Tumor location influences breast cancer prognosis

Women with tumors in the upper lateral quadrant have better survival rates than do other women with breast cancer, according to a report in the July 1st International Journal of Cancer.

Axillary lymph node status is the best prognostic marker in primary breast cancer, the authors explain, but lymphatic drainage patterns are such that some women with breast cancer may be misclassified as low-risk patients and receive less intensive management.Dr. Mads Melbye from Statens Serum Institut in Copenhagen, Denmark and colleagues used data from more than 35,000 women with primary breast cancer registered by the Danish Breast Cancer Cooperative Group to investigate the prognostic effect of tumor location.Tumors located medially tended to be smaller and to have significantly less nodal involvement than laterally situated tumors, the authors report.In contrast, tumors with a central location were larger and were associated with a higher risk of nodal involvement and a lower chance of grade I histology, the report indicates.Women with tumors in the upper lateral quadrant of the breast had survival rates 15% to 20% better than did women with primary tumors in the other quadrants, the researchers note, even after adjustment for other recognized prognostic factors. This survival difference persisted even in the subgroup of women with who were axillary node positive.Estrogen-receptor status did not vary with tumor location, the results indicate, and tumor location was not related to age at diagnosis.”Our study shows that the prognosis in breast cancer patients differs significantly according to tumor location,” the authors write. “An explanation for these seemingly contradictory associations is that treatment allocation according to axillary lymph node spread is insufficient,” they add.”Our results, however, would suggest that a better classification system and thus more accurate treatment allocation alone would not be sufficient to eliminate the observed survival differences by tumor location,” the investigators write.(Source: Int J Cancer 2003;105:542-545: Reuters Health: June 30, 2003: Oncolink)