Читать книгу Veterinary Surgical Oncology - Группа авторов - Страница 125

Incompletely excised grade I or II MCTs have a low chance of local recurrence and low chance of metastatic spread (Séguin et al. 2006). The surgeon has several recommended treatment options in the case of incompletely excised grade I or II MCTs, including monitoring, additional surgery, and adjuvant chemotherapy or radiation therapy. Murphy et al. concluded that dogs with well‐differentiated, incompletely excised tumors that did not receive adjuvant treatment did as well as those that did have additional therapy (Murphy et al. 2004).

The preferred treatment for incompletely excised MCTs, if possible, is excision of the surgical scar with a larger margin of normal tissue at least one fascial plane deep. If the anatomical location does not permit extensive resection, a more conservative re‐resection and/or adjuvant radiation therapy is indicated (Kry and Boston 2014; Karbe et al. 2021). One study evaluated the excision of surgical scars after 19 incompletely excised mast cell tumors and 4 mast cell tumors with close margins (tumor cells within 3 mm of a surgical margin (Kry and Boston 2014). Local recurrence occurred in 13% of these cases whereas local recurrence occurred in 38% in a group where no further treatment was performed. Tumors where the scar was re‐excised had longer median time to local recurrence and dogs with a re‐excision had a longer median survival time than dogs and tumors with no further treatment. Presence of microscopic disease was found in 48% of scars and was not prognostic for local recurrence (Kry and Boston 2014). In a more recent study, scar revision (i.e. re‐excision) of 86 mast cell tumors that had been excised with tumor cells at the margins (87% of the tumors), margins of <1 mm (8%), or margins of 1–3mm (5%), local recurrence occurred in 4% of the scars revised (Karbe et al. 2021). Residual mast cell tumor was found in 27% of the resected scars. Following scar revision surgery, complete margins were achieved in 92% of tumors. Margin status and presence of mast cell tumor in the resected scar were not associated with local recurrence or disease progression but grade III tumors were more likely to develop local recurrence, regional lymph node metastasis, or any disease progression (Karbe et al. 2021).

Incompletely excised grade III MCTs have a high chance of both local recurrence and metastatic spread. These cases should receive additional local therapy (either additional surgery or radiation therapy), as well as chemotherapy (Hahn et al. 2004).