General Session 2: INSEMA – EBCTCG – PATINA

In this video, Dr Kevin Punie further discusses and comments on the data of some interesting studies presented during General Session 2 at SABCS 2024. 

The INSEMA trial, recently published in the New England Journal of Medicine, sought to evaluate whether sentinel lymph node biopsy could be safely omitted in patients presenting with small, node-negative tumours. The trial enrolled over 4,000 patients with clinical tumour sizes up to 5 cm, though most participants had stage 1 breast cancer with clinically node-negative status at diagnosis. Patients were randomised to either surgery with or without sentinel lymph node biopsy. The results were compelling, showing no difference in five-year invasive disease-free survival between the two groups. This aligns with findings from the earlier SOUND trial, which similarly demonstrated the safety of omitting sentinel lymph node biopsy in stage 1 patients.

Based on the INSEMA trial, suitable candidates for skipping sentinel lymph node biopsy include women aged 50 or older with HR+/ HER2- breast cancer (grade 1 or 2) with tumour sizes up to 2 cm and negative axillary lymph nodes. However, proper axillary ultrasound becomes crucial when considering this approach, as accurate axillary staging is paramount. The study also raises concerns for patients with lobular histology, given the limitations of axillary ultrasound in detecting lymph node metastases in this subgroup. Adding non-lobular histology as a selection criterion could further refine patient eligibility. The INSEMA trial has the potential to change the surgical management of early-stage breast cancer by reducing the need for sentinel lymph node biopsy in carefully selected patients.

The EBCTCG consortium presented a meta-analysis investigating the relationship between BMI and 10-year distant recurrence risk in women with early-stage breast cancer. This analysis, encompassing over 200,000 women across 147 trials, found a consistent association between higher BMI and increased risk of distant recurrence, with a relative risk of 1.17 for obese compared to lean women. This association was independent of nodal status and ER status, a finding that differs from earlier studies. The impact of BMI on recurrence risk was more pronounced in premenopausal women compared to postmenopausal women. While the results underscore the influence of obesity on breast cancer outcomes, they leave open the question of whether weight reduction could mitigate recurrence risk. Lifestyle intervention studies will be essential to determine the role of weight management in breast cancer recurrence prevention.

Lastly, the PATINA trial, a phase 3 open-label randomised study, evaluated the addition of palbociclib (a CDK4/6 inhibitor) to maintenance therapy with endocrine therapy and anti-HER2 therapy in patients with HR+/ HER2+ metastatic breast cancer. Patients receiving standard care (endocrine therapy combined with trastuzumab and pertuzumab after induction chemotherapy) were compared to those receiving the same regimen with added palbociclib. The results showed a significant PFS benefit, with a median PFS of 44 months in the experimental arm versus just under 30 months in the standard care arm. This impressive improvement highlights the potential of palbociclib to delay progression and extend the time before patients require second-line treatment. Palbociclib was also shown to have a favourable safety profile, which is consistent with prior studies. While this trial can potentially change clinical practice, regulatory approval and reimbursement will be critical factors in determining its accessibility for routine use in Belgium and other countries.