2ND PRIMARY-CANCER AFTER TREATMENT FOR CERVICAL-CANCER - AN INTERNATIONAL CANCER REGISTRIES STUDY

Background. The pattern of second cancers after treatment for cervical cancer provides important information on the risk of radiation-induce d malignancies. Large numbers of women survive many years and can be s tudied for late effects.Methods. Incident second cancers in 86,193 pat ients with cervical cancer reported to 13 population-based cancer regi stries in 5 countries were evaluated to estimate the risk of second ca ncer among very long term survivors. Results. Overall, 7543 second can cers were observed versus 6015 cancers expected based on population ra tes (observed/expected = 1.2). Lung cancer accounted for nearly half o f the excess cancers. Among the 49,828 women treated with radiation, 3 750 survived 30 or more years and a two-fold risk of cancers of heavil y irradiated organs was seen. Most of the excess cancers were of the r ectum, vagina, vulva, ovary, and bladder. Patterns of risk over time s ince treatment were consistent with a radiation etiology. Significant increases of nonchronic lymphocytic leukemia and cancers of the bone a nd kidney were also linked to radiotherapy. Women treated surgically w ere also at significant risk of second cancers, in all likelihood rela ted to cigarette smoking and risk factors similar to those of cervical cancer. Conclusions. Curative therapy for cervical cancer results in large numbers of long term survivors who develop second cancers very l ate in life. Radiation is an important cause of this increase and ther e is no evidence that risk returns to normal levels.