Intensity-modulated radiation therapy for small cell carcinoma of the prostate: A case report.

Small cell carcinomas (SCC) make up only 1% of malignancies of the prostate. Reports of several case series have described outcomes of surgery and chemotherapy for SCC of the prostate, but few reports address radiotherapy. We treated a case of SCC of the prostate with intensity-modulated radiation therapy (IMRT) consisting of 70 Gy administered in 35 fractions followed by hormonal therapy using only luteinizing hormone-releasing hormone (LH-RH) agonist. The tumor volume decreased remarkably by 4 months after IMRT. The rapid decrease in tumor size of this SCC of the prostate seemed to suggest a similar high radiosensitivity to that of SCC of the lung, but the tumor increased rapidly thereafter within the radiation fields, and pelvic lymph node metastases had developed by 24 months after IMRT. By 28 months after IMRT, multiple lung metastases developed, and the patient died of SCC of the prostate 31 months after initial diagnosis.