Polyp inside which tumour was present is intact

I am 49 years old. Been on dialysis for 28 years now. Also have Chronic Liver Disease from Hep C which was successfully treated in 2017.

I was diagnosed with Stage 1-2 Esophageal Cancer (adenocarcinoma) with a tumour (17 mm X 15 mm X 22 mm) that was inside a polyp (20 mm X 20 mm).

Endoscopic resection was attempted but due to severe bleeding, they had to give up.

I underwent 28 sessions of radiation therapy (50.4 Gy). The radiation oncologist showed me 'before and after' images and said that the polyp is still intact but the tumour appears to have responded to treatment.

They have asked me to do a PET-CT and endoscopy after 2 months which, they say, will tell us the status of the cancer.

The question I have is why the polyp would still be intact? Is there a chance that the tumour would re-grow within it? Any other insights would be welcome. Thanks!