T3 and T4 combined. As expected, higher pretreatment PSA, GS, and T stage were all prognostic of poorer outcome. On univariate analysis, bNED survival was adversely impacted by T stage (p = 0.009), pretreatment PSA (p = 0.0035), and by the GS (p = 0.0038). Cause-specific failure was significantly lower for higher T stage (p = 0.014), GS (p = 0.001), and also pretreatment PSA (p = 0.0004). Overall survival was significantly lower in patients with higher T stage (p = 0.047) or GS (p = 0.0191), but not pretreatment PSA (p = 0.284). On multivariate analysis, pretreatment PSA was found to be statistically significant in association with bNED survival, and GS was associated with overall survival, cause-specific survival, and distant metastasis. Few late complications were reported: 13/391 and 13/391 Grade 2-3 gastrointestinal (GI) and genitourinary (GU) complications respectively, with two patients having required surgery with or without a permanent colostomy.

CONCLUSION

For a representative cross-section of institutions in the United States, radiotherapy achieved high rates of bNED and CSS in selected groups of prostate cancer patients. When studied retrospectively, increased pretreatment PSA was a strong predictor of both biochemical failure and death due to prostate cancer. New strategies for patients with high-stage, high-grade tumors and/or pretreatment PSA >20 deserve testing.

Complications from radiotherapy dose escalation in prostate cancer: preliminary results of a randomized trial

OBJECTIVE

To compare early and late side effects in prostate cancer patients with Stage T1b-T3 disease randomized to receive 70 Gy or 78 Gy.

METHODS

There were 189 patients randomized with a minimum follow-up of 2 years, that were available for this analysis. All patients were initially treated with a 4-field box to an isocenter dose of 46 Gy at 2 Gy per fraction. In the 70-Gy arm, treatment was continued to a reduced volume using a 4-field box technique. In the 78-Gy arm, treatment was continued to a reduced volume using a conformal 6-field arrangement. Side effects were graded on a 1-4 scale, adapted from Radiation Therapy Oncology Group and Late Effects Normal Tissue Task Force criteria.

RESULTS

No significant differences in acute rectal or bladder toxicity were seen between the two treatment techniques (p > 0.6 for all comparisons). The 5-year Kaplan-Meier risks of Grade 2 or higher late bladder toxicity were 20% and 9% for 70-Gy and 78-Gy groups, respectively (log rank, p = 0.8). The 5-year risks of Grade 2 or higher late rectal toxicity were 14% and 21% for 70 Gy and 78 Gy, respectively (p = 0.4). Dose-volume histogram analysis of the 78-Gy patients showed a significant correlation between the percentage of rectum irradiated to 70 Gy or greater and the likelihood of developing late rectal complications. Patients with more than 25% of the rectum receiving 70 Gy or greater had a 5-year risk of Grade 2 or higher complications of 37% compared to 13% for patients with 25% or less (p = 0.05). All three Grade 3 complications occurred when greater than 30% of the rectum received 70 Gy or more.

CONCLUSION

The overall rate of complications was similar in both treatment arms. However, there is evidence for a significant increase in late rectal complications when more than 25% of the rectum received 70 Gy or greater. This parameter may serve as a benchmark for the design of future three-dimensional conformal trials.

The external radiotherapy with three-dimensional conformal boost after the neoadjuvant androgen suppression for patients with locally advanced prostatic carcinoma

PURPOSE

To analyze the results in patients with locally advanced prostatic carcinoma treated by hormonal therapy followed by external radiotherapy using three-dimensional conformal radiation therapy (3D-CRT) boost.

METHODS AND MATERIALS

From 1987 to 1995, 46 patients with histologically proven locally advanced adenocarcinoma of the prostate were treated with 3D-CRT at the National Cancer Center Hospital, Tokyo. The neoadjuvant androgen suppression started immediately after the diagnosis followed by radical radiation therapy, according to the prospective protocol. They were treated with photons of 6-14 MV for wide fields and the boost, of which a multiple-leaf collimator of 2-cm width was available. The boosted dose was delivered with the rotational 3D-CRT, after the delivery of whole pelvis 4-field box from a dose of 40-46 Gy up to 66 Gy. The planning target volume encompassed 1 cm outside throughout the clinical target volume, and the prostate and the seminal vesicles were included in the boost field.

RESULTS

The 3D-CRT boost treatment completed as planned in all 46 patients. The median follow-up for all the patients was 60 months (range, 5-120 months). Nineteen of 46 patients died. Of these, 11 patients died of the intercurrent diseases. For all 46 patients, the 5- and 8-year overall survival rates were 61.3% and 42.4%, and the 5- and 8-year cause-specific survival rates were 82.4% and 64.4%, respectively. The prostate-specific antigen (PSA) relapse-free rates for 5- and 8-year were 64.6% and 52.5%, and the clinical local control rates for 5 and 8 years were 75.3% and 69.9%, respectively. The preradiation therapy PSA and the Gleason score were the factors that significantly associated with PSA relapse-free survival. Sixteen of 46 patients (35%) showed at least one form of late toxicities. Of these, 3 patients experienced late complications of Grade 3 (urinary, 2, proctitis, 1).

CONCLUSION

The treatment results were fairly good and were consistent with those in Western countries, indicating that this study shows the preliminary status of 3D-CRT for the locally advanced prostate cancer in Japan. Preradiation therapy PSA seems to be a significant predictor of PSA relapse-free survival (p = 0.004) after neoadjuvant androgen suppression.

Interim report of image-guided conformal high-dose-rate brachytherapy for patients with unfavorable prostate cancer: the William Beaumont phase II dose-escalating trial

PURPOSE

We analyzed our institution's experience treating patients with unfavorable prostate cancer in a prospective Phase II dose-escalating trial of external beam radiation therapy (EBRT) integrated with conformal high-dose-rate (HDR) brachytherapy boosts. This interim report discusses treatment outcome and prognostic factors using this treatment approach.

METHODS AND MATERIALS

From November 1991 through February 1998, 142 patients with unfavorable prostate cancer were prospectively treated in a dose-escalating trial with pelvic EBRT in combination with outpatient HDR brachytherapy at William Beaumont Hospital. Patients with any of the following characteristics were eligible: pretreatment prostate-specific antigen (PSA) >/= 10.0 ng/ml, Gleason score >/= 7, or clinical stage T2b or higher. All patients received pelvic EBRT to a median total dose of 46.0 Gy. Pelvic EBRT was integrated with ultrasound-guided transperineal conformal interstitial iridium-192 HDR implants. From 1991 to 1995, 58 patients underwent three conformal interstitial HDR implants during the first, second, and third weeks of pelvic EBRT. After October 1995, 84 patients received two interstitial implants during the first and third weeks of pelvic EBRT. The dose delivered via interstitial brachytherapy was escalated from 5.50 Gy to 6.50 Gy for each implant in those patients receiving three implants, and subsequently, from 8.25 Gy to 9.50 Gy per fraction in those patients receiving two implants. To improve implant quality and reduce operator dependency, an on-line, image-guided interactive dose optimization program was utilized during each HDR implant. No patient received hormonal therapy unless treatment failure was documented. The median follow-up was 2.1 years (range: 0.2-7.2 years). Biochemical failure was defined according to the American Society for Therapeutic Radiology and Oncology Consensus Panel definition.

RESULTS

The pretreatment PSA level was >/= 10.0 ng/ml in 51% of patients. The biopsy Gleason score was >/= 7 in 58% of cases, and 75% of cases were clinical stage T2b or higher. Despite the high frequency of these poor prognostic factors, the actuarial biochemical control rate was 89% at 2 years and 63% at 5 years. On multivariate analysis, a higher pretreatment PSA level, higher Gleason score, higher PSA nadir level, and shorter time to nadir were associated with biochemical failure. In the entire population, 14 patients (10%) experienced clinical failure at a median interval of 1.7 years (range: 0.2-4.5 years) after completing RT. The 5-year actuarial clinical failure rate was 22%. The 5-year actuarial rates of local failure and distant metastasis were 16% and 14%, respectively. For all patients, the 5-year disease-free survival, overall survival, and cause-specific survival rates were 89%, 95%, and 96%, respectively. The 5-year actuarial rate of RTOG Grade 3 late complications was 9% with no patient experiencing Grade 4 or 5 acute or late toxicity.

CONCLUSION

Pelvic EBRT in combination with image-guided conformal HDR brachytherapy boosts appears to be an effective treatment for patients with unfavorable prostate cancer with minimal associated morbidity. Our dose-escalating trial will continue.

[Conformal radiotherapy of prostatic cancer: a general review]

Recent progress in radiotherapeutic management of localized prostate cancer is reviewed. Clinical aspects--including dose-effect beyond 70 Gy, relative role of conformal radiation therapy techniques and of early hormonal treatment--are discussed as well as technical components--including patient immobilization, organ motion, prostate contouring, beam arrangement, 3-D treatment planning and portal imaging. The local control and biological relapse-free survival rates appear to be improved by high dose conformal radiotherapy from 20 to 30% for patients with intermediate and high risk of relapse. A benefit of overall survival is expected but not yet demonstrated. Late reactions, especially the rectal toxicity, remain moderate despite the dose escalation. However, conformal radiotherapy demands a high precision at all steps of the procedure.

Correlation of medical dosimetry quality indicators to the local tumor control in patients with prostate cancer treated with iodine-125 interstitial implants

The treatment of prostate cancer by 125I interstitial implants has been extensively studied with mixed results by one institution or another. A recent study from Hahnemann [Int. J. Radiat. Oncol., Biol., Phys. 21,955-960 (1991)] reported results that were extremely poor compared to those reported in an earlier study at Yale [Int. J. Radiat. Oncol., Biol., Phys. 14, 1153-1157 (1988)] or those in an Eastern Virginia Study [Cancer 63, 2415-2420 (1989)]; differences in 5-yr survival rates being more than a factor of 2. Such large discrepancies from institution to institution led us to a reexamination of the dosimetry. This study analyzed quantitatively three-dimensional dosimetric parameters of 110 prostate cancer patients treated with 125I interstitial implants. The study searched for "cutoff" values in each parameter that divided the patients into two groups with statistically significant differences in the local recurrence-free survival rates. A comparison of the three-dimensional isodose surfaces of patients with favorable values in all of the parameters to those patients with all unfavorable parameters show how these characteristics translated into poor dose coverage and much inhomogeneity within the implant even for cases that met the traditional criteria for adequacy (160 Gy to the tumor volume). Patients in the favorable group had 10-yr survival rates higher by a factor of up to 2 compared to those in the unfavorable group. The strong correlation of three-dimensional volume-dose parameters to the local control rate observed in this study further emphasizes how important it is to assess the three-dimensional dosimetric adequacy of interstitial implants before deciding on their clinical efficacy. If implants are performed with appropriate attention to dosimetry parameters, excellent clinical results are obtained. On the other hand, if dosimetry parameters are not correct, the implant results can be poor.

A new look at an old option in the treatment of early-stage prostate cancer: hormone therapy as an alternative to watchful waiting

Watchful waiting is an attractive option in the management of early-stage, low-grade prostate cancer because of the high financial costs and complication risks associated with surgery and radiotherapy. Despite the drawbacks of current local therapy, neither treatment can demonstrate a discernible survival benefit over observation alone. Even the slowest progressing disease, however, can potentially develop into a deadly medical problem. As a result, physicians and patients frequently have difficulty accepting untreated cancer. Therefore, we propose that another option be considered in cases of prostate cancer that would otherwise qualify for observation alone: the use of two oral hormonal agents, flutamide and finasteride, to achieve complete androgen blockade. Some evidence exists which suggests that such therapy may improve symptom-free survival, and perhaps overall survival as well. This 'aggressive' form of 'conservative' therapy may satisfy patient concerns that are not adequately addressed by current forms of therapy.

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.

Daily CT localization for correcting portal errors in the treatment of prostate cancer

INTRODUCTION

Improved prostate localization techniques should allow the reduction of margins around the target to facilitate dose escalation in high-risk patients while minimizing the risk of normal tissue morbidity. A daily CT simulation technique is presented to assess setup variations in portal placement and organ motion for the treatment of localized prostate cancer.

METHODS AND MATERIALS

Six patients who consented to this study underwent supine position CT simulation with an alpha cradle cast, intravenous contrast, and urethrogram. Patients received 46 Gy to the initial Planning Treatment Volume (PTV1) in a four-field conformal technique that included the prostate, seminal vesicles, and lymph nodes as the Gross Tumor Volume (GTV1). The prostate or prostate and seminal vesicles (GTV2) then received 56 Gy to PTV2. All doses were delivered in 2-Gy fractions. After 5 weeks of treatment (50 Gy), a second CT simulation was performed. The alpha cradle was secured to a specially designed rigid sliding board. The prostate was contoured and a new isocenter was generated with appropriate surface markers. Prostate-only treatment portals for the final conedown (GTV3) were created with a 0.25-cm margin from the GTV to PTV. On each subsequent treatment day, the patient was placed in his cast on the sliding board for a repeat CT simulation. The daily isocenter was recalculated in the anterior/posterior (A/P) and lateral dimension and compared to the 50-Gy CT simulation isocenter. Couch and surface marker shifts were calculated to produce portal alignment. To maintain proper positioning, the patients were transferred to a stretcher while on the sliding board in the cast and transported to the treatment room where they were then transferred to the treatment couch. The patients were then treated to the corrected isocenter. Portal films and electronic portal images were obtained for each field.

RESULTS

Utilizing CT-CT image registration (fusion) of the daily and 50-Gy baseline CT scans, the isocenter changes were quantified to reflect the contribution of positional (surface marker shifts) error and absolute prostate motion relative to the bony pelvis. The maximum daily A/P shift was 7.3 mm. Motion was less than 5 mm in the remaining patients and the overall mean magnitude change was 2.9 mm. The overall variability was quantified by a pooled standard deviation of 1.7 mm. The maximum lateral shifts were less than 3 mm for all patients. With careful attention to patient positioning, maximal portal placement error was reduced to 3 mm.

CONCLUSION

In our experience, prostate motion after 50 Gy was significantly less than previously reported. This may reflect early physiologic changes due to radiation, which restrict prostate motion. This observation is being tested in a separate study. Intrapatient and overall population variance was minimal. With daily isocenter correction of setup and organ motion errors by CT imaging, PTV margins can be significantly reduced or eliminated. We believe this will facilitate further dose escalation in high-risk patients with minimal risk of increased morbidity. This technique may also be beneficial in low-risk patients by sparing more normal surrounding tissue.

[Locally advanced prostate carcinoma (T2b-T4 N0) without and with clinical evidence of local progression (Tx N+) with lymphatic metastasis. Is radiotherapy for pelvic lymphatic metastasis indicated or not?]

BACKGROUND

There is a greater controversy regarding the indication of radiotherapy of the pelvic lymphatics in patients with suspected lymph node metastases in locally advanced prostate cancer (T2b-4 N0) on the one hand and in patients with pathologically proven lymph node metastases in locoregional advanced prostate cancer (Tx pN+) on the other hand following definitive radiotherapy and radical prostatectomy. This paper investigates the possible indications for radiotherapy of the pelvic lymphatics in the light of data from the literature.

PATIENTS AND METHODS

Because data from several retrospective studies concerning radiotherapy of the pelvic lymphatics indicated a better outcome, the RTOG conducted 2 prospective randomised studies (RTOG 75-06, 77-06) to address these questions. However, the results of these studies showed no better survival or cause specific survival for patients treated for the paraaortal or pelvic lymphatics and therefore, radiotherapy of the pelvic lymphatics was no more advocated. A reanalysis showed several problems of the study design and it was concluded that the studies couldn't prove the question of elective radiotherapy of the pelvic lymphatics. In RTOG 77-06 patients with T1b/T2 tumors were investigated. Therefore, there is no prospective study investigating the elective radiotherapy in patients with T3-tumors, who are at high risk of pelvic lymph node metastases.

RESULTS

Today there is no indication for treating the paraaortal lymphatics in patients with locoregional advanced prostate cancer. Many radiotherapists perform the elective radiotherapy of pelvic lymphatics when the risk of metastases is above 15 to 20% because retrospective data indicate a better outcome. On the other hand, many others don't treat them because RTOG 75-06 and 77-06 didn't demonstrate a better outcome. Laparoscopic lymphadenectomy with low morbidity seems to be helpful as in pN0 patients radiotherapy is not necessary. Where performing laparoscopic pelvine lymphadenectomy is impossible the probability of the frequency of lymph node metastases can be estimated using the clinical tumor stage, the Gleason-score and the pretherapeutic PSA. In case of proven metastases (pN+) some retrospective data indicate that patients with micrometastasis could profit from aggressive treatment. In case of proven metastases and extirpation by lymphadenectomy it seems that patients with hormonal therapy and radiotherapy have a longer tumor-free interval. However, there are no data from randomized trials.

CONCLUSIONS

Every radiotherapist has to make his own decision for radiotherapy of the pelvic lymphatics as there is no standard treatment. Two randomised studies are open and recruiting patients. These are one study of the ARO, investigating patients with histologically proven lymph node metastases and one study of the RTOG (RTOG 9413), investigating patients with an estimated risk of lymph node metastases > 15%. In case of radiotherapy of the pelvic lymphatics a dose of 45 Gy for suspected metastases and 50.4 Gy for proven metastases is recommended.

Radiation therapy or prostatectomy: an old conflict revisited in the PSA era. A radiation oncologist's viewpoint

A close examination of the outcomes for the radical treatment of prostate cancer in the prostate-specific antigen (PSA) era shows no clear advantage to radical prostatectomy over external-beam radiation. Both modalities are highly effective against small impalpable tumors of low Gleason grade and with PSA values less than 10 ng/mL. Both modalities struggle against all other stages of prostate cancer. Radiation and surgery are currently in states of rapid evolution, and the results emerging become quickly outdated. It is hoped that the newer, more aggressive approaches will help a significant number of patients, perhaps the majority, not currently being cured by radical therapy.

The location of the prostatic apex on retrograde urethrography and its relationship to the bottom of the ischial tuberosities

To determine the proportion of patients undertreated if the inferior border of the prostate field is set at the bottom of the ischial tuberosities, we reviewed the ports of 80 patients with prostate cancer who had retrograde urethrography as part of simulation for radiation therapy. For the 75 evaluable urethrograms, the mean distance from the top of the urethrogram cone to the bottom of ischial tuberosities was 1.38 cm (range, -0.48-2.90 cm). A comparison of the inferior border defined by the bottom of the ischial tuberosities and retrograde urethrography showed that 47 of 75 (62.7%) patients would have been undertreated if a margin of 1.5 cm was employed, and the prostatic apex was thought to be directly above the urethrogram cone. If the apex was thought to be 1 cm above the cone, six of 75 (8.0%) patients would have been undertreated, using a margin of 1.5 cm. Although previously published reports have established that using the bottom of the ischial tuberosities as the inferior border of the prostate field results in 10-45% undertreatment, our findings, when adjusted for the variability of prostatic apex location and margin of normal tissue employed, indicate that only 8% may actually be undertreated.

Daily-diary evaluated side-effects of conformal versus conventional prostatic cancer radiotherapy technique

Conventional 4-field box radiotherapy technique induces high morbidity for patients with localized prostatic cancer. Using a patient daily diary, the present study compared side-effects after conventional radiotherapy with conformal radiotherapy for prostate cancer. Fifty-eight patients treated with the conventional technique (with or without sucralfate) were compared with 72 patients treated with conformal technique. The patient groups were compared with an age-matched control population. Patients treated with conformal technique were also evaluated regarding acute and late urinary problems. Results showed that patients treated with conformal technique reported significantly fewer side-effects as compared with conventional technique. Patients treated with sucralfate also showed slightly decreased intestinal morbidity in comparison to non-sucralfate group. Acute and late morbidity evaluated by the patients was decreased after conformal radiotherapy as compared with the conventional technique. Sucralfate may be of value if conformal radiotherapy is used for dose escalation in prostatic cancer patients.

Enhancement of prostate tumor volume definition with intravesical contrast: a three-dimensional dosimetric evaluation

PURPOSE

To assess the impact of intravesical contrast during computed tomography (CT) simulation on prostate tumor volume definition and dose distribution.

METHODS AND MATERIALS

Sixteen patients with localized adenocarcinoma of the prostate underwent CT-based virtual simulation in preparation for definitive radiotherapy. Patients were immobilized with a foam cradle and an initial CT was performed after oral but without intravesical contrast (noncontrast scan). A second scan was performed following administration of intravesical contrast (contrast scan). Beam apertures were designed on the noncontrast scans and digitized into the contrast scan file. Beam apertures were also designed on the contrast scans. Isodose plans were generated for several beam apertures and arrangements.

RESULTS

There was enhanced visualization of the prostate at the cephalad portion of the field for 15 of the 16 cases. The mean differences between the noncontrast and contrast volumes was significant (p = 0.0001). The mean percent underdosage to the prostate ranged from 3.9% to 18.6%, depending upon the target volume and beam arrangement.

CONCLUSION

This study demonstrates the necessity of using intravesical contrast for defining the location of the prostate during CT simulation. The underestimation of the extent of the prostate when omitting intravesical contrast leads to significant underdosage. The value of intravesical contrast is most evident when small (prostate only) conformal fields are used.

Chronic rectal bleeding after high-dose conformal treatment of prostate cancer warrants modification of existing morbidity scales

PURPOSE

Serious late morbidity (Grade 3/4) from the conformal treatment of prostate cancer has been reported in <1% to 6% of patients based on existing late gastrointestinal (GI) morbidity scales. None of the existing morbidity scales include our most frequently observed late GI complication, which is chronic rectal bleeding requiring multiple fulgerations. This communication documents the frequency of rectal bleeding requiring multiple fulgerations and illustrates the variation in reported late serious GI complication rates by the selection of morbidity scale.

METHODS AND MATERIALS

Between May 1989 and December 1993, 352 patients with T1-T3 nonmetastatic prostate cancers were treated with our four-field conformal technique without special rectal blocking. This technique includes a 1-cm margin from the clinical target volume (CTV) to the planning target volume (PTV) in all directions. The median follow-up for these patients was 36 months (range 2-76), and the median center of prostate dose was 74 Gy (range 63-81). Three morbidity scales are assessed: the Radiation Therapy Oncology Group (RTOG), the Late Effects Normal Tissue Task Force (LENT), and our modification of the LENT (FC-LENT). This modification registers chronic rectal bleeding requiring at least one blood transfusion and/or more than two coagulations as a Grade 3 event. Estimates for Grade 3/4 late GI complication rates were determined using Kaplan-Meier methodology. The duration of severe symptoms with chronic rectal bleeding is measured from the first to the last transrectal coagulation. Latency is measured from the end of radiotherapy to surgery, first blood transfusion, or third coagulation procedure.

RESULTS

Sixteen patients developed Grade 3/4 complications by one of the three morbidity scales. Two patients required surgery (colostomy or sigmoid resection), three required multiple blood transfusions, two required one or two blood transfusions, and nine required at least three coagulations. The median duration of bleeding for those patients requiring multiple procedures was 7 months (range 3-33) and the median latency was 22 months (range 9-40). The 5-year actuarial rate of Grade 3/4 complications by each scale are: RTOG 0.7%, LENT 2%, and FC-LENT 6%. The rate of chronic rectal bleeding increases with increasing dose and is low in patients treated with conventional techniques owing to lower doses.

CONCLUSION

Chronic rectal bleeding requiring any blood transfusion(s) or multiple coagulation procedures is our most frequently observed complication. This complication appears late in follow-up and is present for a long duration. We believe this justifies the inclusion of chronic rectal bleeding requiring multiple coagulation procedures as a Grade 3 event in future morbidity scales. Our data illustrate that published Grade 3/4 morbidity rates are highly dependent on the morbidity scale selected, as our data show 0.7% RTOG, 2% LENT, and 6% FC-LENT. Obviously, a uniform scale is required that includes the newly recognized serious late effects associated with the conformal treatment of prostate cancer.

Neoadjuvant androgen suppression with radiation in the management of locally advanced adenocarcinoma of the prostate: experimental and clinical results

Conventional radiotherapy has been a standard treatment for the management of locally advanced T2c-4 prostatic carcinoma for over 2 decades. The routine use of serum PSA in follow-up makes it clear that > 80% of these patients will show evidence of failure by 10 years. Rebiopsy of those with a rising PSA shows locally persistent disease in the majority of cases. Increasing the radiation dose applied to the prostate increases local control but at the risk of higher morbidity. Experimental data using the Shionogi tumor mouse model suggest a potential gain from neoadjuvant androgen suppression without any increase in normal tissue morbidity. Two randomized trials comparing neoadjuvant androgen suppression prior to radiation therapy with radiation alone in humans show considerable short-term gains in local control and disease-free survival but mature data are still awaited. It is currently unknown whether the positive interaction between radiation and androgen suppression is synergistic or simply additive.

Late GI and GU complications in the treatment of prostate cancer

PURPOSE

To assess the factors that predict late GI and GU morbidity in radiation treatment of the prostate.

METHODS AND MATERIALS

Seven hundred twelve consecutive prostate cancer patients treated at this institution between 1986 and 1994 (inclusive) with conformal or conventional techniques were included in the analysis. Patients had at least 3 months follow-up and received at least 65 Gy. Late GI Grade 3 morbidity was rectal bleeding (requiring three or more procedures) or proctitis. Late Grade 3 GU morbidity was cystitis or stricture. Multivariate analysis (MVA) was used to assess factors related to the complication-free survival. The factors assessed were age, occurrence of side effects > or = Grade 2 during treatment, irradiated volume parameters (use of pelvic fields, treatment of seminal vesicles to full dose or 57 Gy, and use of additional rectal shielding), dose, comorbidities, and other treatments (hormonal manipulation, TURP).

RESULTS

Acute GI and GU side effects (Grade 2 or higher) were noted in 246 and 201 patients, respectively; 67 of these patients exhibited both. GI side effects were not correlated with GU side effects acutely. Late and acute morbidities were correlated (both GI and GU). Fifteen of the 712 patients expressed Grade 3 or 4 GI injuries 3 to 32 months after the end of treatment, with a mean of 14.3 months. One hundred fifteen patients expressed Grade 2 or higher GI morbidity (mean: 13.7 months). The 43 Grade 2 or higher GU morbidities occurred significantly later (mean: 22.7 months). Central axis dose was the only independent variable significantly related to the incidence of late GI morbidity on MVA. No treatment volume parameters were significant for Grade 3. The following parameters were significantly related (by MVA) to Grade 2 GI morbidity: central axis dose, use of the increased rectal shielding, androgen deprivation therapy starting before RT. Acute and late GI morbidities were highly correlated. History of diabetes, treatment of pelvic nodes, and age less than 60 years were significantly related to acute GI side effects. The parameters significantly related to late Grade 2 or higher GU morbidity were central axis dose, androgen deprivation therapy (Zoladex or Lupron) prior to radiation therapy (RT), history of obstructive symptoms, and acute GU side effects. There were too few late Grade 3 GU morbidities to perform multivariate analysis. Acute GU side effects were highly correlated with late GU injury. The following were correlated with acute GU side effects: history of diabetes (+), treatment with conformal fields (-), TURP before RT (-), presentation with urinary obstructive symptoms.

CONCLUSION

Both late GI and GU morbidity demonstrate a dose dependence, but only the volume dependence observed is a reduction in late Grade 2-4 GI morbidity by increasing the rectal shielding in the lateral fields for the final 10 Gy. Moreover, both late GI and GU morbidity was increased in patients treated with hormone manipulation prior to RT. GI and GU injuries were correlated with their corresponding acute side effects. GI and GU complications must not be combined for analysis to determine the factors related to their occurrence.

Combined proton and photon conformal radiation therapy for locally advanced carcinoma of the prostate: preliminary results of a phase I/II study

PURPOSE

A study was developed to evaluate the use of combined photons and protons for the treatment of locally advanced carcinoma of the prostate. This report is a preliminary assessment of treatment-related morbidity and tumor response.

METHODS AND MATERIALS

One hundred and six patients in stages T2b (B2), T2c (B2), and T3 (C) were treated with 45 Gy photon-beam irradiation to the pelvis and an additional 30 Cobalt Gray Equivalent (CGE) to the prostate with 250-MeV protons, yielding a total prostate dose of 75 CGE in 40 fractions. Median follow-up time was 20.2 months (range: 10-30 months). Toxicity was scored according to the Radiation Therapy Oncology Group (RTOG) grading system; local control was evaluated by serial digital rectal examination (DRE) and prostate specific antigen (PSA) measurements.

RESULTS

Morbidity evaluation was available on 104 patients. The actuarial 2-year rate of Grade 1 or 2 late morbidity was 12% (8% rectal, 4% urinary). No patients demonstrated Grade 3 or 4 late morbidity. Treatment response was evaluated on 100 patients with elevated pretreatment serum PSA levels. The actuarial 2-year rate of PSA normalization was 96%, 97%, and 63% for pretreatment PSAs of > 4-10, > 10-20, and > 20, respectively. The 13 patients with rising PSA demonstrated local recurrence (3 patients), distant metastasis (8 patients), or no evidence of disease except increasing PSA (2 patients).

CONCLUSIONS

The low incidence of side effects, despite the tumor dose of 75 CGE, demonstrates that conformal protons can deliver higher doses of radiation to target tissues without increasing complications to surrounding normal tissues. The initial tumor response, as assessed by the high actuarial rate of normalization with pretreatment PSA < or = 20, and the low rate of recurrences within the treatment field (2.8%), are encouraging.

Self-assessed sexual function after pelvic irradiation for prostate carcinoma. Comparison with an age-matched control group

BACKGROUND

Treatment of localized prostate carcinoma is often accompanied by disturbances in sexual function. The patient's own opinion and experience with these problems can be of great importance for his quality of life. In men older than 50 years, disturbances in sexual function are common. Treatment such as radiotherapy (RT), which can induce sexual dysfunction, should be evaluated in relation to the problems in an age-matched population without prostate carcinoma.

METHODS

Sexual function was evaluated with a self-assessment questionnaire using linear-analogue scales. The questionnaire was sent to 199 patients with prostate carcinoma, median age 71 years (range, 51-86 years), who had received pelvic RT with curative intent and to 200 age-matched men in northern Sweden. Mean follow-up time after RT was 48 months (range, 24-56 months).

RESULTS

The response rate was high: 141 (71%) and 181 (91%) in the control and patient groups, respectively. Field reduction and treatment pause during RT was not associated with decreased problems in the patient groups. A failure to achieve erection was indicated in 12% of the control subjects, 56% of the patients who had received (RT only) and 87% of the RT + castration (RT + A) patients. In general, patients < 70 years treated with RT+A indicated more sexual problems than the RT only patients < 70 years. There was a strong negative correlation between age and sexual problems in the RT + A < 70 years group. However, in patients < 70 years, sexual activity after RT only, was not significantly different from the age-matched control population.

CONCLUSIONS

Patients with prostate carcinoma treated with RT only indicated higher levels of sexual dysfunction than age-matched controls. This was most obvious in patients younger than 70 years, although their sexual activity was comparable to age-matched controls. The addition of castration to RT tended to increase sexual problems, especially in patients < 70 years. In men between 70 and 74 years, the maintenance of sexual function seems to be very susceptible to disturbances. For patients older than 74 years, decreased sexual function was not perceived as such a significant problem, despite abolished desire and erection.

Prostate cancer. Who is best benefited by external beam radiation therapy?

The major indications for radical radiation therapy of prostate cancer for both early-stage and locally advanced disease are discussed. Important issues in the interpretation of long-term treatment series are reviewed. The outcomes of therapy are analyzed for both early-stage and locally advanced disease, including alternative therapeutic strategies. On the basis of this review of the literature, current treatment recommendations delineate patients most likely to benefit from radiation therapy as opposed to alternative therapeutic modalities.

Does brachytherapy have a role in the treatment of prostate cancer?

The goal of radiation therapy is to deliver a high dose to the tumor while preserving normal surrounding tissue. For early-stage prostate cancer, the ultimate conformal irradiation is to place radioactive sources directly into the gland either as permanent or temporary seeds. Permanent seed implantation is capable of delivering two times the radiobiologically equivalent dose of external beam irradiation to the prostate and tumor. In the past, the results of prostate brachytherapy were likely poor owing to the technical difficulty in accurately placing the radioactive seeds uniformly throughout the prostate. The use of low-dose-rate I-125 to treat high-grade cancers probably also contributed to the poorer results as compared with external beam irradiation. Over the last 10 years, however, technologic advances in transrectal ultrasonography, computer dosimetry, and template-based transperineal techniques have dramatically improved the accuracy and consistency of the brachytherapist to place radioactive sources directly into the prostate gland. Transperineal ultrasound or CT directed seed implantation has replaced the older retropubic method. Brachytherapists are now able to accurately map out the gland prior to the implant and carefully evaluate preoperatively seed placement. The availability of such radioactive sources as iodine-125, palladium-103, and iridium-192 has also given the brachytherapist isotopes that can be more carefully matched to the biology and stage of the tumor. More sensitive definitions of failure have prompted radiation oncologists and urologists to carefully evaluate the efficacy of external beam irradiation and surgery. Accurate comparison of the efficacy of brachytherapy to surgery and to external beam radiation requires a randomized study. Comparisons of retrospective studies are fraught with the problems of the heterogeneous nature of early-stage prostate cancer. Imbalances in stage, grade, initial PSA extraprostatic disease, and nodal status of patient groups make comparisons difficult. Most of the long-term data for permanent seed implantation are the result of work at a single institution. These results will need to be repeated at other institutions treating patients in a similar manner. Because techniques vary from institution to institution, permanent implant results will need to be carefully evaluated for technique as well as stratified for pretreatment variables. Pretreatment PSA and grade appear to be more sensitive variables than stage in predicting failure after radiation. As more patients are diagnosed with very early and nonpalpable disease, future studies will need to stratify patients based on these pretreatment factors. Patients with early-stage disease but identified as high risk for extraprostatic disease will require more intensive regimens. The treatment outcomes based on biopsy results are inconclusive. A lack of consensus on the definition of a truly positive biopsy remains forthcoming. The value of a positive prostate biopsy as an outcome predictor for clinical failure is still unclear. The use of prostate nuclear cell antigen staining may help clarify the issue. Comparison of treatment outcome based on absolute PSA is also difficult. The Seattle series suggest that brachytherapy by permanent seed implantation is as efficacious as external beam irradiation for early-stage disease in patients with a low PSA (< 10 ng/mL). As the PSA value rises above 10 ng/mL, the probability of failure after external beam rises substantially. Results from the Seattle series suggest an advantage to seed implant alone or the judicious application of seed implant boost to external beam radiation for these patients with more advanced cancer. The most sensitive measurement of therapeutic outcome is progression-free survival. Few studies to date have evaluated progression-free survival.

Lateral rectal shielding reduces late rectal morbidity following high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a significant dose effect

PURPOSE

Using conventional treatment methods for the treatment of clinically localized prostate cancer central axis doses must be limited to 65-70 Gray (Gy) to prevent significant damage to nearby normal tissues. A fundamental hypothesis of three-dimensional conformal radiation therapy (3DCRT) is that, by defining the target organ(s) accurately in three dimensions, it is possible to deliver higher doses to the target without a significant increase in normal tissue complications. This study examines whether this hypothesis holds true and whether a simple modification of treatment technique can reduce the incidence of late rectal morbidity in patients with prostate cancer treated with 3DCRT to minimum planning target volume (PTV) doses of 71-75 Gy.

METHODS AND MATERIALS

The 257 patients with clinically localized prostate cancer who completed 3DCRT by December 31, 1993 and received a minimum PTV dose of 71-75 Gy are included in this report. The median follow-up time was 22 months (range: 4-67 months); 98% of patients had follow-up of longer than 12 months. The calculated dose at the center of the prostate was < 74 Gy in 19 patients, 74-76 Gy in 206 patients, and > 76 Gy in 32 patients. Late rectal morbidity was graded according to the Late Effects Normal Tissue (LENT) scoring system. Eighty-eight consecutive patients were treated with a rectal block added to the lateral fields. In these patients the posterior margin from the prostate to the block edge was reduced from the standard 15 to 5 mm for the final 10 Gy, which reduced the dose to portions of the anterior rectal wall by approximately 4-5 Gy. Estimates of rates for rectal morbidity were determined by Kaplan-Meier actuarial analysis. Differences in morbidity percentages were evaluated by the Pearson chi-square test.

RESULTS

Grade 2-3 rectal morbidity developed in 46 out of 257 patients (18%) and in the majority of cases consisted of rectal bleeding. No patient has developed Grade 4 or 5 rectal morbidity. The actuarial rate of Grade 2-3 morbidity is 23% at 24 months and the median time to the development of Grade 2-3 complications is 15 months. A statistically significant dose effect is evident. The incidence of Grade 2-3 rectal morbidity increased as the dose at the center of the prostate increased (p = 0.05). In patients receiving minimum PTV doses of < or = 76 Gy the use of a rectal block significantly reduced the incidence of Grade 2-3 toxicity; 6 out of 88 (7%) with a block vs. 30 out of 137 (22%) without a block, (p = 0.003).

CONCLUSION

The incidence of late rectal morbidity with 3DCRT to minimum PTV doses of 71-75 Gy is acceptable and to date no Grade 4-5 rectal morbidities have been observed. In our experience, higher doses to the center of the prostate are associated with an increased likelihood of developing Grade 2-3 rectal morbidity but treatment techniques that reduce the total dose to the anterior rectal wall have reduced the incidence of late rectal morbidity. If clinical studies indicate improved tumor control with minimum PTV doses above 71 Gy, then dose escalation above 76 Gy to the center of the prostate should be pursued cautiously with treatment techniques that limit the total dose to the anterior rectal wall.

Orchidectomy prior to definitive radiotherapy for localized prostatic cancer

PURPOSE

To identify potential survival benefits of cytoreductive orchidectomy performed prior to definitive radiation for localized prostate cancer.

METHODS AND MATERIALS

Between 1977-1988, all patients with localized prostatic cancer from the Wellington Region received definitive radiotherapy (n = 200). One referring urologist Peter M. Meffen (P.M.M.) had commenced a program of prior orchidectomy followed by definitive radiation treatment (median time to radiation therapy was 5 months, n = 30).

RESULTS

Five-year overall survival (OS) and relapse-free survival (RFS) for each stage were Stage A 82%, and 82%; Stage B 75%, and 61%; Stage C 57%, and 38%, respectively. Ten-year OS and RFS for each stage were Stage A 78%, and 72%; Stage B 51%, and 18%; Stage C 32% and 0%, respectively. Multivariate analysis identified prior orchidectomy treatment and histological grade as independently significant prognostic factors for OS and RFS. Factors influencing RFS were clinical stage, prior orchidectomy, and histological grade. Prior orchidectomy was associated with an increase in OS at 5 years when compared to those patients receiving radiotherapy alone, 86% vs. 69%, and maintained at 10 years, 82% vs. 46% (p < 0.05). The two groups were comparable by stage, histological grade, and age. There were no changes in the referral pattern during the study period.

CONCLUSIONS

Our results suggest that prior cytoreduction by orchidectomy has a beneficial effect on OS and RFS for patients with localized prostate cancer. It is unclear whether survival benefits are due to the cytoreductive therapy, the adjuvant therapy, or a combination of both. Further study in this area is warranted, ideally in the form of randomized prospective clinical trials.