radiation after TCR and no lymphnodes involved

TNBC is much more likely to recur than hormone positive breast cancer, I'm sure you know that, it's why you did chemo. After FULL treatment, (ie: either mastectomy with clear margins and no lymph nodes, lumpectomy with radiation and no lymph nodes or either of those with lymph nodes involved but removed and radiated) the recurrence they are worried about are distant - elsewhere in the body. With your PCR there's a less likely chance - congratulations!! But it's a lowered chance - not at all a NO chance. TNBC is a breast cancer - it starts in your breast. It's usually grade 3 as yours was - very aggressive, very fast growing. It doesn't have to be big to spread. And seeing it on a mammogram in your breast with all the scarring from surgery? Difficult. I know, I had a rare recurrence 7 years after the first. Same spot. I just....knew. It was not palpable, they couldn't find it with mammogram and ultrasound, but I KNEW. Luckily my Dr. Believes in survivor intuitions I did an MRI - almost 2 cms big, there it was. The point of my story is - why skip radiation on your breast that had cancer?? It lowers the chance of local recurrence - a recurrence that could be very hard to see on scans until... Frankly, until it's too late. You've come so far, think very carefully before you skip a step like that. PCR is no guarantee, stay vigilant. 

That seems like a wise decision