Clinical and Biochemical Evidence of Control of Prostate Cancer at 5 Years After External Beam Radiation

What pretreatment prostate-specific antigen level warrants long-term androgen deprivation?

PURPOSE

Several large randomized prospective studies have demonstrated a survival benefit with the addition of long-term androgen deprivation to definitive radiotherapy for patients with Gleason score 8-10 or T3-T4 prostate cancer. However, these studies were performed before the routine use of prostate-specific antigen (PSA) measurement. The purpose of this study was to determine what pretreatment (initial) PSA (iPSA) level, if any, warrants the addition of long-term androgen deprivation in the PSA era.

METHODS AND MATERIALS

The data set evaluated consisted of 1003 prostate cancer patients treated definitively with three-dimensional conformal radiotherapy between May 1, 1989 and November 30, 1999 (median follow-up, 61 months). Specifically excluded were patients with T3-T4 disease or Gleason score greater than 7 or those who had undergone androgen deprivation as a part of their initial therapy. The median radiation dose was 76 Gy. Patients were randomly split into two data sets, with the first (n = 487) used to evaluate the optimal iPSA cutpoint for which a statistically significant difference in outcome was noted. The second data set (n = 516) served as a validation data set for the initial modeling. The analysis of the optimal iPSA cutpoint was based on a recursive partitioning approach for censored data using the log-rank test for nodal separation of freedom from biochemical failure (FFBF) as defined by the American Society for Therapeutic Radiology and Oncology definition. Cox multivariate regression analysis was used to confirm independent predictors of outcome among the clinical and treatment-related factors: iPSA (grouped as defined by the recursive partitioning analysis), Gleason score (2-6 vs. 7), T stage (T1c-T2a vs. T2b-T2c), and total radiation dose (continuous).

RESULTS

The recursive partitioning analysis data set resulted in an optimal iPSA cutpoint of 35 ng/mL, such that the 5-year Kaplan-Meier estimate of FFBF was 80%, 69%, and 19% for iPSA groups of 0-9.9, 10-35, and >35 ng/mL, respectively. The validation data set demonstrated the optimal iPSA cutpoint to be 30 ng/mL. Conservatively choosing 30 ng/mL as the optimal cutpoint, the 5-year FFBF estimate for the entire 1003 patients was 82%, 69%, and 20% for iPSA groups 0-9.9 (n = 630), 10-30 (n = 329), and >30 (n = 44) ng/mL, respectively. On multivariate regression analysis, with the iPSA grouped as above, the Gleason score and radiation dose were independent predictors of outcome in this patient group (all p < 0.001). On univariate analysis, a higher radiation dose improved FFBF when the iPSA level was between 10 and 30 ng/mL (p = 0.001) but not when the iPSA level was >30 or <10 ng/mL.

CONCLUSION

Recursive partitioning techniques defined an iPSA cutpoint of 30 ng/mL for delineating intermediate vs. high risk. Patients with a PSA level >30 ng/mL in the absence of Gleason score >7 or T3 disease do poorly when treated with radiotherapy alone and should be considered for long-term androgen deprivation or other aggressive systemic therapy.

Impact of Elapsed Treatment Time on Outcome of External-Beam Radiation Therapy for Localized Carcinoma of the Prostate

PURPOSE

The purpose of this study was to evaluate the impact of elapsed treatment time in external-beam radiation therapy for localized prostate carcinoma.

MATERIALS AND METHODS

The medical records of 1083 patients with localized prostate carcinoma treated between 1970 and December 1999 with external irradiation alone were reviewed. Median follow-up was 6 years (range, 4-24 years). Since 1987, prostate-specific antigen levels were obtained in 687 patients before the initiation of radiation therapy, and all patients seen in follow-up had prostate-specific antigen determinations. There were 344 patients with T1c, 496 with T2, and 243 with T3 tumors. The elapsed treatment time was divided into < or = 7, 7.1-9, or > 9 weeks. Local tumor control was determined by rectal examination and cause-specific survival or prostate-specific antigen failure according to American Society of Therapeutic Radiology and Oncology consensus criteria. Because of dose-escalation studies, tumor dose levels ranged from 66-73.8 Gy, given in 1.8- to 2-Gy fractions.

RESULTS

In patients with stage T1c, local failure ranged from 0% to 10% with doses < or = 72 Gy with; elapsed treatment time had no impact. No pelvic failures were detected in 88 patients receiving doses > 72 Gy. In patients with T2 who received < or = 70 Gy, overall pelvic failure rate was 4% (12/306) in those with an elapsed treatment time of < or = 9 weeks, in contrast to 27% (12/44) for those with an elapsed treatment time > 9 weeks; at 10 years, patients with T2 tumors treated in > 9 weeks had a higher actuarial pelvic failure rate (35%), in contrast to 5% to 18% with shorter treatment times. For patients with T2 tumors who received 70-72 Gy, pelvic failure rate ranged from 0% to 32%, and there were no failures in 37 patients treated to higher doses. In patients with prostate-specific antigen values whose tumors were stage T1c, the chemical failure rate was 41% (60/147) with a tumor dose < 70 Gy, compared with 17% (4/24) in those who received higher doses. In patients with stage 2 disease who were treated with < 70 Gy, the chemical failure rate was 31%, and the rate was 12%-18% in those who received higher doses. In stage T3, the clinical pelvic failure rate ranged from 25% to 32% in the three elapsed time groups, and the chemical failure rate ranged from 48% to 69%, and there was no significant correlation with elapsed time or total irradiation dose. Cause-specific survival without chemical failure in patients with stage T1c disease at 10 years was 85%-90% in the three elapsed treatment time groups. In patients with stage T2 disease, the corresponding values were 80% and 90% for elapsed treatment times < 9 weeks, in contrast to 65% for patients treated > 9 weeks. In patients with stage T3 disease, cause-specific survival was about 60% in all elapsed treatment groups. There was no significant correlation of elapsed treatment time with urinary or rectal morbidity.

CONCLUSIONS

Patients treated with radiation therapy for stage T2 localized prostate carcinoma showed a greater incidence of pelvic and chemical failures and a lower cause-specific survival when elapsed treatment time was > 9 weeks in comparison with the failure and survival rates occurring with shorter times. Higher doses of irradiation (> 72 Gy) eliminate the influence of prolongation of treatment time on outcome.

Thermoradiotherapy using interstitial self-regulating thermoseeds: an intermediate analysis of a phase II trial

OBJECTIVE

Thermoradiotherapy in the treatment of prostate cancer is based on a variety of experimental and clinical phase I data which have proven the synergistic effects of this combination. We report on a phase II trial in a special hyperthermia research group (SFB 273) of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) to determine feasibility, acute toxicity and efficacy of this combination for prostate cancer.

METHODS

57 patients with localized prostate cancer were treated with interstitial hyperthermia using cobalt-palladium thermoseeds and conformal radiation between July 1997 and December 2000. Thermoseeds were placed into the prostate homogeneously. Hyperthermia was created using a magnetic field and was delivered in six sessions once weekly for one hour. 3D-conformal radiotherapy of 68.4Gy was given simultaneously in daily fractions of 1.8Gy.

RESULTS

Intraprostatic temperatures were between 42 and 46 degrees C. No major side effects were observed during hyperthermia. Median follow-up was 36 months (range 3-72 months). Median PSA value decreased from 11.6ng/ml to 2.4ng/ml 3 months after treatment, to 1.3ng/ml 12 months after treatment and to 0.55ng/ml 2 years after therapy.

CONCLUSION

Interstitial hyperthermia is feasible, well tolerated and led to a steep decrease of PSA values. Combining effective interstitial hyperthermia with conformal radiotherapy may be an exciting innovative treatment option for prostate cancer.

Utility of the percentage of positive prostate biopsies in predicting PSA outcome after radiotherapy for patients with clinically localized prostate cancer

PURPOSE

To determine the utility of the percentage of positive prostate biopsies (PPPB) in predicting prostate-specific antigen (PSA) outcome after external beam radiotherapy alone.

METHODS AND MATERIALS

The records of 750 clinical Stage T1 and T2 patients treated by external beam radiotherapy alone with a median follow-up of 80 months were reviewed. Of the 750 patients, 345 were eligible for analysis; 255 (74%) had undergone sextant biopsies, 28 (8%) <6 biopsies, and 62 (18%) >6 biopsies. The pretreatment PSA level (<10, 10-20, >20 ng/mL), biopsy Gleason score (2-6, 7, 8-10), and clinical stage (T1-T2a, T2b, T2c), uni- or bilateral positive biopsy, radiation dose, and PPPB were analyzed as potential predictors of PSA outcome. The PPPB data were analyzed as a continuous and as a categorical variable.

RESULTS

PPPB was a significant predictor of the time to PSA failure on univariate analysis as a continuous (p = 0.0053) and as a categorical (<50% vs. >or=50%, p = 0.0077) variable. In multivariate analysis, a trend was noted for worse 5-year PSA failure-free survival based on PPPB >or=50% vs. <50% (p = 0.082). Sixty-four patients experienced biochemical failure according to the American Society for Therapeutic Radiology Oncology definition. The 5-year PSA failure-free survival rate was 79% vs. 69% (p = 0.02) and the clinical disease-free survival rate was 97% vs. 86% (p = 0.0004) for patients with <50% vs. >or=50% PPPB. PPPB was not a significant predictor for the time to PSA failure within the traditional risk groups (low, intermediate, and high) on multivariate analysis.

CONCLUSION

PPPB was a predictor of post-external beam radiotherapy PSA outcome in clinically localized prostate cancer; but in this cohort it did not provide additional information beyond the traditional risk stratification schema.

Use of nomograms to predict the risk of disease recurrence after definitive local therapy for prostate cancer

The generally indolent nature of prostate cancer, as well as the impact that treatment can have on quality of life (QOL) and cancer control, makes the decision analysis difficult for patients facing the task of selecting a treatment for clinically localized disease. Instruments to aid patients and their physicians in this decision analysis are needed. Nomograms are instruments that predict outcomes using specific clinical parameters. Nomograms use algorithms that incorporate several variables to calculate the predicted probability that a patient will achieve a particular clinical end point. Nomograms tend to outperform both clinical experts and predictive models using methods of risk grouping. We briefly outline the uses and limitations of nomograms, principles of nomogram construction, and the available models for predicting the progression-free probability after local definitive therapy with radical prostatectomy, external-beam radiotherapy, or brachytherapy. There is a need for additional nomograms that predict outcomes after salvage therapy, as well other clinical end points, including QOL-adjusted survival.

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.

The use of conformal radiotherapy and the selection of radiation dose in T1 or T2 low or intermediate risk prostate cancer – a systematic review

BACKGROUND AND PURPOSE

The purpose was to develop a systematic review that would address the following questions: (a) when single-modality treatment external-beam radiotherapy is selected as the modality of choice, what is the role of three-dimensional (3D) conformal radiotherapy in treating clinically localized (T1, T2/NO, NX/MO) prostate cancer? The outcomes of interest are biochemical freedom from failure (bNED) rates, clinical recurrence-free survival, disease-specific survival and acute and late toxicity; (b) what is the appropriate dose and fractionation prescription in this clinical setting?

MATERIALS AND METHODS

A systematic review of the English published literature was undertaken to provide evidence relevant to the above outcomes.

RESULTS

One randomized controlled trial comparing conventional radiotherapy to conformal therapy with dose escalation reported bNED rates. Three additional randomized controlled trials reported acute or chronic late outcome assessments. Additionally, phase II studies of dose escalation in sequential patient cohorts and non-randomized comparative assessments of dose-response and bNED rates in controlled analyses were reviewed. There is convincing evidence from randomized trials that the use of conformal therapy reduces acute and late treatment-related morbidity. There is preliminary evidence suggesting that when external-beam therapy alone is used to treat patients, conformal therapy with dose-escalation is more efficacious than doses of 70Gy. The increased efficacy appears to be predominantly seen in the subset of patients with intermediate-risk disease (PSA 10-20). There is conflicting evidence of the efficacy of dose-escalation in patients with low initial PSA (<10) and in patients with initial PSA greater than 20. Conformal radiotherapy at a dose of 78Gy appears to be relatively safe with no increase in acute or late effects compared with conventional treatment (up to 70Gy) so long as appropriate technological principles are considered.

CONCLUSIONS

Patients who have external-beam radiotherapy should be treated using a 3D conformal technique. Patients with intermediate-risk disease (PSA 10-20) who are treated with external-beam radiotherapy alone should be offered doses of 75-78Gy in 180-200cGy fractions.

Three-Dimensional Conformal Therapy Versus Standard Radiation Therapy in Localized Carcinoma of Prostate: An Update

This study updates technical principles and results of 3-dimensional conformal radiation therapy (3D-CRT) in localized carcinoma of the prostate. Between January 1992 and December 1999, 312 patients were treated with 3D-CRT and 135 patients were treated with bilateral arcs standard radiation therapy (SRT) alone for clinical stage T1b-c or T2 histologically confirmed prostate cancer. None of these patients received hormonal therapy. Mean follow-up for patients in the 3D-CRT group was 3.2 years (range, 2-5.9 years) and for SRT patients, 4.7 years (range, 4-7 years). For 3D-CRT, 7 intersecting fields were used (cerrobend blocking or multileaf collimation) to deliver 68-74 Gy to the prostate. Standard radiation therapy consisted of bilateral 120 degree rotational arcs, with portals using 2-cm margins around the prostate to deliver 68-70 Gy to the prostate. The criterion for chemical disease-free survival was a postirradiation prostate-specific antigen (PSA) value following the American Society for Therapeutic Radiology and Oncology guidelines. Symptoms during treatment were quantitated weekly, and late effects were assessed every 4-6 months. Dose-volume histograms showed a two-thirds reduction with 3D-CRT in normal bladder or rectum receiving > or = 70 Gy with 3D-CRT. Higher 5-year chemical disease-free survival was observed with 3D-CRT (75%; for T1b-c and 79%; for T2 tumors) compared with SRT (61% and 65%, P = 0.01 and P = 0.12, respectively). There was no statistically significant difference in chemical disease-free survival in patients with Gleason score of < or = 4 (P = 0.85), but, with Gleason score of 5-7, the 5-year survival rates were 83% with 3D-CRT and 59% with SRT (P < or = 0.01). In 245 patients with pretreatment PSA of < or = 10 ng/mL treated with 3D-CRT, the chemical disease-free rate was 80% versus 72% in 98 patients treated with SRT (P = 0.21). In patients with PSA of 10.1-20 ng/mL, the chemical disease-free survival rate for 50 patients treated with 3D-CRT was 71% compared with 43% for 20 patients treated with SRT (P = 0.02). The corresponding values were 59% and 16%, respectively, for patients with PSA levels > 20 ng/mL (P = 0.09). On multivariate analysis, the most important prognostic factors for chemical failure were pretreatment PSA (P = 0.004), nadir PSA (P = 0.001), and 3D-CRT technique (P = 0.012). Moderate dysuria was reported by 2%-5% of patients treated with 3D-CRT in contrast to 6%-9% of patients treated with SRT. The incidence of moderate loose stools or diarrhea, usually after the fourth week of treatment, was 3%-5% in the 3D-CRT patients and 8%-19% in the SRT group. Late intestinal grade 2 morbidity (proctitis or rectal bleeding) was 1% in the 3D-CRT group in contrast to 7% in SRT patients. The 3D-CRT spares more normal tissues, yields higher chemical disease-free survival, and results in less treatment morbidity than SRT in treatment of stage T1-T2 prostate cancer. Follow-up at > or = 10 years is needed to confirm these observations.

Interstitial hyperthermia using self-regulating thermoseeds combined with conformal radiation therapy

OBJECTIVE

The combination of hyperthermia and radiation in the treatment of malignancies is based on a variety of experimental data which have proven the synergistic effects of these two treatment modalities. We planned a phase II trial in a special hyperthermia research group (SFB 273) of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) to determine feasibility, acute toxicity and efficacy of this combination for prostate cancer.

METHODS

A total of 57 patients with localized prostate cancer were treated with interstitial hyperthermia using cobalt-palladium thermoseeds and conformal radiation between July 1997 and December 2000. Thermoseeds were placed into the prostate homogeneously. Hyperthermia was created using a magnetic field and was delivered in six sessions once weekly. 3D-conformal radiotherapy of 68.4Gy was given simultaneously in daily fractions of 1.8Gy.

RESULTS

Intra-prostatic temperatures were between 42 and 46 degrees C. No major side effects were observed during hyperthermia. Median follow-up was 12 months (range: 3-26 months). Median prostate specific antigen (PSA) value decreased from 11.6 to 2.4 ng/ml 3 months after treatment, to 1.3ng/ml 12 months after treatment and to 0.55 ng/ml 2 years after the therapy.

CONCLUSION

Interstitial hyperthermia is feasible, well tolerated and led to a steep decrease of PSA values. Our current follow-up is too short to comment about efficacy. Combining effective interstitial hyperthermia with conformal radiotherapy may be an exciting innovative treatment option for prostate cancer.

[Clinical and biological surveillance after radiotherapy for localized prostate cancer]

Serum PSA is an excellent marker of disease status after external beam radiotherapy or brachytherapy for patients with prostate carcinoma. A low PSA nadir < or = 1 even < or = 0.5 ng/mL has been shown to be as a surrogate end point for disease control. Three successive increases of this marker after achieving the nadir defines recurrence as recommended by the American Society for Therapeutic Radiology and Oncology. The biochemical relapse or PSA failure after treatment precedes clinical disease relapse by several months. PSA profile or kinetics may have implications for patterns of failure and prognosis. Prostate post-radiotherapy biopsies should not be part of routine follow-up as its interpretation is frequently problematic. Other exams should not be performed unless clinical symptoms are present. Post-radiotherapy relapse treatment has generally no curative intent.

Practice patterns for prostate cancer in nine central and northern Italy radiation oncology centers: a survey including 1759 patients treated during two decades (1980-1998)

PURPOSE

Prostate cancer patients in Italy are offered the choice of the full spectrum of possible treatment options for their disease, but the diffusion of the more recent technological refinements among the Radiation Oncology centers is not homogeneous and there is a need to establish a reference "historical" data source. This retrospective study describes the changing patterns in prostate cancer patient practice and the therapeutic results obtained in nine Radiation Oncology centers of Northern and Central Italy (five in Northern Italy and four in Central Italy).

METHODS AND MATERIALS

A total of 1759 prostate cancer patients, radically treated in the nine radiotherapy (RT) centers between 1980 and 1998, made up the study population. Data collected for each patient included clinical, pathologic, therapeutic features, and toxicity. The overall survival, disease-specific survival (DSS), and clinical relapse-free survival (RFS) were calculated for the whole series and for the subsets of patients defined by different clinical, pathologic, and therapeutic features, according to three accrual periods (A, 1980-1990; B, 1991-1994; and C, 1995-1998). Univariate and multivariate analyses were performed to identify prognostic factors related to survival and late adverse effects (cystitis and proctitis) probability.

RESULTS

Patient accrual increased markedly during the 2 decades considered, and the percentage of cases with Stage C or D disease dropped from 49% (period A) to 43% (period B) to 37% (period C) (p < 0.0001, chi-square). The baseline prostate-specific antigen value was available for 10%, 76%, and 95% of the cases treated in the three different periods. The major changes in the therapeutic options were an increase in dose to the prostate (>66 Gy in 44%, 84%, and 93% of the patients treated in period A, B, and C, respectively); a reduction in treated volumes, including pelvic lymphatic drainage (56-39% before 1995, 22% thereafter); and an increase in cases treated in association with hormonal therapy (50% before 1991, 80% thereafter). Lower energy (<10 MV) photon beams were progressively abandoned (12% before 1990 vs. 6-7% thereafter), along with an increase in the use of blocks (60% in the last 4 years of the study vs. about 30-40% before 1995) and "conformal" RT (applied in 41% of cases treated after 1994). The actuarial RFS, DSS, and overall survival rate at 5 years was, respectively, 60% +/- 2%, 75% +/- 2%, 66% +/- 2% for period A; 74% +/- 2%, 90% +/- 1%, 83% +/- 2%, for period B; and 67% +/- 5%, 90% +/- 2%, 79% +/- 5% for period C. The actuarial overall survival, DSS, and RFS rate for the whole series of 1759 patients was 77% +/- 1%, 86% +/- 1%, and 68% +/- 1% at 5 years, respectively. Multivariate analysis showed that only American Urologic Association stage, grade, dose to the prostate, accrual period, association with hormonal treatment after (or both after and before) RT (only in terms of DSS and RFS), and baseline prostate-specific antigen value (only for RFS) retained prognostic significance in the final Cox model.

CONCLUSION

The increase in the accrual of prostate cancer patients radically treated with RT has been accompanied by considerable changes in the clinical features at presentation, as well as in the staging and treatment procedures. Patients treated more recently had better survival results. An earlier stage and more favorable grade were linked with better overall, DSS, and RFS at multivariate analysis. Lower prostate-specific antigen baseline values were also related to better RFS. Better results were obtained with higher radiation doses, and the dose to tumor seemed the most important treatment-related prognostic factor. The toxicity (cystitis and proctitis, every Radiation Therapy Oncology Group grade) was substantially the same in the different accrual periods, but larger treated volumes and higher doses appeared to increase the incidence of late effects.

Predicting prostate specific antigen outcome preoperatively in the prostate specific antigen era

PURPOSE

We evaluated the ability of previously defined risk groups to predict prostate specific antigen (PSA) outcome 10 years after radical prostatectomy in patients diagnosed with clinically localized prostate cancer during the PSA era.

MATERIALS AND METHODS

Between 1989 and 2000, 2,127 men with clinically localized prostate cancer underwent radical prostatectomy, including 1,027 at Hospital of the University of Pennsylvania (study cohort) and 1,100 at Brigham and Women's Hospital (validation cohort). Cox regression analysis was done to calculate the relative risk of PSA failure with the 95% confidence interval (CI) in patients at intermediate and high versus low risk. The Kaplan-Meier actuarial method was used to estimate PSA outcome 10 years after radical prostatectomy.

RESULTS

Compared with low risk patients (stages T1c to 2a disease, PSA 10 ng./ml. or less and Gleason score 6 or less) the relative risk of PSA failure in those at intermediate (stage T2b disease or PSA greater than 10 to 20 ng./ml. or less, or Gleason score 7) and high (stage T2c disease, or PSA greater than 20 ng./ml. or Gleason score 8 or greater) risk was 3.8 (95% CI 2.6 to 5.7) and 9.6 (95% CI 6.6 to 13.9) in the study cohort, and 3.3 (95% CI 2.3 to 4.8) and 6.3 (95% CI 4.3 to 9.4) in the validation cohort. The 10-year PSA failure-free survival rate in the 1,020 patients in the low, 693 in the intermediate and 414 in the high risk groups was 83%, 46% and 29%, respectively (p <0.0001).

CONCLUSIONS

Based on 10-year actuarial estimates of PSA outcome after radical prostatectomy 3 groups of patients were identified using preoperative PSA, biopsy Gleason score and 1992 clinical T category.

Retrospective stratification of a consecutive cohort of prostate cancer patients treated with a combined regimen of external-beam radiotherapy and brachytherapy

PURPOSE

The evaluation of clinical variables that influence biochemical relapse-free survival in a cohort of patients treated by combined radiotherapy over a fixed interval.

METHODS AND MATERIALS

Three hundred forty-eight patients diagnosed with clinical Stage T1--T3a prostate cancer were treated with a course of (103)Pd or (125)I brachytherapy followed by a limited course of external beam radiation formed the basis for study. All censored patients had a minimum 2-year follow-up. Biochemical relapse-free survival (BRFS) was estimated using a modified American Society for Therapeutic Radiology and Oncology consensus definition. Discrete "risk groups" were developed based on BRFS as influenced by pretreatment parameters.

RESULTS

Significant risk factors contributing to biochemical failure were serum prostate-specific antigen (PSA) greater than 20 ng/mL, Gleason sum of 7 or greater, or clinical stage T2c or greater. Five-year biochemical control for those exhibiting no risk factor was 88%; one risk factor, 75%; two or more risk factors, 51%. The differences in BRFS among all three risk groups were statistically significant. Outcomes for patients presenting with PSA 10 to 20 ng/mL, but otherwise low-risk disease, fared no differently from those low risk patients presenting with PSA less than 10 ng/mL.

CONCLUSIONS

Combined radiotherapy with (103)Pd or (125)I followed by external beam radiotherapy achieves a high rate of biochemical and clinical control in patients with low- to intermediate-risk clinically organ confined disease.

Chemical disease-free survival in localized carcinoma of prostate treated with external beam irradiation: comparison of American Society of Therapeutic Radiology and Oncology Consensus or 1 ng/mL as endpoint

PURPOSE

To compare postirradiation biochemical disease-free survival using the American Society of Therapeutic Radiology and Oncology (ASTRO) Consensus or elevation of postirradiation prostate-specific antigen (PSA) level beyond 1 ng/mL as an endpoint and correlate chemical failure with subsequent appearance of clinically detected local recurrence or distant metastasis.

METHODS AND MATERIALS

Records of 466 patients with histologically confirmed adenocarcinoma of the prostate treated with irradiation alone between January 1987 and December 1995 were analyzed; 339 patients were treated with bilateral 120 degrees arc rotation and, starting in 1992, 117 with three-dimensional conformal irradiation. Doses were 68--77 Gy in 1.8 to 2 Gy daily fractions. Minimum follow-up is 4 years (mean, 5.5 years; maximum, 9.6 years). A chemical failure was recorded using the ASTRO Consensus or when postirradiation PSA level exceeded 1 ng/mL at any time. Clinical failures were determined by rectal examination, radiographic studies, and, when clinically indicated, biopsy.

RESULTS

Six-year chemical disease-free survival rates using the ASTRO Consensus according to pretreatment PSA level for T1 tumors were: < or = 4 ng/mL, 100%; 4.1--20 ng/mL, 80%; and > 20 ng/mL, 50%. For T2 tumors the rates were: < or = 4 ng/mL, 91%; 4.1--10 ng/mL, 81%; 10.1--20 ng/mL, 55%; 20.1--40 ng/mL, 63%; and > 40 ng/mL, 46%. When postirradiation PSA levels higher than 1 ng/mL were used, the corresponding 6-year chemical disease-free survival rates for T1 tumors were 92% for pretreatment PSA levels of < or = 4 ng/mL, 58--60% for levels of 4.1--20 ng/mL, and 30% for levels > 20 ng/mL. For T2 tumors, the 6-year chemical disease-free survival rates were 78% in patients with pretreatment PSA levels of 4--10 ng/mL, 45% for 10.1--40 ng/mL, and 25% for > 40 ng/mL. Of 167 patients with T1 tumors, 30 (18%) developed a chemical failure, 97% within 5 years from completion of radiation therapy; no patient has developed a local recurrence or distant metastasis. In patients with T2 tumors, overall 45 of 236 (19%) had chemical failure, 94% within 5 years of completion of radiation therapy; 4% have developed a local recurrence, and 10%, distant metastasis. In patients with T3 tumors, overall, 24 of 65 (37%) developed a chemical failure, 100% within 3.5 years from completion of radiation therapy; 4% of these patients developed a local recurrence within 2 years, and 12% developed distant metastasis within 4 years of completion of irradiation. The average time to clinical appearance of local recurrence or distant metastasis after a chemical failure was detected was 5 years and 3 years, respectively.

CONCLUSION

There was a close correlation between the postirradiation nadir PSA and subsequent development of a chemical failure. Except for patients with T1 tumors and pretreatment PSA of 4.1--20 ng/mL, there is good agreement in 6-year chemical disease-free survival using the ASTRO Consensus or PSA elevations above 1 ng/mL as an endpoint. Although the ASTRO Consensus tends to give a higher percentage of chemical disease-free survival in most groups, the differences with longer follow-up are not statistically significant (p > 0.05). It is important to follow these patients for at least 10 years to better assess the significance of and the relationship between chemical and clinical failures.

The clinical utility of the percent of positive prostate biopsies in predicting biochemical outcome following external-beam radiation therapy for patients with clinically localized prostate cancer

PURPOSE

An investigation was performed of the clinical utility of the percent of positive prostate biopsies in predicting prostate-specific antigen (PSA) outcome following external-beam radiation therapy (RT) for men with PSA-detected or clinically palpable prostate cancer.

METHODS AND MATERIALS

A Cox regression multivariable analysis was used to determine whether the percent of positive prostate biopsies provided clinically relevant information about PSA outcome following external beam RT in 473 men while accounting for the previously established risk groups based on the pretreatment PSA level, biopsy Gleason score, and the 1992 American Joint Commission on Cancer (AJCC) clinical T stage.

RESULTS

Controlling for the known prognostic factors, the percent of positive prostate biopsies added clinically significant information (p = 0.02) regarding time to PSA failure following RT. Specifically, 76% of the patients in the intermediate risk group (1992 AJCC T(2b) or biopsy Gleason 7 or PSA > 10 ng/mL and < or = 20 ng/mL) could be classified into either an 30% or 85% 5-year PSA control cohort using the preoperative prostate biopsy data.

CONCLUSION

The previously validated stratification of PSA outcome following radical prostatectomy (RP) using the percent of positive prostate biopsies in intermediate-risk patients is also clinically significant for men treated with external beam RT. The percent positive prostate biopsies should be considered in conjunction with the PSA level, biopsy Gleason score, and 1992 AJCC clinical T stage when counseling patients with newly diagnosed and clinically localized prostate cancer about PSA outcome following RP or external beam RT.

Simultaneous irradiation for prostate cancer: intermediate results with modern techniques

PURPOSE

In this study of men with early stage prostate cancer we evaluated treatment outcome after modern simultaneous irradiation, comprising transperineal implantation followed by external beam radiation. Disease-free survival rates were calculated according to an undetectable prostate specific antigen (PSA) nadir.

MATERIALS AND METHODS

From 1992 to 1996, 689 men with clinical stage T1-T2, N0, Nx prostate cancer were treated with ultrasound guided transperineal 125iodine seed implantation followed 3 weeks later by external beam radiation. Disease-free status was defined as the achievement and maintenance of a PSA nadir of 0.2 ng./ml. or less. Median followup was 4 years (range 3 to 7). None of these men received neoadjuvant or adjuvant hormonal therapy.

RESULTS

Overall 5-year disease-free survival was 88%. The 5-year rate according to PSA 4.0 ng./ml. or less, 4.1 to 10.0, 10.1 to 20.0 and greater than 20.0 was 94%, 93%, 75% and 69%, respectively. Multivariate analysis revealed that pretreatment PSA was the strongest indicator of subsequent disease-free status in regard to Gleason score or clinical stage.

CONCLUSIONS

Intermediate treatment outcome analysis of modern simultaneous radiation supports the principles of radiation dose intensification for intracapsular disease plus the treatment of potential microscopic capsular penetration.

Is there a subset of patients with PSA > or = 20 ng/ml who do well after conformal beam radiotherapy?

To determine if there is a subgroup of patients with pretreatment PSA > or = 20 ng/ml with a favorable outcome after external beam radiation therapy. We analyzed retrospectively treatment outcomes of 129 patients with pretreatment PSA > or = 20 ng/ml treated in our department from 2/88-8/94. Median patient age was 70 years (range 51-89 years). Tumor stage was T1/T2ab in 68, T2c/T3 in 61 patients. Initial Gleason grade was < 7 in 82 and > or = 7 in 47 patients. Median PSA was 35 ng/ml (mean 45 ng/ml, range 20-191 ng/ml). Ninety-seven patients received four-field conformal external beam radiation therapy. No patient received surgery or hormonal therapy prior to treatment. Median central axis dose was 73 Gy (range 68-79 Gy). Covariates considered in univariate and multivariate analyses included central axis dose, pretreatment PSA, presence of perineural invasion, Gleason score, palpable tumor stage and patient age. bNED failure was defined as a PSA > or = 1.5 and rising on two consecutive determinations. Median follow up was 50 months (range 3-100 months). Overall bNED control for the entire patient population was 22% at five years. Of the covariates analyzed, dose (P < 0.01), stage (P < 0.01), Gleason Score (P < 0.01), and the presence of PNI (P = 0.01) were significant on multivariate analysis. Based on these results, patients could be stratified into two distinct groups. Group I consisted of 19 patients with favorable features including T1/T2ab disease, Gleason Score 2-6, no perineural invasion treated to a dose > 73 Gy to the central axis. Patients in Group II had at least one of the above poor prognostic features or were treated to central axis doses < 73 Gy. The bNED control was significantly higher for patients in Group I than those in Group II (58% vs. 23%, P = 0.0027). There appears to be a favorable subgroup of patients with PSA > or = 20 ng/ml where treating to doses over 73 Gy to the central axis is warranted (four-year bNED rate of 58%). However, because of the small patient numbers, these results will need to be validated with longer follow up.

Three-dimensional conformal therapy or standard irradiation in localized carcinoma of prostate: preliminary results of a nonrandomized comparison

PURPOSE

We present preliminary results of a nonrandomized comparison of three-dimensional conformal radiation therapy (3D CRT) and standard radiation therapy (SRT) in localized carcinoma of the prostate in two groups of patients with comparable prognostic factors treated during the same period.

METHODS AND MATERIALS

Between January 1992 and December 1997, 146 patients were treated with 3D CRT and 131 with SRT alone for clinical stage T1c or T2 histologically confirmed carcinoma of the prostate. None of these patients received hormonal therapy. Mean follow-up for all patients is 3 years (range, 1-6 years). For 3D CRT, 7 intersecting fields were used (Cerrobend blocking or multileaf collimation) to deliver 68-73.8 Gy to the prostate; 3D dose distributions and dose-volume histograms (DVHs) of the planning target volume, bladder, and rectum were obtained. SRT consisted of bilateral 120 degrees rotational arcs, with portals with 2-cm margins around the prostate to deliver 68-70 Gy to the prostate. The criterion for chemical disease-free survival was a postirradiation prostate-specific antigen (PSA) (Tandem-R, Hybritech) value following the American Society for Therapeutic Radiology and Oncology guidelines. Symptoms during treatment were quantitated weekly, and late effects were assessed every 4-6 months.

RESULTS

DVHs showed a two-thirds reduction in normal bladder or rectum receiving 70 Gy or more with 3D CRT. Higher 5-year chemical disease-free survival was observed with 3D CRT (91% for T1c and 96% for T2 tumors) compared with SRT (53% and 58%, respectively). There was no statistically significant difference in chemical disease-free survival in patients with Gleason score of 4 or less (p = 0.83), but with Gleason score of 5-7, the 5-year survival rates were 96% with 3D CRT and 53% with SRT (p < or = 0.01). In 111 patients with pretreatment PSA of 10 ng/mL or less, treated with 3D CRT, the chemical disease-free rate was 96% vs. 65% in 94 patients treated with SRT (p < or = 0.01). In patients with PSA of 10. 1-20 ng/mL, the chemical disease-free survival rate for 26 patients treated with 3D CRT was 88% compared with 40% for 20 patients treated with SRT (p = 0.05). The corresponding values were 71% and 26%, respectively, for patients with PSA levels of greater than 20 ng/mL (p = 0.30). On multivariate analysis, the most important prognostic factors for chemical failure were pretreatment PSA (p = 0. 023), nadir PSA (p = 0.001), and 3D CRT technique (p = 0.033). Moderate dysuria and difficulty in urinating were reported by 2-5% of patients treated with 3D CRT in contrast to 6-9% of patients treated with SRT; moderate urinary frequency and nocturia were reported by 18-24% treated with 3D CRT and 18-27% of patients in the SRT group. The incidence of moderate loose stools/diarrhea, usually after the 4th week of treatment, was 3-5% in the 3D CRT patients and 8-19% in the SRT group. Late intestinal morbidity (proctitis, rectal bleeding) was very low (1.7%) in the 3D CRT group in contrast to the SRT patients (8%).

CONCLUSION

Three-dimensional CRT spares more normal tissues, yields higher chemical disease-free survival, and results in less treatment morbidity than SRT in treatment of Stage T1-T2 prostate cancer. Longer follow-up is needed to confirm these preliminary observations.

Minimally invasive treatment for localized adenocarcinoma of the prostate: review of 1048 patients treated with ultrasound-guided palladium-103 brachytherapy

PURPOSE

To assess the effectiveness of palladium-103 brachytherapy in stage T1 and T2 adenocarcinoma of the prostate.

PATIENTS AND METHODS

The charts of 1048 patients treated between 1991 and 1999 with transperineal realtime ultrasound-guided (103)Pd (Theraseed) implants were reviewed to assess the effects on serum prostate specific antigen (PSA) values and tissue (biopsy). Of the 1048 patients, 780 had sufficient data for this report. Preoperative total androgen blockade (leuprolide and flutamide) was used selectively in patients whose prostate size was >50 cc and those whose tumors had a Gleason score of >7.

RESULTS

At 1 year, 86% of the evaluable 766 patients had stable PSA concentration <1.5 ng/mL; at 5 years, 86% of the 166 patients with data available had stable PSA values <1.5 ng/mL. Biopsies were negative in 92% of the patients studied at 2 years. Patients with pretreatment PSA values <10 ng/mL had the best outcomes, and those treated with (103)Pd plus hormone ablation achieved PSA reduction more rapidly than those treated with radioisotope monotherapy. There was one disease-related death; the principal morbidity was short-term bladder and bowel irritation without permanent sequelae. Impotence occurred in approximately 15% of patients, and incontinence occurred in 5% of those who had undergone prior transurethral resection of the prostate.

CONCLUSION

The technique used in this study proved effective in reducing PSA concentrations to <1.5 ng/mL and in producing negative biopsies 1 and 2 years postoperatively. These results are comparable to those of external-beam radiation therapy and radical prostatectomy while demonstrating a significant reduction in morbidity.

Clinical utility of the percentage of positive prostate biopsies in defining biochemical outcome after radical prostatectomy for patients with clinically localized prostate cancer

PURPOSE

To determine the clinical utility of the percentage of positive prostate biopsies in predicting prostate-specific antigen (PSA) outcome after radical prostatectomy (RP) for men with PSA-detected or clinically palpable prostate cancer.

METHODS

A Cox regression multivariable analysis was used to determine whether the percentage of positive prostate biopsies provided clinically relevant information about PSA outcome after RP in 960 men while accounting for the previously established risk groups that are defined according to pretreatment PSA level, biopsy Gleason score, and the 1992 American Joint Committee on Cancer (AJCC) clinical T stage. The findings were then tested using an independent surgical database that included data for 823 men.

RESULTS

Controlling for the known prognostic factors, the percentage of positive prostate biopsies added clinically significant information (P <.0001) regarding time to PSA failure after RP. Specifically, 80% of the patients in the intermediate-risk group (1992 AJCC T2b, or biopsy Gleason 7 or PSA > 10 ng/mL and </= 20 ng/mL) could be classified into either an 11% or 86% 4-year PSA control cohort using the preoperative prostate biopsy data. These findings were validated in the intermediate-risk patients using an independent surgical data set.

CONCLUSION

The validated stratification of PSA outcome after RP using the percentage of positive prostate biopsies in intermediate-risk patients is clinically significant. This information can be used to identify men with newly diagnosed and clinically localized prostate cancer who are at high risk for early (</= 2 years) PSA failure and, therefore, may benefit from the use of adjuvant therapy.

Clinical predictors of upgrading to Gleason grade 4 or 5 disease at radical prostatectomy: potential implications for patient selection for radiation and androgen suppression therapy

PURPOSE

A survival benefit has been suggested by the Radiation Therapy Oncology Group (RTOG) for the addition of androgen suppression to external beam radiation therapy for patients with locally advanced and high-grade disease. This study was performed to identify clinical factors that predicted high-grade disease at prostatectomy (i.e., Gleason grade 4 or 5) in patients with clinically localized and low-grade disease (i.e., Gleason grades 1-3) at biopsy. These pretreatment factors may allow for the identification of patients likely to derive a survival benefit from the addition of androgen suppression to external beam radiation therapy while awaiting the results of the prospective randomized trials.

METHODS AND MATERIALS

Concordance testing of both the primary and secondary biopsy and prostatectomy Gleason grades was performed in 693 patients with clinical Stage T1c, 2 prostate cancer managed with a radical prostatectomy (RP). For the subset of 420 patients with low-grade disease (i.e., Gleason grade < or =3) a logistic regression multivariable analysis was performed to evaluate the ability of the preoperative prostate-specific antigen (PSA), clinical stage, and ultrasound determined prostate gland volume to predict for upgrading to high-grade disease (i.e., Gleason grade 4 or 5).

RESULTS

Forty percent of men with low-grade disease at biopsy were found to have high-grade disease at RP. Men who have at least a 50% chance of being upgraded from biopsy Gleason grade < or =3 to prostatectomy Gleason grade > or =4 disease included those with prostate gland volumes < or =75 cm3 and a PSA > 20 ng/ml or a PSA >10 and < or =20 and clinical Stage T2b,2c. For men with prostate gland volumes >75 cm3, only those with both PSA > 20 ng/ml and clinical Stage T2b,2c were at a significant risk of upgrading.

CONCLUSION

Until the randomized data become available, clinical factors may be useful in identifying patients with clinically localized prostate cancer who are likely to benefit from combined androgen suppression and external beam radiation therapy.

Assessment of relative tumor burden in patients with clinical T1c prostate cancer treated with either external beam or radical prostatectomy

The choice between external beam radiation therapy (EBRT) or retropubic radical prostatectomy (RPX) as potentially curative treatment for localized carcinoma of the prostate gland (CaP) has not been delineated in randomized studies. Both treatments are more effective if tumor burden is low. We sought to compare these two treatments in patients who had clinical stage T1c (cT1c) lesions and who were thought to have limited tumor burdens pretreatment. Sixty cT1c patients referred to the Department of Radiation Oncology received 66 Gy in 33 sessions of EBRT to localized prostate ports and 59 cT1c patients had RPX. No neoadjuvant nor early adjuvant therapies were prescribed. Radiotherapy success was defined biochemically as a nonrising prostate-specific antigen (PSA) of +/- 1.5 ng/ml. RPX success required a postoperative PSA that was undetectable (PSA <0.2 ng/ml by the Hybritech or Abbott IMx technics). Analysis for nonrising posttreatment PSA levels was performed using Kaplan-Meier and Cox regression methods. Mantel-Haenszel methods were used to determine odds ratios for treatment groups adjusting for potential confounders. We ultimately assessed the relative tumor burden by histologic examination of the RPX specimens. The two treatment groups, although not randomized, were statistically similar in biopsy Gleason Scores, transrectal ultrasonography calculated gland volumes, number of positive biopsy cores, and estimated amount of cancer identified on initial biopsies. Pathologic stage T3 was identified in 25% of RPX patients. Fifty to 60% of RPX specimens histologically had substantial tumor burden and by inference also the EBRT patients. At a median follow-up (F/U) of 36 months, 76% of RPX patients maintained an undetectable PSA, whereas 62% of EBRT patients had a PSA < 1.5 ng/ml at a median F/U of 29 months. The pretreatment PSA values significantly affected EBRT patients' risk of a rising posttreatment PSA level. Twenty-four months after treatment, RPX patients were 3.7 times more likely to maintain a nonrising PSA level (RPX patients posttreatment PSA < 0.2 ng/ml), than EBRT patients (posttreatment PSA < or = 1.5 ng/ml) (p = 0.006). Sixty-six gray in 33 sessions to localized EBRT ports is not sufficiently aggressive therapy for one third or more of patients with cT1c CaP. RPX alone is insufficient therapy for one fourth of cT1c patients. Analysis of the RPX specimens showed that many cT1c tumors have a significant tumor burden. Selection methodologies to separate out patients who require more than conventional dose or type of radiotherapy or more than RPX as monotherapy are needed. Pretreatment PSA and number of positive biopsies may assist this selection process.

Prostate brachytherapy: treatment strategies

PURPOSE

Patients who present with localized and locally advanced prostate cancer may be candidates for prostate brachytherapy. We evaluated the treatment outcomes in a diverse group of prostate cancer patients who presented with low, moderate and high risk features.

MATERIALS AND METHODS

A total of 301 patients who presented with T1 to T3 prostate cancer were treated with brachytherapy alone or combined with hormonal therapy and/or external beam irradiation. Of these patients 109 at low risk with prostate specific antigen (PSA) 10 ng./ml. or less, Gleason score 6 or less and clinical stage T2a or less were treated with 125iodine alone, 152 at moderate risk with PSA greater than 10 ng./ml., Gleason score greater than 6 or stage T2b or greater were treated with 125iodine or 103palladium or combined implant alone with 5 months of hormonal therapy, and 40 at high risk with PSA greater than 15 ng./ml., Gleason 8 or greater, clinical stage T2c to T3 or positive seminal vesicle biopsy (20) were treated with combination brachytherapy, external beam irradiation and 9 months of hormonal therapy. Patients with a positive seminal vesicle biopsy (T3c disease) and negative pelvic lymph nodes were included in the high risk group, and the walls of the seminal vesicles were also treated with implantation. Followup was performed every 6 months with digital rectal examination and ultrasound evaluation. Prostate biopsy was routinely recommended 2 years after completion of the radiation. Failure was defined as PSA increase on 2 consecutive determinations above 1 ng./ml. or evidence of local recurrence on digital rectal examination, transrectal ultrasound or biopsy. Kaplan-Meier projections were used to calculate progression-free survival rates.

RESULTS

Of the 109 patients at low risk followed from 1 to 7 years (median 18 months) 91% were free of PSA failure at 4 years. No patient experienced urinary incontinence following implantation, although grade 1 to 2 radiation proctitis occurred in 5 (4.5%). Of the 152 patients at moderate risk 73 received implantation and 79 received implantation combined with hormonal therapy. The 4-year biochemical freedom from failure rate for the hormone group was 85% versus 58% for the no hormone group (p = 0.08). The difference was more significant for those with Gleason score 7 or greater (90 versus 43%, p = 0.01) and for those with PSA greater than 10 ng./ml. (87 versus 59%, p = 0.04). Grade 1 to 2 radiation proctitis occurred in 1 of the 79 patients (1.3%) receiving hormonal therapy and in 3 (4%) treated with implantation only. There were no cases of urinary incontinence. Of the 40 patients at high risk 71% were free of biochemical failure at 3 years. Of the 4 patients with failure (10%) 3 (75%) originally had positive seminal vesicle biopsies. Five patients experienced gastrointestinal complications, although none was grade 3 or 4. The actuarial freedom from grade 2 proctitis was 82%. No patient experienced urinary incontinence. Prostate biopsies were negative in 87% of the low risk, 96.8 (hormone group) versus 68.6% (no hormone group) of the moderate risk (p = 0.0023) and 86% of the high risk patients.

CONCLUSIONS

Brachytherapy appears to offer comparable results to external beam irradiation and radical prostatectomy when patients are stratified by disease extent. Adopting a strategy of implant alone, implant with hormonal therapy or implant with hormonal therapy and external beam irradiation in patients who present with low to high risk features can improve the overall results in the more advanced cases.

Recent advances in the treatment of prostate cancer

As new evidence for prostate cancer treatment has emerged in the last few years, longstanding controversies in the treatment of prostate cancer have resurfaced. A number of long-held tenets of prostate cancer therapy have been revisited, sometimes with surprising and challenging results. Although neoadjuvant hormonal therapy prior to radical prostatectomy decreases positive surgical margin rates, longer follow-up is needed to support survival improvement of this combined modality therapy. Androgen deprivation combined with radiation therapy appears to improve disease-free survival (and survival in one series) in patients with locally advanced cancer. Another approach to locally advanced prostate cancer using three-dimensional conformal radiation therapy may improve long term outcome. The data are currently insufficient to conclude that interstitial low dose rate brachytherapy is equivalent to conventional treatments: patients with small tumor volumes and low Gleason grade seem to obtain more benefit, whereas for large tumors with higher gleason grades this approach seems inferior to conventional treatments. In advanced prostate cancer recent data suggest that immediate hormonal therapy improves survival. In this group of patients the use of maximum androgen blockade remains controversial but may adversely affect quality of life compared to orchiectomy alone. Intermittent hormonal therapy may improve quality of life, although effect upon survival is unknown. Chemotherapy in combination with androgen deprivation is currently being studied as front-line therapy in advanced prostate cancer. Palliative benefit of chemotherapy for hormone refractory prostate cancer remains an important endpoint; survival advantage has not been seen in any randomized trials. Suramin may delay disease progression in hormone refractory prostate cancer. Many aspects of prostate cancer treatment will remain controversial until results of large, randomized trials with longer follow-up are available.

Permanent radioactive seed implantation in the treatment of prostate cancer

Prostate brachytherapy has come a long way in the last 15 years, from an open free-hand technique with which seed placement was often inaccurate to the highly technical and accurate procedure of today. It has become a viable treatment option for low-risk patients along with EBRT and prostatectomy. Its most promising use may be in combination with hormonal therapy and EBRT in moderate- to high-risk patients, for whom it may offer improved outcomes over standard single-modality therapies.

Conformal proton beam therapy of prostate cancer--update on the Loma Linda University medical center experience

BACKGROUND

The ability to eradicate localized prostate cancer is dependent upon the radiation dose which can be delivered to the prostate. This dose is often limited by the tolerance of normal organs (rectum, bladder). Conformal beam therapy takes advantage of the unique depth dose characteristics of heavy charged particles (the Bragg Peak) to escalate the radiation dose delivered to the prostate while minimizing treatment-related toxicity.

METHOD

643 patients with localized prostate cancer were treated with protons alone or a combination of protons and photons. All treatment was planned on a 3-D planning system and all received doses between 74-75 CGE (Cobalt Gray Equivalent) at 1.8-2.0 CGE/day. Patients were evaluated for toxicity and response to treatment.

RESULTS

Five-year actuarial clinical and biochemical disease-free survival rates for the entire group are 89 and 79% respectively. A statistically significant difference in biochemical disease-free survival was seen between patients in the "early" (T1b-2b, PSA < 15) and "advanced" (T1b-2b, PSA > 15 or T2c-T4, PSA < 50) subgroups (89% vs. 68% at 4.5 years, p < 0.001). A PSA nadir of less than 0.51 ng/ml predicted for the highest chance of freedom from biochemical recurrence. Minimal radiation proctitis was seen in 21% of patients; toxicity of greater severity was seen in less than 1%.

CONCLUSIONS

Conformal proton beams therapy produced high rates of response and minimal toxicity. A phase III dose escalation trial is in progress to help define the optimum radiation dose for the treatment of early stage prostate cancer.

Conformal proton therapy for early-stage prostate cancer

OBJECTIVES

To assess the effect of proton radiation on clinical and biochemical outcomes for early prostate cancer.

METHODS

Three hundred nineteen patients with T1-T2b prostate cancer and initial prostate-specific antigen (PSA) levels 15.0 ng/mL or less received conformal radiation doses of 74 to 75 cobalt gray equivalent with protons alone or combined with photons. No patient had pre- or post-treatment hormonal therapy until disease progression was documented. Patients were evaluated for biochemical disease-free survival, PSA nadir, and toxicity; the mean and median follow-up period was 43 months.

RESULTS

Overall 5-year clinical and biochemical disease-free survival rates were 97% and 88%, respectively. Initial PSA level, stage, and post-treatment PSA nadir were independent prognostic variables for biochemical disease-free survival: a PSA nadir 0.5 ng/mL or less was associated with a 5-year biochemical disease-free survival rate of 98%, versus 88% and 42% for nadirs 0.51 to 1.0 and greater than 1.0 ng/mL, respectively. No severe treatment-related morbidity was seen.

CONCLUSIONS

It appears that patients treated with conformal protons have 5-year biochemical disease-free survival rates comparable to those who undergo radical prostatectomy, and display no significant toxicity. A Phase III randomized dose-escalation trial is underway to define the optimum radiation dose for early-stage prostate cancer.

Fractionated radiotherapy of rat prostatic adenocarcinoma (Dunning R3327-PAP) in nonanesthetized animals

BACKGROUND

The dose-response effect of fractionated external beam radiotherapy on nonanesthetized rats bearing the androgen-sensitive prostatic adenocarcinoma Dunning R3327-PAP was studied.

METHODS

The radiation was given with a photon beam from a 4-MeV linear accelerator in doses from 4 to 11 Gray per fraction during 5 consecutive days. When the tumors with low and intermediate radiation doses relapsed into regrowth, the rats were castrated. Tumor volumes and rat weights were followed, and at the end of the study a morphometric analysis of the tumors was done.

RESULTS

Fractionated irradiation induced a dose-dependent delay in tumor growth in hormonally intact rats. Castration stopped the tumor regrowth, showing that some of the tumor cells were still hormone-sensitive. The study was facilitated by the nonanesthesia procedure.

CONCLUSIONS

The Dunning R3327-PAP hormone-sensitive rat tumor is sensitive to radiotherapy in a dose-dependent way. Regrowing, irradiated tumors contain hormone-sensitive cells. This work provided basic knowledge for further experimental studies of the effects of radiation on prostatic adenocarcinoma.

Defining the implant treatment volume for patients with low risk prostate cancer: does the anterior base need to be treated?

PURPOSE

An increased incidence of acute urinary retention has been reported after interstitial prostate radiation therapy when the anterior base of the prostate gland receives 100% of the prescription dose. The frequency of prostate cancer in this location as a function of the pre-treatment prostate specific antigen (PSA), biopsy Gleason score, and 1992 American Joint Commission on Cancer Staging (AJCC) was determined.

METHODS AND MATERIALS

One hundred four men treated at the Brigham and Women's Hospital with radical prostatectomy for clinically localized prostate cancer between 1995-1996 comprised the study population. Prostatectomy specimens were whole mounted and the location of each tumor foci enumerated.

RESULTS

Of 269 foci of prostate cancer found in 39 low-risk prostate cancer patients (PSA < 10 ng/ml, biopsy Gleason score < or = 6, and 1992 AJCC clinical stage T1c,2a), a single focus (0.37%) was noted in the anterior base. Conversely, 20/355 (5.6%) and 18/251 (7.2%) tumor foci were noted in the anterior base in 43 patients with intermediate risk and 24 patients with high-risk disease, respectively.

CONCLUSIONS

A new definition of the treatment volume excluding the anterior base for low-risk prostate cancer patients may be justified.

Pretreatment nomogram for prostate-specific antigen recurrence after radical prostatectomy or external-beam radiation therapy for clinically localized prostate cancer

PURPOSE

To present nomograms providing estimates of prostate-specific antigen (PSA) failure-free survival after radical prostatectomy (RP) or external-beam radiation therapy (RT) for men diagnosed during the PSA era with clinically localized disease.

PATIENTS AND METHODS

A Cox regression multivariable analysis was used to determine the prognostic significance of the pretreatment PSA level, 1992 American Joint Committee on Cancer (AJCC) clinical stage, and biopsy Gleason score in predicting the time to posttherapy PSA failure in 1,654 men with T1c,2 prostate cancer managed with either RP or RT.

RESULTS

Pretherapy PSA, AJCC clinical stage, and biopsy Gleason score were independent predictors (P < .0001) of time to posttherapy PSA failure in patients managed with either RP or RT. Two-year PSA failure rates derived from the Cox regression model and bootstrap estimates of the 95% confidence intervals are presented in the format of a nomogram stratified by the pretreatment PSA, AJCC clinical stage, biopsy Gleason score, and local treatment modality.

CONCLUSION

Men at high risk (> 50%) for early (< or = 2 years) PSA failure could be identified on the basis of the type of local therapy received and the clinical information obtained as part of the routine work-up for localized prostate cancer. Selection of these men for trials evaluating adjuvant systemic and improved local therapies may be justified.

Biochemical response to testicular androgen ablation among patients with prostate cancer for whom flutamide and/or finasteride therapy failed

OBJECTIVES

To evaluate the response of testicular androgen ablation in patients with advanced prostate cancer with a biochemical recurrence after finasteride or combined finasteride and flutamide therapy.

METHODS

Eighteen hormone naïve men with advanced prostate cancer (10 with detectable prostate-specific antigen [PSA] levels after radical prostatectomy, 4 with rising PSA levels after definitive radiation therapy, and 4 with Stage D2 disease) were treated with finasteride (5 mg/day) alone or in combination with flutamide (250 mg three times a day). All men experienced an initial reduction in serum PSA, but later had treatment failure with two consecutive rising PSA measurements. All men were then treated with testicular androgen ablation (bilateral orchiectomy in 15 and luteinizing hormone-releasing hormone analogue in 3).

RESULTS

Overall, serum PSA declined by more than 80% in 15 (83%) of 18 and to undetectable levels in 14 (78%) of 18. With a median+/-semi-interquartile range follow-up of 22+/-14.5 months from the initiation of hormone therapy, 12 (67%) of 18 currently have undetectable PSA levels. Two men having rising serum PSA levels above 100 ng/mL and 1 man has died from complications of metastatic prostate cancer.

CONCLUSIONS

Testicular androgen ablation effectively lowers serum PSA levels in most men with advanced prostate cancer who have experienced a biochemical recurrence despite initial response and subsequent relapse on finasteride or combined finasteride and flutamide therapy.

Analyzing outcome-based staging for clinically localized adenocarcinoma of the prostate

BACKGROUND

A clinical staging system based on the prostate-specific antigen (PSA) and the calculated prostate carcinoma volume (cVCa) construct previously has been proposed. This study was performed to assess whether this proposed clinical staging system was valid in an independent surgical and radiation data set in patients with clinically localized disease.

METHODS

Cox regression multivariable analyses were used to assess the significance of staging systems (1992 American Joint Commission on Cancer Staging [AJCC] clinical and pathologic stage, versus cVCa-PSA clinical stage) to predict time to posttherapy PSA failure in 441 and 465 patients managed by surgery and radiation, respectively. Significant staging systems identified using Cox regression were tested further using established comparative measures to define the most clinically useful system.

RESULTS

Both the 1992 AJCC pathologic stage and the cVCa-PSA clinical stage were significant predictors of time to postoperative PSA failure (P = 0.0001), whereas only the cVCa-PSA clinical stage was a significant predictor of time to postradiation PSA failure (P = 0.0001) using a Cox regression multivariable analysis. Further analyses using a pairwise comparison of the 1992 AJCC pathologic stage and cVCa-PSA clinical stage found the cVCa-PSA staging system provided a more clinically useful prediction of time to postoperative PSA failure. Specifically, the cVCa-PSA staging system was able to identify surgically managed patients with pathologic AJCC T2 disease who did poorly (3-year bNED = 22%) while also selecting patients with clinical AJCC T2b,c disease that was managed by radiation who did well (3-year bNED = 100%).

CONCLUSIONS

A clinical staging system based on parameters obtained during the routine evaluation for AJCC clinical T1,2 prostate carcinoma provided a clinically useful stratification of both postoperative and postradiation PSA failure free survival.

Update on the treatment of prostate cancer with external beam irradiation

BACKGROUND

We review the recent changes in the radiotherapeutic management of clinically localized prostate cancer, including the implementation of three-dimensional (3-D) conformal radiation therapy (3DCRT), biochemical disease-free survival (bNED control) using conventional and 3DCRT techniques, and the morbidity of these treatment strategies.

METHODS

The components of 3DCRT are discussed, including patient immobilization, 3-D treatment planning, multileaf collimation, and electronic portal imaging. bNED control rates from institutions using conventional and 3DCRT techniques are compared. The gastrointestinal (GI) and genitourinary (GU) morbidity from prospective trials using conventional doses of radiation are compared to data from 3DCRT series. bNED control rates stratified by pretreatment prostate-specific antigen (PSA) are compared between surgical and radiation series.

RESULTS

bNED control rates (3-5 years) for patients treated with conventional and 3DCRT techniques ranged from 44-70% and 30-72% with pretreatment PSA levels 4-10 and 10-20, respectively. Although direct comparisons are difficult between treatment modalities, no difference in bNED control stratified by pretreatment PSA was observed between surgical and radiation patients.

CONCLUSIONS

Patients with clinically localized prostate cancer treated with 3DCRT demonstrate durable bNED control at 5 years. Conformal radiation techniques, multileaf collimation, electronic portal imaging, and patient immobilization have reduced acute and chronic GI and GU morbidity while allowing safe dose escalation in an effort to further improve local control and overall survival.

Conformal proton therapy for prostate carcinoma

BACKGROUND

The role and optimum dose of radiation to eradicate prostate cancer continues to be evaluated. Protons offer an opportunity to increase the radiation dose to the prostate while minimizing treatment toxicity.

METHODS

Six hundred forty-three patients with localized prostate cancer were treated with protons, with or without photons. Treatments were planned with a 3D planning system; patients received 74-75 CGE (Cobalt Gray Equivalent) at 1.8-2.0 CGE per fraction. Patients were evaluated for response to therapy and treatment-related toxicity.

RESULTS

The overall clinical disease-free survival rate was 89% at 5 years. When post-treatment prostate-specific antigen (PSA) was used as an endpoint for disease control, the 4.5-year disease-free survival rate was 100% for patients with an initial PSA of < 4.0 ng/ml, and 89%, 72%, and 53% for patients with initial PSA levels of 4.1-10.0, 10.1-20.0, and > 20.0, respectively. Patients in whom the post-treatment PSA nadir was below 0.5 ng/ml did significantly better than those whose nadir values were between 0.51-1.0 or > 1.0 ng/ml: the corresponding 5-year disease-free survival rates were 91%, 79%, and 40%, respectively. Minimal radiation proctitis was seen in 21% of patients; toxicity of greater severity was seen in less than 1%.

CONCLUSION

Proton therapy to 74-75 CGE produced minimal treatment-related toxicity and excellent PSA normalization and disease-free survival in patients with low initial PSA levels. A prospective randomized dose-escalation trial is now underway to help define the optimum dose of radiation for patients with early stage prostate cancer.

Ten-year disease free survival after transperineal sonography-guided iodine-125 brachytherapy with or without 45-gray external beam irradiation in the treatment of patients with clinically localized, low to high Gleason grade prostate carcinoma

BACKGROUND

The authors report observed 10-year brachytherapy results in the treatment of 152 consecutive patients with clinically organ-confined prostate carcinoma.

METHODS

One hundred and fifty-two consecutive patients with T1-T3, low to high Gleason grade, prostate carcinoma were treated between January 1987 and June 1988 at Northwest Hospital in Seattle, Washington. Their median age was 70 years (range, 53-92 years). Of these 152 patients, 98 (64%) received an iodine-125 implant alone (Group 1), and the remaining 54 patients (36%), who were judged to have a higher risk of extraprostatic extension, also were treated with 45 gray (Gy) of external beam irradiation to the pelvis (Group 2). No patient underwent lymph node sampling, and none received androgen ablation therapy. Multivariate regression and the Mann-Whitney rank sum test were used for statistical analysis. Preoperative patient data with associated success or failure outcomes at 10 years after treatment were used for training and validating a back-propagation neural network prediction program.

RESULTS

The average preoperative prostate specific antigen (PSA) value, clinical stage, and Gleason grade were 11.0 ng/mL, T2, and 5, respectively. The median posttreatment follow-up was 119 months (range, 3-134 months). Overall survival 10 years after treatment was 65%. At last follow-up only 3 of the 152 patients (2%) had died of prostate carcinoma. Ninety-seven patients (64%) remained clinically and biochemically free of disease at 10 years of follow-up and had an average PSA value of 0.18 ng/mL (range, 0.01-0.5 ng/mL). In these patients a period of 42 months was required to reach the average PSA (0.5 ng/mL). The median to last PSA follow-up was 95 months (range, 3-134 months). Postoperative needle biopsies were negative in 56% of patients, positive in 15% of patients, and not available in 29% of patients. Only 6% of patients developed bone metastasis. At 10 years there was no statistically significant difference in treatment outcome between patients who received iodine-125 alone, and those who received iodine-125 with 45-Gy external beam irradiation (P = 0.08). Nevertheless, in these two groups preoperative PSA, stage, and Gleason grade were significantly different (P < 0.01). In the artificial neural network analysis, pretreatment serum PSA was the most accurate predictor of disease-free survival.

CONCLUSIONS

Percutaneous prostate brachytherapy is a valid and efficient option for treating patients with clinically organ-confined, low to high Gleason grade, prostate carcinoma. Observed 10-year follow-up documents serum PSA levels superior to those reported in several published external beam irradiation series, and comparable to those published in a number of published radical prostatectomy series.

Perineural invasion and Gleason 7-10 tumors predict increased failure in prostate cancer patients with pretreatment PSA <10 ng/ml treated with conformal external beam radiation therapy

PURPOSE

It has been well established that prostate cancer patients with pretreatment PSA <10 ng/ml enjoy excellent bNED control when treated with definitive external beam radiation therapy. This report identifies predictors of failure for patients with pretreatment PSA <10 ng/ml. These predictors are then used to define favorable and unfavorable prognostic subgroups of patients for which bNED control is compared.

METHODS AND MATERIALS

Between 3/87 and 11/94, 266 patients with T1-T3NXM0 prostate cancer and pretreatment PSA values <10 ng/ml were treated with definitive external beam radiation therapy. Median central axis dose and median follow-up for the entire group was 72 Gy (63-79 Gy) and 48 months (2-120 months). Predictors of bNED control were evaluated univariately using Kaplan-Meier methodology and the log-rank test and multivariately using Cox proportional hazards modeling. Covariates considered were pretreatment PSA, palpation stage, Gleason score, presence of perineual invasion (PNI) and central axis dose. Independent predictors based on multivariate results were then used to stratify the patients into two prognostic groups for which bNED control was compared. bNED failure is defined as PSA > or = 1.5 ng/ml and rising on two consecutive determinations.

RESULTS

Univariate analysis according to pretreatment and treatment factors for bNED control demonstrates a statistically significant improvement in 5-year bNED control for patients with Gleason score 2-6 vs. 7-10, patients without evidence of perineural invasion (PNI) vs. those with PNI, and patients with palpation stage T1/T2AB vs. T2C/T3. Multivariate analysis demonstrates that Gleason score (p = 0.0496), PNI (p = 0.0008) and palpation stage (p = 0.0153) are significant independent predictors of bNED control. Based on these factors, patients are stratified into a more favorable prognosis group (Gleason 2-6, no PNI, and stage T1/T2AB, n = 172) and a less favorable prognosis group (Gleason 7-10 or PNI or T2C/T3, n = 94). A comparison of the two groups reveals that bNED control is significantly lower in the less favorable prognosis group (74% vs. 91% at 5 years, p = 0.0024).

CONCLUSIONS

(1) This report identifies Gleason 7-10 and the presence of PNI as well as palpation stage T2C/T3 as factors that predict worse bNED outcome for patients with pretreatment PSA <10 ng/ml who are treated with radiation therapy alone. (2) Patients with these pretreatment prognostic factors may benefit from adjuvant therapies or altered treatment programs. (3) In order to make fair comparisons between radiation therapy and prostatectomy series, the distribution of perineual invasion and Gleason 7-10 must be taken into account.

Gene therapy for prostate cancer

Prostate cancer remains one of the most significant challenges in clinical oncology, yet present therapies provide incomplete treatment in many cases. Innovative and practical gene therapy-based approaches will prove invaluable in filling the gaps that now exist in the treatment of localized and distant disease. Although multiple potential strategies have been developed, early clinical trials in prostate cancer gene therapy are now in the phase I/II stage of development. Novel preclinical and early clinical data should be considered optimistically, yet cautiously, as this field emerges from its infancy.