Anal Sac Cancer

Surgery is first treatment

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The first sign of anal sac cancer in cats is usually ulceration and discharge from the perineal area (tissue around the anus), according to a study in JAVMA that looked at apocrine gland anal sac adenocarcinomas (anal sac cancer). Surgery is usually the treatment, although work has been done with chemotherapy and/or radiation.

This is a tricky area for surgery. With any cancer, surgeons want “clean margins,” meaning the tissue surrounding the cancer is free of cancer cells after surgery. There is not a lot of extra tissue in the rectal area to begin with and surgeons want to avoid damaging nerves and muscles involved with bowel control.

Still, removal of part of the rectal wall led to clear margins in at least three of the cats. The entire anal sac was removed in all of the cats. For cats whose tumors were not completely resected, local recurrence was common. Of the 30 cats, 11 had local recurrence and some others had metastatic disease.

It appears that aggressive surgery is the first line of treatment for this cancer. Follow up with chemotherapy and/or radiation needs to be more fully explored before it is used in the clinics.

JAVMA 3/15/2019 Vol 254 #6