1079MO - Survival before and after the introduction of adjuvant treatment in stage III melanoma: A nationwide registry-based study

Background

Based on recurrence-free survival outcomes, adjuvant treatments (Adj Tx) with PD-1 and BRAF + MEK inhibitors were approved in stage III cutaneous malignant melanoma (CMM) and have since been widely implemented. However, there are significant side effects and costs of the treatments, and the overall survival (OS) effect is still uncertain. We previously reported that no OS benefit has been noted in stage III CMM patients after the introduction of Adj Tx in Sweden in 2018 (JNCI 2023). Here we present OS with one more year of follow-up in sentinel lymph node positive (SLN+) patients, together with data on received Adj Tx and OS in different subgroups.

Methods

The population based Swedish Melanoma Registry (SweMR), the Cause of Death Registry and medical records were used to gather data on patient and tumor parameters, received Adj Tx and survival. Patients diagnosed with SLN+ CMM, between 2016 and 2020 were included and divided depending on if they were diagnosed with SLN+ CMM January 2016 to August 2018 (pre cohort) or September 2018 to December 2020 (post cohort), based on the timepoint when Adj Tx was implemented in Sweden. Patients were followed until the end of 2022.

Results

There were 1117 patients registered with a SLN+ CMM in SweMR in 2016-2020. In the pre (n=506) and post (n=611) cohorts, 0.4% and 64% received Adj Tx, respectively (81% anti-PD1 and 19% BRAFi + MEKi). In the post-cohort, the most common reasons for not giving Adj Tx were, favorable tumor characteristics (64%) or comorbidity and/or high age (20%). The 3-year OS rates, in the post vs. the pre cohorts, were 80.9% (95% CI 77.6-84.4) and 80.1% (95% CI 76.6-83.8), respectively, HR 0.92 (95% CI 0.71-1.18 P=0.514). Among patients <75 years old (n=867), in stage IIIB-D (n=850), or with ulcerated tumors (n=505), the HR for OS in the post vs. the pre cohort was 1.13 (95% CI 0.80-1.60), 0.96 (95% CI 0.72-1.28), and 1.21 (95% CI 0.85-1.74), respectively, where 68%, 77% and 78% in the post cohort had received Adj Tx, respectively.

Conclusions

This population-based study is the first to assess the impact on OS following a national introduction of Adj Tx in stage III CMM. At a median follow-up of 3 years in the cohort diagnosed after the implementation of Adj Tx, there is still no evidence for an OS benefit.

Clinical trial identification

Legal entity responsible for the study

Karolinska Institutet.

Funding

Swedish Cancer Society (Cancerfonden).

Disclosure

H. Helgadottir: Financial Interests, Personal, Invited Speaker: Pierre Fabre, MSD, BMS. L. Ny: Financial Interests, Personal, Advisory Board, Melanoma Expert Board: BMS, MSD, Pierre Fabre; Financial Interests, Personal, Invited Speaker, Lecture in medical oncology: Johnson&Johnson; Financial Interests, Personal, Invited Speaker, Lectures in TIL therapy: Miltenyi; Financial Interests, Personal, Invited Speaker, Lectures in Melanoma therapy: Novartis; Financial Interests, Personal, Invited Speaker, Lectures in medical oncology: Roche; Financial Interests, Personal, Advisory Board, Melanoma expert review: Zealth; Financial Interests, Personal, Stocks/Shares, Academic Drug discovery. No present activities: SATMEG Ventures AB; Financial Interests, Institutional, Research Grant, Support for clinical trial: MSD, Syndax Pharmaceuticals. G.J. Ullenhag: Financial Interests, Personal, Invited Speaker: Pierre Fabre, MSD, BMS, Novartis; Financial Interests, Personal, Other, Interview: Pierre Fabre; Financial Interests, Personal, Advisory Board: MSD, AstraZeneca, Novartis, SeqCure Immunology AB, AI Medical Technology, Sanofi; Financial Interests, Personal, Other, Protocol writing: Ilya, Boehringer Ingelheim-Ingelheim, SeqCure Immunology AB; Financial Interests, Personal, Stocks/Shares: Essity; Non-Financial Interests, Principal Investigator, LOKON 002 and LOKON 003: Lokon Pharma; Non-Financial Interests, Principal Investigator, Scandium 2: BMS; Non-Financial Interests, Principal Investigator, T-cell study: SeqCure Immunology AB; Non-Financial Interests, Principal Investigator, First line in malignant melanoma patients: Immunocore. R. Olofsson Bagge: Financial Interests, Personal, Invited Speaker: Roche, Pfizer, Pierre Fabre; Financial Interests, Personal, Advisory Board: Amgen, BMS, BD/BARD, MSD, Novartis, Roche, Sanofi-Genzyme; Financial Interests, Personal, Stocks/Shares: SATMEG Ventures AB; Financial Interests, Institutional, Funding: BMS, NeraCare GmbH; Financial Interests, Institutional, Research Grant: Endomagnetics Ltd. All other authors have declared no conflicts of interest.