Brachytherapy versus Traditional External Beam Radiation Therapy

Hi everyone-I've not yet posted under this forum 'cause I've just completed Chemotherapy Cycle #4 yesterday (Tamoxifen and Cytoxan) out of a required 6 cycles.  The women here have been incredibly helpful to me and because I am so alone, I'd be lost without everyone!  I'm hoping someone out here can provide me with some much needed advice and help!

The issue of my required Radiation Therapy is surfacing and I've already met once with a Radiation Oncologist at my Cancer Center to discuss the process of External Beam Radiation Therapy.  I am Stage 2, Grade 1, ER+, HER2- (but high negative) IDC with metastasis to at least one Sentinel Node.  I opted for a lumpectomy at the URGING of my Breast Cancer Surgeon, which I've since come to terms with...was initially going to do a left-sided mastectomy.

I am 56 years old with an extensive family history of cardiac disease (thus my Medical Oncologist passed on adriamycin for treatment). I am very concerned about receiving radiation therapy, in some ways much more concerned than I have been about receiving chemotherapy (primarily due to the 7-8 week commitment and the long-term cardiac and other side effects).

From what I've gathered, I am a pretty good candidate for Brachythrapy (radioactive internal seed implantation).  However, I DO have Sentinel Node Metastasis, ie: a 4mm tumor was detected by pathology in my main (first) Sentinel Node.

Has anyone explored the pros and cons of internal versus external radiation therapy when there is node involvement?  I would appreciate any information you have on the appropriateness and effectiveness of Brachytherapy as a radiation option for breast cancer versus 35 sessions of external beam.

So far, I've found only 3 hospitals in a 150 mile radius of my home that offer Brachytherapy.  Most procedures require a 3-5 night stay, so the distance isn't the issue...it's the effectiveness of the treatment.

Thank you everyone in advance for any help!

We'll get through this!