Short-term Outcomes Of Hypofractionated Helical Tomotherapy For Older Aged Prostate Cancer Patients

Part One Acute toxicities of hypofractionated helical tomotherapy for older aged prostate cancer patientsObjective:To evaluate the feasibility and related acute toxicities of hypofractionated helical tomotherapy (HT) in older aged prostate cancer (PC) patients.Methods and Materials:Between February 2009 and February 2014,67 patients (older than 65 years) were enrolled in a prospective phase I-II study. Patients in Arm-1 (n=33) and Arm-2 (n=34) received 76 Gy in 34 fractions (2.25 Gy/F) and 71.6 Gy in 28 fractions (2.56 Gy/F), respectively, to the prostate and seminal vesicles (SV). While 25 patients in Arm-2 also received integrated elective lymph node irradiation (50.4 Gy). All patients were treated with HT and daily MVCT guidance was performed before each treatment. Acute toxicities were assessed with RTOG/EORTC criteria.Results:No significant difference was detected between the two arms in the incidence of acute toxicities.In the Arm-1, the incidences of grade 1-2 genitourinary (GU) and gastrointestinal (GI) toxicities were 45.5% and 45.4%, respectively; without grade 3-4 toxicities. In the Arm-2, the incidences of acute grade 1-2 GU and GI toxicities were 47.1% and 55.9%, respectively; grade 3 GU toxicity (hematuria) was noted only in one patient. No significant difference was detected in the incidence of acute toxicities between the patients receiving integrated elective lymph node irradiation and those receiving irradiation to prostate-SV alone in the Arm-2. Univariate and multivariate analyses were performed with clinical parameters. Only the baseline weight was found negatively correlated with GU toxicities at a weak level (RR= 0.946,95% CI= 0.896-0.998, p= 0.043).Conclusions:This study shows that two hypofractionation regimens (76 Gy/34F and 71.6 Gy/28F) delivered with helical tomotherapy are well tolerated in older aged PC patients without significant difference for late toxicities between the two arms. Long-term observations are under investigation.Part Two Long-term outcoms of hypofractionated helical tomotherapy for older aged prostate cancer patientsObjective:To evaluate late toxicities and survival in older aged prostate cancer (PC) patients treated with hypofractionated helical tomotherapy (HT).Methods and Materials:64 patients (older than 65 years) were enrolled in a prospective phase â… -â…¡ study between February 2009 and February 2014. Patients in Arm-1 (n=33) and Arm-2 (n=34) received 76 Gy in 34 fractions (2.25 Gy/F) and 71.6 Gy in 28 fractions (2.56 Gy/F), respectively, to the prostate and seminal vesicles (SV). While 25 patients in Arm-2 also received integrated elective lymph node irradiation (50.4 Gy). Late toxicities were assessed with RTOG/EORTC criteria. The American Society for Therapeutic Radiology and Oncology (ASTRO) biochemical failure definition was used.Results:The 1-year cumulative incidences of late GU and GI toxicities were 3.6% and 6.9% in Arm-1,5.9% and 14.9% in Arm-2; respectively. The 4-year cumulative incidences of late GU and GI toxicities in Arm-1 were 12% and 11%, respectively. All patients tolerated well hypofractioned HT. No significant difference was detected between the two arms. The 3-year FFF of the two arms was 89.6% and 87.7% in Arm-1 and Arm-2, respectively. The 2-year OS of the two arms was 90% and 95.7% respectively. No significant difference was detected in the Kaplan-Meier survival analysis between the two arms.Conclusions:Two hypofractionation regimens (76 Gy/34F and 71.6 Gy/28F) delivered with helical tomotherapy are well tolerated in older aged PC patients without significant difference for late toxicities between the two arms. The OS and incidence of toxicities were acceptable when comparing with other clinical trials without limiting age in recruiting patients. This study showed that hypofractionation IMRT is a safe and efficient treatment for older aged PC patients. Longer follow-up are needed for further study.