Management of high-risk localized prostate cancer: the integration of local and systemic therapy approaches

Contemporary treatment of high-risk localized prostate cancer

High-risk prostate cancer poses a significant challenge to the treating physician and much debate exists regarding the ideal treatment approach. The purpose of this article is to enable physicians to identify patients with high-risk localized prostate cancer and evaluate whether monotherapy is sufficient for these patients. We review the current data on use of surgery, radiation therapy and hormonal therapy independently and in combination. We also discuss emerging therapeutics for high-risk disease including neoadjuvant chemotherapy and protocols under current and future investigation.

Trends and predictors of aggressive therapy for clinical locally advanced prostate carcinoma

OBJECTIVE

To determine the patterns and predictors of aggressive local therapies for patients with clinically advanced (cT3) prostate carcinoma, as the USA National Cancer Institute considers external beam radiotherapy (EBRT) to be the most appropriate treatment for these patients, and currently there is less evidence supporting the use of radical prostatectomy (RP).

PATIENTS AND METHODS

We used the Surveillance, Epidemiology and End Results (SEER) cancer registries to identify patients diagnosed with cT3 disease between 1995 and 2001. Sociodemographic and clinical data included patient age, race/ethnicity, marital status, SEER registry, year of diagnosis, tumour stage and grade, and treatment. Multivariate logistic regression was used to identify significant predictors of receiving (i) RP vs EBRT, (ii) any aggressive local treatment (RP or EBRT) or no treatment.

RESULTS

Between 1995 and 2001, the proportion of men receiving aggressive local therapy for cT3 disease increased by 11% (58.4% to 69.4%), with a 20% increase in EBRT (40.3% to 60.2%) but a decline by half in RP (18.1% to 9.3%). Younger age was the strongest predictor of receiving RP rather than EBRT, and younger age with being married being a predictor of receiving aggressive local therapy (adjusted relative risk for marriage 1.33, 95% confidence interval 1.18-1.87). Black men were significantly less likely than non-Hispanic white men to receive aggressive therapy, with a relative risk of 0.56 (0.45-0.69).

CONCLUSION

By 2001, 70% of patients with cT3 disease were receiving aggressive local therapy, with EBRT 6.5 times more common than RP. Clinical trials are needed to rigorously assess the effects of different local treatment strategies on clinical outcomes in men with cT3 prostate carcinoma.

Adjunctive therapy for men with high risk localized and locally advanced prostate cancer: targeting disseminated tumor cells

PURPOSE

Our research into the pathophysiology of micrometastatic dissemination and cancer recurrence has resulted in the initiation of a clinical trial for men with clinically localized and locally advanced disease.

MATERIALS AND METHODS

We describe the development of this trial, which exploits anti-angiogenesis therapy, and delineate how our understanding of prostate cancer metastasis influenced its design.

RESULTS

Prostate cancer is a heterogeneous disease. Although many men can be cured with local therapy, a large majority with clinically localized disease will experience a relapse usually at a distant site. This result is most likely due to micrometastatic dissemination early in the disease process. Therefore, successful contemporary treatment of many men with prostate cancer should include a combination of local and systemic therapies. Fortunately, cellular, molecular and genetic features that may predict which men are most in need of this therapeutic approach are being identified and characterized. This insight not only supports the rationale for a combination therapeutic approach to prostate cancer management, but will help identify the pathways and agents that provide the most promising targets for intervention.

CONCLUSIONS

Despite advances in prevention and early detection, refinements in surgical technique, and improvements in radiation and systemic therapies, the ability to cure all men with prostate cancer remains unattainable. The continuing challenge is the successful eradication of recurrent and metastatic disease.

Radical versus postoperative radiotherapy for localized prostate cancer: a 10-year experience of an academic hospital

This study is a presentation of our department's experience in the treatment of localized prostate cancer with either radical or postoperative radiotherapy (RT). Fifty-five patients with clinical localized prostate cancer were reviewed. Thirty-three patients (T1-T2AN0M0 stage) were treated with radical RT and 22 (T2B-T3N0M0 stage) with postoperative RT. All patients received hormonal therapy. Primary end points of the study were the incidence of clinical and biochemical recurrences and death in the whole group and according to treatment modality. Within a median follow-up of 18 months the overall incidence of clinical relapse was 16.9%, of biochemical relapse 12.7% and of death 10.9%. Both treatment options achieved similar outcomes despite the fact that the patients in the postoperative RT group were of higher stage. Radical RT group tended to have better overall and disease-free survival compared to postoperative RT group, but there was no statistically significant evidence. Long-term toxicity was negligible.

Virus specific immune responses after human neoadjuvant adenovirus-mediated suicide gene therapy for prostate cancer

PURPOSE

Neoadjuvant gene therapy potentially improves the outcome of primary treatment of prostate cancer by radical prostatectomy in patients with high risk of recurrence. We conducted a Phase I escalating dose study with a replication-defective adenovirus expressing the herpes simplex virus-thymidine kinase gene (Adv-HSV-tk vector). The primary end point was toxicity, while the evaluation of the patients' cellular and humoral immune responses served as a secondary endpoint.

MATERIAL AND METHODS

The Adv-HSV-tk vector was injected into the prostate in two doses (2x10(10) to 2x10(11) viral particles), followed by ganciclovir twice daily for 14 days and retropubic radical prostatectomy on day 21. Adenovirus-specific neutralizing, IgG and IgA antibodies were evaluated. Peripheral blood mononuclear cells (PBMC) were stimulated by Adv-HSV-tk and analysed for IFN-gamma production and 3H-thymidine incorporation. Prostate specimens were immunostained for B (CD20+) and for T (CD3+) lymphocytes.

RESULTS

Toxicity was minor in all 8 patients treated. In the prostate, no virus related cytopathic effect could be observed. Dose-dependent infiltration of T and B lymphocytes in the whole prostate and in tumor areas was observed. Boosting of adenovirus-specific antibody responses was observed in 7 patients, and an increased adenovirus-specific PBMC proliferation and IFN-gamma production was seen after Adv-HSV-tk stimulation.

CONCLUSION

Neo-adjuvant adenovirus-mediated cytotoxic gene therapy prior to prostatectomy for prostate cancer is feasible and safe in an outpatient setting for intraprostatic vector doses up to 2x10(11) viral particles. Activation of the immune system was observed. Application of higher vector doses may be considered.

Multimodal treatment strategies combining neoadjuvant hormonal therapy and/or chemotherapy with radical prostatectomy in high-risk localised prostate cancer

By combining the readily available clinical parameters of tumour stage, Gleason score of the diagnostic biopsy specimen and serum prostate-specific antigen level, men with newly diagnosed prostate cancer can be assessed as to their risk of treatment failure after radiotherapy or radical prostatectomy. For men considered to be at high-risk of treatment failure after local therapy alone, multimodal treatment strategies may result in improved cancer-control outcomes. This strategy has proven effective in the setting of clinical stage T3 - T4 tumours in which the combination of radiotherapy followed by hormonal therapy has improved patient survival. The benefit of neoadjuvant or adjuvant hormonal and/or chemotherapy followed by radical prostatectomy in this setting is unclear but is the subject of ongoing or planned Phase III clinical trials. These studies will help examine the role of multimodal treatment strategies in these high-risk patients.

Outcome Predictors for the Increasing PSA State After Definitive External-Beam Radiotherapy for Prostate Cancer

Purpose

To identify predictors of distant metastases (DM) among patients who develop an isolated prostate-specific antigen (PSA) relapse after definitive external-beam radiotherapy for clinically localized prostate cancer.

Materials and Methods

A total of 1,650 patients with clinical stage T1 to T3 prostate cancer were treated with high-dose three-dimensional conformal radiotherapy. Of these, 381 patients subsequently developed three consecutive increasing PSA values and were characterized as having a biochemical relapse. The median follow-up time was 92 months from the completion of radiotherapy.

Results

The 5-year incidence of DM after an established PSA relapse was 29%. In a multivariate analysis, PSA doubling time (PSA-DT; P < .001), the clinical T stage (P < .001), and Gleason score (P = .007) were independent variables predicting for DM after established biochemical failure. The PSA-DT for favorable-, intermediate-, and unfavorable-risk patients who developed a biochemical failure was 20.0, 13.2, and 8.2 months, respectively (P < .001). The 3-year incidence of DM for patients with PSA-DT of 0 to 3, 3 to 6, 6 to 12, and more than 12 months was 49%, 41%, 20%, and 7%, respectively (P < .001). Patients with PSA-DT of 0 to 3 and 3 to 6 months demonstrated a 7.0 and 6.6 increased hazard of developing DM or death, respectively, compared with patients with a DT more than 12 months.

Conclusion

In addition to clinical stage and Gleason score, PSA-DT was a powerful predictor of DM among patients who develop an isolated PSA relapse after external-beam radiotherapy for prostate cancer. Patients who develop biochemical relapse with PSA-DT ≤ 6 months should be considered for systemic therapy or experimental protocols because of the high propensity for rapid DM development.

AN OVERVIEW OF CHEMOTHERAPY TRIALS IN LOCALIZED AND RECURRENT NONMETASTATIC PROSTATE CANCER

PURPOSE

High risk localized and recurrent prostate cancers remain difficult problems for clinicians. Definitive local treatments such as surgery and radiation therapy cure only a minority of these patients. As a result, efforts are being made to decrease the risk of recurrence and delay progression to symptomatic hormone refractory disease using chemotherapy prior to, during or after definitive local therapy.

MATERIALS AND METHODS

A MEDLINE literature review was performed of studies evaluating chemotherapy and other systemic therapies for localized prostate cancer. In addition, ongoing randomized clinical trials were reviewed.

RESULTS

Chemotherapy in the management of localized and recurrent disease is evolving. Early studies demonstrated the feasibility of administering chemotherapy to patients prior to and immediately after local therapy, and in the setting of an increasing prostate specific antigen state. Although chemotherapy has established activity and acceptable toxicity in patients with hormone refractory prostate cancer, more extensive use in patients with androgen dependent disease will require data from randomized studies to determine its efficacy. At least 5 ongoing, randomized, phase III trials currently are evaluating the role of chemotherapy in various prostate cancer disease states, including nonmetastatic, hormone refractory disease, the increasing prostate specific antigen state, and adjuvant and neoadjuvant settings in patients at high risk.

CONCLUSIONS

Chemotherapy is being investigated actively in randomized trials of earlier states of prostate cancer. Enrollment onto clinical trials should be the highest priority for investigators and clinicians.

Use of neoadjuvant and adjuvant therapy to prevent or delay recurrence of prostate cancer in patients undergoing surgical treatment for prostate cancer

There have been improvements in the outcome of patients with clinically localized prostate cancer treated by radical prostatectomy. However, some patients treated with radical prostatectomy will have clinical or biochemical progression. These men are at increased risk of dying of their disease. Identification of patients with adverse features at the time of radical prostatectomy may permit the use of additional multimodality therapies to improve outcomes. Whether this additional multimodality therapy should be administered in the neoadjuvant or adjuvant setting remains controversial. Further, whether a patient at increased risk for progression after radical prostatectomy requires additional therapy before the development of documented progression remains controversial. This article reviews the potential multimodality approaches to prevent or delay recurrence of prostate cancer in patients undergoing surgical treatment for prostate cancer.