Metachronous Carcinomas of the Colon

Metachronous cancers of the large bowel are unique enough in occurrence to be considered almost bizarre. Ewing and Boyd, among others, formerly believed that one carcinoma developing in a person conferred a certain immunity that prevented another primary carcinoma from developing, in contradistinction to a recurrence or a distant metastasis. As late as 1930, Lockhart-Mummery1stated that there seemed to be sufficient clinical evidence to support the belief that one malignant growth inhibited the development of a second malignant lesion. However, more recently, with the increasing number of reports2of multiple cancers occurring simultaneously (synchronous carcinomas) and with an interval of time between (metachronous carcinmas), an almost diametrically opposite opinion has been thought to be correct. Indeed, Brindley3has gone so far as to state that "a patient with one cancer is a good subject for the development of a second, and is more susceptible than one