We have had some bad news, in that the biopsy of the first tumor showed vascular invasion of the cancer (i.e., the cancer was in the blood vessels of the gland, so it's possible the cancer could spread anywhere in his body). At this point, it is unclear whether he'll need another surgery to remove his lymph nodes (with this disease there's a 50-75% chance that it spread to the lymph nodes, but his biopsy showed no lymphatic invasion of the cancer cells). We also need to decide whether to give him radiation therapy, chemotherapy, or both.
As a student of science, with the good fortune to have access to lots of journal databases, I've been doing literature searches on and reading about studies of dogs with this disease (officially called apocrine gland carcinoma). I wanted to weigh the scientific evidence before making decisions on his treatment. Unfortunately, I've been disappointed. There are fairly few studies (makes sense given that this disease comprises only 2% of doggy skin diseases and it is probably deemed of less import than human study), and many studies have horribly small sample sizes (like 5 or 14 dogs). And results do not take into account doggy breed (which already creates a highly variable life-span)! So it's frustratingly difficult to take seriously the projected outcomes of radiation vs chemo vs surgery alone.
While my research on this topic has mostly been disappointing, a positive outcome has emerged. I contacted the lead researcher on a paper about this disease to get a copy of the paper. It turns out her oncology department can do a free consult for Buddie if my vet provides my pup's records. It would be really great to get advice from people really on top of the current literature and research on this topic!
In case anyone ever has the misfortune to have to a furry child with cancer, the The Oncology Service at North Carolina State University can provide consultation at no charge (either a written or phone consult can be done). Their consult request form can be found here (fax the completed form with your pet's records).