Mammographic screening in women at increased risk of breast cancer after treatment of Hodgkin's disease.

Treatment regimens for Hodgkin's disease (HD) that have included radiation to lymph node regions in the thorax have contributed to high rates of long-term disease-free survival. However, incidental radiation exposure of breast tissue in young women has significantly increased the risk of breast cancer compared to expected rates in the general population. After informing patients about risks associated with previous treatment of HD, we studied screening mammograms and call-back rates in women at increased risk for developing breast cancer at a younger age. We contacted by mail a cohort of 291 women between 25 and 55 years of age who had received thoracic irradiation before 35 years of age for HD with or without chemotherapy. Subjects were offered information about risks identified after HD therapy with questionnaires to assess response to this information. Ten patients refused participation, 93 did not respond, and 21 were excluded after they reported a prior diagnosis of invasive (1) or in situ (2) breast cancer. One hundred and sixty seven women received information about secondary breast cancer risk and were advised to initiate or maintain mammographic screening. Available mammograms were reviewed by two radiologists and classified according to the ACR BI-RADS Mammography Lexicon. Abnormal findings were correlated to pathology results from biopsies. One hundred and fifteen subjects reported that they obtained new mammograms during the period of the study. Ninety-nine were available for secondary review. Patients were studied an average of 16.9 years after HD treatment (Range: 4.5-32.5 years) at an average of 41 years of age (range 25-55 years). High density breast tissue was identified in 60% (60/99). Seventeen of the women (17.2%) were recalled for further imaging. This was more common in women with heterogeneously dense breast tissue. Seven of those recalled (41%) were advised to undergo biopsies that identified ductal carcinoma in situ (DCIS) in one and benign findings in the others. Among 16 women whose mammograms were unavailable for review, three were diagnosed with DCIS; two of these had microscopic evidence of invasive breast cancer. The four in situ or microinvasive cancers were diagnosed in the study participants at 25-40 years of age and from 5 to 23 years after HD therapy. Biopsies were performed because mammograms detected microcalcifications without palpable abnormality in three of these cases. Women who have had thoracic nodal irradiation for Hodgkin's disease have an increased risk of developing secondary breast cancer at an unusually young age. As expected in younger women, high density breast tissue was common on mammography, and the recall and biopsy rates were unusually high. However, early mammographic screening facilitated diagnosis of in situ and early invasive cancer in 3.5% of our subjects.