Now, that's different as "back cancer" because at first I'd think: "I don't think the back has "cancer cells" in the first place, must be something else", and yeah, spinal cells being affected are more appropriate to imagine as a possible cause of cancer.
Which reminds me, in highschool I had a classmate that had a limpy walking, she missed a lot of classes and at the end of the semester I was told by another classmate that "she had leg cancer" and I was like... what? is that even possible?
But I guess... we're a horrible species and at this point of existing I'd be surprised if we didn't develop "finger cancer" at some point.