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

Feasibility of amifostine administration in conjunction with high-dose rate brachytherapy

This ongoing study was initiated to determine the feasibility of administering amifostine (Ethyol, WR-2721; MedImmune, Inc, Gaithersburg, MD) with monomodal high-dose rate (mHDR) brachytherapy and to assess the tolerability and side effects of this combination. To date, 18 patients suitable for prostate implant brachytherapy (<or=T2aN0; prostate-specific antigen <or= 10 ng/mL; Gleason score <or= 6) have been treated with mHDR brachytherapy, receiving four 9-Gy fractions administered twice daily for 2 days. Amifostine (500 mg) is administered subcutaneously on the day before implant and 30 to 60 minutes before the first and third mHDR treatments. All 18 patients have received amifostine and brachytherapy as planned. Nausea was manageable with oral prochlorperazine in the pretreatment phase and our standard antiemesis protocol (intravenous promethazine, with granisetron if needed) during the implant; hypotension and asthenia were not problematic. During the 2-week post-treatment phase, grade 1 cystitis occurred in eight of 18 patients; grades 1 and 2 proctitis occurred in six of 18 and five of 18 patients, respectively. Six patients developed urinary obstruction symptoms. Preliminary results support the feasibility and tolerability of subcutaneous amifostine in conjunction with mHDR brachytherapy. Total accrual goal is 50 patients to assess long-term efficacy. Additional studies of HDR with amifostine are planned for patients with recurrent prostate and gynecologic cancer.

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.

Predictors of Extracapsular Extension and Its Radial Distance in Prostate Cancer

PURPOSE

Tightly constricted isodose lines are generated using brachytherapy or intensity-modulated radiation therapy (IMRT) treatment planning systems for prostate cancer. Definition of margins that encompass subclinical disease extension is important to maximize dose escalation while attemptingto adhere to normal tissue dose tolerances. In this study, we attempted to find predictors of extracapsular extension (ECE) and its radial distance.

MATERIALS AND METHODS

Pathological assessment of ECE and its radial distance was performed on 712 radical prostatectomy specimens. Preoperative data (initial prostate-specific antigen, clinical stage, ultrasound volume, and biopsy Gleason score) were evaluated for their ability to predict the presence of ECE and its radial distance.

RESULTS

Measurable disease was noted outside the prostatic capsule in 185 of 712 (26.0%) specimens. All preoperative parameters except ultrasound volume were able to predict the presence of ECE. However, none of them was predictive of the radial ECE distance. In this group, the median and the range of the maximum depth of invasion (radial extension from the capsule) were 2.00 and 0.5-12.00 mm, respectively. The mean radial distance from the capsule was 2.93 mm, SD +/- 2.286 mm. All subgroups had some patients with radial extension ranging from 0-2 mm, 2-5 mm, to > 5 mm. Only patients with a prostate-specific antigen of 0-4 ng/mL had no extension > 5 mm.

CONCLUSIONS

This is the largest series in the literature thus far that quantitatively assesses radial extracapsular extension. Coverage of subclinical disease must be addressed carefully before successful implementation of intensity-modulated radiation therapy, brachytherapy, or prostatectomy in order to avoid geographical miss.

Prostate implant nomograms for the North American Scientific 103Pd seed

Palladium-103-(103Pd) seed has been increasingly used in prostate implantation as either definitive or boost therapy because of its shorter half-life and higher initial dose rate. Because a growing number of radiation oncologists prefer real-time implantation in the operating room, it will be helpful if the total activity of the seeds can be determined based on the gland size before the patient is taken to the operating room. Based on our clinic data, nomograms have therefore been developed for one of the widely used 103Pd seeds, the MED3633 seed, which is produced by North American Scientific, Inc. (NASI). The total activities for implant volume ranging from 15 cc to 55 cc are provided for both seed "monotherapy" and seed boost.

Is intraoperative nomogram-based overplanning of prostate implants necessary?

PURPOSE

Several investigators have described intraoperative planning of prostate implants based on a nomogram. The aim of this work was to investigate the adequacy of the nomogram in predicting the total activity necessary for optimal dosimetry.

METHODS AND MATERIALS

Eighty CT-based postimplant treatment plans were performed for patients who underwent ultrasound guided I-125 permanent implants alone between April 2000 and March 2001. The cohort of 40 patients had early stage (T1-T2) prostatic carcinoma and pre-treatment prostate volumes of 19-50 cc. I-125 seeds (0.391 mCi/seed) were implanted to achieve a distribution of 75% of the activity peripherally and 25% centrally. The CT studies were obtained on the day of (CT1) and at 1 month (CT2) after implant. All patients were catheterized at CT1, and 28 patients were catheterized at CT2 to visualize the urethra. For each patient, the percentage difference (dA) between the total implanted and nomogram predicted activity for a known prostate volume was calculated. The V200 (volume receiving 200% of the prescribed dose), V150, V100, V90, D100 (maximum dose received by 100% of the volume), D90, and D80 were measured for the prostate at CT1 and CT2. For the urethra, V275, V250, V200, and V150 were evaluated, and V100 and V70 were evaluated for the rectum. The Pearson test was used to correlate the dosimetric parameters with dA. Linear regression was used to fit the correlation of the volume and dose parameters with dA.

RESULTS

The median V100 at CT1 and CT2 was 91.8% and 94.2%, respectively. The Pearson test was significant for the prostate V100 and dA measured at CT1 (p = 0.005) but not at CT2 (p = 0.106). A similar correlation was found for the prostate D90 at CT1 (p = 0.002), but not at CT2 (p = 0.076). D100 (maximum dose received by 100% of volume) for prostate did not correlate with dA at CT1 (p = 0.094) and CT2 (p = 0.148). The volume of the prostate receiving higher doses (greater than 150% and 200% of the prescribed dose) correlated with dA. There were no significant correlations between V275, V250, V200, and V150 at CT1 and CT2 as a function of dA for the urethra. V100 and V70 for the rectum correlated significantly with dA; for V100, p = 0.041 at CT1 and p = 0.014 at CT2 and for V70, p = 0.041 at CT1 and p = 0.026 at CT2. A linear regression model fitted to the prostate data obtained from CT1 with the goal of achieving a V100 of 90% and D90 of 145 Gy suggests that no increase in the number of seeds may be warranted using intraoperative planning. The implants examined showed no concomitant increase of urethral doses with increase in activity relative to the nomogram, but showed an increase in the rectal doses for the same increase in activity.

CONCLUSION

The doses evaluated at CT1 represent an underestimate, whereas those obtained at CT2 represent an overestimate of the actual delivered protracted permanent implant dose. Based on these results and consideration of the dynamic nature of the dose distribution, target coverage obtained with intraoperative planning using the nomogram predicted activity is consistent with published guidelines for a quality implant and critical structure doses are within tolerance.

Primary radiation therapy for localized prostate cancer

Prostate cancer in men is similar to breast cancer in women; both cancers rank first, respectively, in incidence and are normally responsive to radiation therapy. In addition, advances in mammography help detect earlier breast cancers, and the development and refinement of prostatic specific antigen (PSA) has resulted in early detection of low-stage localized prostate cancers. This has generated debate over the proper management of localized prostate cancer. While there have not been any controlled, prospective, randomized trials of sufficient power to compare the various local therapies, based on the current available data, the three commonly used local modalities, surgery, and external beam radiation therapy and brachytherapy (radioactive seed implant), have similar efficacy controlling the disease up to 10 years in many patients. Technological advances in treatment delivery and planning have improved the treatment of prostate cancer with external-beam radiotherapy using three-dimensional conformal radiotherapy (3DCRT), ultrasound-guided transperineal implant, or intensity-modulated radiotherapy (IMRT), as well as proton or neutron beam based therapies.

Radioactive sources embedded in suture are associated with improved postimplant dosimetry in men treated with prostate brachytherapy

BACKGROUND AND PURPOSE

Reports using the retropubic and transperineal technique of prostate brachytherapy suggest that adequate radiation doses are required for good clinical results with I-125. After 3 years of using loose sources (LS), radioactive sources embedded in suture (SES) were introduced into our prostate brachytherapy technique. The purpose of the present report is to determine whether dosimetric quantifiers of implant adequacy were affected by the use of SES.

MATERIALS AND METHODS

Between September 1999 and April 2000, 20 patients were treated with prostate brachytherapy alone with a preplanned, preloaded needle technique using LS. Between May 2000 and February 2001, 20 patients were treated with prostate brachytherapy alone with a preplanned, preloaded needle technique using SES. Dosimetric quantifiers (DQ) of implant adequacy were calculated using a computed tomography scan performed 1 month following prostate brachytherapy. DQ were compared between patients treated with LS and patients treated with SES.

RESULTS

The demographic characteristics were similar for each group. Men treated with SES had slightly smaller prostate glands compared to men treated with LS. The mean total activity and activity per seed were similar for each group but the activity per unit volume was slightly higher for the SES group. Patients treated with SES were found to have significantly improved DQ compared to patients treated with LS. The mean V100 for patients treated with SES was 94.10% compared to 86.54% in those patients treated with LS (P<0.001).

CONCLUSIONS

In our experience using preplanning and preloaded needles, the use of SES is associated with improved postimplant DQ.

Treatment of prostate cancer with radiotherapy: should the entire seminal vesicles be included in the clinical target volume?

PURPOSE

When treating high-risk prostate cancer with radiation therapy, inclusion of the seminal vesicles (SVs) within the clinical target volume (CTV) can dramatically increase the volume of radiated normal tissues and hinder dose escalation. Because cancer may involve only the proximal portion of the frequently lengthy SVs, we performed a complete pathology review of prostatectomy specimens to determine the appropriate length of SV to include within the CTV when SV treatment is indicated.

METHODS AND MATERIALS

A detailed pathologic analysis was performed for 344 radical prostatectomy specimens (1987-2000). All slides from each case were reviewed by a single pathologist (N.S.G.). Factors recorded for each case included length of each SV (cm), length of cancer involvement in each SV (cm) measured from the prostate-SV junction, and percentage of SV length involved.

RESULTS

Fifty-one patients (15%) demonstrated SV involvement in 81 SVs (21 unilateral, 30 bilateral SV involvement). The median SV length was 3.5 cm (range: 0.7-8.5 cm). Factors associated with SV involvement included the pretreatment PSA level, biopsy Gleason score, and clinical T classification. The commonly used risk group stratification was very effective at predicting SV positivity. Only 1% of low-risk patients (PSA <10 ng/mL, Gleason <or=6, and clinical stage <or=T2a) demonstrated SV involvement vs. 27% of high-risk patients. Patients with only one high-risk feature still demonstrated a 15% risk of SV involvement, whereas 58% of patients with all three high-risk features had positive SVs. The median length of SV involvement was 1.0 cm (90th percentile: 2.0 cm, range: 0.2-3.8 cm). A median of 25% of each SV was involved with adenocarcinoma (90th percentile: 54%, range: 4%-75%). For the 81 positive SVs, no factor was associated with a greater length or percentage of SV involvement. In the entire population, 7% had SV involvement beyond 1.0 cm. There was an approximate 1% risk of SV involvement beyond 2.0 cm or 60% of the SV. In addition, this risk was less than 4% for all subgroups, including high-risk patients.

CONCLUSIONS

A portion of the SV should be included in the CTV only for higher-risk patients (PSA >or=10 ng/mL, biopsy Gleason >or=7, or clinical T stage >or=T2b). When treating the SV for prostate cancer, only the proximal 2.0-2.5 cm (approximately 60%) of the SV should be included within the CTV.

Pathologic evidence of dose-response and dose-volume relationships for prostate cancer treated with combined external beam radiotherapy and high-dose-rate brachytherapy

PURPOSE

The clinical significance of postradiotherapy (RT) prostate biopsy characteristics is not well understood relative to the known prognostic factors. We performed a detailed pathologic review of posttreatment biopsy specimens in an attempt to clarify their relationship with clinical outcome and radiation dose.

METHODS AND MATERIALS

Between 1991 and 1998, 78 patients with locally advanced prostate cancer were prospectively treated with external beam RT in combination with high-dose-rate brachytherapy at William Beaumont Hospital and had post-RT biopsy material available for a complete pathologic review. Patients with any of the following characteristics were eligible for study entry: pretreatment prostate-specific antigen level > or =10.0 ng/mL, Gleason score > or =7, or clinical Stage T2b-T3cN0M0. Pelvic external beam RT (46.0 Gy) was supplemented with three (1991-1995) or two (1995-1998) ultrasound-guided transperineal interstitial (192)Ir high-dose-rate implants. The brachytherapy dose was escalated from 5.50 to 10.50 Gy per implant. Post-RT prostate biopsies were performed per protocol at a median interval of 1.5 years after RT. All pre- and post-RT biopsy specimen slides from each case were reviewed by a single pathologist (N.S.G.). The presence and amount of residual cancer, most common RT-effect score, and least amount RT-effect score were analyzed. The median follow-up was 5.7 years. Biochemical failure was defined as three consecutive prostate-specific antigen rises.

RESULTS

Forty patients (51%) had residual cancer in the post-RT biopsies. The 7-year biochemical control rate was 79% for patients with negative biopsies vs. 62% for those with positive biopsies with marked RT damage vs. 33% for those with positive biopsies with no or minimal RT damage. A greater percentage of positive pre-RT biopsy cores (p = 0.01), lower total RT dose (p = 0.001), lower dose per implant (p = 0.001), and greater percentage of positive post-RT biopsy cores (p = 0.01) were each associated with biochemical failure (Cox regression, univariate analysis). For patients with <25% positive post-RT biopsy cores, the 7-year biochemical control rate was 81% vs. a 62% biochemical control rate for those with 25-49% positive cores and only 32% for those with > or =50% positive cores (p = 0.01). On Cox multiple regression analysis, only the percentage of positive pre-RT biopsy cores and RT dose remained significantly associated with biochemical failure. Of all the factors analyzed, only the pretreatment cancer volume and lower RT dose were significantly associated with residual cancer and/or residual cancer with no or minimal RT damage. A greater percentage of positive pre-RT biopsy cores was associated with both a positive post-RT biopsy (p = 0.08) and a greater percentage of positive post-RT biopsy cores (p = 0.04). A lower total RT dose was associated with both a positive post-RT biopsy (p = 0.08) and a greater percentage of positive post-RT biopsy cores (p = 0.02). For patients who received <80 Gy (equivalent in 2-Gy fractions), 73% had positive post-RT biopsies vs. a 56% biopsy positivity rate for those who received 84-90 Gy and only 39% for those who received > or =92 Gy (p = 0.07).

CONCLUSION

Patients with positive post-RT biopsies are more likely to experience biochemical failure, especially when the RT damage is minimal. Patients who have a larger pretreatment tumor volume or receive a lower RT dose are more likely to demonstrate post-RT biopsy positivity and biochemical failure.

Changes in extent and zonal distribution of prostatic adenocarcinoma in patients preoperatively treated with neoadjuvant endocrine therapy: analysis on whole-mounted prostatectomy specimens

BACKGROUND

An increasing number of pharmacologic agents that induce reversible androgen deprivation are available for neoadjuvant endocrine therapy (NET) for prostatic adenocarcinoma (PCA). If information about the regression pattern of PCA after NET is recognized, more effective decision-making for subsequent therapies such as prostatectomy and radiotherapy, will be possible.

METHODS

The extent and zonal distribution of PCA with or without NET were examined in totally embedded radical prostatectomy specimens obtained from 103 patients with PCA. Seventy-nine of the 103 patients received androgen deprivation therapy (castrated). The zonal location of PCA lesions (non-transition vs transition zone), was identified in three slices from the inferior, middle and superior parts of the prostate. The area of the PCA lesions in these zones was measured.

RESULTS

Prostatic adenocarcinoma was identified in 94 of 103 cases: 24 of 24 cases (100%) and 70 of 79 cases (87%) in the non-castrated and castrated groups, respectively. The NET induced a mean of 21% reduction of the prostate volume and lowered the serum PSA level by one eighth. The frequency of capsular penetration in the castrated cases (57%) was lower than in the non-castrated cases (83%) and confinement of the PCA lesion was found in 32% of the castrated and 17% of the non-castrated cases. The reduction rate of the extent of the PCA lesions in the non-transition and transition zone was 33% and 28%, respectively. The extent of the PCA lesions were smaller in the anterior parts, especially at the superior portion of the prostate.

CONCLUSION

Neoadjuvant endocrine therapy induced involutional changes of the PCA evenly across both the non-transition and transition zones. The density of the PCA lesions was low in the anterior part of the prostate. This information is useful for decision-making in post-NET.

Defining a dose-response relationship with radiotherapy for prostate cancer: is more really better?

PURPOSE

Data were reviewed addressing the association between radiation therapy (RT) dose and treatment outcome for localized prostate cancer to help clarify the existence of a potential dose-response relationship.

METHODS AND MATERIALS

Articles were identified through the MEDLINE database, CancerLit database, and reference lists of relevant articles. Studies were categorized into four groups based upon the endpoint analyzed, including biochemical control (BC), local control (LC), pathologic control (PC), and cause-specific survival (CSS). The impact of increasing RT dose with each endpoint was recorded.

RESULTS

Twenty-two trials involving a total of 11,297 patients were identified. Of the 11 trials addressing the association of RT dose with LC, 9 showed statistically significant improvements. Of the 12 trials that reported BC with RT dose, all showed statistically significant improvements. Two out of 4 studies analyzing PC with increasing dose showed a positive correlation. Finally, 3 out of 9 studies addressing RT dose with CSS showed statistically significant improvements. Despite inconclusive results, patients with poor risk features (e.g., prostate-specific antigen [PSA] > or = 10, Gleason score [GS] > or = 7, or tumor stage > or = T2b) were most likely to benefit from increasing dose with respect to each endpoint. However, the optimal RT dose and the magnitude of benefit of dose escalation could not be identified.

CONCLUSIONS

Although RT dose appears to correlate with various measures of treatment outcome, objective, high-quality data addressing this critical issue are still lacking. At the present time, the absolute improvement in outcome due to dose escalation, the subset of patients benefitting most, and the optimal dose remain to be defined.

High-dose-rate brachytherapy in the treatment of carcinoma of the prostate

BACKGROUND

Although radical prostatectomy for localized disease is considered as a standard of care, external-beam radiotherapy and brachytherapy are equally effective. We report on the technique and preliminary results of high-dose-rate (HDR) brachytherapy using a temporary iridium-192 implant technique.

METHODS

The authors reviewed the literature on the techniques, treatment protocols, and results of HDR brachytherapy in the treatment of carcinoma of the prostate, and they report their own protocols, technique, and results.

RESULTS

The combination of HDR brachytherapy and external irradiation has been well tolerated by all 200 patients in our series, with less than 3% grade 3 late complications and with 95% PSA relapse-free survival with a median follow-up of 24 months.

CONCLUSIONS

HDR brachytherapy may be the most conformal type of irradiation in the treatment of carcinoma of the prostate regardless of tumor size, anatomical distortion, and organ mobility.

The treatment of prostate cancer: an overview of current options

PURPOSE

The purpose of this report is to discuss the current treatment options available to the patient with prostate cancer in all stages of the disease.

OVERVIEW

With the exception of skin cancer, prostate cancer is the most common cancer in men in the United States. Most patients in the current era will present with organ-confined disease, amenable to curative treatment. Treatment for organ-confined disease includes watchful waiting, radical prostatectomy, radiation therapy, and cryosurgery in selective cases. Hormone therapy is the cornerstone of treatment of patients with advanced prostate cancer. There is no curative treatment for hormone-refractory prostate cancer.

CLINICAL IMPLICATIONS

The availability of several therapeutic options for localized prostate cancer warrants careful consideration when planning treatment with curative intent. Patients need to be active participants in decision making, and they must be aware of the benefits and possible complications of the different types of treatment. Patients with advanced prostate cancer need to be aware that hormone treatment will provide temporization and palliation in the majority of cases. Hormone-resistant prostate cancer is refractory to most forms of conventional and experimental therapy.

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.

On the determination of an effective planning volume for permanent prostate implants

PURPOSE

In current practice, planning for prostate brachytherapy is based on the state of the prostate at a particular instant in time. Because treatment occurs over an extended period, changes in the prostate volume (gland shrinkage) and seed displacement lead to disagreement between planned dosimetry to the prostate and the dose actually received by the prostate. Discrepancies between planned and actual dose to the rectum and urethra also occur. The purpose of this study is to investigate the possibility of defining an "effective planning volume" that compensates for changes in prostate volume and seed displacement.

METHODS AND MATERIALS

Waterman's formula is used to estimate prostate shrinkage and seed displacement. The prostate volume and potential seed positions at days 0, 6, 12, 18, 24, and 30 are used in formulating time-dependent dosimetric treatment planning models. Both single-period and multi-period models are proposed and analyzed. A state-of-the-art computational engine generates unbiased, high-quality treatment plans in a matter of minutes. Plans are evaluated using coverage and conformity indices computed at specific times over a period of 30 days. The models allow dose to urethra and rectum to be strictly controlled at specific instants in time, or throughout the 30-day horizon.

RESULTS

For plans generated from the single-period models-based on projected prostate volumes and potential seed positions on days t = 0, 6, 12, 18, 24, 30, respectively-as t increases, the conformity index improves while the coverage worsens. In particular, the best coverage and worst conformity are achieved for the plan generated using t = 0 (day 0) information. This plan provides over 99% coverage over the entire 30-day period, and while it has initial conformity index 1.24, the conformity index climbs to 1.58 by day 30. Conversely, the worst coverage and best conformity are achieved when the plan is generated using projected information from t = 30 (day 30). Plans based on projected data at day 30 yield an initial coverage of only 84%, with conformity scores less than 1.34 over the entire 30-day period. Among the multi-period plans, with the exception of the two-period plan obtained using day 0 and projected day 6 data, the average coverage is 98% while conformity indices below 1.46 are maintained throughout the 30-day horizon. Excessive dose to the urethra and rectum is observed when only day 0 dosimetric and volumetric data are imposed in the planning procedure. In this case, by day 30, 89% of urethra volume receives dose in excess of 120% of the remaining prescription dose. Similarly, 40% of rectum volume receives dose in excess of the prescribed upper dose bound of 78% of the remaining prescription dose. When multi-period dosimetric constraints for urethra and rectum are imposed, dose to these structures is controlled throughout the 30-day period.

CONCLUSIONS

A planning method that takes into account prostate shrinkage and seed displacement over time can be used to adjust the balance between coverage and conformity. Incorporating projected future volumetric information is useful in providing more conformal plans, in some cases improving conformity by as much as 21% while sacrificing roughly 7% of initial coverage. Evidence of possible morbidity reduction to urethra and rectum via the use of multi-period dosimetric constraints on these structures is demonstrated. Among all plans considered, the plan obtained via the six-period model provides the best coverage and conformity over the 30-day horizon.

Localized prostate cancer

Much controversy still surrounds the diagnosis and treatment of localized prostate cancer. Urologists generally believe that early detection and aggressive surgical therapy saves lives despite the absence of confirmatory randomized trials. Furthermore, a recent survey of radiation oncologists and urologists revealed marked polarization toward their own specialties when asked how they would counsel patients on therapy for newly diagnosed localized disease. Some issues are not controversial, however. There is general agreement that pretreatment tumor characteristics, including serum prostate-specific antigen level at diagnosis, tumor grade, and clinical stage as judged by digital rectal examination, are important prognosticators for treatment outcomes independent of the type of treatment. Also, there is sufficient experience with standard therapies (radical prostatectomy and external beam radiotherapy) to counsel patients on the chance for cure and the expected incidence of acute and chronic toxicities. A comparative evaluation of various therapies for prostate cancer should include consideration of cancer control, acute toxicity, treatment-related quality of life issues, salvage of treatment failures, and cost. Within this context, we believe that newly diagnosed patients should be counseled on all available treatment options before embarking on a course of therapy.

Long-term urinary toxicity after 3-dimensional conformal radiotherapy for prostate cancer in patients with prior history of transurethral resection

PURPOSE

To report on the long-term urinary morbidity among prostate cancer patients with a prior history of a transurethral resection of the prostate (TURP) treated with high-dose 3-dimensional conformal radiotherapy (3D-CRT).

METHODS AND MATERIALS

Between 1988 and 1997, 1100 patients with clinically localized prostate cancer were treated with 3D-CRT. Of these, 120 patients (8%) were identified as having had a prior TURP and are the subjects of this analysis. The median age was 71 years (range: 49-83 years). The clinical stages of the patients were T1c: 33 (28%); T2a: 38 (32%); T2b: 15 (13%); and T3: 34 (27%). Neoadjuvant androgen ablation therapy was given to 39 (33%). The median radiation dose prescribed to the planning target volume was 75.6 Gy (range: 64.8-81 Gy). The median elapsed time from TURP to initiation of 3D-CRT was 69 months (range: 4-360 months). The median follow-up time was 51 months (range: 18-109 months).

RESULTS

Five patients of the 120 with a prior history of TURP (4%) developed a urethral stricture after 3D-CRT which was corrected with dilatation. The 5-year actuarial likelihood of >/= Grade 2 late urinary toxicities was 9%. No Grade 4 urinary toxicities were observed in this group of patients. Among 110 patients who were completely continent of urine prior to 3D-CRT, 10 (9%) developed stress incontinence requiring 1 pad daily for protection or experienced occasional leakage (not requiring pad protection). The 5-year incidence of >/= Grade 1 stress incontinence was 18% in patients who developed acute >/= Grade 2 GU symptoms during the course of 3D-CRT compared to 7% for patients who experienced Grade 1 or no acute urinary symptoms (p = 0.05). The radiation dose (>/=75.6 Gy vs. <75.6 Gy), the number of prior TURP procedures, or the volume of resected tissue at the time of TURP had no significant impact on the long-term urinary morbidity outcome. A multivariate analysis demonstrated that the presence of Grade 2 acute urinary symptoms was the only predictor of >/= Grade 1 stress incontinence after 3D-CRT in this group of patients.

CONCLUSIONS

Despite prior TURP, the incidence of >/= Grade 3 urinary toxicities is low. Nevertheless, especially among patients with a prior history of TURP who experience Grade 2 acute urinary symptoms during radiation treatment, a higher risk of stress incontinence is observed.

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.

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.

Matched-pair analysis of conformal high-dose-rate brachytherapy boost versus external-beam radiation therapy alone for locally advanced prostate cancer

PURPOSE

We performed a matched-pair analysis to compare our institution's experience in treating locally advanced prostate cancer with external-beam radiation therapy (EBRT) alone to EBRT in combination with conformal interstitial high-dose-rate (HDR) brachytherapy boosts (EBRT + HDR).

MATERIALS AND METHODS

From 1991 to 1998, 161 patients with locally advanced prostate cancer were prospectively treated with EBRT + HDR at William Beaumont Hospital, Royal Oak, Michigan. Patients with any of the following characteristics were eligible for study entry: pretreatment prostate-specific antigen (PSA) level of >/= 10.0 ng/mL, Gleason score >/= 7, or clinical stage T2b to T3c. Pelvic EBRT (46.0 Gy) was supplemented with three (1991 through 1995) or two (1995 through 1998) ultrasound-guided transperineal interstitial iridium-192 HDR implants. The brachytherapy dose was escalated from 5.50 to 10.50 Gy per implant. Each of the 161 EBRT + HDR patients was randomly matched with a unique EBRT-alone patient. Patients were matched according to PSA level, Gleason score, T stage, and follow-up duration. The median PSA follow-up was 2.5 years for both EBRT + HDR and EBRT alone.

RESULTS

EBRT + HDR patients demonstrated significantly lower PSA nadir levels (median, 0.4 ng/mL) compared with those receiving EBRT alone (median, 1.1 ng/mL). The 5-year biochemical control rates for EBRT + HDR versus EBRT-alone patients were 67% versus 44%, respectively (P <.001). On multivariate analyses, pretreatment PSA, Gleason score, T stage, and the use of EBRT alone were significantly associated with biochemical failure. Those patients in both treatment groups who experienced biochemical failure had a lower 5-year cause-specific survival rate than patients who were biochemically controlled (84% v 100%; P <.001).

CONCLUSION

Locally advanced prostate cancer patients treated with EBRT + HDR demonstrate improved biochemical control compared with those who are treated with conventional doses of EBRT alone.

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.

[Prostatic brachytherapy: an alternative therapy. Review of the literature]

Radical prostatectomy remains the 'golden standard' therapy for localized prostate carcinoma for patients with a survival rate of more than ten years. However, because of the complications inherent in this surgical procedure, prostatectomy is presently increasingly challenged by various radiotherapy procedures. In the last decade, more sophisticated conformal therapy techniques have been proposed for prostate cancer patients. In parallel, for highly selected patients, brachytherapy is being promoted by an increasing number of medical centers. In fact, brachytherapy techniques for prostate cancers can be traced back to 1911, but recently developed techniques offer reliability and reproducibility, with satisfactory results in terms of tumor control and reduced toxicity, in selected patients. We present here the different techniques that are available today in prostate cancer brachytherapy.

Treatment planning for prostate implants using magnetic-resonance spectroscopy imaging

PURPOSE

Recent studies have demonstrated that magnetic-resonance spectroscopic imaging (MRSI) of the prostate may effectively distinguish between regions of cancer and normal prostatic epithelium. This diagnostic imaging tool takes advantage of the increased choline plus creatine versus citrate ratio found in malignant compared to normal prostate tissue. The purpose of this study is to describe a novel brachytherapy treatment-planning optimization module using an integer programming technique that will utilize biologic-based optimization. A method is described that registers MRSI to intraoperative-obtained ultrasound images and incorporates this information into a treatment-planning system to achieve dose escalation to intraprostatic tumor deposits.

METHODS

MRSI was obtained for a patient with Gleason 7 clinically localized prostate cancer. The ratios of choline plus creatine to citrate for the prostate were analyzed, and regions of high risk for malignant cells were identified. The ratios representing peaks on the MR spectrum were calculated on a spatial grid covering the prostate tissue. A procedure for mapping points of interest from the MRSI to the ultrasound images is described. An integer-programming technique is described as an optimization module to determine optimal seed distribution for permanent interstitial implantation. MRSI data are incorporated into the treatment-planning system to test the feasibility of dose escalation to positive voxels with relative sparing of surrounding normal tissues. The resultant tumor control probability (TCP) is estimated and compared to TCP for standard brachytherapy-planned implantation.

RESULTS

The proposed brachytherapy treatment-planning system is able to achieve a minimum dose of 120% of the 144 Gy prescription to the MRS positive voxels using (125)I seeds. The preset dose bounds of 100-150% to the prostate and 100-120% to the urethra were maintained. When compared to a standard plan without MRS-guided optimization, the estimated TCP for the MRS-optimized plan is superior. The enhanced TCP was more pronounced for smaller volumes of intraprostatic tumor deposits compared to estimated TCP values for larger lesions.

CONCLUSIONS

Using this brachytherapy-optimization system, we could demonstrate the feasibility of MRS-optimized dose distributions for (125)I permanent prostate implants. Based on probability estimates of anticipated improved TCP, this approach may have an impact on the ability to safely escalate dose and potentially improve outcome for patients with organ-confined but aggressive prostatic cancers. The magnitude of the TCP enhancement, and therefore the risks of ignoring the MR data, appear to be more substantial when the tumor is well localized; however, the gain achievable in TCP may depend quite considerably on the MRS tumor-detection efficiency.

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

PURPOSE

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

METHODS AND MATERIALS

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

RESULTS

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

CONCLUSION

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

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.

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.

Historical perspective on prostate brachytherapy

Brachytherapy--radiation delivered close to or within a tumor--had its origins at the beginning of this century. Its use in prostate cancer was delayed first by the view that this was a relatively radioresistant cancer and then by clinical experience showing high failure and morbidity rates. More recently, technological innovations such as ultrasonography and computer-based treatment planning have made prostate brachytherapy a reasonable treatment option for many patients.

Imaging and radiotherapy of the prostate

Prostate cancer is the most common malignancy diagnosed in men. Over the past 10 to 20 years, advances in screening and diagnostic and management paradigms have led to improved treatment outcomes. This article offers an overview of the evolution of the role and nature of diagnostic imaging techniques in the management of prostate cancer.

The American Brachytherapy Society recommendations for permanent prostate brachytherapy postimplant dosimetric analysis

PURPOSE

The purpose of this report is to establish guidelines for postimplant dosimetric analysis of permanent prostate brachytherapy.

METHODS

Members of the American Brachytherapy Society (ABS) with expertise in prostate dosimetry evaluation performed a literature review and supplemented with their clinical experience formulated guidelines for performing and analyzing postimplant dosimetry of permanent prostate brachytherapy.

RESULTS

The ABS recommends that postimplant dosimetry should be performed on all patients undergoing permanent prostate brachytherapy for optimal patient care. At present, computed tomography (CT)-based dosimetry is recommended, based on availability cost and the ability to image the prostate as well as the seeds. Additional plane radiographs should be obtained to verify the seed count. Until the ideal postoperative interval for CT scanning has been determined, each center should perform dosimetric evaluation of prostate implants at a consistent postoperative interval. This interval should be reported. Isodose displays should be obtained at 50%, 80%, 90%, 100%, 150%, and 200% of the prescription dose and displayed on multiple cross-sectional images of the prostate. A dose-volume histogram (DVH) of the prostate should be performed and the D90 (dose to 90% of the prostate gland) reported by all centers. Additionally, the D80, D100, the fractional V80, V90, V100, V150 and V200 (i.e., the percentage of prostate volume receiving 80%, 90%, 100%, 150%, and 200% of the prescribed dose, respectively), the rectal, and urethral doses should be reported and ultimately correlated with clinical outcome in the research environment. On-line real-time dosimetry, the effects of dose heterogeneity, and the effects of tissue heterogeneity need further investigation.

CONCLUSION

It is essential that postimplant dosimetry should be performed on all patients undergoing permanent prostate brachytherapy. Guidelines were established for the performance and analysis of such dosimetry.

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.

American Brachytherapy Society (ABS) recommendations for transperineal permanent brachytherapy of prostate cancer

PURPOSE/OBJECTIVE

To develop and disseminate the American Brachytherapy Society (ABS) recommendations for the clinical quality assurance and guidelines of permanent transperineal prostate brachytherapy with 125I or 103Pd.

METHODS AND MATERIALS

The ABS formed a committee of experts in prostate brachytherapy to develop consensus guidelines through a critical analysis of published data supplemented by their clinical experience. The recommendations of the panels were reviewed and approved by the Board of Directors of the ABS.

RESULTS

Patients with high probability of organ-confined disease are appropriately treated with brachytherapy alone. Brachytherapy candidates with a significant risk of extraprostatic extension should be treated with supplemental external beam radiation therapy (EBRT). Patient selection guidelines were developed. Dosimetric planning of the implant should be carried out for all patients before seed insertion. A modified peripheral loading is preferred. The AAPM TG-43 recommendations requiring a change in prescription dose for 125I sources should be universally implemented. The recommended prescription doses for monotherapy are 145 Gy for 125I and 115-120 Gy for 103Pd. The corresponding boost doses (after 40-50 Gy EBRT) are 100-110 Gy and 80-90 Gy, respectively. Clinical evidence to guide selection of radionuclide (103Pd or 125I) is lacking. Post implant dosimetry and evaluation must be performed on all patients. It is suggested that the dose that covers 90% (D90) and 100% (D100) of the prostate volume and the percentage of the prostate volume receiving the prescribed dose (V100) be obtained from a dose-volume histogram (DVH) and reported.

CONCLUSION

Guidelines for appropriate patient selection, dose reporting, and improved quality of permanent prostate brachytherapy are presented. These broad recommendations are intended to be technical and advisory in nature, but the ultimate responsibility for the medical decisions rests with the treating physician. This is a constantly evolving field, and the recommendations are subject to modifications as new data becomes available.

A comprehensive review of prostate cancer brachytherapy: defining an optimal technique

PURPOSE

A comprehensive review of prostate cancer brachytherapy literature was performed to determine if an optimal method of implantation could be identified, and to compare and contrast techniques currently in use.

METHODS AND MATERIALS

A MEDLINE search was conducted to obtain all articles in the English language on prostate cancer brachytherapy from 1985 through 1998. Articles were reviewed and grouped to determine the primary technique of implantation, the method or philosophy of source placement and/or dose specification, the technique to evaluate implant quality, overall treatment results (based upon pretreatment prostate specific antigen, (PSA), and biochemical control) and clinical, pathological or biochemical outcome based upon implant quality.

RESULTS

A total of 178 articles were identified in the MEDLINE database. Of these, 53 studies discussed evaluable techniques of implantation and were used for this analysis. Of these studies, 52% used preoperative ultrasound to determine the target volume to be implanted, 16% used preoperative computerized tomography (CT) scans, and 18% placed seeds with an open surgical technique. An additional 11% of studies placed seeds or needles under ultrasound guidance using interactive real-time dosimetry. The number and distribution of radioactive sources to be implanted or the method used to prescribe dose was determined using nomograms in 27% of studies, a least squares optimization technique in 11%, or not stated in 35%. In the remaining 26%, sources were described as either uniformly, differentially, or peripherally placed in the gland. To evaluate implant quality, 28% of studies calculated some type of dose-volume histogram, 21% calculated the matched peripheral dose, 19% the minimum peripheral dose, 14% used some type of CT-based qualitative review and, in 18% of studies, no implant quality evaluation was mentioned. Six studies correlated outcome with implant dose. One study showed an association of implant dose with the achievement of a PSA nadir < or = 0.5. Two studies showed an improvement in biochemical control with a D90 (dose to 90% of the prostate volume) of 120 to 140 Gy or higher, and 2 additional studies found an association of clinical outcome with implant dose. One study correlated implant quality with biopsy results. Of the articles, 33 discussed evaluable treatment results, but only 16 reported findings based upon pretreatment PSA and biochemical control. Three- to 5-year biochemical control rates ranged from 48% to 100% for pretreatment PSAs < or = 4, 55% to 90% for PSAs between 4 and 10, 30% to 89% for PSAs > 10, < or = 20 and < 10% to 100% for PSAs > 20. Due to substantial differences in patient selection criteria (e.g., median Gleason score, clinical stage, pretreatment PSA), number of patients treated, median follow-up, definitions of biochemical control, and time points for analysis, no single technique consistently produced superior results.

CONCLUSIONS

Our comprehensive review of prostate cancer brachytherapy literature failed to identify an optimal treatment approach when studies were analyzed for treatment outcome based upon pretreatment PSA and biochemical control. Although several well-designed studies showed an improvement in outcome with total dose or implant quality, the numerous techniques for implantation and the varied and inconsistent methods to specify dose or evaluate implant quality suggest that standardized protocols should be developed to objectively evaluate this treatment approach. These protocols have recently been suggested and, when implemented, should significantly improve the reporting of treatment data and, ultimately, the efficacy of prostate brachytherapy.

Use of three-dimensional radiation therapy planning tools and intraoperative ultrasound to evaluate high dose rate prostate brachytherapy implants

PURPOSE

We performed a pilot study to evaluate the quality of high dose rate (HDR) prostate implants using a new technique combining intraoperative real-time ultrasound images with a commercially available 3-dimensional radiation therapy planning (3D RTP) system.

METHODS AND MATERIALS

Twenty HDR prostate implants performed by four different physicians on a phase I/II protocol were evaluated retrospectively. Radiation therapy (RT) consisted of pelvic external beam RT (EBRT) to a dose of 46 Gy in 2-Gy fractions over 5 weeks and 2 HDR implants (prescribed dose of 950 cGy per implant). Our in-house real-time geometric optimization technique was used in all patients. Each HDR treatment was delivered without moving the patient. Ultrasound image sets were acquired immediately after needle placement and just prior to HDR treatment. The ultrasound image sets, needle and source positions and dwell times were imported into a commercial computerized tomography (CT) based 3D RTP system. Prostate contours were outlined manually caudad to cephalad. Dose-volume histograms (DVHs) of the prostate were evaluated for each implant.

RESULTS

Four patients with stage T2a carcinoma, 4 with stage T2b, and 3 with stage T1c were studied. The median number of needles used per implant was 16 (range 14-18). The median treated volume of the implant (volume of tissue covered by the 100% isodose surface) was 82.6 cc (range 52.6-96.3 cc). The median target volume based on the contours entered in the 3D RTP system was 44.83 cc (range 28.5-67.45 cc). The calculated minimum dose to the target volume was 70% of the prescribed dose (range 45-97%). On average 92% of the target volume received the prescribed dose (range 75-99 %). The mean homogeneity index (fraction of the target volume receiving between 1.0 to 1.5 times the prescribed dose) was 80% or 0.8 (range 0.55-0.9). These results compare favorably to recent studies of permanent implants which report a minimum target volume dose of 43% (range 29-50%) and an average of 85% of the target volume (range 76-92%) receiving the prescribed dose.

CONCLUSIONS

The feasibility of evaluating HDR prostate implants using ultrasound images (acquired immediately prior to treatment) with a commercially available 3D RTP system was established. The dosimetric characteristics of these HDR implants appear to be substantially different compared to permanent implants. These developments allow quantitative evaluation of the dosimetric quality of HDR prostate treatments. Future studies will examine any correlation between the dosimetric quality of the implant and clinical/biochemical outcomes.

Actuarial disease-free survival after prostate cancer brachytherapy using interactive techniques with biplane ultrasound and fluoroscopic guidance

PURPOSE

To evaluate the effectiveness and safety of interactive transperineal brachytherapy under biplane ultrasound and fluoroscopic guidance in patients with localized prostate cancer.

METHODS AND MATERIALS

Brachytherapy using 125I or 103Pd radioactive seeds either alone or in combination with adjunctive external beam radiotherapy (XRT) was administered to 490 patients at a single institution. Post-treatment follow-up included clinical assessment of disease status, assays of serum prostate-specific antigen (PSA) levels and documentation of treatment-related symptoms and complications.

RESULTS

Actuarial disease-free survival at 5 yr was 79% (95% CI, 71-85%), and the 5-yr actuarial rate of local control was 98% (95% CI, 94-99%). Post-treatment PSA nadir and pretreatment PSA level were found to be significant predictors of disease-free survival. In patients with a PSA nadir < 0.5 ng/ml, 5-yr disease-free survival was 93% (95% CI, 84-97%), compared with 25% (95% CI, 5-53%) in patients whose PSA nadir was 0.5-1.0 ng/ml and 15% (95% CI, 3-38) in patients with a PSA nadir > 1.0 ng/ml. Brachytherapy was well tolerated with few post-treatment complications.

CONCLUSION

A broad range of patients with localized prostate cancer can benefit from transperineal brachytherapy with minimal morbidity. A post-treatment PSA nadir below 0.5 ng/ml provides a useful prognostic indicator of favorable long-term outcome.