Evaluation of Intraoperative Radiation Therapy for Incompletely Resected or Recurrent Canine Hemangiopericytomas: Seventeen Cases

The objective of this study was to evaluate conservative surgery and intraoperative radiation therapy (IORT) for incompletely resected or recurrent hemangiopericytoma. Dogs that had been resected at our faculty and diagnosed as incompletely resected or recurrent hemangiopericytoma were studied. Dogs that had previously undergone surgery or had frequent radiotherapy were excluded. Seventeen dogs met these criteria, of which 10 underwent surgery alone (surgery group), and 7 underwent consecutive surgery and IORT (IORT group). After resection of the tumor, an acrylic cone was set to irradiate underlying tissue and avoid surrounding skin. The tumor bed was irradiated with a 3-MeV electron beam. The median radiation dose was 10 Gy (range, 10 – 15 Gy). After IORT, the incision was closed in a routine manner. Ten tumors recurred locally, 6 of 10 (60%) of the surgery group and 4 of 7 (57%) of the IORT group. Tumor-free survivals were 441 days (range, 183 – 1,071 days) in the surgery group and 810 days (range, 660 – 1,576 days) in the IORT group. The IORT group had significantly longer tumor-free survival than the surgery group (p = 0.043). No radiation side effects were detected. Although the recurrence rate was not significantly different with or without IORT, consecutive surgery and IORT may be able to prolong tumor-free survival without radiation side effects. Evaluation of Intraoperative Radiation Therapy for Incompletely Resected or Recurrent Canine Hemangiopericytomas: Seventeen Cases Takuya Maruo,1 DVM, Ms Takuo Shida,1 DVM, MS, PhD Yasuhiro Fukuyama,1 DVM, MS Yasunori Hino,2 DVM, MS Toru Yamada,3 DVM, MS Hiroo Madarame,1 DVM, MS, PhD 1Veterinary Teaching Hospital, Azabu University, 1-17-71 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5201, Japan 2Seek Pet Clinic, 53 Azahigasihiyodorihira, Konobunakajima, Ichinomiya, Aichi 494-0007, Japan 3Yamada Animal Hospital, 2-1, Koorikitanomachi, Neyagawa, Osaka 572-0080, Japan