Pelvic lymphadenectomy and transperineal interstitial implantation of IR 192 combined with external beam radiotherapy for bulky stage C prostatic carcinoma

Long-term results of treatment for prostate carcinoma by staging pelvic lymph node dissection and definitive irradiation using low-dose rate temporary iridium-192 interstitial implant and external beam radiotherapy

BACKGROUND

The objective of this study was to evaluate long-term treatment outcome of definitive irradiation by using temporary interstitial implant and limited dose of external beam radiotherapy in treatment of localized prostate carcinoma.

METHODS

In total, 536 patients with biopsy-proven adenocarcinoma of the prostate, classification T1-T3, underwent staging pelvic lymph node dissection and brachytherapy delivering an average tumor dose of 30 grays (Gy), supplemented by external beam radiation therapy for an additional dose of 36 Gy delivered over 4 weeks. One hundred of 536 (18%) patients had pathologic D1 disease. A total of 181 patients had undergone transurethral prostatectomy before the treatment. Repeat prostate biopsy was performed on 132 patients 18 or more months after treatment. None of the patients received neoadjuvant or adjuvant hormone therapy.

RESULTS

Cumulative disease free survival (DFS) including biochemical DFS at 10 and 15 years for classification T1B,C was 78% and 72%; for T2A, 78% and 78%; for T2B,C, 68% and 66%; and for T3A-C, 45% and 45%, respectively. Cause specific survival for the entire group at 10 and 15 years was 89% and 87%, respectively. Severe complications occurred only in the early developmental phase of the study.

CONCLUSIONS

In univariate analysis, the clinical stage, histologic grade, pretreatment PSA level, lymph node status, and results of repeat posttreatment biopsy were all independently significant prognostic factors. However, the authors' study indicates that in multivariate analysis, only two factors emerged with statistical significance-the status of pelvic lymph nodes and the results of posttreatment biopsy. This signifies the importance of local tumor control to achieve ultimate cure and the importance of assessment of pelvic lymph nodes before definitive local therapy other than radical prostatectomy, especially in the high-risk group.

High dose rate brachytherapy in the treatment of prostate cancer

Because the HDR brachytherapy treatments are delivered within minutes and on an outpatient basis, HDR brachytherapy is very well tolerated by patients and offers complete radiation safety. Published studies2, 11, 12, 13, 16, 17, 18, 22, 24, 25 have shown high local clinical and biochemical control rates. Chronic complications have been acceptably low. Very low rates of urinary incontinence and high sexual potency rates have been reported. Gastrointestinal morbidity has been minimal. The development of Ir-192 HDR afterloading brachytherapy and refinements in the dosimetry have ushered in a new era in prostate brachytherapy. The control of the radiation dose and the ability to shape the radiation treatment envelope using a stepping source have allowed a giant step forward in radiation oncology technology. It is now possible to deliver tumoricidal doses of radiation conformally to the prostate while minimizing the dose to the bladder, urethra, and rectum. At present, HDR afterloaded brachytherapy is the optimal whole-organ and tumor-specific conformal radiation therapy for prostate cancer.

Hyperfractionated conformal radiotherapy in locally advanced prostate cancer: results of a dose escalation study

PURPOSE

This study was initiated to assess the incidence of chronic complications and histologic and biochemical control following hyperfractionated conformal radiotherapy in patients with locally advanced prostate cancer.

METHODS AND MATERIALS

Between October 1991 and October 1994, 49 patients with locally advanced prostate cancer were entered on the first two dose levels of a prospective dose-escalation study using hyperfractionated three dimensional conformal radiotherapy. The first 25 patients received a minimum tumor dose of 78 Gy to the prostate and seminal vesicles in 6 weeks at 1.3 Gy, b.i.d. No increase in chronic toxicity compared with conventional radiotherapy was noted; therefore, an additional 24 patients were treated to a minimum tumor dose of 82.8 Gy to the prostate and seminal vesicles in 7 weeks at 1.15 Gy, b.i.d. Toxicity was scored according to the Radiation Therapy Oncology Group morbidity grading scale. Efficacy was assessed through scheduled postradiation prostate specific antigen values and ultrasound-guided biopsies. The median follow-up for the entire group was 20 months.

RESULTS

The hyperfractionated external radiation was well tolerated with minimal acute morbidity. At 30 months, the actuarial probability of Grade 2 gastrointestinal toxicity was 17%. At 30 months, the actuarial probability of Grade 2 genitourinary toxicity was 16%. There was no statistically significant difference between the two dose levels. No Grade 3 or 4 gastrointestinal or genitourinary toxicity was noted. At 12 months, 84% of patients had a prostate specific antigen < or = 4; and 53% < or = 1 ng/ml. At 12 months, 71% of patients had post radiation biopsies that were either negative (55% or showed a marked therapeutic effect (16%).

CONCLUSION

The use of hyperfractionated conformal radiotherapy facilitated dose escalation with no increase in chronic toxicity compared to standard doses. The initial tumor response based on prostate specific antigen measurements and postradiation biopsies is highly encouraging. Based on these results, an increase in dose to 87.4 Gy has been planned according to the schema of this ongoing dose escalation study.

Conformal prostate brachytherapy: initial experience of a phase I/II dose-escalating trial

PURPOSE

To improve treatment results on prostatic adenocarcinoma, conformal radiation therapy (CRT) has been used. Two major drawbacks of external CRT are: (a) internal organ motion/daily set-up variations, and (b) exclusion of several patients for CRT based on poor geometrical relationships as identified by three dimensional (3D) treatment planning. To overcome the above problems, we began the first prospective Phase I/II dose-escalating clinical trial of conformal brachytherapy (CB) and concurrent external beam irradiation.

METHODS AND MATERIALS

Fifty-nine patients with T2b-T3c prostatic adenocarcinoma received 176 transperineal ultrasound-guided conformal high-dose rate (HDR) boost implants. All patients received concomitant external beam pelvic irradiation. Dose escalation of the three HDR-CB fractions proceeded as follows: 5.5 Gy (30 patients), 6 Gy (20 patients), and 6.5 Gy (9 patients). The CB dose was prescribed to the prostate contour as outlined using an online biplanar transrectal ultrasound probe. The urethra, anterior rectal wall, and prostate boundaries were identified individually and outlined at 5 mm intervals from the base to the apex of the gland. The CB using real-time ultrasound guidance with interactive online isodose distributions was performed on an outpatient basis. As needles were placed into the prostate, corrections for prostate displacement were recorded and the isodose distributions were recalculated to represent the new relationship between the needles, prostate, and normal structures. No computerized tomography (CT) planning or implant preplanning was required.

RESULTS

No patient was rejected based on poor geometrical relation of pelvic structures. In every implant performed, prostate displacement was noted. Craniocaudal motion of the gland ranged from 0.5-2.0 cm (mean = 1.0 cm), whereas lateral displacement was 0.1-0.4 cm. With the interactive online planning system, organ motion was immediately detected, accounted for, and corrected prior to each HDR treatment. The rectal dose has ranged from 45 to 87%, and the urethral dose from 97 to 112% of the prostate dose. It is significant to note that operator dependence has been completely removed because the interactive online planning system uniformly guides the physicians.

CONCLUSIONS

With ultrasound guidance and the interactive online dosimetry system, organ motion (as compared to external beam) is insignificant because it can be corrected during the procedure without increasing target volume margins. Common pitfalls of brachytherapy, including operator dependence and difficulty with reproducibility, have been eliminated with the intraoperative online planning system.

Ultrasound-guided high dose rate conformal brachytherapy boost in prostate cancer: treatment description and preliminary results of a phase I/II clinical trial

PURPOSE

To improve results for locally advanced prostate cancer, a prospective clinical trial of concurrent external beam irradiation and fractionated iridium-192 (Ir-192) high dose rate (HDR) conformal boost brachytherapy was initiated.

METHODS AND MATERIALS

Between November 1991 and February 1994, 99 implants were performed on 33 patients with prostatic adenocarcinoma at William Beaumont Hospital. Using AJCC staging criteria, 9 patients had T2b tumors, 17 patients had T2c tumors, and 7 patients had T3 disease. Patients were treated with (a) 45.6 Gy whole pelvis external irradiation and (b) three HDR fractions of 5.5 Gy each (18 patients) or 6 Gy each (15 patients) to the prostate. Transperineal needle implants using real-time ultrasound guidance with interactive on-line isodose distributions were performed on an outpatient basis during weeks 1, 2, and 3 of external irradiation. Acute toxicity was scored using the Radiation Therapy Oncology Group (RTOG) morbidity grading system.

RESULTS

This technique of concurrent external pelvic irradiation and conformal HDR brachytherapy was well tolerated. No significant intraoperative or perioperative complications occurred. Three patients (9%) experienced Grade 3 acute toxicity (two dysuria and one diarrhea). All toxicities were otherwise Grades 1 or 2 and were primarily as expected from pelvic external irradiation. Persistent implant-related toxicities included Grades 1-2 perineal pain (12%) and hematospermia (15%). Median follow-up time was 13 months. Serum prostatic-specific antigen (PSA) levels normalized in 91% of patients (29 out of 32) within 1-14 months (median 2.8 months) after irradiation. PSA levels were progressively decreasing in the other three patients at last measurement. Prospectively planned prostatic rebiopsies done at 18 months in the first 10 patients were negative in 9 out of 10 (90%).

CONCLUSIONS

Acute toxicity has been acceptable with this unique approach using conformal high dose rate Ir-192 boost brachytherapy with concurrent external irradiation. The initial tumor response as assessed by serial PSA measurement and rebiopsy is extremely encouraging. Dose escalation will proceed in accordance with the protocol guidelines. Further patient accrual and longer follow-up will allow comparison to other techniques.

Improved local control and survival for surgically staged patients with locally advanced prostate cancer treated with up-front low dose rate iridium-192 prostate implantation and external beam irradiation

PURPOSE

In an effort to improve upon the historically poor local control and survival rates for locally advanced prostate carcinoma, a prospective multidisciplinary clinical trial was initiated using low dose rate Iridium-192 prostate implantation and external beam irradiation.

METHODS AND MATERIALS

Between January 1983 and September 1989, 57 patients with newly diagnosed bulky prostatic carcinoma (5 Stage B2, 52 Stage C) were treated at the Mayo Clinic (34 patients) and William Beaumont Hospital (23 patients) with (a) 5 Gy delivered preoperatively in one fraction, (b) pelvic lymphadenectomy with interstitial implantation of the prostate using Iridium-192 seeds via a perineal template to 30-35 Gy, and (c) 30.6 Gy external irradiation to prostate only in 17 fractions.

RESULTS

After lymphadenectomy, 30/57 (53%) patients had pathologically confirmed positive lymph nodes or "D1" disease. Thirty-four patients (60%) had Gleason scores > or = 7. Mean age at diagnosis was 63.3 years. Median overall follow-up was 72 months. The 5-year actuarial survival rate was 85% and disease-free survival was 63%. The 5-year survival for patients with negative nodes was 93% and with positive nodes was 79%. The corresponding survival for patients with Gleason scores < or = 6 was 96% and > or = 7 was 78%. Multivariate analysis demonstrated that of all covariates considered, only Gleason score had prognostic significance for disease-free survival (p < 0.05) and no covariates were statistically significant for overall survival. Thirty-nine of the 57 patients had a prostatic re-biopsy performed at 18 months. Pathologically confirmed local control was ultimately achieved in 31/39 (79.5%). There was no difference in survival in patients with positive re-biopsies vs. those with negative results. The 5-year actuarial rate of clinical local control was 94%. Three patients clinically failed locally and 21 demonstrated distant progression. The median time to progression was 34 months. Nineteen percent received some form of hormonal manipulation at the time of their treatment course and an additional 42% were treated with hormones during their follow-up period, primarily after distant failure. The grade 4 rectal ulceration rate decreased to 4.5% with modification of the brachytherapy technique. Three patients experienced grade 4 urinary incontinence and three patients experienced grades 3 or 4 chronic perineal pain.

CONCLUSION

These results indicate that bulky prostate carcinoma can be successfully controlled locally by this novel and aggressive approach with moderate toxicity and improved survival.

Concurrent treatment planning for outpatient high dose rate prostate template implants

PURPOSE

Since November of 1991, we have treated locally advanced (B2-C) prostate cancer using external beam radiotherapy integrated with outpatient high dose rate interstitial implant boost as part of a Phase II clinical trial. This required (a) rapid, automated planning; (b) incorporation of image data and (c) dose optimization.

METHODS AND MATERIALS

A treatment planning system was designed which integrates imaging and needle guidance with source reconstruction and dose display. All components of treatment planning (reconstruction, optimization, dose prescription, dose display) are largely automated. A rectal reference point was defined which was reproducible and easily verified. No pretreatment planning was required.

RESULTS

As of November 1992, 83 treatments were delivered using this system. Intra-operative treatment decisions were made possible due to the speed and ease of interpretation of the system. The system has proven satisfactory in the operating room. Rectal doses were calculated for all patients, and ranged from 35-79% of the prescribed dose, with a mean of 58%. The first echelon of a Phase II escalating dose trial has been completed, with 22 patients treated over a period of 1 year.

CONCLUSION

Outpatient high dose rate brachytherapy appears to be a practical means of boosting locally advanced prostate cancer patients. Rapid treatment planning is possible incorporating on-line ultrasound images to allow immediate dose optimization to be performed during and after implant placement.

Localized carcinoma of the prostate (stages T1B, T1C, T2, and T3). Review of management with external beam radiation therapy

BACKGROUND

Optimal treatment for patients with localized carcinoma of the prostate is controversial. Radiation therapy is an established modality in the management of these patients, and several reports indicate the results are comparable to those achieved with radical prostatectomy. Recently effectiveness of therapy for carcinoma of the prostate is being evaluated in light of post-treatment prostate-specific antigen (PSA) determinations.

METHODS

A review was performed of multiple publications and data from selected institutions with large experience in the management of carcinoma of the prostate. Survival and clinical incidence of local recurrence and distant metastases were analyzed as well as preliminary data on postirradiation PSA levels. Factors that affect the outcome of therapy and relevant clinical trials are discussed.

RESULTS

Reported differences in the age of patients treated with radical prostatectomy (59-63 years), irradiation (63-69 years), or observation (69-75.5 years) were identified. The effect of surgical staging on outcome of irradiation was significant. In multiple series of patients clinically and radiographically staged, the 5-year disease-free survival (DFS) with external irradiation was 95-100% for clinical stage T1a, 80-90% for Stage T1b,c, and 50-70% for clinical Stage T3. A correlation has been identified between the initial PSA levels and the probability from freedom of chemical failure (PSA elevation) after definitive irradiation. In five series comprising 814 patients with Stage T1c and T2 tumors, the DFS (end point chemical failure) was 95%, with initial PSA of less than 4 ng/ml, 83-92% with 4.1-10 ng/ml, 35-85% with 10.1-20 ng/ml, and 10-63% with PSA higher than 20 ng/ml. In the various series, follow-up ranged from a median of 1.5 years to a minimum of 4 years. In two series of 225 and 201 patients receiving doses of 7500-8000 cGy, less morbidity has been observed with three-dimensional treatment planning conformal radiation therapy than with conventional irradiation. New directions for future clinical trials are discussed, including dose escalation studies; use of high linear energy transfer to improve locoregional tumor control; and combination of irradiation and androgen suppression to enhance local tumor control, decrease distant metastasis, and improve survival. Preliminary results of a randomized study recently reported by RTOG strongly suggest that the use of goserelin acetate and flutamide decreases the incidence of clinical local recurrence (12.4% in 225 patients) compared with a control group treated with irradiation alone (25.2% in 230 patients) and enhances disease-free survival.

CONCLUSIONS

Although modern approaches to the management of patients with localized carcinoma of the prostate with irradiation are effective, investigators must continue to critically assess policies of treatment, develop appropriately designed prospective clinical trials, and define the optimal management of patients with localized carcinoma of the prostate.

Preliminary results of a hyperfractionated dose escalation study for locally advanced adenocarcinoma of the prostate

The objective of this study was to build on our experience with 3-D conformal radiotherapy (CRT) by using a hyperfractionated dose escalation scheme to maximize the therapeutic ratio between improved local control and reduced morbidity in patients with locally advanced prostate cancer. Twenty patients with locally advanced (T3, T4) adenocarcinoma of the prostate were treated with a hyperfractionated radiotherapy schedule. All fields were designed with a conformal therapy based beam's eye view, 3-D planning system. The pelvic lymph nodes received 1.8 Gy/day to a total dose of 45 Gy in 5 weeks. Using partial transmission blocks, the prostate and periprostatic tissues received 1.3 Gy twice daily (minimum interval of 6 h) to a total dose of 78 Gy in 6 weeks. The dose was chosen by calculating the biologically effective dose (BED) which would produce the same effect in late reacting tissue but an increase for the tumor as our standard dose of 69 Gy delivered in 1.8-2.0 Gy fractions. The alpha/beta chosen for late damage was 3 Gy and 10 Gy was used for the tumor. All 20 patients completed the planned course of treatment. Although an increase in the tumor BED would be expected to result in increased acute effects, no significant worsening of acute side-effects was observed compared with standard treatment. All patients had only mild (Grade 1) rectal or bladder toxicity during treatment. One patient had an exacerbation of diverticulitis during treatment requiring hospitalization for antibiotics but completed treatment on schedule.(ABSTRACT TRUNCATED AT 250 WORDS)

Short-term morbidity from CT-planned transperineal I-125 prostate implants

PURPOSE

To summarize short-term morbidity and tumor response following transperineal CT-guided I-125 prostate implantation.

METHODS AND MATERIALS

Twenty-one patients were treated with CT-based transperineal I-125 prostate implantation between June, 1988 and May, 1990. An average of 75 I-125 seeds were placed, with an average activity of .62 mCi/seed. Symptoms were quantified after interviewing each patient in detail.

RESULTS

Nearly all patients developed substantial dysuria, nocturia and frequency from 2-24 weeks following implantation. Urinary symptoms usually resolved within 4-6 months of implantation. The one year actuarial potency rate among 18 patients who were potent prior to implantation was 94%. By 6 months after implantation, 14/17 patients (82%) with Stage B tumors had complete regression of palpable disease. Of 17 patients with Stage A or B tumors who presented with an elevated PSA, 76% returned to the normal range within 6 months of implantation.

CONCLUSION

CT-guided transperineal prostate implants entail moderate, temporary urinary and rectral morbidity. Short-term tumor responses are encouraging.

Frequency of residual neoplasm in the prostate following three-dimensional conformal radiotherapy

The incidence of residual neoplastic cells on prostatic biopsy following conventional external beam radiotherapy is reported to range from 40-90%. As a result, it has been stated that current modalities of radiotherapy may carry an unacceptable local failure rate even in patients irradiated for low stage disease. In order to assess the potential benefits of three-dimensional (3-D) treatment planning, an unselected, consecutive group of patients with localized adenocarcinoma of the prostate was evaluated. This study was designed to determine the frequency of residual cancer in the prostate two years following definitive external beam radiotherapy designed, using a 3-D planning system. Between February 1988 and February 1989, 30 consecutive patients with localized (Stage T1-T3NxMo) adenocarcinoma of the prostate received definitive external beam radiotherapy. All treatment fields were designed with a computed tomography (CT)-based 3-D treatment planning system, resulting in a static conformal radiotherapy plan. The minimum dose delivered to the target volume, which included the prostate, periprostatic tissues, and a 1 cm margin, was between 65 and 69 cGy. Twenty-six patients had Stage T1, T2NxMo primary tumors and four were T3NxMo. Two years following the completion of treatment, all patients underwent digital rectal examination, transrectal ultrasound examination of the prostate with multiple biopsies, bone scan, and serum prostate specific antigen (PSA) determinations. Residual prostate cancer was proven by biopsy in six of 30 patients (20%). Four of 26 (15%) with Stage T1 and T2 tumors had a positive biopsy. However, two of the four Stage T3 tumors had postradiation biopsies positive for cancer (50%). Only one patient with a positive biopsy had an abnormal rectal examination. Five of the eight patients with elevated serum PSA levels after two years had residual neoplasia identified on biopsy. One of six patients with an abnormal postradiation ultrasound had residual tumor. Only one of the 22 patients (5%) with a normal serum PSA at two years had a positive postradiation biopsy. In patients with localized prostate cancer, the use of 3-D static conformal radiotherapy followed by multiple ultrasound guided biopsies confirmed the efficacy of external beam radiotherapy in low stage disease. We believe that the low incidence of positive biopsies in this study resulted from the benefits of 3-D treatment planning as well as the fact that all patients were evaluated, whereas past studies have been in selected patient groups when suspicion of residual disease existed prior to biopsy.(ABSTRACT TRUNCATED AT 400 WORDS)

The clinical significance of a positive post-irradiation prostatic biopsy without metastases

To define the prognostic value of a post-irradiation prostatic biopsy, the outcome of 203 previously irradiated patients who underwent post-treatment biopsy was analyzed. The majority of patients were selected for biopsy based on an abnormal digital rectal exam or elevated prostate specific antigen. Patients with distant metastases found at the time of biopsy were excluded from further analysis. One hundred thirty-nine (139) of these had a positive biopsy and 64 were negative. Those with a positive biopsy tended to present with more locally-advanced (Stage B2/C) tumors (61%) compared to those with negative biopsies (42%). The 10- and 15-year survival and cause-specific survival from the time of initial presentation were similar for both groups. However, those with a negative biopsy had a more favorable survival and cause-specific survival from the time of post-treatment biopsy and were less likely to develop distant metastases than the positive biopsy group. These data suggest that a positive prostatic biopsy is associated with a greater likelihood of subsequent distant relapse and decreased survival following biopsy relative to patients with negative biopsies. Since a positive post-treatment biopsy is more likely among patients presenting with locally-advanced disease, perhaps more aggressive initial therapy (i.e., interstitial boost or hyperthermia) would benefit this subgroup.

Analysis of iodine-125 interstitial therapy in the treatment of localized carcinoma of the prostate

Definitive treatment of localized carcinoma of the prostate has included radical surgery, external beam radiation therapy, and interstitial radiation therapy. The interstitial agent most commonly used is Iodine-125. Forty-eight patients were treated with interstitial radiation therapy using Iodine-125 implants with a median follow-up of 55 months. Forty-three percent of the evaluable patients had progressive disease with approximately 50% progressing at 5 years by Kaplan-Meier analysis. Overall actuarial survival in the group was 80% at 5 years. This and several other studies suggest that control of prostate cancer with Iodine-125 seeds may be suboptimal as compared with other treatment modalities, especially the radical retropubic prostatectomy. Analysis of treatment parameters is presented along with a discussion of the current status and future prospects for treatment of localized carcinoma of the prostate with interstitial radiation therapy.