It is likely that by now most of you have been made aware of the results of the RxPONDER Trial (SWOG S 1007). Nonetheless, a brief review seems appropriate. The trial was international in scope and conducted at 632 sites. The researchers screened 9383 women with hormone receptor (HR)-positive, HER2-negative breast cancer, who had 1-3 positive axillary lymph nodes to identify those with an Oncotype Dx recurrence score (RS) of 25 or less. A total of 5083 patients were identified and randomized to receive hormone therapy or hormone therapy plus chemotherapy. Two-thirds of the women in the trial were postmenopausal. The current analysis used data from 5015 eligible patients. The median follow-up was 5 years. The primary endpoint was invasive cancer disease free survival (IDFS).
Surprisingly, there was no association between recurrence score and chemotherapy benefit. Patients with higher scores had no better outcome from chemotherapy than those with lower scores. However, there was an association with menopausal status. Postmenopausal women had no benefit from chemotherapy regardless of RS. Contrast that with premenopausal women where a significant benefit from chemotherapy was noted. The 5-year IDFS for premenopausal women was 94.2% for women receiving chemotherapy plus hormonal therapy compared with 89.0% for the hormone-therapy only group. This benefit was seen regardless of RS. There was also noted a small but significant overall survival benefit for women receiving chemotherapy (98.6% vs 97.3%).
Postmenopausal women with 1-3 positive nodes, and with RSs less than or equal to 25, received no significant benefit from chemotherapy when added to hormonal therapy. However, premenopausal women did benefit from the addition of chemotherapy.