Comparison of dosimetric parameters and acute toxicity after whole-pelvic versus prostate-only volumetric-modulated arc therapy with daily image guidance for prostate cancer.

OBJECTIVE - To compare dosimetric parameters and acute toxicity rates between whole-pelvic (WP) and prostate-only (PO) volumetric-modulated arc therapy (VMAT) in patients with localized prostate cancer.

METHODS - A total of 224 consecutive patients treated with definitive VMAT to 78 Gy in 39 fractions were enrolled.

Of these, 119 patients received initial WP VMAT to 46.8 Gy in 26 fractions using a simultaneous integrated boost technique, and 105 patients received PO VMAT. Image-guided radiotherapy (RT) was practiced with daily cone-beam CT.

RESULTS -  The mean rectal dose, the rectal volume receiving more than 30 Gy (V30Gy), rectal V50Gy, the mean bladder dose, bladder V30Gy, and bladder V50Gy were significantly increased in the WP group (p

CONCLUSIONS - Despite larger rectum and bladder volumes at low- and medium-dose levels, WP VMAT resulted in no significant increase in acute proctitis or GU toxicity when compared to PO VMAT. Advances in knowledge: This study demonstrates WPRT has comparable acute toxicity to those observed with PORT when VMAT with daily image guidance is used.

The British journal of radiology. 2016 Mar 09 [Epub ahead of print]

Kentaro Ishii, Ryo Ogino, Yukinari Hosokawa, Chiaki Fujioka, Wataru Okada, Ryota Nakahara, Ryu Kawamorita, Takuhito Tada, Yoshiki Hayashi, Toshifumi Nakajima

1 Department of Radiation Oncology, Tane General Hospital, Osaka, Japan., 1 Department of Radiation Oncology, Tane General Hospital, Osaka, Japan., 2 Department of Urology, Tane General Hospital, Osaka, Japan., 1 Department of Radiation Oncology, Tane General Hospital, Osaka, Japan., 1 Department of Radiation Oncology, Tane General Hospital, Osaka, Japan., 1 Department of Radiation Oncology, Tane General Hospital, Osaka, Japan., 1 Department of Radiation Oncology, Tane General Hospital, Osaka, Japan., 3 Department of Radiology, Izumi Municipal Hospital, Osaka, Japan., 2 Department of Urology, Tane General Hospital, Osaka, Japan., 1 Department of Radiation Oncology, Tane General Hospital, Osaka, Japan.