Capecitabine-Based Regimen Benefit May be Limited To TNBC

Women with early breast cancer may benefit from capecitabine chemotherapy if they have triple-negative disease

medwireNews: Using capecitabine in standard adjuvant chemotherapy does not improve survival outcomes for women with early breast cancer generally, confirm 10-year findings of the FinXX trial.

However, the subgroup of patients with triple-negative breast cancer (TNBC) in the study showed a “substantial” recurrence-free survival (RFS) benefit with additional capecitabine compared with patients with other biological subgroup classifications.

“As TNBC is associated with substantial mortality, and improvements in therapy are much needed, this finding is of potential interest”, write Heikki Joensuu, from Helsinki University Hospital in Finland, and co-investigators.

The authors explain in JAMA Oncology that the phase III trial protocol was amended to allow a third analysis of efficacy in the overall patient population and in biological subgroups by hormone receptor and HER2 status after a median follow-up of at least 10 years.

As expected, RFS and overall survival (OS) did not significantly differ between the 747 patients who received three cycles of docetaxel followed by three cycles of cyclophosphamide, epirubicin and fluorouracil (T+CEF) and the 753 patients who received three cycles of docetaxel plus capecitabine followed by three cycles of cyclophosphamide, epirubicin and capecitabine (TX+CEX).

There was also no significant difference in RFS or OS between the T+CEF and TX+CEX groups when assessing patients who were positive for oestrogen receptors (ER) and progesterone receptors (PR) and negative or positive for HER2, or for patients who were ER/PR-negative and positive for HER2.

By contrast, TNBC patients derived both significant RFS and OS benefits from TX+CEX over T+CEF, with hazard ratios of 0.53 and 0.55, respectively, although the researchers say that this relationship should be “interpreted with caution because it resulted from an exploratory subgroup analysis.”

They note that TX+CEX was associated with capecitabine-specific toxicities, such as stomatitis and hand–foot syndrome, and that the regimen had a higher rate of discontinuation than T+CEF, mostly attributed to side effects (24 vs 3%).

“These data suggest that the TX+CEX regimen may be more acceptable for higher-risk patients, such as those with TNBC, owing to its toxic effect profile”, comment Heikki Joensuu et al.

Thus, they write: “A conclusion that capecitabine has no role in the adjuvant treatment of early breast cancer may be premature, and ongoing trials, such as the CIBOMA trial (NCT00130533) may provide further guidance.”

Reference

Joensuu H, Kellokumpu-Lehtinen P-L, Huovinen R, et al. Adjuvant capecitabine in combination with docetaxel, epirubicin, and cyclophosphamide for early breast cancer. The randomized clinical FinXX trial. JAMA Oncol; Advance online publication 2 March 2017. doi:10.1001/jamaoncol.2016.6120

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