Radiation therapy for breast cancer and increased risk for esophageal carcinoma.
BACKGROUND
Several case reports have suggested an association between radiation therapy for breast cancer and the subsequent occurrence of esophageal carcinomas.


OBJECTIVE
To examine the association between radiation therapy for breast cancer and subsequent esophageal squamous-cell carcinomas and adenocarcinomas.


METHODS
Population-based retrospective cohort study.


METHODS
Population-based U.S. cancer registries.


METHODS
220,806 women in whom breast cancer was diagnosed between 1 January 1973 and 31 December 1993; 1,216,853 person-years of follow-up.


METHODS
Age- and period-adjusted standardized incidence ratio as a measure of relative risk for the second primary cancer.


RESULTS
In women who had received radiation therapy for breast cancer, the relative risk for esophageal squamous-cell carcinoma increased to 5.42 (95% CI, 2.33 to 10.68) and the relative risk for esophageal adenocarcinoma increased to 4.22 (CI, 0.47 to 15.25) 10 or more years after radiation therapy. No increased risk was seen for either type of carcinoma among patients with breast cancer who did not receive radiation therapy.


CONCLUSIONS
The risk for esophageal carcinoma is increased in women who receive radiation therapy for breast cancer.
Ahsan
H
H
Neugut
A I
AI
D000230:Adenocarcinoma / Q000209:etiology*; D001943:Breast Neoplasms / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000209:etiology*; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D004938:Esophageal Neoplasms / Q000209:etiology*; D005260:Female; D006801:Humans; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D011878:Radiotherapy / Q000009:adverse effects; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors