Early Experience of Prostate Cancer Treated with CyberKnife(TM) Radiotherapy

ABSTRACT

PURPOSE: We investigated the outcome in patients with prostatic cancer treated by means of CyberKnife(TM) radiotherapy. MATERIALS AND METHODS: Between July 2007 and April 2009, 16 patients with prostate cancer underwent CyberKnife(TM) radiotherapy. The histologic diagnosis was established by transrectal ultrasonography-guided biopsy. Radiotherapy was performed for a dose of 34 Gy at 8.5 Gy per day over 4 to 18 days. Nine patients were treated with hormone therapy. After treatment, prostate-specific antigen (PSA) relapse was evaluated with periodic PSA follow-up. RESULTS: The numbers of patients in clinical stages T2 and T3 were 13 and 3, respectively. Two patients had lymph node metastasis with no distant metastasis. The numbers of patients with a Gleason grade of 5, 6, 7, 8, and 9 were 1, 5, 4, 3, and 2, respectively. The mean time to PSA nadir and the mean PSA at nadir were 7 months and 0.43 ng/ml, respectively. To date, there has been no biochemical failure or clinical recurrence. No severe complications were observed in any patients; observed minor complications [n (%)] were perianal pain [2 (12.5%)] and defecation discomfort [2 (12.5%)]. CONCLUSIONS: Generally good responses were observed in patients treated with CyberKnife(TM) radiotherapy for prostate cancer. No severe complications were observed. More patients and a longer follow-up are required for further conclusions.