I am also a bc survivor and avid diver. I posted on this in response to questions about breast implants and diving on the women's board a while back. I was stage 1C, but as I was 33 and had a grade 3 tumor, I had pretty aggressive treatment. I was presented with lumpectomy plus rads or mastectomy - chemo not optional - I initially had a lumpectomy and SN removal (would have had to have radiation), then chemo. Just as I was about to start rads, I changed my mind and I opted for bilateral mastectomy and reconstruction.
I dove about 5 days after my lumpectomy and sentinel node removal with waterproof dressings on and my doctor's blessing. I did not dive during chemo...but I dove again 2 months after my mastectomies and expander placements. I dove actively all through the time I had expanders, and then I dove again about a month and a half after I had my exchange surgery to put in my implants. Since I have had my permanent implants (last March), I've logged about 100 dives in cold and warm water, various levels of technicality and difficulty - no problems, but I carry Dan insurance just in case.
I wonder if lymphedema would be a concern - you increase the pressure on your arm/node area, so maybe not! No matter - ask your doctors - and be sure that they know that this is an important part of your lifestyle. In my experience, my oncologists/surgeons have been very supportive of my continuing a normal lifestyle. They love to hear about my recent diving stuff!!
My best to both of you (jdcloyd and kathy)- please pm me if you need any support during treatment. Keep your chin up - I know it sucks, but it IS temporary.
Also, for the rest of you, as photocoz says - the rest of you - be proactive!! Breast cancer is NOT an old lady's disease!!!