[The incidence of new (second) lesions after surgery and irradiation (author's transl)].

A comparative analysis of 1286 patients with squamous cell carcinomas of the upper respiratory and digestive tracts successfully treated either by surgery, irradiation or a combination of both showed that the incidence of new (second) lesions in these regions is practically identical with the different treatment modalities up to 25 years following treatment. Only within five years following surgery the incidence of new cancers in the vicinity of the original cancer is statistically significantly higher than in patients treated by irradiation alone or in combination with surgery. This is explained by probable eradication of in situ carcinomas or microscopic foci of invasive cancer located in the vicinity and hence receiving a significant dose of irradiation. These new (second) lesions occur about 1000 times more frequently than it would be expected from the estimated cancer-incidence in these sites and are to be separated from the extremely rare therapeutically induced malignancies.