What radiation and systemic treatment options should I discuss with owners of dogs with nasal carcinoma?

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Radiation therapy (RT) is the standard of care for canine nasal carcinoma, with median survival times (MSTs) ranging from 6 to 18 months depending on modality, stage, and systemic therapy combinations.9 Without treatment, the MST is 95 days, dropping to 88 days in dogs presenting with epistaxis.5 Staging drives prognosis before any treatment discussion. The modified Adams system is predictive of outcome across multiple studies, and cribriform plate erosion (Stage 4) carries a worse prognosis regardless of clinical signs.5 Metastatic rates are 0–13% at diagnosis but rise to approximately 45% at necropsy, so three-view thoracic radiographs and regional lymph node cytology are part of the staging workup.59 CT or MRI is critical for treatment planning and for assessing cribriform plate integrity.79 Conventionally fractionated megavoltage RT produces MSTs of 10.5 to 21.4 months and remains a well-established approach for local disease control.8 Carcinomas tend to show better size reduction in response to RT than sarcomas, though this does not translate to a significant survival difference between histologic types.6 Stereotactic body radiation therapy (SBRT) delivers curative-intent treatment in 3 fractions and produces MSTs within the range of conventionally fractionated RT. In one cohort treated with curative-intent SBRT, the MST was 388 days (12.9 months).8 Intensity-modulated RT (IMRT)-based stereotactic RT demonstrated clinical benefit in 88% of dogs with nasal carcinomas, with an MST of 563 days; severe acute adverse effects were absent, though 6 dogs developed Grade 3 late side effects.4 Stereotactic RT in a larger cohort of dogs with nonlymphomatous sinonasal carcinoma yielded a disease-specific survival time of 482 days; 7% developed oro- or naso-cutaneous fistula, and 61% exhibited possible chronic rhinitis.4 Brain invasion by the tumor is associated with shorter survival following SBRT.8 Palliative RT is appropriate when curative intent is not the goal, improvi