Dynamic conformal arc radiotherapy with rectum hollow-out technique for localized prostate cancer.

Purpose: To report the feasibility of dynamic conformal arc radiotherapy with rectum hollow-out technique (DCAT-HO) for localized prostate cancer.

Methods And Materials: Between October 2000 and April 2007, 204 patients with clinically localized or locally advanced prostate cancer were treated with DCAT-HO. All patients were given neoadjuvant total androgen deprivation (AD) therapy (median 6 months, range 2-27 months). All patients with T3 or T4 stage received post-irradiation AD for 24 months. A total of 128 patients (63%) were treated with 70Gy, and 76 patients (37%) were treated with 74Gy. Acute and late toxicities were scored by the Radiation Therapy Oncology Group morbidity grading scales. PSA relapse was defined as three successive PSA elevations after a post-treatment nadir. The median follow-up was 37 months.

Results: Both the acute Grade 2 rectal and urinary toxicities were 1.0%, and no patients experienced acute Grade 3 or higher symptoms. The 3-year rates of both late Grade 2 rectal and urinary toxicities were 3.4%. The 3-year PSA relapse-free survival for low, intermediate, and high-risk group patients treated with 70 Gy were 54%, 75%, and 87%, respectively.

Conclusions: These findings demonstrate the feasibility of DCAT-HO in a large number of patients with short follow-up. DCAT-HO reduced the volume of the rectum exposed to higher doses and this led to an overall reduction in late rectal toxicity.