Preliminary results of intensity-modulated radiation therapy with helical tomotherapy for prostate cancer

Abstract

We present the preliminary results of intensity-modulated radiation therapy with helical tomotherapy (HT) for clinically localized prostate cancer. Regularly followed 241 consecutive patients, who were treated with HT between June 2006 and December 2010, were included in this retrospective study. Most patients received both relatively long-term neoadjuvant and adjuvant androgen deprivation therapy (ADT). Patients received 78 Gy in the intermediate high-risk group and 74 Gy in the low-risk group. Biochemical disease-free survival (bDFS) followed the Phoenix definition. Toxicity was scored according to the Radiation Therapy Oncology Group morbidity grading scale. The median follow-up time from the start date of HT was 35 months. The rates of acute Grade 2 gastro-intestinal (GI) and genitor-urinary (GU) toxicities were 11.2 and 24.5 %. No patients experienced acute Grade 3 or higher symptoms. The rates of late Grade 2 and 3 GI toxicities were 6.6 and 0.8 %, and those of late Grade 2 and 3 GU toxicities were 8.3 % and 1.2 %. No patients experienced late Grade 4 toxicity. The 3-year bDFS rates for low, intermediate, and high-risk group patients were 100, 100, and 95.8 %, respectively. We observed clinical relapse in two high-risk patients, resulting in a 3-year clinical DFS of 99.4 %. This preliminary report confirms the feasibility of HT in a large number of patients. We observed that HT is associated with low rates of acute and late toxicities, and HT in combination with relatively long-term ADT results in excellent short-term bDFS.