High-dose intensity-modulated radiotherapy as primary therapy for prostate cancer: Report on dosimetry aspects and acute toxicity in the Indian scenario

Background and Purpose: Dose escalation improves local control in prostate cancer. In this study we assess the feasibility of dose escalation to prostate and / or seminal vesicles to 76 Gy with intensity-modulated radiotherapy (IMRT); report data on dosimetry and acute toxicity in 40 patients at P. D. Hinduja National Hospital and Medical Research Center, Mumbai.
Materials and Methods: In the period from May 2006 to September 2008, 40 consecutive patients with localized prostate adenocarcinoma (T1- 3 N0) were definitively treated with IMRT to a dose of 76 Gy / 38 fractions. Patients were seen on a weekly basis during treatment, and one month (M1) and three months (M3) thereafter. The radiation therapy oncology group (RTOG) toxicity scale was used to evaluate acute gastrointestinal (GI) and genitourinary (GU) toxicities. Additional symptoms such as rectal blood loss, urgency, dysuria, urinary frequency, nocturia, incontinence were scored as well.
Results: All 40 patients completed treatment successfully. Acute RTOG Grade 1 and Grade 2 GI toxicities were noted in 47.5% (19 patients) and 12.5% (five patients) respectively, leaving 40% (16 patients) free of any acute toxicity. Thirty-six (90%) and four patients (10%) had Grade 0-1 and Grade 2 acute RTOG-scaled GU toxicity respectively. There was no Grade 3 or higher GI / GU toxicity.
Conclusions: The escalated dose of 76 Gy to the prostate with IMRT was very well tolerated by all our patients with acceptable acute GU and GI toxicity, thereby, establishing the feasibility of dose escalation in the Indian scenario.

Keywords
Prostate cancer, intensity-modulated radiotherapy, dose escalation, acute toxicity