Can we consider always an esophageal carcinoma as radiation associated cancer after irradiation for breast cancer?

OBJECTIVE

To assess in a large-scale single-institution study whether radiotherapy (RT) for breast cancer increases the incidence of esophageal carcinoma as reported in a meta-analysis and in population studies, or does not increase incidence as suggested by smaller single-institution studies that take account of RT technique, dose, and possible confounding factors such as disease stage, smoking history, and the use of chemotherapy or hormone therapy.

PATIENTS AND

METHODS

We reviewed the cases of esophageal cancer after RT in our prospective institutional database of 16,705 patients treated for nonmetastatic BC between 1981 and 1997.

RESULTS

We found 5 cases of esophageal cancer among the RT patients (n = 13,472) and 1 case among nonirradiated patients (n = 3233). The relative risk of developing esophageal cancer after RT was 0.76 (95% confidence interval: 0.54-1.07); P = 0.118. However, the estimated dose delivered to the esophagus according to radiation field positions and energies was low (< or =0.5 Gy) in all patients except one (2 Gy). All 6 patients were smokers and all 5 irradiated patients were also regular consumers of alcohol.

CONCLUSION

The risk of a secondary esophageal carcinoma is low but the prognosis is severe. There was a probable association between esophageal cancer and factors such as smoking, alcohol consumption, and chronic inflammatory disease, rather than RT. Confounding factors should be investigated in large epidemiologic studies and evaluated for each patient.