I'm not sure how helpful this is, because I was never told the size of the tumour and I didn't think to ask.
I was staged at 2B/3 with lymph node involvement on the left side of my pelvis and my para aorta node. In one conversation with my Consultant she said, 'It's not so much the size of your tumour We've successfully treated bigger tumours, but one of your pelvic lymph nodes and in particular the para aorta node are very enlarged.' (The left pelvic node had significantly affected my ability to walk, but she was especially concerned by the size of the para aorta node.) This was why they initially said to me that the realistic aim was to 'manage' the cancer rather than to expect a 'cure'. I was pretty terrified at the beginning of it all and throughout treatment. The risk of spread beyond my pelvis via my lymphatic system was pretty high and is still a recurrence risk.
My week 5 pre-brachytherapy scan showed that everything (including the para-aorta node) had shrunk by 'at least 50%' and by the time I went for my second brachytherapy I was told that the main tumour had visibly shrunk even more. Although the team viewed that as a great result, I was disappointed. Only a week and a half to go, but still 50% left, not so great to my mind. I was resigned (and prepared myself mentally) for a second round of combination chemo.
At my three monthly check up last week I was told it had all gone. None of us were expecting that.
I don't know how much the Brachytherapy contributed to further shrinkage relative to the external radiotherapy & chemo, but it really is only aimed at the main tumour and is unlikely to have affected my enlarged lymph nodes. I put that down to the external radiotherapy & chemo. I know you had two more weeks of external rather than the Brachytherapy, but external radiotherapy is first line treatment with chemo being 'the cherry on the top' as my Consultant put it. It's pretty effective these days. Quite a lot of radiation also carries on doing it's thing for weeks & months after formal treatment ends.
I don't want to give you platitudes. Given the lymph involvement that I've had, it's far too early for me to know how things will be over the next few months & years. That said, my body has already responded far more positively to the treatment than had been envisaged by my Oncology team and subsequently, me. There is hope.