Cancer below the elbow or below the knee is medically unheard of
Actually there are soft tissue malignancies (epithelioid sarcoma; clear cell sarcoma; probably rare cases of Ewing's sarcoma) which have a predilection for the distal extremities. You perhaps have not heard of them because they're uncommon and haven't generated the same kind of political/public attention that other cancers have. They're also more difficult to treat, with fewer chemotherapeutic options than breast, colon or prostate cancer, so yes, sometimes amputations are necessary.
I thought the Luke arm was awesome when the videos for it were posted, but getting that sensory feedback is even cooler. Unfortunately with an artificial implant there's always a risk of infection, so it would be even cooler if somehow the next iteration should somehow provide a scaffolding for natural tissue to regrow...maybe we'll see that in a couple of years. Or at least we can hope.
All that's needed is the saw blades.
I've always found that a crowbar works well against these kind of machines. Failing that, I'd grab a gravity gun (better known as the zero-point energy manipulator) from the local scrapyard.
On the Internet, nobody knows you're a dog. -- Cartoon caption