Local Failure After Definitive Radiation or Surgical Therapy for Carcinoma of the Prostate and Options for Prevention and Therapy

Salvage cryosurgery for locally recurrent prostate cancer following radiotherapy

The popularity of radiotherapy as a minimally invasive treatment for prostate cancer is increasing. Despite advancements in radiation delivery, a number of patients will fail treatment. Salvage radical prostatectomy has been the main therapeutic option for locally recurrent radiation failure prostate cancer with curative intent. The operation is technically difficult to perform and associated with significant comorbidities. Salvage cryotherapy has emerged as a minimally invasive alternative option. In this article, we review the role of cryotherapy in recurrent prostate cancer and compare its outcome with salvage radical prostatectomy.

Salvage brachytherapy for localized prostate cancer after radiotherapy failure

OBJECTIVES

To evaluate the effectiveness and morbidity of salvage brachytherapy for locally recurrent or persistent prostate cancer after radiotherapy failure.

METHODS

In this retrospective study, 49 patients of median age 73.3 years (range 52.9 to 86.9) with biopsy-proven localized prostate cancer underwent interactive transperineal fluoroscopic-guided and biplane ultrasound-guided brachytherapy with either iodine 125 or palladium 103 after prior radiotherapy failure. Post-treatment follow-up was conducted for a median of 64.1 months (range 26.6 to 96.8) and included clinical assessment of disease status, assays of serum prostate-specific antigen (PSA) levels, and documentation of treatment-related symptoms and complications. Determination of biochemical treatment failure was based on two successive rising PSA values above the post-treatment PSA nadir value.

RESULTS

The actuarial rate of local prostate cancer control was 98% (95% confidence interval [CI] 94% to 99%). Actuarial disease-specific survival at 3 and 5 years was 89% (95% CI 73% to 96%) and 79% (95% CI 58% to 91%), respectively. At 3 and 5 years, actuarial biochemical disease-free survival was 48% (95% CI 32% to 63%) and 34% (95% CI 17% to 51%), respectively. Post-treatment PSA nadir was found to be a significant predictor of biochemical disease-free survival. Actuarial biochemical disease-free survival of patients who achieved a PSA nadir less than 0.5 ng/mL was 77% (95% CI 53% to 90%) and 56% (95% CI 25% to 78%) at 3 and 5 years, respectively. Of 49 patients, 23 (47%) achieved a post-treatment PSA nadir less than 0.5 ng/mL. The incidence of serious complications after salvage brachytherapy, such as incontinence and rectal complications, was lower than that reported after other types of salvage procedures.

CONCLUSIONS

Interactive transperineal fluoroscopic-guided and biplane ultrasound-guided brachytherapy is a novel, potentially curative salvage modality for patients in whom prior radiotherapy failed. In a population of patients with poor prognosis, this modality was associated with a high rate of local prostate cancer control and a 34% actuarial rate of biochemical disease-free survival at 5 years. The incidence of major complications after salvage brachytherapy appears to be lower than that after other potentially curative salvage procedures, such as radical prostatectomy and cryoablation. Salvage brachytherapy warrants further investigation.

Mapping, genomic organization and promoter analysis of the human prostate-specific membrane antigen gene

Prostate-specific membrane antigen (PSMA) is a 100 kDa type II transmembrane protein with folate hydrolase and NAALAdase activity. PSMA is highly expressed in prostate cancer and the vasculature of most solid tumors, and is currently the target of a number of diagnostic and therapeutic strategies. PSMA is also expressed in the brain, and is involved in conversion of the major neurotransmitter NAAG (N-acetyl-aspartyl glutamate) to NAA and free glutamate, the levels of which are disrupted in several neurological disorders including multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease and schizophrenia. To facilitate analysis of the role of PSMA in carcinoma we have determined the structural organization of the gene. The gene consists of 19 exons spanning approximately 60 kb of genomic DNA. A 1244 nt portion of the 5' region of the PSMA gene was able to drive the firefly luciferase reporter gene in prostate but not breast-derived cell lines. We have mapped the gene encoding PSMA to 11p11-p12, however a gene homologous, but not identical, to PSMA exists on chromosome 11q14. Analysis of sequence differences between non-coding regions of the two genes suggests duplication and divergence occurred 22 million years ago.

Combined treatment with temporary short-term high dose rate iridium-192 brachytherapy and external beam radiotherapy for irradiation of localized prostatic carcinoma

PURPOSE

To evaluate the treatment outcome after radical radiotherapy of localized prostate cancer in 50 patients (38 patients with stage T1-2 and 12 patients with stage T3) after a median follow-up time of 45 months (range 18-92 months).

METHODS

The treatment was given by combination of external beam radiotherapy (50 Gy) and brachytherapy (2 x 10 Gy). The brachytherapy was given using TRUS-guided percutaneously inserted temporary needles with a high dose rate remote afterloading technique with Ir-192 as the radionuclide source. Three target definitions and dose levels inside the prostate gland were used. Local control was evaluated by digital rectal examination, TRUS-guided biopsies and serum PSA evaluations.

RESULTS

Clinical and biopsy verified local control was achieved in 48 of the 50 (96%) patients; for stage T1-2 in 37 of 38 (97%) patients and for stage T3 in 11 of 12 (92%) patients. A posttreatment serum PSA level < or =1.0 ng/ml was seen in 42 (84%) patients, values from >1.0 to < or =2.0 ng/ml were seen in four (8%) patients and values exceeding 2.0 were seen in four (8%) patients. The late toxicity was minimal.

CONCLUSION

The local control results and the minimal toxicity after the combined radiotherapy treatment are promising. However, long term results are necessary before general use.

Treatment options for localized recurrence of prostate cancer following radiation therapy

Patients with radioresistant clinically localized prostate cancer may be treated by various means. Although androgen ablation is relatively noninvasive, it cannot be considered a curative option. We believe that a subset of patients with locally recurrent prostate cancer without subclinical metastatic disease exists and would benefit from maximally aggressive local therapy. Salvage surgery may offer long-term cancer control, particularly when the tumor is organ-confined, but is a technically challenging operation with a high incidence of postoperative incontinence. Cryoablation of the prostate for postirradiation recurrence may offer a less invasive alternative to radical surgery, but its long-term efficacy remains to be fully determined. Each therapeutic option has its characteristic attendant morbidity and the choice of therapy for local recurrence should be made with informed consent after frank discussion between physician and patient. We propose the treatment algorithm shown in Figure 1 for the management of patients with suspected recurrence after radiation therapy with the caveat that individual therapeutic strategies must be patterned around individual patient needs.

Radioimmunoscintigraphy with 111indium labeled CYT-356 for the detection of occult prostate cancer recurrence

We assessed the safety and ability of the 111indium labeled immunoconjugate 7E11-C5.3-glycyl-tyrosyl-(N,e-diethylenetriaminepentaacetic acid)-lysine (CYT-356) to detect sites of occult prostate cancer in 27 subjects who had undergone radical prostatectomy and whose only evidence of recurrent disease was an increasing (0.8 ng./ml. or greater) serum prostate specific antigen (PSA). All subjects underwent whole body scintigraphy between 2 and 4 days following the radiopharmaceutical injection. Routine blood work and human anti-mouse antibody titers were monitored. Scintigraphic findings were compared with clinical parameters, prostatic fossa biopsy results and conventional imaging techniques. Except for transient hypotension in 1 subject following the second infusion, no side effects or human anti-mouse antibody titers were detected. In 22 subjects 1 or more lesions were detected, of which 11 (50%) were confirmed by biopsy, computerized tomography or magnetic resonance imaging. Of 14 subjects with lesions in the prostatic fossa 13 had biopsies performed, 8 (62%) of which were positive. Magnetic resonance imaging confirmed tumor in the spine and chest computerized tomography findings were compatible with lesions seen in the mediastinum in 1 subject each. There was a statistically significant relationship between detecting a scan abnormality and the initial pathological stage of disease but not with the serum PSA. These data provide preliminary evidence that 111indium labeled CYT-356 can be safely administered and readministered, and it detects sites of occult prostate cancer recurrence in subjects whose PSA is increasing following radical prostatectomy.

The effects of local and regional treatment on the metastatic outcome in prostatic carcinoma with pelvic lymph node involvement

PURPOSE

The effect of local and regional treatment on the development of distant metastases in patients with localized node negative and node positive carcinoma of the prostate is examined.

METHODS AND MATERIALS

Distant metastases-free survival was evaluated in 1078 patients with Stage B-C node negative (733 patients) or node positive (345 patients) carcinoma of the prostate, staged with pelvic lymph node dissection and treated with retropublic 125I implantation at the Memorial Sloan-Kettering Cancer Center between 1970 and 1985.

RESULTS

The 15-year actuarial distant metastases-free survival rate for the entire group of patients was 27%. Lymph node involvement was the most significant covariate affecting distant metastases-free survival, although local failure, stage, and grade were also independent variables. Distant metastases-free survival varied with the extent of lymph node involvement (N0 vs. N1, p < 0.0001; N1 vs. N2, p < 0.0001). However, the difference between N1 and N2 patients was due to a faster rate of development of distant metastases in N2 patients. The ultimate 10-year distant metastases-free survival rate was similar for the two patient groups (11% for N1 and 9% for N2). Local failure correlated with the metastatic outcome in patients with B-C/N0 disease (p < 0.00001), but not in N1 or N2 patients. Although distant metastases-free survival in locally controlled N1 patients was improved compared to N2 patients (p = 0.004), when stratified by primary tumor stage and grade, the differences were no longer significant.

CONCLUSION

Essentially all node positive patients with carcinoma of the prostate will develop distant metastatic disease if followed for sufficiently long periods of time. This is consistent with the hypothesis that in such patients distant micrometastatic dissemination already exists at the time of initial diagnosis. The data suggest that clinical trials designed to test whether improvements in local therapy impact on survival should be restricted to node negative patients. The data also raise concerns regarding the therapeutic value of elective whole pelvic irradiation.

Three-dimensional conformal radiation therapy in locally advanced carcinoma of the prostate: preliminary results of a phase I dose-escalation study

PURPOSE

The acute morbidity of doses of 64.8-75.6 Gy and preliminary observations of late complications and tumor response using 3-dimensional conformal radiation therapy in carcinoma of the prostate are assessed.

METHODS AND MATERIALS

123 patients (Stage A2-12, B1-17, B2-43, C-51) were irradiated to the prostate and seminal vesicles using a 3-dimensional conformal radiation therapy technique. The median follow-up time was 15.2 months. The minimum tumor dose was 64.8-66.6 Gy in 49 patients, 70.2 Gy in 46, and 75.6 Gy in 28. Toxicity was scored according to the Radiation Therapy Oncology Group morbidity grading system.

RESULTS

This technique of 3-dimensional conformal radiation therapy was well-tolerated with minimal acute morbidity. Only 32% of patients had grade 2 or 3 acute morbidity requiring short-term medication for relief of urinary symptoms or diarrhea. Only one patient (0.8%) has so far developed a severe (grade 4) late complication. Serum prostate specific antigen concentrations normalized in 67% of patients (64/96) within 1-14 months (median 4.5 months) after treatment and were progressively decreasing at last measurement in an additional 22% (21/96). Abnormal rising prostate specific antigen levels were observed in 15 patients, 11 of whom have already developed other evidence of relapsing disease.

CONCLUSION

Acute toxicity for the doses tested with this 3-dimensional conformal radiation therapy technique is reduced compared to traditional treatment techniques, and the initial tumor response as assessed by prostate specific antigen measurement is highly encouraging with prostate specific antigen levels returning to normal in the majority of patients. Based on these results, a further increase of the dose to 81 Gy has been implemented in accordance with the schema of an ongoing Phase I dose-escalation study.

Radiation therapy for prostate cancer. Long-term results and implications for future advances

BACKGROUND

There are surprisingly few studies that concurrently report the 10-year overall survival (OS) rate, 10-year adjusted survival (AS) rate, 10-year recurrence free (NED) survival rate, and 10-year local tumor control (LC) rate using external beam radiation therapy (RT) for Stages A2, B, and C prostate cancer. A simultaneous analysis of OS, AS, NED survival, and LC rates is useful in terms of establishing priorities for future research efforts.

METHODS

Actuarial LC, NED survival, AS, and OS rates were analyzed for 289 patients with Stages A2, B, and C prostate cancer treated with RT between 1975 and 1990 in the Department of Therapeutic Radiology, Yale University School of Medicine.

RESULTS

The 10-year LC, NED survival, AS, and OS rates for 168 patients with Stage A2 and B disease were 88% (standard error [SE], 5%), 50% (SE, 10%), 70% (SE, 7%), and 38% (SE, 7%), respectively. The 10-year LC, NED survival, AS, and OS rates for 121 patients with Stage C disease were 82% (SE, 6%), 41% (SE, 6%), 25% (SE, 7%), and 21% (SE, 6%), respectively.

CONCLUSION

External beam radiation provides excellent local clinical tumor control for early prostate cancer. However, 60% of all prostate cancer deaths of patients with Stage A2 and B disease and 76% of all prostate cancer deaths of patients with Stage C disease were attributable to metastatic disease without clinical local failure. The major obstacle in improving the death rate associated with Stages A2, B, and C prostate cancer remains the inability to control metastatic disease; research efforts must concentrate on overcoming this problem.