In an analysis involving the phase III SENOMAC trial reported in The Lancet Oncology, de Boniface et al found that the use of completion axillary lymph node dissection (cALND) to identify pN2-3 status (at least four nodal metastases) in patients with breast cancer, and thus qualification for adjuvant CDK4/6 inhibitor treatment, was associated with a substantial risk of severe or very severe impairment of physical arm function.
Study Details
The study involved data from a subgroup of patents in the SENOMAC trial, in which patients from sites in five European countries were randomly assigned to undergo cALND or sentinel lymph node biopsy alone. The subgroup consisted of patients with luminal estrogen receptor–positive, HER2-negative, T1-2, histologic grade 1 to 2 breast cancer, with tumor size ≤ 5 cm. These patients were matched with a cohort of patients from the monarchE trial who had an indication for adjuvant abemaciclib only if they were found to have four or more nodal metastases.
The primary study objective was to determine the number of patients who developed patient-reported severe or very severe impairment of physical arm function after cALND 1 year after surgery to avoid one invasive disease–free survival event at 5 years with 2 years of adjuvant abemaciclib, using invasive disease–free survival event data from the monarchE cohort.
Key Findings
Among 1,342 patients from the SENOMAC cohort who responded to questionnaires, after a median follow-up of 45.2 months, severe or very severe impairment of physical arm function was reported by 84 (13%) of 634 patients who had cALND vs 30 (4%) of 708 who had sentinel lymph node biopsy only (P < .0001).
Using data from the monarchE cohort, it was calculated that cALND would need to be performed in 104 patients to avoid one invasive disease–free survival event at 5 years with adjuvant abemaciclib, with 9 patients having severe or very severe impairment of physical arm function 1 year after surgery.
The investigators concluded, “As a method to potentially identify an indication for abemaciclib, and subsequently avoid invasive disease–free survival events at 5 years with 2 years of adjuvant abemaciclib, cALND carries a substantial risk of severe or very severe arm morbidity and so cALND should be discouraged for this purpose.”
Jana de Boniface, MD, PhD, of the Breast Center, Capio St Göran’s Hospital, Stockholm, Sweden, is the corresponding author for The Lancet Oncology article.
Disclosure: The study was funded by the Swedish Research Council, Swedish Cancer Society, Nordic Cancer Union, and Swedish Breast Cancer Association. For full disclosures of the study authors, visit thelancet.com.
