Dose‐escalated simultaneously integrated boost radiation protocol fails to result in a survival advantage for sinonasal tumors in dogs. Issue 5 (29th March 2022)

• Record Type: Journal Article
• Authors: Meier, Valeria; Staudinger, Chris; Körner, Maximilian; Soukup, Alena; Rohrer Bley, Carla
• Is Part Of: Veterinary radiology & ultrasound. Volume 63:Issue 5(2022)
• Page Start: 633
• Page End: 648
• Publication Date: 2022-03-29
• Subjects: canine -- IMRT -- nasal tumor -- ocular -- SIB; Veterinary radiology -- Periodicals; Radiologie vétérinaire -- Périodiques; Échographie vétérinaire -- Périodiques; Radiography -- Periodicals; Ultrasonography -- Periodicals; Diagnosis -- Periodicals; Veterinary Medicine -- Periodicals; Societies, Medical -- Periodicals; 636.089607
• DOI: 10.1111/vru.13086
• Languages: English
• ISSNs: 1058-8183

Abstract

Abstract: The prognosis for canine sinonasal tumors remains rather poor despite definitive‐intent radiotherapy (RT). Theoretical calculations predicted improved outcomes with simultaneously integrated boost (SIB) protocols. With the hypothesis of clinically detectable differences in outcome between groups, our retrospective study evaluated prognostic variables and outcome in dogs treated with regular versus SIB RT. Dogs with sinonasal tumors treated with either a regular (10 × 4.2 Gy) or new SIB protocol (10 × 4.83 Gy to macroscopic tumor) were included. Information regarding signalment, tumor stage, type, clinical signs, radiation toxicity, response, and outcome was collected. Forty‐nine dogs were included: 27 treated regularly and 22 treated with SIB RT. A total of 69.4% showed epistaxis, 6.1% showed epileptic seizures, 46.9% showed stage IV tumors, and 6.1% showed lymph node metastases. Early toxicity was mostly mild. Late grade 1 skin toxicity (alopecia/leucotrichia) was seen in 72.1% of dogs, and a possible grade 3 ocular toxicity (blindness) was seen in one dog. Complete/partial resolution of clinical signs was seen in 95.9% of patients as best clinical response and partial remission was seen as best imaging response in 34.7%. The median progression‐free survival (PFS) was 274 days (95% CI: 117–383) for regular and 300 days (95% CI: 143–451) for SIB RT, which was not significantly different ( P = 0.42). Similarly, the median overall survival (OS) was 348 days (95% CI: 121–500) for regular and 381 days (95% CI: 295–634) for the SIB RT ( P = 0.18). Stratified by protocol, the hazard ratio of stage IV versus stage I–III tumors was 2.29 (95% CI: 1.156‐4.551, P = 0.02) for OS but not PFS. All dogs showed acceptable toxicity. In contrast to theoretical predictions, however, we could not show a statistically significant better outcome with the new protocol.