Background Introduction of immune checkpoint inhibitors (ICIs) has modified treatment modalities for patients with lung cancer, offering new alternatives for treatment. Despite improved survival benefits, ICIs may cause side-effects impacting patients quality of life (QoL). We aim to study the changes in global QoL (gQoL) up to 18 months of patients with advanced stage lung cancer after treatment with ICIs between 2015-2021. Patients and methods A longitudinal cohort study was conducted using OncoLifeS data-biobank from the University Medical Center Groningen. Participants completed the EORTC QLQ-C30 questionnaire, at the beginning of their ICI treatment (baseline) and then at 6, 12 and 18 months. Using joint modelling, the predicted trajectory of gQoL was studied by treatment regimens up to 18 months, while accounting for the competing risk of death and adjusting for pre-specified covariates. Results Of 418 participants with median age 66 years, 39% were women. Patients receiving first line immuno-monotherapy with palliative intent had a small improvement ([5-8] points) in their gQoL within first six months, and no clinically significant change ([-5 to 5] points) thereafter, while patients with second/further line immunotherapy with palliative intent had no clinically significant change in their gQoL over 18 months. Patients receiving first line chemo-immunotherapy with palliative intent had a small improvement in their gQoL over 18 months, while patients receiving first line chemo-radiotherapy followed by Durvalumab with curative intent had no clinically significant change in their gQoL over 18 months. Conclusion The differences in gQoL over time among patients with varying treatment regimens based on drug intensity, line and intent of treatment may help clinicians and patients understand the potential dynamic of treatments on QoL. It may further influence treatment decisions and patient management strategies, reflecting the practical implications of different treatment regimens.

The authors have declared no competing interest.

This study was funded by European Union Horizon 2020 research and innovation programme under grant agreement number 875171

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethics committee of the London School of Hygiene & Tropical Medicine gave ethical approval for this work Scientific committee OncoLifeS of University Medical Center Groningen gave ethical approval for this work

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present study are available upon reasonable request to the authors