The effect of prognostic factors on therapeutic outcome following transperineal prostate brachytherapy

Degarelix monotherapy compared with luteinizing hormone-releasing hormone (LHRH) agonists plus anti-androgen flare protection in advanced prostate cancer: an analysis of two randomized controlled trials

OBJECTIVES

The objective of this study was to assess differences in efficacy outcomes between luteinizing hormone-releasing hormone (LHRH) agonist plus antiandrogen (AA) flare protection and monotherapy with the gonadotrophin-releasing hormone antagonist degarelix in patients with prostate cancer.

METHODS

Data from 1455 patients were pooled from two prospective, phase III randomized 1-year clinical trials of degarelix versus LHRH agonist with or without AA. The AA bicalutamide was administered at the investigator's discretion. Adjusted hazard ratios (HRs) were calculated using a Cox proportional hazards regression model and a conditional logistic regression model was used for a case-control analysis of odds ratios (ORs).

RESULTS

Patients received degarelix monotherapy (n = 972) or LHRH agonist (n = 483) of whom 57 also received AA. Overall, prostate-specific antigen progression-free survival (PSA PFS) was improved with degarelix versus LHRH agonist + AA (Cox proportional hazards regression model-adjusted HR for PSA PFS failure was 0.56 [95% confidence interval (CI) 0.33-0.97, p = 0.038]). To compensate for a higher proportion of patients with metastases, Gleason score 7-10, and PSA >20 ng/ml in the LHRH agonist + AA group, a case-control analysis using a conditional logistic regression model was utilized. This resulted in an OR for PSA PFS of 0.42 (95% CI 0.20-0.89; p = 0.023) in the overall population, and 0.35 (95% CI 0.13-0.96; p = 0.042) in patients with PSA >50 ng/ml at baseline, when treated with degarelix versus LHRH agonists + AA. There were a small number of deaths, 1.9% with degarelix and 7% with LHRH agonists + AA (case-control analysis OR = 0.37; p = 0.085).

CONCLUSIONS

Degarelix monotherapy produced a more favorable effect on PSA PFS outcomes than a LHRH agonist + AA flare protection therapy in patients with prostate cancer when a case-control analysis was used to compensate for differences between treatment groups.

Experience with degarelix in the treatment of prostate cancer

Degarelix is a gonadotrophin-releasing hormone (GnRH) antagonist for the first-line treatment of androgen-dependent advanced prostate cancer. It has a direct mechanism of action that blocks the action of GnRH on the pituitary with no initial surge in gonadotrophin or testosterone levels. Degarelix is the most extensively studied and widely available GnRH antagonist worldwide. Clinical studies have demonstrated similar efficacy to the GnRH agonist leuprolide in achieving testosterone suppression in patients with prostate cancer. However, degarelix produces a faster suppression of testosterone and prostate-specific antigen (PSA), with no testosterone surge or microsurges, thus preventing the risk of clinical flare in advanced disease. Clinical trials have demonstrated that degarelix can offer improved disease control when compared with a GnRH agonist in terms of superior PSA progression-free survival (suggesting that degarelix likely delays progression to castration-resistant disease), and a more significant impact on bone serum alkaline phosphatase and follicle-stimulating hormone. Degarelix is generally well tolerated, with no reports of systemic allergic reactions in any clinical studies. In conclusion, degarelix offers clinicians a rational first-line hormonal monotherapy option for the management of advanced prostate cancer.

Low-dose rate brachytherapy for men with localized prostate cancer

BACKGROUND

Localized prostate cancer is a slow growing tumor for many years for the majority of affected men. Low-dose rate brachytherapy (LDR-BT) is short-distance radiotherapy using low-energy radioactive sources. LDR-BT has been recommended for men with low risk localized prostate cancer.

OBJECTIVES

To assess the benefit and harm of LDR-BT compared to radical prostatectomy (RP), external beam radiotherapy (EBRT), and no primary therapy (NPT) in men with localized prostatic cancer.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 1950), and EMBASE (from 1980) were searched in June 2010 as well as online trials registers and reference lists of reviews.

SELECTION CRITERIA

Randomized, controlled trials comparing LDR-BT versus RP, EBRT, and NPT in men with clinically localized prostate cancer.

DATA COLLECTION AND ANALYSIS

Data on study methods, participants, treatment regimens, observation period and outcomes were recorded by two reviewers independently.

MAIN RESULTS

We identified only one RCT (N = 200; mean follow up 68 months). This trial compared LDR-BT and RP. The risk of bias was deemed high. Primary outcomes (overall survival, cause-specific mortality, or metastatic-free survival) were not reported. Biochemical recurrence-free survival at 5 years follow up was not significantly different between LDR-BT (78/85 (91.8%)) and RP (81/89 (91.0%)); P = 0.875; relative risk 0.92 (95% CI: 0.35 to 2.42).For severe adverse events reported at 6 months follow up, results favored LDR-BT for urinary incontinence (LDR-BT 0/85 (0.0%) versus RP 16/89 (18.0%); P < 0.001; relative risk 0) and favored RP for urinary irritation (LDR-BT 68/85 (80.0%) versus RP 4/89 (4.5%); P < 0.001; relative risk 17.80, 95% CI 6.79 to 46.66). The occurrence of urinary stricture did not significantly differ between the treatment groups (LDR-BT 2/85 (2.4%) versus RP 6/89 (6.7%); P = 0.221; relative risk 0.35, 95% CI: 0.07 to 1.68). Long-term information was not available.We did not identify significant differences of mean scores between treatment groups for patient-reported outcomes function and bother as well as generic health-related quality of life.

AUTHORS' CONCLUSIONS

Low-dose rate brachytherapy did not reduce biochemical recurrence-free survival versus radical prostatectomy at 5 years. For short-term severe adverse events, low-dose rate brachytherapy was significantly more favorable for urinary incontinence, but radical prostatectomy was significantly more favorable for urinary irritation. Evidence is based on one RCT with high risk of bias.

Impact of primary Gleason grade on risk stratification for Gleason score 7 prostate cancers

PURPOSE

To evaluate the primary Gleason grade (GG) in Gleason score (GS) 7 prostate cancers for risk of non-organ-confined disease with the goal of optimizing radiotherapy treatment option counseling.

METHODS

One thousand three hundred thirty-three patients with pathologic GS7 were identified in the Duke Prostate Center research database. Clinical factors including age, race, clinical stage, prostate-specific antigen at diagnosis, and pathologic stage were obtained. Data were stratified by prostate-specific antigen and clinical stage at diagnosis into adapted D'Amico risk groups. Univariate and multivariate analyses were performed evaluating for association of primary GG with pathologic outcome.

RESULTS

Nine hundred seventy-nine patients had primary GG3 and 354 had GG4. On univariate analyses, GG4 was associated with an increased risk of non-organ-confined disease. On multivariate analysis, GG4 was independently associated with seminal vesicle invasion (SVI) but not extracapsular extension. Patients with otherwise low-risk disease and primary GG3 had a very low risk of SVI (4%).

CONCLUSIONS

Primary GG4 in GS7 cancers is associated with increased risk of SVI compared with primary GG3. Otherwise low-risk patients with GS 3+4 have a very low risk of SVI and may be candidates for prostate-only radiotherapy modalities.

Changes in alkaline phosphatase levels in patients with prostate cancer receiving degarelix or leuprolide: results from a 12-month, comparative, phase III study

Study Type - Therapy (RCT) Level of Evidence 1b OBJECTIVE To compare the activity of degarelix, a new gonadotrophin-releasing hormone (GnRH) blocker, with leuprolide depot 7.5 mg in the control of total serum alkaline phosphatase (S-ALP) levels in patients with prostate cancer. PATIENTS AND METHODS In the randomized, phase III trial (CS21), patients with histologically confirmed prostate cancer (all stages), were randomized to one of three regimens: degarelix subcutaneous 240 mg for 1 month followed by monthly maintenance doses of 80 mg or 160 mg, or intramuscular leuprolide 7.5 mg/month. Patients receiving leuprolide could also receive antiandrogens for flare protection. We report exploratory S-ALP analyses from CS21, focusing on the comparison of degarelix 240/80 mg with leuprolide 7.5 mg, in line with the recent approvals of this dose by the USA Food and Drug Administration and the European Medicines Agency. RESULTS Overall, 610 patients were included, with a median age of 73 years and median prostate-specific antigen (PSA) level of 19.0 ng/mL. Baseline S-ALP levels were high in metastatic patients and highest in patients with metastatic disease and a haemoglobin level of <13 g/dL. In metastatic disease, after initial peaks in both groups, S-ALP levels were suppressed below baseline with degarelix but were maintained around baseline with leuprolide. The late rise in S-ALP seen with leuprolide was not apparent with degarelix. The pattern of S-ALP response was similar in patients with a baseline PSA level of > or =50 ng/mL. Between-treatment differences in patients with metastatic disease and those with a PSA level of > or =50 ng/mL were significant at day 364 (P = 0.014 and 0.007, respectively). CONCLUSION Patients with metastatic disease or those with PSA levels of > or =50 ng/mL at baseline had greater reductions in S-ALP levels with degarelix than with leuprolide. Patients in the degarelix group maintained S-ALP suppression throughout the study, in contrast to those in the leuprolide group. This suggests that degarelix might offer better S-ALP control than leuprolide and might prolong control of skeletal metastases, compared with GnRH agonists, over a 1-year treatment period.

15-Year biochemical relapse free survival in clinical Stage T1-T3 prostate cancer following combined external beam radiotherapy and brachytherapy; Seattle experience

PURPOSE

Long-term biochemical relapse-free survival (BRFS) rates in patients with clinical Stages T1-T3 prostate cancer continue to be scrutinized after treatment with external beam radiation therapy and brachytherapy.

METHODS AND MATERIALS

We report 15-year BRFS rates on 223 patients with clinically localized prostate cancer that were consecutively treated with I(125) or Pd (103) brachytherapy after 45-Gy neoadjuvant EBRT. Multivariate regression analysis was used to create a pretreatment clinical prognostic risk model using a modified American Society for Therapeutic Radiology and Oncology consensus definition (two consecutive serum prostate-specific antigen rises) as the outcome. Gleason scoring was performed by the pathologists at a community hospital. Time to biochemical failure was calculated and compared by using Kaplan-Meier plots.

RESULTS

Fifteen-year BRFS for the entire treatment group was 74%. BRFS using the Memorial Sloan-Kettering risk cohort analysis (95% confidence interval): low risk, 88%, intermediate risk 80%, and high risk 53%. Grouping by the risk classification described by D'Amico, the BRFS was: low risk 85.8%, intermediate risk 80.3%, and high risk 67.8% (p = 0.002).

CONCLUSIONS

I(125) or Pd(103) brachytherapy combined with supplemental EBRT results in excellent 15-year biochemical control. Different risk group classification schemes lead to different BRFS results in the high-risk group cohorts.

Results of permanent prostate brachytherapy, 13 years of experience at a single institution

BACKGROUND AND PURPOSE

To understand the influence of treatment techniques on the final outcome, as well as the relation of risk groups and of PSA nadir on the outcome, we reviewed our experience over more than 10 years.

PATIENTS AND METHODS

Patients were treated in the period 1989 through 2000. Available for this evaluation are 351 patients. The distribution of cases by T stage was T1a, b (9%), T1c (49%), T2 (42%), and by grading G1 (58%), G2 (38%), G3 (1%) and Gx (3%). The technique of plantation of seeds varied over the years, starting with single seeds using a Mick applicator (104 patients), followed by Rapid strands without (70) and with pre-planning (177). Risk groups are categorised as low (iPSA <10 ng/ml, T1-2, grade 1), 116 patients; intermediate (iPSA 10-20 ng/ml, or grade 2-3), 114 patients; and high risk (both factors, or iPSA >20 ng/ml), 121 patients. The mean follow-up time was 50 months, median 48 and range 24-123 months.

RESULTS

Overall actuarial survival at 5 and 7 years was 85 and 76%, respectively. Forty patients died, eight (2%) because of or with prostate cancer. Alive are 310 patients (88%), with 223 patients bNED (71%), 51 (16%) with PSA failure, 21 (7%) with local and 15 (5%) with distant recurrence. Total bNED was 72%. Although results are better since the introduction of Rapid strands, 79% bNED versus 54% bNED for single seeds (P = 0.14) also the increase in activity per cm(3) prostate volume accounts for this improvement. With pre-planning a significant better result (P < 0.03) is obtained as compared to single seeds or strands without planning. Categorisation into risk groups results in a significant difference (P < 0.007) of bNED with risk factors, respectively, 57% for the high, 75% for the intermediate and 89% for the low risk group. Also PSA nadir had a significant effect on outcome; patients who reach a nadir of < or =0.5 ng/ml have a 91% chance of cure.

CONCLUSIONS

Results of permanent seed implantation improved with the introduction of strands, however, better staging and the increase in activity per cm(3) prostate volume also contributed to this improvement. A significant better result was obtained with pre-planning. Categorisation in risk groups corresponds very well with treatment outcome. Finally, a strong relation is found with PSA nadir.

Ten-year biochemical relapse-free survival after external beam radiation and brachytherapy for localized prostate cancer: the Seattle experience

PURPOSE

The role of external beam radiation therapy in addition to brachytherapy continues to be scrutinized for long term control of PSA levels after prostate cancer diagnosis.

METHODS AND MATERIALS

We report 10-year biochemical relapse-free survival (BRFS) on 232 patients presenting with localized prostate cancer and consecutively treated with iodine(125) (I(125)) or palladium(103) (Pd(103)) brachytherapy and neoadjuvant external beam radiation therapy. Multivariate regression analysis was used to create a pretreatment clinical prognostic risk model using a modified ASTRO consensus definition (two consecutive rises in serum PSA) as the outcome. Gleason scoring was performed by pathologists at a small community hospital. Derived risk categories are the following: low = PSA <or=10 ng/mL, Gleason sum score <7, and stage <T2c; intermediate = PSA >10 ng/mL or Gleason Score >or=7 or stage >or=T2c (1 intermediate risk factor); and high = 2 or more intermediate risk factors. Time to PSA failure (local, distant, or biochemical) was calculated and compared using Kaplan-Meier plots.

RESULTS

Ten-year BRFS for the entire treatment group was 70%. Biochemical control rates by risk cohort analysis (95% confidence interval): low risk, 85% (83.3-90.7%); intermediate risk, 77% (73.0-84.5%); and high risk, 45% (45.4-57.2%). Using a risk grouping proposed by the Mt. Sinai group, the BRFS was: low risk, 84%; intermediate risk, 93%; and high risk, 57%. Grouping by the risk classification used by D'Amico, the BRFS was: low risk, 86%; intermediate risk, 90%; and high risk, 48%.

CONCLUSIONS

I(125) or Pd(103) brachytherapy, as a boost combined with EBRT, continues to result in high rates of biochemical control at 10 years. Different risk group classification schemes lead to different BRFS results.

Biochemical outcomes after prostate brachytherapy with 5-year minimal follow-up: Importance of patient selection and implant quality

PURPOSE

A prostate brachytherapy program was initiated in 1990, when comparatively little was known of the relative importance of disease- and treatment-related factors on outcome. Patients treated during the first 6 years of the program were analyzed to determine the value of patient selection and implant quality on biochemical control.

METHODS AND MATERIALS

We treated 243 patients with clinically localized prostate cancer with radioactive seed implantation and underwent 1-month CT-based dosimetric analysis. Follow-up ranged from 61 to 135 months (median 75). The Gleason score was < or =6 in 78% (n = 189), 7 in 14% (n = 35), and 8-10 in 8% (n = 19). The initial prostate-specific antigen (PSA) level was < or =10 ng/mL in 61% (n = 149), 10.1-20 ng/mL in 26% (n = 63), and >20 ng/mL in 13% (n = 31). The disease stage was T2a or less in 49% (n = 120), and Stage T2b-T2c in 51% (n = 123). A real-time ultrasound-guided technique was used with (125)I (n = 138) and (103)Pd (n = 105) isotopes. No patient underwent external beam radiotherapy as part of their primary treatment. Of the 243 patients, 60% also received hormonal ablation for at least 3 months before and 2-3 months after seed implantation. All patients included underwent a 1-month CT-based dosimetric analysis. The implant dose was defined as the dose delivered to 90% of the prostate volume on postimplant dosimetry (D(90)). On the basis of prior dose-response analyses, patients were retrospectively grouped into optimal D(90) ((125)I > or =140 Gy Task Group 43 or (103)Pd >/=100 Gy) and suboptimal D(90) ( (125)I <140 Gy or (103)Pd <100 Gy) dose groups. Biochemical failure was defined using the American Society for Therapeutic Radiology Oncology definition.

RESULTS

Disease-related factors, including initial PSA level, Gleason score, and stage, were significant predictors of biochemical failure. The actuarial 8-year freedom from biochemical failure (bFFF) rate was 80% for those with a PSA level < or =10 ng/mL, 86% for PSA 10.1-20 ng/mL, and 45% for PSA >20 ng/mL (p = 0.0019). Patients with a Gleason score of < or =6 had an 8-year bFFF rate of 81% vs. 67% for those with Gleason score 7 and 53% for those with Gleason score 8-10 (p = 0.0003). Patients with Stage T2a or less had an 8-year bFFF rate of 85% compared with 69% for those with Stage T2b-T2c (p = 0.013). The 8-year bFFF rate was 88% for low-risk patients (Stage T2a or less, Gleason score < or =6, and initial PSA level < or =10 ng/mL; n = 75), 81% for moderate-risk patients (Stage T2b or Gleason score 7 or initial PSA level >10.1-20 ng/mL; n = 70), and 65% for high-risk patients (two or more moderate-risk features or Gleason score > or =8 or initial PSA level >20 ng/mL; n = 98; p = 0.0009). Patients with optimal dose implants (n = 145) had an 8-year bFFF rate of 82% compared with 68% for those with suboptimal dose implants (n = 98; p = 0.007). Hormonal therapy did not significantly affect biochemical failure (p = 0.27). In multivariate analysis, the statistically significant variables included initial PSA level (p <0.0001), Gleason score (p = 0.024), and dose group (p = 0.046). Because our current practice limits implantation alone to low-risk patients, an analysis of this subgroup was undertaken to validate the importance of dose. In the optimal dose group, low-risk patients had an 8-year bFFF rate of 94% vs. 75% for the low-risk patients in the suboptimal dose group (p = 0.02).

CONCLUSION

With minimal follow-up of 5 years, these data continue to support the use of implantation alone in low-risk prostate cancer patients and demonstrate the importance of implant quality (dose) in achieving optimal outcomes. Low-risk patients who receive an optimal dose implant have a 94% bFFF rate at 8 years.

Four-year biochemical outcome after radioimmunoguided transperineal brachytherapy for patients with prostate adenocarcinoma

PURPOSE

To evaluate 4-year biochemical outcomes for patients with prostate adenocarcinoma who underwent radioimmunoguided (Prostascint) permanent prostate brachytherapy.

METHODS AND MATERIALS

Eighty patients with clinical T1C-T3A NxM0 prostate cancer underwent ProstaScint-guided prostate brachytherapy using either (103)Pd or (125)I between February 1997 and December 2000. Sixty-seven patients underwent prostate brachytherapy alone, whereas 13 patients received neoadjuvant hormonal manipulation before implantation. Risk factors (RF) included PSA >10, Stage >or=T2b, and Gleason grade >or=7. Sixty patients had low-risk disease (0 RF), 17 were intermediate risk (1 RF), and 3 were high risk (2 RF). Biochemical disease-free survival (bDFS) was calculated using the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus criteria, a PSA cutoff of 1.0 ng/mL, and a PSA cutoff of 0.5 ng/mL.

RESULTS

Four-year bDFS for the entire cohort was 97.4% using the ASTRO consensus criteria. Low-risk patients (60) had a 4-year bDFS of 100%; intermediate- and high-risk patients (20 patients) were 89.2%. The hormonally naïve group (67 patients) had a 4-year bDFS of 96.9% and a median PSA nadir of 0.2 ng/mL. Median time to nadir was 19.8 months (range: 1.9-53.2 months). For the neoadjuvant hormonal therapy group (13 patients), ASTRO-defined bDFS was 100%. Overall, 85.2% of patients had a posttreatment PSA <or=1.0 ng/mL, and 75.9% had a PSA <or=0.5 ng/mL at a median follow-up of 36 months.

CONCLUSIONS

At a median follow-up of 36 months, ProstaScint-guided transperineal brachytherapy results in a high probability of actuarial 4-year biochemical disease-free survival for patients with localized prostate cancer.

Brachytherapy: update and results

Prostate cancer is the most common noncutaneous malignancy and the second most common cause of cancer mortality in American men. Treatment options for these patients include radical prostatectomy, external beam radiation therapy, hormonal therapy, and prostate brachytherapy. Patients with clinically and radiographically localized disease, especially young patients with few comorbid illnesses, are good candidates for prostate brachytherapy. Prostate brachytherapy has gained widespread acceptance throughout the past two decades and data from several large series of patients are now available. This article describes current techniques, treatment issues, and clinical results of permanent seed implants.

Combination conformal radiotherapy and radioimmunoguided transperineal 103Pd implantation for patients with intermediate and unfavorable risk prostate adenocarcinoma

PURPOSE

To report outcomes for prostate cancer patients treated with external beam radiation therapy (EBRT) and permanent prostate brachytherapy utilizing radioimmunoguided targeting of biological tumor volumes (BTVs).

METHODS AND MATERIALS

Between February 1997 and October 2001, 66 patients with intermediate- to high-risk prostate cancer underwent EBRT and ProstaScint-guided transperineal brachytherapy. Thirty patients received neoadjuvant hormonal manipulation, while 36 patients did not. Median patient age was 66 years (range, 49-78 years). The median follow-up was 41 months (range, 24-78 months). No patients were lost to follow-up. Risk factors (RF) used for risk stratification included PSA >10 ng/ml (35 patients), Stage T2b or greater (22 patients), and Gleason score > or = 7 (55 patients). Results for biochemical disease free survival (bDFS) were reported using the ASTRO consensus definition for biochemical failure, PSA < or = 1.0 ng/mL or PSA< or = 0.5 ng/mL. Survival was estimated by the Kaplan-Meier method.

RESULTS

Five-year overall survival was 93.1% and 5-year bDFS by the ASTRO definition was 89.3% with a median follow up of 41 months. Patients with intermediate- (1 RF) and high-risk (2-3 RF) prostate cancer exhibited 5-year ASTRO-defined bDFS of 100% and 81.9%, respectively. There was no significant difference in bDFS between the patients treated with or without hormone therapy (HT). The 5-year ASTRO-defined bDFS was 89.8% for the 30 patients treated with HT and 88.9% for the 36 patients who did not receive HT (p = 0.843). For the patients without HT the median PSA nadir was 0.11 ng/mL. The median time to nadir was 23 months (range, 6-66 months).

CONCLUSIONS

With limited follow-up, the results of EBRT plus radioimmunoguided brachytherapy for intermediate- to high-risk prostate cancer appear favorable. The addition of HT did not appear to affect bDFS significantly, but interpretation is confounded by possible selection bias and the limited power of this study.

Role of hormonal therapy in the management of intermediate- to high-risk prostate cancer treated with permanent radioactive seed implantation

PURPOSE

To study the impact of hormonal therapy (HTx) on intermediate- to high-risk prostate cancer treated with permanent radioactive seed implantation.

METHODS AND MATERIALS

Patients with Stage T1b-T3bN0 prostate cancer, and Gleason score > or = 7 or prostate-specific antigen (PSA) level >10 ng/mL were treated with seed implantation with or without HTx. Their disease was defined as intermediate risk (PSA 10-20, Gleason score 7, or Stage T2b) or high risk (two or more intermediate criteria, or PSA >20 ng/mL, Gleason score 8-10, or Stage T2c-T3). The median follow-up for 201 eligible patients was 42 months (range 18-110). Biochemical failure was defined as a rising PSA >1.0 ng/mL. Pretreatment disease characteristics, implant dose, and HTx were evaluated using univariate and multivariate analyses.

RESULTS

HTx significantly improved 5-year actuarial freedom from biochemical failure rate, 79% vs. 54% without HTx. In addition, high-dose, PSA < or = 15 ng/mL, intermediate risk, and Stage T2a or lower significantly improved outcome in the univariate analyses. HTx was the most significant predictor of 5-year actuarial freedom from biochemical failure (p <0.0001) in a multivariate analysis. The best outcome was in the intermediate-risk patients treated with a high implant dose and HTx, resulting in a 4-year actuarial freedom from biochemical failure rate of 94%.

CONCLUSION

In this retrospective review, HTx improved outcome in intermediate- to high-risk prostate cancer patients treated with brachytherapy. HTx was the most important prognostic factor in the univariate and multivariate analyses.

Brachytherapy for carcinoma of the prostate: techniques, patient selection, and clinical outcomes

Brachytherapy for prostate carcinoma has developed as either low dose rate permanent implants or high dose rate afterloading. Both approaches offer unsurpassed dose escalation and, particularly with permanent implants, the convenience of a single outpatient treatment. These therapies have now entered the mainstream of treatment options and are in the refinement phase of development. Techniques of implantation, treatment planning approaches, innovative fractionation schemes, and appropriate patient selection are the subject of current investigation. Treatment results are available beyond 10 years and appear equivalent or superior to other modalities. Although short term morbidity can be significant with brachytherapy, most current series report low long-term urinary and rectal complications. Meaningful quality of life studies and randomized cooperative group trials are now underway and should help define the role of brachytherapy in the near future.

External-beam radiotherapy in the management of carcinoma of the prostate

BACKGROUND

External-beam radiotherapy (EBRT) has been used in the treatment of adenocarcinoma of the prostate gland for more than 30 years. Well-documented clinical series have demonstrated the effectiveness of EBRT in achieving both cause-specific survival and freedom from biochemical (prostate-specific antigen [PSA]) progression.

METHODS

The indications and expected treatment results for treatment by EBRT in the management of adenocarcinoma of the prostate gland are reviewed. The treatment of early-stage disease definitively by EBRT alone or as complement to radioactive seed implant is emphasized. In the management of locally advanced disease, the use of EBRT with combined androgen ablation is discussed as definitive therapy and also as indicated in the postoperative adjuvant management of surgically identified pathologic stage T3 disease.

RESULTS

The relative clinical benefit of EBRT compared with the mostly predictable and well-defined moderate side effects, which are manageable in most instances by conservative measures treatment, is well established. Advances in defining radiation-beam parameters have led to more effective and safer treatment for prostate cancer.

CONCLUSIONS

EBRT has historically been a mainstay in the management of prostate cancer. It remains a useful and indicated treatment modality in patients with early-stage, locally advanced, and metastatic disease.

A comprehensive review of CT-based dosimetry parameters and biochemical control in patients treated with permanent prostate brachytherapy

PURPOSE

The American Brachytherapy Society recommends that postprostate implant dosimetry be performed on all patients undergoing transperineal interstitial permanent prostate brachytherapy (TIPPB) utilizing CT scan clinical target volume reconstructions. This study was undertaken to assess the recommended dosimetry parameters from a large cohort of patients undergoing TIPPB that would predict for PSA relapse-free survival (PSA-RFS).

METHODS AND MATERIALS

Seven hundred nineteen consecutive patients with clinical stage T1/T2 adenocarcinoma of the prostate underwent TIPPB using either I-125 or Pd-103. Postimplant dosimetry was performed at 2 to 3 weeks with CT scan 3-dimensional reconstructions obtained on all patients. The D90 and D100 doses (defined as the minimum dose covering 90% and 100% of the prostate volume, respectively) and the V100 (defined as the percent of the prostate receiving 100% of the prescribed dose) were obtained for each patient. Regression analysis was performed on the D90 dose, D100 dose, and V100 to test for cutoff points that would predict for PSA-RFS, defined by a modification of the American Society for Therapeutic Radiology and Oncology consensus panel statement. A cutoff value was found and was subjected to subset analysis to assess for its robustness. Treatment-related factors were tested for their ability to achieve dosimetry at or above the cutoff dose.

RESULTS

The median follow-up from this cohort is 30 months (7-71 months) with a 48-month PSA-RFS of 89.5%. A D90 dose-response cutoff value > or =90% of the prescribed dose was identified. Prostate implants with a D90 dose <90% of the prescribed dose had an 80.4% 4-year PSA-RFS, while those with a D90 dose > or =90% of the prescribed dose had a 92.4% 4-year PSA-RFS (p = 0.001). No cutoff value was found for the V100 and D100 dose that predicted for PSA-RFS. Using the cutoff value, the D90 dose at 90% of the prescribed dose, a difference in 4-year PSA-RFS survival was identified for patients treated with I-125 (p = 0.04), Pd-103 (p = 0.01), TIPPB as monotherapy (p = 0.001), the addition of hormone therapy (p = 0.005), and TIPPB without hormone therapy (p = 0.001). The D90 dose was not significant for the group of patients treated with external beam radiotherapy and TIPPB (p = 0.15). The only significant finding from Cox regression analysis to predict for a poor D90 dose (<90% of the prescribed dose) was a CT/TRUS volume ratio >1.5 (p = 0.02).

CONCLUSIONS

The American Brachytherapy Society recommends that postimplant CT-based dosimetry be performed for all patients treated with TIPPB. This prospective study identified that the D90 dose > or =90% of the prescribed dose can be used as a factor for predicting PSA-RFS in patients treated with brachytherapy. A dose-response using the D90 dose was observed for several typical clinical treatment variations used in the practice of TIPPB. Using the D90 dose appears to be a satisfactory parameter for predicting outcome in patients treated with TIPPB.

Radiation therapy for prostate cancer

OBJECTIVES

To review the advances in radiation therapy for prostate cancer and the nursing care of patients with prostate cancer.

DATA SOURCES

Peer-reviewed journal articles, including research studies and review articles.

CONCLUSIONS

Radiation therapy is used to cure early stage prostate cancer, control locally advanced disease, and effectively palliate symptoms of metastasis. The three forms of treatment used include external beam radiation therapy, brachytherapy; and radiopharmaceutical treatments.

IMPLICATIONS FOR NURSING PRACTICE

Nursing care of patients receiving radiation therapy for prostate cancer includes managing the symptoms associated with the disease and treatment, educating patients and families about self-care measures, and providing support throughout the course of the disease.

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.

The evolving role of prostate brachytherapy

BACKGROUND

The publication of several large studies with long-term results on the use of prostate brachytherapy has resulted in increased use of this option for patients with localized prostate cancer.

METHODS

A historical review of brachytherapy as an approach to prostate cancer management is provided, as well as a general summary of the implant technique and the results to date according to patient risk. The effects of combination therapies for specific patient groups are also reviewed.

RESULTS

A recent 12-year follow-up reported no failures after 10 years, and 75% of recurrences occurred with-in the first 5 years. Patients at low risk for failure based on stage, grade, and prostate-specific antigen (PSA) parameters are likely to have disease confined to the prostate. Those with more advanced disease are likely to have a lower probability of cure with brachytherapy as monotherapy. Complications involve primarily the urinary tract. Ideal candidates have a PSA of =10, Gleason score of =7, and low-volume/low-stage disease (stage T1c or T2a). Patients with more-advanced disease are candidates for brachytherapy combined with external-beam radiation therapy (EBRT). For high-risk men with multiple adverse prognostic features, consideration should be given to clinical trials investigating innovative treatment combinations (eg, the addition of androgen blockade, and EBRT).

CONCLUSIONS

The rarity of failures after 5 years and the absence of recurrence after 10 years suggest a that brachytherapy for localized prostate cancer can provide durable disease control. Future improvements in pathologic tools may lead to selection of patients more likely to respond well to brachytherapy.

The effect of disease and treatment-related factors on biopsy results after prostate brachytherapy: implications for treatment optimization

BACKGROUND

Posttreatment prostate biopsy is a method of assessing local control after irradiation for prostate carcinoma. An analysis of the effect of disease- and treatment-related factors on biopsy results after prostate brachytherapy was performed to aid in patient selection and treatment optimization.

METHODS

Two hundred sixty-eight patients underwent posttreatment prostate biopsy (6-8 cores) 2 years after brachytherapy alone without external beam irradiation. Follow-up ranged from 24 to 111 months (median, 43 months). Implants were performed using a real-time ultrasound guided technique with the isotopes (125)I in 186 and (103)Pd in 82 patients. Ninety-eight patients underwent hormonal therapy (HT) 3 months before and 2-3 months after implant. Implant dose was defined as the D90 (dose delivered to 90% of the gland from the dose volume histogram generated using 1-month computed tomography-based dosimetry).

RESULTS

Overall, 89% of patients (238 of 268) had negative biopsies. A positive biopsy was a predictor of biochemical failure. Patients with a positive biopsy had a 5-year freedom from biochemical failure of 40% versus 76% for patients with a negative biopsy (P = 0.0003). Univariate and multivariate analysis found that risk group, HT, and implant dose significantly affected biopsy outcome. Patients with low risk features (prostate specific antigen [PSA] </= 10 ng/mL; Gleason score </= 6; and classification T2a or lower) (n = 104) had a negative biopsy rate of 95% versus 85% for those with high risk features (PSA > 10 ng/mL or Gleason score >/= 7 or classification T2b or higher) (n = 164) (P = 0.008). Hormonal therapy was associated with a negative biopsy rate of 98% versus 84% for implant alone (P = 0.003). Patients receiving a high implant dose (D90 >/= 140 grays [Gy] for (125)I or >/= 100 Gy for (103)Pd) (n = 174) had a negative biopsy rate of 95% versus 77% for those receiving a low dose (D90 < 140 Gy for (125)I or < 100 Gy for (103)Pd) (n = 87; P < 0.001).

CONCLUSIONS

Biopsy results support the use of brachytherapy without external beam irradiation for patients with low risk features and highlight the importance of achieving an adequate implant dose.

Postimplantation dosimetric analysis of permanent transperineal prostate implantation: improved dose distributions with an intraoperative computer-optimized conformal planning technique

PURPOSE

To compare the target coverage and dose to normal tissues after I-125 transperineal permanent implantation (TPI) of the prostate in 90 patients treated with one of three different transperineal techniques.

METHODS AND MATERIALS

Detailed postimplant dosimetric evaluations of permanent I-125 implantation procedures were performed on 30 consecutive patients treated between 1995-1996 who underwent TPI using a preplanning CT-based technique, on 30 consecutive patients treated in 1997-1998 who underwent an ultrasound-guided approach with intraoperative determination of seed distribution based on an I-125 nomogram, and on 30 consecutive patients in 1998-1999 who underwent TPI with intraoperative computer-based 3-dimensional conformal optimization. For all three techniques, postimplant CT scans were obtained 4-6 hours after TPI. Dosimetric parameters included V(100), V(90), V(150), D(100), D(90), D(80), as well as maximal and average doses to the urethra and rectal wall. These parameter outcomes are reported as a percentage of the prescription dose.

RESULTS

The intraoperative 3D-optimized technique (I-3D) provided superior target coverage with the prescription dose for all dosimetric variables evaluated compared to the other treatment techniques. The median V(100), V(90), and D(90) values for the I-3D technique were 96%, 98%, and 116%, respectively. In contrast, the V(100), V(90), and D(90) values for the CT preplan and ultrasound manual optimization approaches were 86%, 89%, and 88%, respectively and 88%, 92%, and 94%, respectively (I-3D versus other techniques: p < 0.001). The superior target coverage with the I-3D technique was also associated with a higher cumulative implant activity required by the optimization program. A multivariate analysis determined that the treatment technique (I-3D versus other approaches) was an independent predictor of improved target coverage for each parameter analyzed (p < 0.001). In addition, higher cumulative implant activities and smaller prostate target volumes were independent predictors of improved target coverage. The maximum and average urethral doses were significantly lower with the I-3D technique compared to the other techniques; a modest increase in the average rectal dose was also observed with this approach.

CONCLUSION

Three-dimensional intraoperative computer optimized TPI consistently provided superior target coverage with the prescription dose and significantly lower urethral doses compared to two other techniques used. These data provide proof-of-principle that improved therapeutic ratios can be achieved with the integration of more sophisticated intraoperative planning for TPI and may potentially have a profound impact on the outcome of patients treated with this modality.

Potency preservation after three-dimensional conformal radiotherapy for prostate cancer: preliminary results

We sought to assess potency preservation after three-dimensional conformal radiotherapy (3D-CRT) in prostate cancer patients eligible for radical prostatectomy, conventional radiotherapy, 3D-CRT, or transperineal prostate implantation. Patients with more advanced disease are commonly treated with hormonal therapy, which can cause impotence, and were consequently excluded from the analysis. Between December 1991 and June 1998, 198 prostate cancer patients were treated with 3D-CRT at the University of California, Davis Medical Center. Fifty-two of these patients had a pretreatment prostate-specific antigen (PSA) level of 10.0 ng/ml or less, a Gleason score of 6 or less, and a 1997 AJCC clinical stage T1bN0M0 to T2bN0M0. One patient was not evaluable. None of the 51 evaluable patients had diabetes mellitus. In 40 patients, the prostate gland only was irradiated to a total dose of 66 to 79.2 Gy by using daily 1.8-Gy fractions. In 11 patients, the prostate and seminal vesicles were treated to 44 to 55.8 Gy. Lymph nodes were not included in the clinical target volume. The median age was 68 years, and the median length of follow-up was 15 months. Potency in this study is defined as an erection sufficient for vaginal penetration. Kaplan-Meier analysis was used to describe potency as a function of time after 3D-CRT. Of the 51 evaluable patients, 35 (69%) were potent, 15 were impotent, and 1 was sexually inactive before 3D-CRT. Kaplan-Meier estimates of the potency preservation rates 1, 2, and 3 years after 3D-CRT are 100%, 83%, and 63%, respectively. On multivariate analysis, age, total radiation dose, and a history of transurethral resection of the prostate did not significantly affect potency preservation rates. Three (43%) of 7 patients who became impotent after 3D-CRT and used sildenafil were subsequently able to achieve erections sufficient for vaginal penetration. The preliminary results reported herein suggest that approximately two thirds of prostate cancer patients will retain their potency 3 years after 3D-CRT. Further follow-up is necessary to assess long-term potency after 3D-CRT. Sildenafil should be considered in patients who develop radiation-induced impotence.

Five-year biochemical outcome and toxicity with transperineal CT-planned permanent I-125 prostate implantation for patients with localized prostate cancer

PURPOSE

To report the 5-year prostate-specific antigen (PSA) relapse-free survival outcome and incidence of long-term morbidity for patients with localized prostate cancer treated with CT-planned permanent I-125 prostate implantation using a transperineal technique (TPI).

METHODS AND MATERIALS

Between 1989-1996, 248 patients with clinically localized prostate cancer were treated with TPI. The median age was 65 years (range: 45-80 years). The clinical stage was T1c in 143 patients (58%), Stage T2a in 102 (41%), and T2b in 3 (1%). Thirty patients (12%) had Gleason scores <6, 158 patients (64%) had Gleason scores of 6, and 60 (24%) had scores >or =7. The median pretreatment PSA was 7 ng/mL (range: 1-58 ng/mL). The median prescribed implant dose was 150 Gy. Patients were characterized as having favorable risk disease if their pretreatment PSA level was < or =10.0 ng/mL and Gleason score < or = 6; those with one and two adverse prognostic features (PSA > 10 ng/mL and Gleason score >6) were classified as having intermediate and unfavorable risk disease, respectively. PSA relapse was defined according to the American Society of Therapeutic Radiation Oncology Consensus Statement, and toxicity was scored according to the Radiation Therapy Oncology Group morbidity scoring scale. The median follow-up was 48 months (range: 12-126 months).

RESULTS

Thirty-eight patients (15%) developed a PSA relapse, and the overall 5-year PSA relapse-free survival (PRFS) rate was 71%. The 5-year PRFS rates for favorable-risk (n = 146), intermediate-risk (n = 85), and unfavorable-risk (n = 17) patients were 88%, 77%, and 38%, respectively (p < 0.0001). The 5-year PRFS rates among patients treated with a 2-month course of neoadjuvant androgen deprivation (NAAD) prior to TPI compared to patients treated with TPI only were 100% and 77%, respectively (p = 0.03). Multivariate analysis identified pretreatment PSA > 10 ng/mL and Gleason score >6 as independent predictors for biochemical relapse after TPI. The 5-year actuarial likelihood of late Grade 2 urinary toxicity was 41%. The 5-year likelihood of urethral stricture development was 10%, and the median time to stricture development was 18 months. One patient (0. 4%) in the early phase of this clinical experience developed a Grade 4 urethral complication. The actuarial incidence of late Grade 2 rectal bleeding was 9%. One patient (0.4%) developed a Grade 4 rectal complication.

CONCLUSIONS

Especially for favorable risk disease, the 5-year biochemical outcome with this approach was excellent and appears to be comparable to other therapeutic interventions. Grade 2 urinary symptoms were common in these patients but gradually resolved in most. Improved treatment planning approaches that further constrain the urethral dose without compromising the target volume dose will likely decrease the incidence of Grade 2 and 3 urinary symptoms after TPI.

Minimizing rectal and urinary complications in prostate brachytherapy

With any therapy for early prostate cancer, control must be evaluated with a view to toxicities. Brachytherapy may be associated with urethral and rectal toxicity and erectile impotence. Patients with large glands or significant symptoms before treatment are at greatest risk. Long-term toxicity can be minimized by understanding the tolerance of the normal tissues and meticulous placement of the radioactive seeds.

Salvage radical prostatectomy after radiation therapy and brachytherapy

Local recurrence after any type of radiation therapy presents the clinician with a significant challenge. If there is no evidence of metastatic disease, patients can be offered a potentially curative salvage prostatectomy. To qualify for such surgery, patients should be at least 12 months from the completion of radiation and have at least a 10-year life expectancy; ideally, they will have a serum prostate specific antigen concentration <10 ng/mL and a Gleason score of 7 or less. Perioperative complications are substantial, with urinary incontinence rates of 40% to 50% and rectal injury rates of 10% to 15%. Long-term disease-free survival rates of 30% to 40% can be expected.

Biopsy results after real-time ultrasound-guided transperineal implants for stage T1-T2 prostate cancer

PURPOSE

To analyze the results of ultrasound-guided brachytherapy for stage T1-T2 prostate cancer, as shown by biopsy results.

PATIENTS AND METHODS

The 268 patients (mean age 66 years; range 41-83 years) underwent real-time ultrasound-guided implantation of either iodine-125 (N = 186) or palladium-103 (N = 82) seeds. Of these patients, 96 (36%) received total androgen suppression for 3 months prior to and 3 months after implantation. Prostate biopsy was performed 24 months later, with the six to eight cores all being interpreted by the same pathologist. Each specimen was rated either positive or negative for cancer.

RESULTS

Of the 268 patients, 238 (89%) had a negative biopsy at 24 months. Among the patients receiving androgen suppression, 2% were found to have positive biopsies compared with 16% of those not given hormones (P = 0.004). Of the 155 patients with stage T1-T(2a) cancer, 6% had a positive biopsy compared with 19% of patients with stage T(2b) or T(2c) cancer (P = 0.001). In the entire series, the pretreatment serum concentration of prostate specific antigen, Gleason score, and isotope (I v Pd) were not significant predictors of a positive biopsy. However, among the 172 patients who did not receive androgen suppression, all three factors were predictive: 42% for Gleason score of 7 to 10 v 13% for Gleason score < or =6 (P = 0.001): 25% for pretreatment PSA concentration >10 ng/mL v 13% for PSA < or = 10 ng/mL (P = 0.05); and 27% for stage T(2b) or T(2c) v 9% for stage T1 or T(2a) (P = 0.001). The isotope used and the last PSA value were not significant predictors.

CONCLUSION

Brachytherapy provides excellent local control of prostate cancer, with 89% of patients having negative biopsies 2 years after treatment. High-risk patients may benefit from the addition of androgen suppression.

Acute toxicity of three-dimensional conformal radiotherapy in prostate cancer patients eligible for implant monotherapy

PURPOSE

To assess the acute toxicity of three-dimensional conformal radiotherapy (3D-CRT) in prostate cancer patients eligible for implant monotherapy.

METHODS AND MATERIALS

Between December 1991 and June 1998, 198 prostate cancer patients were treated with 3D-CRT at the University of California Davis Medical Center. Fifty-two of these patients had a prostate-specific antigen (PSA) level </= 10.0 ng/ml, Gleason score </= 6, and a 1997 AJCC clinical stage T1bN0-T2bN0. Eleven (21%) patients received radiotherapy to the prostate and seminal vesicles; the remaining patients were treated to the prostate only. The 3D-CRT treatment planning guidelines in Radiation Therapy Oncology Group (RTOG) 9406 were followed after 1994 (similar treatment planning was used before the protocol became available). Typically, 4 oblique and 2 lateral fields were treated. All patients were seen at least weekly while under treatment, 1 month postirradiation and then every 3 months. Total radiation doses ranged from 66.0-79.2 Gy, with a median dose of 73.8 Gy in 41 fractions over 8 weeks. Acute toxicity is described according to the RTOG acute toxicity scoring system.

RESULTS

Overall, 3D-CRT was well-tolerated: 29% of patients experienced RTOG Grade 1 and 27% experienced Grade 2 acute lower gastrointestinal (GI) toxicity. Forty percent and 33% of patients experienced Grade 1 and 2 acute genitourinary (GU) toxicity, respectively. As expected, more acute morbidity, especially GI, was observed with a larger clinical target volume (prostate and seminal vesicles versus prostate only; p = 0. 05). Neoadjuvant hormonal therapy did not increase the incidence or severity of radiation-induced side effects. No acute toxicity >/= Grade 3, e.g., hourly nocturia, gross hematuria, diarrhea requiring parenteral support, narcotics for pain control, or catheterization for acute urinary retention, was observed.

CONCLUSION

Although relatively high doses of radiation are delivered to prostate cancers with 3D-CRT compared with conventional radiotherapy, 3D-CRT is surprisingly well-tolerated. No patients in the cohort eligible for implant monotherapy experienced acute toxicity >/= Grade 3.

Palladium-103 brachytherapy for prostate carcinoma

PURPOSE

A report of biochemical outcomes for patients treated with palladium-103 (Pd-103) brachytherapy over a fixed time interval.

METHODS AND MATERIALS

Two hundred thirty patients with clinical stage T1-T2 prostate cancer were treated with Pd-103 brachytherapy and followed with prostate-specific antigen (PSA) determinations. Kaplan-Meier estimates of biochemical failure on the basis of two consecutive elevations of PSA were utilized. Multivariate risk groups were constructed. Aggregate PSA response by time interval was assessed.

RESULTS

The overall biochemical control rate achieved at 9 years was 83.5%. Failures were local 3.0%; distant 6.1%; PSA progression only 4.3%. Significant risk factors contributing to failure were serum PSA greater than 10 ng/ml and Gleason sum of 7 or greater. Five-year biochemical control for those exhibiting neither risk factor was 94%; one risk factor, 82%; both risk factors, 65%. When all 1354 PSA determinations obtained for this cohort were considered, the patients with a proportion of PSAs < or = 0.5 ng/ml continued to increase until at least 48 months post-therapy. These data conformed to a median PSA half-life of 96.2 days.

CONCLUSIONS

Prostate brachytherapy with Pd-103 achieves a high rate of biochemical and clinical control in patients with clinically organ-confined disease. PSA response following brachytherapy with low-dose-rate isotopes is protracted.

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.

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.

PSA kinetics following I-125 radioactive seed implantation in the treatment of T1-T2 prostate cancer

Although there is renewed interest in prostate brachytherapy, little information is available on the effect of the procedure on prostate-specific antigen (PSA) changes over time. This study describes PSA kinetics after iodine-125 (I-125) transrectal ultrasound-guided transperineal implantation of the prostate. From February 1991-September 1997, 207 patients were treated with an I-125 prostate implant alone for T1-T2 prostate cancer. PSA values were obtained prior to treatment and at 1-73 months (median, 24 months). The change in PSA after implantation of the prostate was measured as a fraction of the pretreatment PSA (PSA at follow-up/pretreatment PSA). PSA failure was defined as two elevations in PSA or PSA > 1 ng/ml. One hundred fifty-five patients had PSA values recorded at the 1-month time period. A PSA value greater than the pretreatment PSA at 1 month was found in 27% (42/155). This had no significant effect on future PSA failure. The median percentage change in PSA after implantation for all patients were as follows: 1 month, 0.73; 3 months, 0.30; 6 months, 0.18; 12 months, 0.12; 18 months, 0.12; 24 months, 0.08; 30 months, 0.07; 36 months, 0.08; 42 months, 0.08; and 48 months, 0.05. The most significant decline occurred in the first 12 months. This was followed by a more gradual decline between 12-24 months. There was little change in PSA values after 24 months. The 1-year PSA value had a significant effect on PSA failure. Patients with a 1-year PSA <1 ng/ml (66) had an actuarial 4-year freedom-from-failure rate of 90%, compared to a rate of 62% for those with values >1 ng/ml (69) (P = 0.002). Twenty-seven patients developed PSA failure. The time to PSA failure ranged from 12-48 months (median, 24 months), but most (20/27) failures occurred after 18 months. We conclude that the greatest decline in PSA after I-125 implantation of the prostate occurs during the first year, and little change occurs after 2 years. A 1-year PSA value > 1 ng/ml is highly predictive of eventual PSA failure, which occurs in most patients after 18 months posttreatment.

Comparison of the 5-year outcome and morbidity of three-dimensional conformal radiotherapy versus transperineal permanent iodine-125 implantation for early-stage prostatic cancer

PURPOSE

To compare the prostate-specific antigen (PSA) relapse-free survival outcome and incidence of late toxicity for patients with early-stage prostate cancer treated at a single institution with either three-dimensional conformal radiotherapy (3D-CRT) or transperineal permanent implantation (TPI) with iodine-125 seeds.

MATERIALS AND METHODS

Patients with favorable-risk prostate cancer, defined as a pretreatment PSA of less than or equal to 10.0 ng/mL, Gleason score of 6 or lower, and stage less than or equal to T2b, were selected for this analysis. Between 1989 and 1996, 137 such patients were treated with 3D-CRT and 145 with TPI. The median ages of the 3D-CRT and TPI groups were 68 years and 64 years, respectively. The median dose of 3D-CRT was 70.2 Gy, and the median implant dose was 150 Gy. Prostate-specific antigen relapse was defined according to the American Society of Therapeutic Radiation Oncology Consensus Statement, and toxicity was graded according to the Radiation Therapy Oncology Group morbidity scoring scale. The median follow-up times for the 3D-CRT and TPI groups were 36 and 24 months, respectively.

RESULTS

Eleven patients (8%) in the 3D-CRT group and 12 patients (8%) in the TPI group developed a biochemical relapse. The 5-year PSA relapse-free survival rates for the 3D-CRT and the TPI groups were 88% and 82%, respectively (P = .09). Protracted grade 2 urinary symptoms were more prevalent among patients treated with TPI compared with 3D-CRT. Grade 2 urinary toxicity, which was manifest after the implant and persisted for more than 1 year after this procedure, was observed in 45 patients (31%) in the TPI group. In these 45 patients, the median duration of grade 2 urinary symptoms was 23 months (range, 12 to 70 months). On the other hand, acute grade 2 urinary symptoms resolved within 4 to 6 weeks after completion of 3D-CRT, and the 5-year actuarial likelihood of late grade 2 urinary toxicity for the 3D-CRT group was only 8%. The 5-year actuarial likelihood of developing a urethral stricture (grade 3 urinary toxicity) for the 3D-CRT and TPI groups was 2% and 12%, respectively (P<.0002). Of 45 patients who developed grade 2 or higher urinary toxicity after TPI, the likelihood of resolution or significant improvement of these symptoms at 36 months from onset was 59%. The 5-year likelihood of grade 2 late rectal toxicity for the 3D-CRT and TPI patients was similar (6% and 11%, respectively; P = .97). No patient in either group developed grade 3 or higher late rectal toxicity. The 5-year likelihood of posttreatment erectile dysfunction among patients who were initially potent before therapy was 43% for the 3D-CRT group and 53% for the TPI group (P = .52).

CONCLUSION

Both 3D-CRT and TPI are associated with an excellent PSA outcome for patients with early-stage prostate cancer. Urinary toxicities are more prevalent for the TPI group and subsequently resolve or improve in most patients. In addition to evaluating long-term follow-up, future comparisons will require detailed quality-of-life assessments to further determine the impact of these toxicities on the overall well-being and quality of life of the individual patient.

Acute urinary morbidity following I-125 interstitial implantation of the prostate gland

The objective of this paper was to evaluate the acute urinary morbidity associated with I-125 interstitial implantation of the prostate gland. From 1991-1995, 117 patients underwent ultrasound (U/S)-guided implantation of the prostate gland. Median dose to 90% of the gland (d90) was 14.68 Gy (range = 1.65-21.75 Gy). The patients' urinary symptoms were recorded pre-implantation and at regular intervals after implantation using the International Prostate Symptom Score (IPSS), a self-assessment questionnaire in which patients scored 7 symptoms: incomplete emptying, frequency, intermittency, urgency, weak stream, straining, and nocturia. Median follow-up was 12 months. The natural history of implant-related urinary symptoms was assessed in this manner. In addition, dosimetric factors including U/S prostate volume, total activity, activity per seed, dose volume histogram (DVH) values for dose to gland, and dose area histogram (DAH) values for dose to urethra and bladder were examined for correlation to the severity of each symptom as well as to total IPSS (sum of the individual symptom scores). Total IPSS peaked at 1 month post-implant and gradually returned to approximately baseline at 24 months. Total IPSS directly correlated with total activity and DVH for the prostate. Total IPSS, however, did not correlate with bladder or urethral DAH. With the exception of frequency, individual symptoms did not correlate with dose to gland, bladder, or urethra. Frequency scores did, however, correlate not only with dose to prostate gland but also dose to urethra. The acute urinary side effects of I-125 prostate implantation are transient and peak at 1 month post-implant. The severity of the urinary irritative symptoms developed are closely related to total dose to the gland. Urethral dose appears to affect frequency most significantly. Urinary symptoms, therefore, may be a limiting factor when considering dose escalation with I-125.