Purpose: We present the preliminary results of intensity-modulated radiation therapy with helical tomotherapy (HT) for clinically localized prostate cancer.
Methods: 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.
Results: 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 %.
Conclusions: 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.