Holland and Stewart (1990) have collapsed these principles into four categoriescondition, diagnosis, treatment and cost.
The possible benefits are listed as life years gained for those with curable cancer and avoidance of morbidity related to radical treatment. The disadvantages are the complications resulting from the screening test itself (eg. bruising following a blood test). There is also extended morbidity if the prognosis is unaltered, as well as the possibility of over diagnosis, resulting in women receiving unnecessary treatment for lesions which otherwise might have regressed spontaneously.