A retrospective comparison of first and second opinion histopathology with patient outcomes in veterinary oncology cases (2011-2019).

Mandatory second opinion histopathology is common practice in human surgical pathology. It is intended to confirm the original diagnosis or identify clinically significant discrepancies, which could alter the course of disease, cost of treatment, patient management or prognosis. This retrospective analysis aimed to evaluate agreement between first and second opinion histopathology cases, examine their correlation with natural history of disease and investigate the rationale for pursuing this test. Medical records from 2011 to 2019 were reviewed, identifying 109 cases where second opinion histopathology was sought. Reasons for seeking second opinion and clinical disease course were also reviewed to determine whether case progression favoured first or second opinion findings in cases of diagnostic disagreement. Diagnostic disagreement was found in 49.5% of cases. Complete diagnostic disagreement (a change in degree of malignancy or tumour type) occurred in 15.6% cases and partial disagreement (a change in tumour subtype, grade, margins and mitotic count) occurred in 33.9%. Major disagreement (a change in diagnosis resulting in alteration of treatment recommendations) occurred in 38.5% of cases. The most common reasons for seeking second opinion were an atypical/poorly differentiated tumour (31.2%; 34/109) or a discordant clinical picture (24.8%; 27/109). Among cases with any form of disagreement, natural history of disease favoured second opinion findings in 33.3%. The first opinion was favoured over the second in a single case. These findings reinforce previous literature supporting a role for second opinion histopathology in optimizing therapy and predicting outcomes in veterinary oncology, particularly in cases where diagnosis is in question based on the overall clinical picture.

Definitive-intent intensity-modulated radiation therapy provides similar outcomes to those previously published for definitive-intent three-dimensional conformal radiation therapy in dogs with primary brain tumors: A multi-institutional retrospective study.

Radiotherapy with or without surgery is a common choice for brain tumors in dogs. Although numerous studies have evaluated use of three-dimensional conformal radiotherapy, reports of definitive-intent, IMRT for canine intracranial tumors are lacking. Intensity-modulated radiation therapy has the benefit of decreasing dose to nearby organs at risk and may aid in reducing toxicity. However, increasing dose conformity with IMRT calls for accurate target delineation and daily patient positioning, in order to decrease the risk of a geographic miss. To determine survival outcome and toxicity, we performed a multi-institutional retrospective observational study evaluating dogs with brain tumors treated with IMRT. Fifty-two dogs treated with fractionated, definitive-intent IMRT at four academic radiotherapy facilities were included. All dogs presented with neurologic signs and were diagnosed via MRI. Presumed radiological diagnoses included 37 meningiomas, 12 gliomas, and one peripheral nerve sheath tumor. One dog had two presumed meningiomas and one dog had either a glioma or meningioma. All dogs were treated in the macroscopic disease setting and were prescribed a total dose of 45-50 Gy (2.25-2.5 Gy per fraction in 18-20 daily fractions). Median survival time for all patients, including seven cases treated with a second course of therapy was 18.1 months (95% confidence of interval 12.3-26.6 months). As previously described for brain tumors, increasing severity of neurologic signs at diagnosis was associated with a worse outcome. Intensity-modulated radiation therapy was well tolerated with few reported acute, acute delayed, or late side effects.

Definitive-intent radiotherapy for sinonasal carcinoma in cats: A multicenter retrospective assessment.

Treatment of epithelial sinonasal tumours in cats is not commonly reported. In the newer reports, palliative radiation protocols have been described more often than definitive-intent protocols. In this multi-institutional retrospective study, we included 27 cats treated with single-modality radiotherapy. Cats were irradiated using 10 daily fractions of 4.2 Gy. Three cats (11.1%) experienced a complete clinical response and 17 (63%) had a partial clinical response. Stable clinical disease was noted in three cats (11.1%). Four cats (14.8%) showed progression within 3 months following treatment. The median time to progression for all cases was 269 days (95 % confidence intervals [CI]: 225; 314). The proportion of cats free of progression at 1 and 2 years was 24% (95% CI: 22%; 26%) and 5% (95% CI: 5%; 6%), respectively. None of the prognostic factors evaluated were predictive of outcome (anaemia, tumour volume at the time of staging, modified Adams stage, intracranial involvement, facial deformity, epistaxis, inappetence or weight loss). Median overall survival (OS) for all deaths was 452 days (95% CI: 334; 571). The proportion of cats alive at 1 and 2 years was 57% (95% CI: 37%; 77%) and 27% (95% CI: 25%; 29%), respectively. Surprisingly, cats with epistaxis had a longer median OS of 828 days (95% CI: 356; 1301) compared to 296 days (95% CI: 85; 508) in cats without epistaxis, (P = .04, Breslow). Radiation therapy used as a single modality for the treatment of feline sinonasal carcinoma improved clinical signs and was well tolerated but progression within a year was common.