Adjuvant treatment in
hormone-receptor positive, HER2-negative early
breast cancer is controversial.
Chemotherapy benefit in this subset of patients is generally small, and a wide variability exists among dif-ferent subgroups of patients, depending on various patient and
tumor characteristics. To select subsets of patients who will really benefit from
chemotherapy, one of the possible strategy is based on multigene expression analysis. This approach is providing deeper insights into the biological heterogeneity of
breast cancer, allowing to further sub-divide
hormone-receptor positive
tumors into groups, with different clinical behavior and response to treatments. Among less expensive and better validated methods, high levels of Ki67, a routinely assessed immunohistochemical marker of cell proliferation, can suggest the use of
chemotherapy in this subset of patients. Generally, regimen used should include a
taxane. In fact, retrospective analyses of clinical trials suggest that
anthracyclines may be less active in
hormone-receptor positive HER2-negative patients, while several other trials and meta-analyses involving
taxanes, showed a benefit in terms of risk of relapse and death reduction. Among
taxanes,
docetaxel should be preferred because of a better therapeutic index, and a higher activity in comparison to
paclitaxel. At present, reliable and accurate evaluation of histopathological and immunohistochemical factors may allow the choice of omitting
adjuvant chemotherapy in patients with low risk
hormone receptor positive HER2-negative
breast cancer. Uncertainty still exists about
chemotherapy benefit for a substantial proportion of women of this subgroup. Nevertheless, the addition of
taxanes, mainly
docetaxel, to
anthracyclines, seems to overcome the relative chemoresistance of
hormone-receptor positive
tumors, providing a benefit in disease free survival and overall survival.