>“non-malignant conditions at enrolment” (it would be nice to know more what that means) My guess is they're referring to the neoplasm behavior codes defined b

>“non-malignant conditions at enrolment” (it would be nice to know more what that means) My guess is they're referring to the neoplasm behavior codes defined by the WHO in the International Classification of Diseases for Oncology (see article's references for info). Which means "malignant" is a neoplasm which has begun spreading beyond the tissue it appeared in. Non-malignant neoplasms are either benign (not likely to ever spread), borderline (could go either way), or in situ (still in the original tissue, but it will spread). North American cancer registries typically don't even bother collecting records of benign or borderline tumors. The only exceptions are brain tumors, which can be deadly without metastasizing. Registries also don't collect cervical cancer in situ records because there are so many and a lot of physicians never bothered reporting them. And finally, oncologists and epidemiologists classify urinary bladder cancer in situ as malignant because it's really hard for physicians to differentiate. Better safe than sorry, in case.