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You have mentioned that the pathology report has come as cancerous. it is a cancer in the form of malignant polyp.
I presume that entire colon was screened and no other lesion was found.
I also presume, the endoscopic removal of the malignant polyp was complete and there is no residual lesion left. If the removal is complete, then it is curative.
There are chances of recurrence and hence follow up colonoscopy
Since your polyp was large, you come under high risk category for surveillance.
The recommendation is repeat colonoscopy after 3 years.