Trends in primary androgen depletion therapy for patients with localized and locally advanced prostate cancer: Japanese perspective

Abstract

It has been conventionally accepted that primary androgen depletion therapy (PADT) is effective only as a palliative treatment against localized prostate cancer (LPC) and locally advanced prostate cancer (LAPC), like its effect against advanced (metastatic) prostate cancer. In Japan, however, PADT has long been the treatment of choice for LPC and LAPC. The frequency of PADT being chosen to treat LPC and LAPC is also on the rise in clinical practice in the USA. Very little evidence to support this trend has so far been available. A study on the outcomes of endocrine therapy is currently being conducted in Japan by the Japanese Prostate Cancer Surveillance Group. Results of several domestic and overseas randomized trials have recently been published, and evidence for the efficacy of PADT in LPC and LAPC has been accumulating. The effectiveness of PADT in LAPC, in particular, is worthy of attention. There is a possibility that therapeutic strategies for LPC and LAPC may change dramatically in the near future.

Figure 1

Initial therapy at each stage. HR, androgen depletion therapy; PADT, primary androgen depletion therapy; RP, radical prostatectomy; Rx, radiation therapy; WW, watchful waiting.

Figure 2

Japanese Prostate Cancer Surveillance Group (J‐CaP) surveillance data. (a) Percentage of patients registered in each clinical stage; (b) purpose of androgen depletion therapy (ADT); (c) method of ADT. LH‐RH, luteinizing hormone‐releasing hormone; PADT, primary androgen depletion therapy.

Figure 3

Ten‐year prognosis of primary androgen depletion therapy (PADT) performed in patients who did not undergo radical prostatectomy for one reason or another. A characteristic feature is that the expected survival curve of same‐generation individuals perfectly matches the test patients’ overall survival curve. ( … ) Cause‐specific survival; (‐) overall survival; (‐‐‐) expected survival.

Figure 4

Time to disease progression among patients with stage C prostate cancer treated with luteinizing hormone‐releasing hormone (LHRH)‐A with and without bicalutamide. P < 0.001. (‐) Bicalutamide 80 mg combination therapy (n = 52; three events [5.8%]); (‐‐‐) LHRH‐A monotherapy (n = 47; 20 events [42.6%]).