Hello I am Dr. Joey. Thanks for trusting me to help you and your pet today. I am a licensed veterinarian with over 15 years of experience. I look forward to working with you.
What an ordeal for you and Megan. Removing the masses is the first step in this process. With the new mass that you discovered, I cannot say anything with regard to if your veterinarian checked (or found) this while she was in for the surgery. It is disappointing, but the best step is to consider either doing a fine needle aspiration to confirm this is another mammary tumor, or if it is associated with her mammary gland to consider removal of that mass with wide margins. I am not sure I would put her through a complete masectomy on that side (simply because it is such a painful recovery; I am assuming this is the surgery she went through based on your description).
With regard to the dressing, this is usually removed within 3 to 5 days post-surgery. So, I think it should come off or at a minimum be replaced/checked. You should contact your vet to discuss what his plan is for this. We need to be able to see what is going on underneath the bandage. It will heal faster, if everything is closed properly, when exposed to the air. I am again a bit disappointed that he did not want to look. Usually at 5 days post-op I would want to remove the dressing and look at what is going on. I am not sure to what he is referring when he is making sure her stomach is not hard (perhaps pain?).
And then as a next step after removal of the mass, hopefully you were offered referral to see an oncologist and discuss chemotherapy. There are multiple protocols available for dogs with this type of cancer. I cannot be optimistic about outcome, but those that receive the drugs do tend to survive longer before we have progression of the cancer.
You asked for some details. With surgery alone for mammary adenocarcinoma, tumors > 5 cm in diameter have a median disease-free interval of only 7 months, and median survival is < 1 year. Also, ductular carcinomas are more aggressive than the more common tubulo-alveolar carcinomas. Was a local lymph node tested for metastasis? This helps us with prognosis. As well did the pathologist comment as to whether or not there was evidence of vascular/lymphatic invasion within the tumor? Did he comment on whether or not excision was complete? If you don't have this info, I would call the pathologist and ask for it.I assume you and your vet have already done the routine staging recommendations - baseline blood work, regional lymph node assessment, and three-view thoracic rads. If the local lymph node come back positive for tumor, then I absolutely would want an abdominal ultrasound to assess the medial iliac lymph nodes since they are the next in line. With a negative local lymph node aspirate/biopsy, it is reasonable to still have the ultrasound to look at the abdominal lymph nodes and look at the other abdominal viscera, but I would not insist on it.Personally, I would recommend adjuvant chemotherapy for Megan. There is not great info on how much better we do with chemo, though. Most people use doxorubicin-based protocols (single-agent doxorubicin, doxorubicin/platinum), but there is not anything published looking at these protocols. The only study I am aware of used a combination of alternating doxorubicin and docetaxel (Docetaxel is not routinely used in veterinary medicine because of the allergic reactions associated with IV administration.). There was no statistically significant difference with or without chemo, but the sample size was small and the study was not randomized. In short, while the study did not show an obvious benefit, in no way did it prove there isn't a benefit.If she is not spayed, then this is recommended. No clear evidence that spaying improves prognosis. At the same time, though, we do not routinely evalute mammary tumors for sex hormone receptor expression. There may be a subset of dogs that do benefit. Additionally, if you are not breeding her, it reduces the risk of ovarian cancer as well as pyometra (uterine infection).
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Dear Dr Joey
That is such a thorough and helpful reply!!! I am so appreciative of all this information.
Many, many thanks