Definitive-intent intensity-modulated radiation therapy for treatment of canine prostatic carcinoma: A multi-institutional retrospective study

Vet Comp Oncol. 2020 Sep;18(3):381-388. doi: 10.1111/vco.12561. Epub 2019 Dec 20.


No standard of care is currently recognized for treatment of canine prostatic carcinoma (PC). This retrospective study assesses outcome following definitive-intent, intensity-modulated radiation therapy (RT) in dogs with PC. Medical records review was performed, including 18 patients from four institutions undergoing definitive-intent intensity-modulated radiotherapy to treat PC. Diagnosis was incidental in 7/18 (39%) patients. Five dogs (28%) had evidence of metastasis to loco-regional lymph nodes at diagnosis. Seventeen patients received concurrent non-steroidal anti-inflammatory drugs; 15/18 (83%) patients received maximally-tolerated dose (MTD) chemotherapy, with variable drugs and protocols employed. Total prescribed radiation dose ranged from 48 to 54 Gy (median 50 Gy) delivered as daily doses of 2.5-2.8 Gy. One patient was euthanized prior to completing radiotherapy. Acute toxicity was observed in nine patients; Grade 1-2 diarrhoea was the most common toxicity observed. Suspected late toxicity (urethral stricture, ureteral stricture and hindlimb oedema) was observed in three patients. Median event-free survival (EFS) following RT was 220 days, and median overall survival was 563 days. Local progression occurred in seven patients at a median of 241 days. Median overall survival was significantly longer in incidentally diagnosed dogs (581 vs 220 days in symptomatic dogs, P = .042). EFS was significantly longer in patients treated with MTD chemotherapy (241 vs 25 days, P < .001), and significantly shorter in patients presenting with evidence of metastatic disease (109 days) vs those without (388 days, P = .008). These findings suggest that definitive-intent radiotherapy is a valuable treatment option for local control of canine PC with moderate risk of toxicity.

Keywords: dogs; prostatic neoplasms; radiotherapy, intensity-modulated; retrospective studies.

MeSH terms

  • Animals
  • Antineoplastic Agents / therapeutic use
  • Carcinoma / drug therapy
  • Carcinoma / pathology
  • Carcinoma / radiotherapy
  • Carcinoma / veterinary*
  • Dog Diseases / drug therapy
  • Dog Diseases / radiotherapy*
  • Dogs
  • Male
  • Prostatic Neoplasms / drug therapy
  • Prostatic Neoplasms / pathology
  • Prostatic Neoplasms / radiotherapy
  • Prostatic Neoplasms / veterinary*
  • Radiotherapy Dosage
  • Radiotherapy, Intensity-Modulated / adverse effects
  • Radiotherapy, Intensity-Modulated / veterinary*
  • Retrospective Studies
  • Treatment Outcome


  • Antineoplastic Agents