Kuerer and his colleagues studied clinical and pathological factors from 1,022 stage I or II breast cancer patients who received a mastectomy at M. D. Anderson between 1997 and 2002. Of those women, 79 percent had no lymph node involvement, 26 percent had 1-3 positive lymph nodes, with the majority having just one positive node. None received post-mastectomy radiation and/or pre-operative chemotherapy; 77 percent received post-operative chemotherapy and/or hormonal therapy. The median age was 54 years and the median follow up time was 7.5 years.

The researchers found that there was no statistical difference in the 10-year risk of LRR in women without lymph node spread versus those with spread to one node - 2.1 percent to 3.3 percent, respectively.

The only independent risk factor for LRR was age; patients age 40 and younger, regardless of node involvement, were at significant increased risk for LRR.

"For these younger women, not less, but more treatment may be needed," said Rajna Sharma, M.D., a fellow in M. D. Anderson's Department of Surgical Oncology, who presented the findings.

"For the overwhelming majority of early-stage breast cancer patients treated with modern surgery and systemic therapies, LRR rates may be too low to justify routine use of post-mastectomy radiation," said Kuerer. "This research will provoke much discussion among those caring for women with early-stage breast disease. Replicating these findings should be a priority to ensure that patients only receive therapy that is medically necessary."

Source: University of Texas M. D. Anderson Cancer Center