Thymectomy and cancer--a follow-up study.

Three hundred and eighty-two patients undergoing thymectomy for myasthenia gravis at 4 London hospitals during the years 1942-64 have been followed to the end of 1967. Five of these patients died from extrathymic tumours while 5·5 would have been expected to do so from the national experience. An additional 5 patients developed non-fatal extrathymic tumours during the period of follow-up. These data provide no evidence that adult thymectomy is followed by an increased risk of neoplastic disease, but more prolonged follow-up will be required before a final conclusion can be drawn.