The findings of a new study conducted at five university hospitals suggest that young women surviving pediatric Hodgkin's disease have a 45.6% greater relative risk for breast cancer, particularly bilateral breast disease. While malignancy secondary to Hodgkin's disease is not a novel finding, the evidence of increased incidence of cancer in both breasts does add new knowledge to the field. The study was presented by Swati Basu, MD, to attendees at the annual meeting of the American Society of Clinical Oncology in Orlando.

Patients included in the study were at least 19 years old at the time that Hodgkin's disease was diagnosed, and they were treated between 1960 and 1990 at Harvard University, St. Jude Children's Research Center, the Johns Hopkins Hospital, the University of Florida, or the University of Rochester. The 928 patients (530 males and 398 females) enrolled in the study were monitored for secondary malignancy beginning at six months after diagnosis. Monitoring continued through death or until the time of the last patient contact. A cohort study using SEER data was used as an external control.

Secondary cancers developed in 87 patients (24 males and 63 females) from the entire cohort, producing a relative risk of 15.7% (8.2% for males and 23.8% for females) overall. Of the 63 women with secondary malignancies, four had ductal carcinoma in situ and 22 had breast cancer. The breast tumors tended to be less than 2 centimeters in most patients.

Notably, 100% of the women in whom breast cancer developed were diagnosed with early stage (stage I or II) Hodgkin's disease, despite an original patient pool that included patients with all stages of disease: 253 had stage I or II disease and 145 had stage III or IV disease. Furthermore, women in whom breast cancer eventually developed had been older than the average age when Hodgkin's disease was diagnosed. The significant associations between age and stage of disease with increased risk of breast cancer may provide clinicians with additional information to guide treatment decisions, Basu said.

According to Basu, there are several clinical applications of the findings. Survivors of Hodgkin's disease should be made aware of the increased risk of bilateral breast cancer and should be advised to avoid other predisposing factors. Also, screening for breast cancer should begin no more than nine years after diagnosis of Hodgkin's disease. In some cases, modifying treatment of the disease by lowering the dose of field radiation may be warranted. Finally, preventive treatment with tamoxifen or prophylactic mastectomy are options that might be considered, he said.

During the presentation, an inquiry was made regarding the possibility that radiation therapy could be the cause of increased risk. In response, Basu said, "I think in our study we had too few patients who did not receive radiation to draw conclusions about its contribution," suggesting that this would be an important variable to investigate in future studies.

SOURCE:
Annual Meeting of the American Society of Clinical Oncology, May 21, 2002, Orlando, Florida