1234P - Stage migration in resectable NSCLC

Background

Following the success of immune checkpoint inhibitors (ICIs) in advanced non-small cell lung cancer (NSCLC), the current focus of immunotherapy trials is on resectable NSCLC. In the context of perioperative treatment decision-making, upfront pathological confirmation and adequate clinical staging are fundamental. We analysed resection rates without an upfront pathological diagnosis. Furthermore, we studied the prevalence of up- and downstaging in resectable NSCLC in an era before immunotherapy in this setting, potentially leading to modified perioperative treatment strategies in the near future.

Methods

In this retrospective observational study, sequential patients with resectable NSCLC diagnosed between 2015 and 2019 were selected. The resection rate without preoperative pathological confirmation of NSCLC was evaluated. Stage migration was analyzed in the overall population and in two cohorts of patients with either a present or absent upfront pathological diagnosis. Relevant upstaging was defined as migration from clinical stage I to pathological stage II-III and relevant downstaging from clinical stage II-III to pathological stage I, without any neoadjuvant treatment. Upstaging was corrected by time-to-treatment.

Results

In our total population of 817 cases with resectable NSCLC, relevant upstaging occurred in 101 cases (12.4%) and relevant downstaging in 65 cases (8.0%). In 278 patients (34%) no upfront pathological diagnosis was obtained. In the cohort without an upfront pathological diagnosis, relevant up- en downstaging occurred in 32 (11.5%) and 22 cases (7.9%), respectively. In the subgroup with an upfront pathological diagnosis, relevant up- and downstaging existed in 72 (13.4%) and 43 cases (8.0%). Stage migration was therefore present in 115 cases (21.4%) with an upfront pathological diagnosis. Overall, relevant stage migration and the lack of an upfront pathological NSCLC diagnosis occurred in 393 cases (48.1%). Time-to-treatment did not significantly differ across the stage migration cohorts.

Conclusions

Relevant stage migration occurred in a substantial part of the total resectable NSCLC population, potentially leading to under- and overtreatment in the upcoming era of perioperative chemoimmunotherapy.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

H.J.M. Smit.

Funding

Merck Sharp & Dohme.

Disclosure

K. Azijli: Financial Interests, Institutional, Funding: Merck Sharp & Dohme. All other authors have declared no conflicts of interest.