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however, individuals who received chemotherapy plus endocrine therapy had an overa ll surviva l rate of 98.6% vs. 97.3% for endocrine therapy alone. Interim results published in December 2021 show similar outcomes. "What was surprising, recognizing this is only about 50% of the anticipated events we'll see, is that there were no subgroups that benefited from the addition of chemotherapy in the postmenopausal group," Dr. Kalinsky says. "For the premenopausal group, we couldn't identify a subpopulation that did not benefit from the addition of chemotherapy." Li ke R x PON DER , ea rlier st udies used t he Oncotype DX test to attempt to identify which breast cancer patients needed chemotherapy, and these studies pinpointed subgroups of patients that benefited from chemotherapy. SWOG 8814, for example, found that postmenopausal women w ith HR-positive, HER 2-negative a nd ly mph node-positive disease with a high RS (31–100) derived a significant breast cancer-specific survival benef it from the addition of chemotherapy to hormone therapy vs. hormone therapy alone. The TAILORx trial — an NCI-sponsored precursor to R xPONDER — concluded that postmenopausal women with HR-positive, HER2-negative and lymph node-negative disease with a RS of 0–25 did not benefit from chemotherapy and hormone therapy compared with hormone therapy alone. 'PRACTICE CHANGING' RESULTS Sa ra h Sa mmons, MD, A ssista nt Professor of Me d ici ne at D u ke Un iver sit y Ho s pit a l a nd Duke Ca ncer Institute, was encouraged by its initial findings. "I think that these ... results were immediately practice changing," says Dr. Sammons, who was not involved with the study, in a 2021 interview. "Clinicians should now discuss ordering the RS with postmenopausal women with HR-positive, HER2- negative breast cancer and one to three positive lymph nodes [who] are candidates for chemotherapy. In most circumstances, chemotherapy can be safely eliminated in those postmenopausal women with a RS between 0–25." Dr. Kalinsky agrees. "These data support potentia lly not needing to treat patients who are postmenopausa l with chemotherapy and sparing them the unnecessary side effects and costs … that can be associated with chemotherapy," he says. "This also gives us reassurance right now about the use of the Oncotype DX test for patients who are premenopausal in terms of giving them chemotherapy." ■ Decoding a Benefit Disparity LEF T UN A NS W ERED BY RxPONDER is the reason for the disparity between the benefit that premenopausal women obtained from chemotherapy compared with the lack of benefit observed in postmenopausal women. The interim report on RxPONDER refers to studies finding ovarian suppression associated with better outcomes in premenopausal women as a possible answer. Ovarian suppression may not tell the whole story, however. "I do not believe that ovarian suppression in most premenopausal women is the only reason for improved outcomes with chemotherapy," says Sarah Sammons, MD, Assistant Professor of Medicine at Duke University Hospital and Duke Cancer Institute, who was not involved with the study. "Cytotoxic chemotherapy also has the ability to eliminate some micro-metastatic disease [thereby] reducing distant recurrence, which is critical." "When you look at the kinds of events we were seeing, in postmenopausal women, only about a quarter of those events as first events were distant metastases," says Kevin Kalinsky, MD, MS, Director of the Glenn Family Breast Center at the Winship Cancer Institute at Emory University, Associate Professor in the department of Hematology and Medical Oncology at the Emory University School of Medicine and RxPONDER Principal Investigator. "Patients were having other events — they were older and having deaths from other causes — as opposed to premenopausal patients where about 50% of those events were distant events." M D N E W S . C O M /// M D N E W S L O N G I S L A N D ■ 2 0 2 2 2 5 SPECIAL CLINICAL SECTION: WOMEN'S HEALTH

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