Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am very sorry to hear about about your girl Lucy's anal gland mass.
Ideally these should be surgically removed as soon as possible with wide margins as anal gland tumors tend to be very aggressive, infiltrative tumors that metastasize (spread to other parts of the body) relatively quickly.
But there are some questions I would ask before surgery because they will help determine whether surgery is worth doing.
Is her blood calcium level normal?
Are her kidney enzymes normal and is she concentrating her urine pointing toward normal kidney function?
Is there any evidence of sublumbar lymph node enlargement (seen with abdominal radiographs or an ultrasound)?
Is there any evidence of metastases to the lungs on radiographs?
The most common tumor in anal sacs in dogs is an anal gland adenocarcinoma (malignant, invasive tumor that spreads) or an anal gland adenoma (more benign). If this tumor is an anal gland adenocarcinoma and it has spread it usually spreads to the sublumbar lymph nodes (lymph nodes found between the colon and spine near the back of the body) first so it is worth looking for their enlargement as that would indicate that the tumor has spread. This tumor also causes an increase in blood calcium which in turn leads to kidney failure.
If she is healthy otherwise, has no signs of tumor spread, her blood calcium is normal and her kidney function is normal then I would go ahead with surgery. It is her best chance of a normal, comfortable life because benign or malignant tumors continue to grow and at some point you won't be able to keep her comfortable even with medication. I do recommend surgery be done by a board certified surgeon because this is a tricky surgery that can lead to incontinence and it is important to remove all of the tumor with the first surgery. In cases where we cannot remove the entire tumor or histopathology shows close margins radiation therapy after surgery is ideally done as a follow-up.
But if she already has lymph node enlargement or metastases to the lungs, high blood calcium levels and kidney failure I would be more hesitant about surgery because she will quickly succumb to the disease, usually within 6 months to a year. In those cases I recommend medical management only to keep her comfortable. That would include a nonsteoridal anti-inflammatory to reduce inflammation and slow tumor growth, a stool softener, and a low residue, highly digestible diet to keep stools soft and small and thus easy to pass by the mass.
If you'd like to read more about anal gland tumors here is a link to a very good article:
Please let me know if you have any further questions.