Background: Malignant effusion in invasive breast cancer, either pleural or pericardial, is associated with a poor survival rate. We investigated the role of the location of invasive breast cancer in developing malignant pleural or pericardial effusion.
Methods: Three thousand eight hundred and fifty six women with a history of invasive breast cancer between 1960 and 1994 were analyzed in a retrospective study. Two hundred and six patients (5.34%; group A) developed malignant pleural and/or pericardial fluid as the first visible clinical sign of distant metastasis. A control group of 206 patients (group B) without malignant effusions were matched in terms of clinical and pathological characteristics. The two groups were compared in respect of the location of the primary tumor. Fifty patients in group A (n = 50; 24.2%) had tumors in the inner quadrants, 83 patients (n = 83; 40.3%) in the outer quadrants, and 13 patients (n = 13; 6.3%) in a central location. No data were available for 60 patients (n = 60; 29.1%). In group B, 12 patients (n = 12; 5.9%) had tumors in the inner quadrants, 140 patients (n = 140; 68.0%) in the outer quadrants, 14 patients (n = 14; 6.8%) had centrally located tumors, while no data were available for 40 patients (n = 40; 19.4%). Invasive ductal carcinomas (IDC) located in the inner quadrants were highly significantly associated with increased pleural or pericardial effusion as the first site of distant metastasis (p <or= 0.0001; chi-square tests).
Conclusion: IDC in the inner quadrants were associated with a 4-fold higher rate of malignant pleural or pericardial effusions. Further studies will have to determine whether tumor location is a criterion for more aggressive adjuvant therapy.