Well, there is caveat here as well...
If I had a mid, very early cT3 cN0 tumor, I could potentially get away with simply 5 x 5 Gy (confined to the mesorectum) + surgery or even (God forbid!) upfront surgery and possible adjuvant chemotherapy, depending on the final histology.
That is still surgey, but I would avoid any chemotherapy and large volume radiotherapy.
I understand the pro-TNT arguments, but multiple cycles of oxaliplatin can also bear some lasting toxicity (polyneuropathy) and getting my whole pelvis treated to 50 Gy is also not an atoxic treatment.
I do understand that surgery is the most GI-toxic treatment in the long term, but a full course radiochemotherapy + FOLFOX/CAPOX are also treatment. Add to that the issue of me having an only 50% chance of avoiding surgery at the end.
So, with an early cT3 cN0, I can twist the agument in both ways:
a) 50% avoid surgery with TNT, because they respond
b) 50% are potentially overtreated with TNT followed by surgery, because they don't respond. They may have been cured with upfront surgery.