Primary endocrine therapy vs surgery: Comparable survival in older Chinese breast cancer patients

Primary endocrine therapy (ET) alone may be appropriate for treatment of frail elderly patients aged ≥70 years with limited life expectancy diagnosed with stage I–III oestrogen receptor (ER)–positive breast cancer (BC), whereas those with longer life expectancy may gain overall survival (OS) benefit from local operation, a matched case-control study by the University of Hong Kong (HKU) has shown.

“This is the first study in a Chinese population to assess the response to and clinical outcomes with primary ET in a Chinese cohort,” said the researchers. “Results of our study may justify the use of primary ET in patients with life expectancy <5 years instead of the 2–3 years recommended by international guidelines.” [Cancer Treat Res Commun 2020, doi: 10.1016/j.ctarc.2020.100227]

In the study, the researchers retrieved data of 292 patients with stage I–III ER-positive breast cancer treated with either primary ET (n=83; mean age, 84.17 years) or primary operation (OT) followed by adjuvant therapy if indicated (n=209; mean age, 76.73 years) at a university-affiliated tertiary hospital from 2008 to 2017. Propensity score (PS) matching was performed to adjust for confounding factors, including age, Charlson comorbidity index (CCI), American Society of Anaesthesiologists (ASA) grade, functional status, and overall stage.

Mastectomy plus sentinel lymph node biopsy (SLNB) (42.11 percent) and adjuvant radiotherapy without chemotherapy (29.19 percent) were the most common type of OT and adjuvant therapy received by patients in the OT group.

At baseline, significant differences in BC stage were observed between the two groups, with 80.8 percent vs 52.6 percent of patients in the primary ET vs OT group having stage II–III BC. In addition, patients treated with primary ET had significantly higher CCI and ASA grade scores (ie, with more severe comorbidities and higher anaesthetic risk,) as well as significantly poorer functional status compared with those treated with OT (both p<0.0001). Nonetheless, there was no significant difference between the groups in terms of histological features (p=0.120), histological grading (p=0.751) and HER2 status (p=0.757).

At 5 years following treatment, OS probability was comparable between patients treated with primary ET and OT (0.700 vs 0.706; p=0.63). The survival curves for primary ET and OT diverged after 5 years. At 10 years following treatment, OT demonstrated significant OS benefit compared with primary ET (probability, 0.615 vs 0.247; p=0.0029).

“Our study showed that primary ET and surgery could achieve similar survival within the first 5 years, whereas improved survival outcome was seen in the OT group beyond 5 years. It could be argued that primary ET is justified in patients with life expectancy of up to 5 years, instead of the recommended 2–3 years,” the researchers wrote.