Greater Role for Trastuzumab in Smaller HER2-Positive Cancers?

February 2011, Vol 2, No 1 -

A point-of-view essay by 2 English physicians outlines the controversies inherent in treating patients with breast cancer with small (≤1 cm) HER2-positive tumors and the possible benefit that adjuvant trastuzumab (Herceptin) might offer (Lancet Oncol. 2010;11:1193-1199).

Although the combination of trastuzumab and chemotherapy has now been established as a care standard in HER2-positive tumors >1 cm, the lack of randomized, phase 3 trials using this combination in smaller tumors leaves clinicians with the dilemma of balancing possible benefits with toxic effects and potential risks.

In addition, the various European and American guidelines for treating patients with these tumors are “uncertain and inconsistent,” they write. The number of these small tumors diagnosed has increased as mammography screening has improved.

A subset analysis of 1 trastuzumab trial showed that patients with 1-cm to 2-cm tumors derived at least as much clinical benefit from 1 year of adjuvant trastuzumab as did the overall co – hort, and this “lends support to the pos t ulation” that patients with smaller, node-negative can cers “would benefit significantly from adjuvant chemo – therapy with trastuzumab,” according to the authors.

“We believe that there is now strong circumstantial evidence to justify some form of trastuzumab-based adjuvant therapy in most women with T1b,N0 (>0.5 to ≤1 cm), HER2-positive breast cancers,” the authors conclude