This waiting is the worst!

First, as always, the disclaimer:  I'm no doctor.  I can only comment on what I personally experienced, that has anything to do with your situation.

As for chemo but no Tamoxifen: It can be impossible to know how you will react to these treatments. That's not the answer you want, I'm sure. But...I hated Tamoxifen (and Aromasin less so), but I could always work through it (though I had a desk job - BIG difference than your situations).  I mostly had hot flashes and bone pain. Yet my digestive system is extremely sensitive and I could NOT work after my chemo for several days, and continued to be miserable at my desk even after day 5.  Then again, it also depends on the type chemo you'd get, and whether your anti-emetics work better than mine. I actually quit chemo after first treatment. When I got a new oncologist, she said that in my situation, the hormonal therapy was more important than the chemo.  Was she right?  Who knows?  Is my situation like yours?  Who knows? Bottom line - look for a lot of information but hold your decisions until you get all the advice from all the doctors.

As for dense breasts, MRI, and "what could be hiding"... I had one tumor that did not show up on mammogram, barely showed up on ultrasound, the ultrasound tech DID think it was something but the doc/radiologist did NOT--but she gave in and did a core biopsy. She sounded SO surprised when she said it was "a cancer"! She practically gasped. I had already decided on an MRI, so it didn't matter in my situation, but an MRI was performed anyway, the day before surgery so they could mark it properly.  Seemed like overkill to me but I knew nothing at that point and asked no questions.  They never told me, I found it on my report, that a 2nd primary tumor was found in that breast.  If I'd had a lumpectomy--it probably would have been left there.  So - definitely have the MRI - it can help with your decisions.

As for hearing from it through your technician or radiologist, it's a tough call.  Others say they don't want to spend time sitting at home and wait and worry until they can get an appointment. Some want to have a loved one with them, others want to know asap.  If I remember correctly, I had mammogram, and I always get an ultrasound because I'd had a finding in my other breast that made me high risk.  The ultrasound tech was very obviously concerned, and sent me directly to the radiologist who used her own portable ultrasound. They argued. I was sent home to wait for 2 months, but went I came back it went FAST.  I may not remember it all correctly, but I think it was ultrasound on a Monday or Tuesday, biopsy on Thursday.  And the radiologist called me at me office first thing Monday morning at work -- my first call of the day was "it's a cancer!" She must have been going through all her reports because, when I got a copy, I saw they'd had the reports the Friday before.  Or maybe she wanted me to have one last fun weekend (which is silly because of course we're worried).  I'd personally rather hear it FAST.  I remember getting a heart ECHO because I developed a murmur during treatment.  When we were done, the tech said "I can't talk to you about what I find" (which I hear all the time, so I'm amazed so many of you had a technician tell you what they found).  I said "I know the drill, if it's bad news, there is usually a lot of "typing."  He said "And I didn't type anything at all."  He was telling me I was fine. Heehee. 

As for it not being "cut and dried" - that's because you're now the patient and not the caregiver. Have you seen the older move, I think it's called "The Doctor" with William Hurt.  I think all medical students should have to watch it before they can get their credentials.  It's never cut and dry.  Looking back, we all talk about numbers.  For making decisions, we all talk about odds and numbers. But in our hearts and minds, we know there are no guarantees and we just have to take  leap of faith and do what we think is best. But nothing is perfect. When I quit chemo, I knew that, if I got a recurrence, I would never look back and worry that I'd decided incorrectly.  I made the best risk: benefit decision I could. I was 46, and a single Mom (8 kids?  Whoa!).

So, hang in there, and best to you as you run this gauntlet.