Incidence of second solid cancer in patients after treatment of Hodgkin's disease

An analysis of the incidence of second malignant solid tumors in our patients after radiotherapy or radiotherapy plus chemotherapy for Hodgkin's disease has been performed.

340 patients had curative treatment with mantle or paraaortic and pelvic radiotherapy (1964 to 1972) or mantle plus paraaortic and spleen or splenic pedicle or total nodal radiotherapy with or without chemotherapy (1973 to 1992) and have a follow-up of at least 1.5 years. Since 1987, after chemotherapy only modified involved fields were irradiated. All second tumors have been histologically verified. The cumulative incidence of second solid cancer of the patients have been compared with the age and sex specific expected rates according to the "Zürcher Krebsregister 1980 to 1990".

We observed seven patients with leukemia after radiotherapy plus chemotherapy, five patients with non-Hodgkin-lymphoma and 21 patients with solid cancers after radiotherapy or radiotherapy and chemotherapy with a cumulative risk of all second malignancies of 7.0% (ten years), 30.7% (20 years) and 40.5% (24 years). Cumulative risk of second solid cancer was 3.1% (ten years), 9.3% (15 years), 23.5% (20 years) and 34.3% (24 years). Cumulative risk of second solid cancer was significantly higher than expected with no decrease of the relative risk after more than 20 years of follow-up. Comparable to the observations from Stanford, we observed a significantly higher risk of breast cancer in women less than 30 years of age at treatment. Relative risk of second solid cancer was higher after radiotherapy plus chemotherapy compared to radiotherapy alone, but the difference was not statistically significant. Nearly all patients with radiotherapy plus chemotherapy and a follow-up of ten years or more had radiotherapy with large fields.

In patients after treatment of Hodgkin's disease with radiotherapy or radiotherapy plus chemotherapy, incidence of second solid cancer is significantly higher than expected. Incidence of second solid cancer after chemotherapy and large field radiotherapy is higher than after radiotherapy alone, but this difference is statistically not significant.