Treatment of advanced canine anal sac adenocarcinoma with hypofractionated radiation therapy: 77 cases (1999–2013)

Abstract

Currently no standard of care exists for advanced, inoperable or metastatic anal sac adenocarcinoma (ASAC). The objective of this retrospective study was to assess the role of hypofractionated radiation therapy (RT) in 77 dogs with measurable ASAC. A total of 38% of dogs experienced a partial response to RT. For dogs presenting with clinical signs related to the tumour, improvement or resolution of signs was noted in 63%. For dogs presenting with hypercalcemia of malignancy, resolution was noted in 31% with RT alone and an additional 46% with radiation, prednisone, and/or bisphosphonates. Median overall survival was 329 days (range: 252-448 days). Median progression free survival was 289 days (range: 224-469). There was no difference in survival based on radiation protocol, use of chemotherapy, previous surgery or advanced stage. Radiation toxicities were mild and infrequent. Hypofractionated RT is well tolerated and is applicable in the treatment of advanced primary, locoregional or metastatic ASAC.

Prognostic significance of histopathology in canine anal sac gland adenocarcinomas: Preliminary results in a retrospective study of 39 cases

“…Similar to previous publications, several clinical variables were related to the outcome in univariate analyses in our study. The presence of clinical signs associated with the tumour, the size of the primary tumour and the presence of nodal metastasis were significantly associated with PFI and OS, whereas hypercalcaemia was significantly associated with OS only. The presence of clinical signs associated with the tumour could reflect increasing size of the primary tumour and metastatic disease within lymph nodes as well as the presence of hypercalcaemia.…”

“…In previous studies, several factors have been identified as negative prognosticators for dogs with ASGAC, including increasing primary tumour size, presence of lymph node metastasis, presence of distant metastasis and lack of therapy . The prognostic influence of hypercalcaemia (reported to occur in 16%‐53% of the cases) remains controversial, with some studies showing significantly decreased survival with hypercalcaemia, while others found no predictive value …”

“…[4][5][6][7][8][9][10][11] Many treatment modalities have been described for canine ASGACs, alone or in combination, including surgical resection of both primary tumours and metastatic lymph nodes, chemotherapy with various agents and radiotherapy of primary tumours and regional lymph nodes. [4][5][6][7][8][9][10][11][12][13] Reported median survival times for dogs receiving different treatment modalities vary considerably, ranging from 5 to 31 months in published studies. [4][5][6][7][8][9][10][11][12][13] This variability likely reflects the heterogeneity in patient groups and treatments undertaken among studies, but it may also be partly because of variable biological behaviour of this tumour.…”

“…[4][5][6][7][8][9][10][11][12][13] Reported median survival times for dogs receiving different treatment modalities vary considerably, ranging from 5 to 31 months in published studies. [4][5][6][7][8][9][10][11][12][13] This variability likely reflects the heterogeneity in patient groups and treatments undertaken among studies, but it may also be partly because of variable biological behaviour of this tumour. Ultimately, this variability leads to difficulty in accurately predicting the prognosis of individual dogs with ASGACs.…”

“…4,7,[9][10][11] The prognostic influence of hypercalcaemia (reported to occur in 16%-53% of the cases 2,4,5,7-11 ) remains controversial, with some studies showing significantly decreased survival with hypercalcaemia, 4,7 while others found no predictive value. 5,6,8,[10][11][12] For other canine tumours, such as mast cell tumours, 14,15 soft tissue sarcomas 16 and mammary carcinomas, 17,18 specific histological Presented in oral abstract form at the ESVONC-ECVP Congress, Nantes, France, October 2016.…”