Development of anemia and recovery in prostate cancer patients treated with combined androgen blockade and radiotherapy.

Background: The objective of this study was to document previously unreported anemia in prostate cancer patients treated with neoadjuvant combined androgen blockade (CAB) and pelvic radiotherapy (XRT).
Methods: Four institutions treated 141 patients (mean age +/- SD, 70.9 +/- 6.5 years) with zoladex 3.6 mg injection subcutaneous depot monthly and flutamide 250 mg orally three times per day for 2 months (CAB), followed by zoladex and flutamide with concurrent XRT (65-70 Gy) for 7-8 weeks.
Results: After the XRT, the patients were randomized to receive no further treatment (Z- group, 71 patients) or zoladex alone (Z+ group, 70 patients) for 2 years. Hemoglobin (Hb) levels decreased > or = 1 g/dl (mean +/- SE, 2.1 +/- 0.1 g/dl) in 98/131 patients (75%) after 2 months of CAB, and > or = 2 g/dl (3.1 +/- 0.1 g/dl; range, 0.1-6.8 g/dl) in 106/131 patients (81%) after an additional 2 months of CAB with concurrent XRT. The decrease in Hb levels paralleled the decreased in testosterone levels. No evidence of blood loss or hemolysis was found.
Conclusions: There was no association between incidence or rate of Hb decrease and race, age, or pretreatment prostate-specific antigen (PSA) levels. However, the recovery from anemia after completion of CAB in African-Americans was slower than in Whites in the Z+ group (P < 0.04). Whereas grade 1 hematologic toxicity may occur in < 5% of the patients with zoladex alone, and approximately 6% with flutamide alone, in our study 81% showed mild to pronounced anemia. Since anemia has not been observed after treatment with XRT alone or XRT followed by zoladex, we conclude that the anemia was due to CAB. Recognition of this side effect should avoid unnecessary diagnostic evaluations.