Has your vet recommended any form of chemo for Yidda? 7 years ago our cat Suki (~15 yrs old) received chemo treatments every 3 weeks or so following surgery to remove a fibrosarcoma (not a cure with that type of cancer, but slowed it down so we could have a little more time with her). Luckily, the type of chemo she got did not produce any ill-effects; no nausea, no hair loss (though it didn't help her hatred for going to the vet at all). Also, had our other cat at the time survived exploratory surgery (likely stomach or intestinal cancer), the vet had talked about a pill-form of chemo that we could administer at home.

I've also heard/read about radiation treatments for cancer in cats and dogs. I don't know if that's an option, but you vet would know if it's worth exploring.

I hope you have many more happy and cancer-free years with your Yidda.

Ask about removing all the mammary glands. Extreme, but the best protection.

I've removed all the mammary glands from cats before- it's a booger of an operation but relatively healthy cats do fine. I'd certainly get chest rads before any type of surgery because any metastasis there can be a problem for prolonged anesthesia. Also may not be worth a radical mastectomy if she is going to die of tumors in her chest. So definitely a must on the rads. If the chest looks clean, a bilateral radical mastectomy may be the safest thing for Yidda to both get any tumor left and prevent recurrence. If she isn't spayed, you must get that done ASAP because estrogen is the cause of the tumors.

I'm assuming the biopsy was read by a pathologist. Didn't the vet submit the entire lump so margins could be evaluated? There shouldn't be a question of margins if the whole lump was sent off. All the reports I get (I use the State Lab for NC) state clearly how far away the cancer was located from the margins, or if the cancer was found at the margins (didn't get it all).

Be diligent about looking for lumps and have ALL of them tested. Do NOT rely on what the lump feels like- cancer can feel like anything it wants. Have every single new lump tested either by removing it or at least an FNA.

In the mean time, love your girl a LOT. I hope this lump in the only bad one and she lives a long happy life.