Method of tumor detection influences disease-free survival of women with breast carcinoma

Abstract

Screening mammography provides the primary means of reducing breast cancer mortality. Clinical breast examination (CBE) and breast self-examination (BSE) may be complementary screening modalities enabling palpation of interval cancers and detection of tumors not visualized by mammography; however, their combined contribution to improving prognosis has not been evaluated adequately. Disease-free survival was assessed in relation to method of tumor detection among 729 consecutive patients treated by mastectomy and axillary dissection for primary breast carcinoma between 1976 and 1978. Disease-free survival at 10 years was significantly higher after detection by mammography (77% of 30 patients) or CBE (78% of 101 patients) compared to self-detection (64%). The hazard ratio of recurrence associated with clinical examination or mammography in contrast to self-detection was significantly reduced to 0.55 (95% CI, 0.37-0.81; P = 0.001). In addition, annual CBE, compared to less frequent clinical palpation, reduced the risk of recurrence controlling for detection modality (P = .03). In multivariate analyses, the method of detection and frequency of clinical breast examination remained statistically significant prognostic factors after controlling for number of screening mammograms, history of prior breast surgery, family history of breast cancer, and age at diagnosis. Differences in self-examination frequency were not associated with prognosis. Among patients diagnosed before widespread mammography screening, tumor detection by CBE was associated with a significant reduction in recurrence compared with detection by self-palpation. Improvement in the frequency and quality of CBE and BSE may enhance the contribution of these modalities to early detection, complementing the role of screening mammography in reducing breast cancer mortality rates.