February 3, 2023

My cat’s cancer keeps coming back!

Q Several years ago when I first got my neutered rescue cat, she regularly displayed signs of coming into season. My vet found a piece of her ovary had been left behind on spaying, and years after, that piece of ovary had turned into a cyst. The cyst was successfully removed with no further problems, but then I found a lump around one of her nipples.

The vet removed it and asked if I wanted it to be sent away for analysis. He told me that there was no option of treatment if it turned out to be cancerous. I felt it was better not knowing whether Rosie had cancer if there was nothing that could be done, so I did not have the lump analyzed. I was told to keep checking for any reoccurrence.

Six months later, I noticed another lump near the top of the wound in the middle of her tummy. The vet removed it and analysis has revealed that it is a low-grade cancer. Once again, he says there is no treatment available, only vigilance.

My concern is that she is 13 years old and her last operation was quite a big one for her age. What if a lump comes back again? Should she have more surgery? Is there anything I can do to try to slow the recurrence down, or anything the vet could do for her?

The vet told me that chemotherapy could knock her about and as the cancer is low-grade, I feel that chemo should not be an option. What do you suggest?

Vet Andrea Harvey advises: I am very sorry to hear about your cat’s mammary tumours; what a shock for you. Unfortunately, mammary tumours in cats do tend to be very malignant, and without having seen the lump, assessed your cat or seen the biopsy report myself, it is difficult to be more precise about what the prognosis for her is, and if anything more can be done.

The best chance for effective treatment for the cancer is complete removal of the mass with what we call ‘wide margins’. This means that when it is removed we want to have also removed a good area of cancer-free tissue on each side of the tumour as well, in order to reduce the risk of its recurrence.

If the biopsy result showed ‘cancer-free margins’ suggesting that it was all removed, that is a good sign. Although it is frustrating that it has grown back since the first surgery, the fact that it has taken a few months to grow back is relatively good, as often these tumours will grow back and spread extremely quickly.

While there are chemotherapy options that may help reduce the risk of recurrence, as your vet says, there are risks associated with chemotherapy, and it won’t be guaranteed to help at all since these types of tumours tend to be relatively unresponsive to chemotherapy.

If you want to explore every possible treatment option available I would suggest speaking to your vet about referral to an oncologist. These are vets who specialize in treating cancer and will be able to give you the best advice regarding further management of her.