Is there a medical cure for stage 1 rectal cancer?

Surgical resection..: This is where the cancer does not go past the muscle layer. Surgery can cure this but there are risks. Surgery can be through the abdomen with or without surgery on the anus. The first way might need a temporary or permanent colostomy, an opening for expulsion of waste. The other way requires a permanent colostomy. Surgery may be done that just involves the anus, but that risks recurrence.

Possible: Either transanal wide excision of the tumor with or without radiation and chemotherapy could avoid the need for more major surgery.

Not without surgery: If by medical you mean with medication alone , then no. Early stage rectal cancer can be treated by transanal excision followed by radiation in some cases. Careful evaluation by an experienced surgeon and radiation oncologist is recommended.