Principal investigator(s)
Corneel Coens
Brussels, Belgium
Project coordinator(s)
Jammbe Musoro
Brussels, Belgium
, Andrew Bottomley
Brussels, Belgium

Project summary

As patient assessment of health-related quality of life (HRQOL) in cancer clinical trials has increased over the years, so has the need to attach meaningful interpretations to aggregated HRQOL scores, whether differences in HRQOL scores between groups or within-patient changes in HRQOL over time. Determining what represents a minimally important difference (MID) in HRQOL scores is useful to clinicians, patients and researchers, and can be used as a benchmark for assessing the success of a healthcare intervention (e.g., a new treatment) or the design of future clinical trials (e.g., determining sample sizes).

The aim of this project is to establish MIDs for all QLQ-C30 scales according to cancer sites, using individual patient data from archive EORTC trials. The project focuses on the anchor-based approach and relies on constructing clinical anchors using available clinical variables. A disease-oriented and methodological panel provide independent guidance on anchor selection. The project will also examine how the estimated MIDs compare with previously published guidelines, hence further contributing to robust MID guidelines for the EORTC QLQ-C30.


The first findings from the MID project were presented at the ISOQOL 23rd Annual Conference in Copenhagen, Denmark (October 2016). In 2017, we gave two presentations at ISOQOL 24th Annual Conference in Philadelphia, USA (October 2017) where more results were presented. Full details of the abstract references are found below.  We have also published a paper that highlights the methodological considerations of the MID project.

Future plans

The project is in its final phase which entails mainly- performing final analysis and drafting manuscripts for publications. A manuscript on MIDs for adjuvant melanoma is in preparation. This will be followed by the publication of other disease specific MIDs e.g., head and neck, breast and prostate cancer. We are also looking forward to continually disseminating our results in international conferences such as ASCO and ISOQOL.

For patients

In a cancer trial, it is common, to use questionnaires in order to get an evaluation of a therapeutic intervention (e.g. a new treatment) by the patient him/herself. However, it is often unclear how much better should the score given by a patient be in order to influence decision about treatment. The concept of “minimal important difference (MID)” is the size of a difference in a Quality of Life score that would be comparable to a change normally considered by clinicians as relevant (i.e. warranting a change in treatment or examinations). Our project aims to estimate disease specific MIDs for the most widely used cancer specific questionnaire (the EORTC-QLQ-C30) which will aid interpreting QOL scores in a manner that is clinically meaningful to doctors and patients. This project will supplement previously published MID guidelines research by using individual patient data to estimate MIDs for different cancer sites separately, hence, further providing evidence to robust and practical MID guidelines for the EORTC QLQ-C30.


  • Musoro ZJ, Hamel J-F,Ediebah DE, et al. Establishing anchor-based minimally important differences (MID) with the EORTC quality of life measures: a meta-analysis protocol. BMJ Open 2017; 7:e019117. doi:10.1136/bmjopen-2017-019117
  • Fiteni F, Musoro J, Coens C, Sprangers M, Eggermont A, Bottomley A, Brandberg Y. Selection of anchors for the EORTC QLQ-C30 scales in adjuvant melanoma studies: on Behalf of the EORTC melanoma Group and EORTC Quality of Life Department. Qual Life Res (2017) 26(Suppl 1): ab202.2.
  • Musoro J, Coens C, Ediebah D, Eggermont A, et all. Empirical Evaluation of the Minimal Important Differences (MID) with the EORTC Quality of Life Group Measures: Embarking on a New Research Initiative on behalf of the EORTC Quality of Life Group and EORTC Quality of Life Department. Oral presented at 23rd International Society for Quality of Life Research (ISOQOL), Copenhagen, Denmark, 19 – 22 October 2016.
  • Musoro J, Coens C, Ediabah DE, et al. Evidence-based approach to determine meaningful change in HRQOL scores of the EORTC QLQ-C30 in adjuvant melanoma cancer: on Behalf of the EORTC Melanoma Group and EORTC Quality of Life Group. 24th Annual Conference of the International Society for Quality of Life Research, Philadelphia (PA), USA, October 2017.  Qual Life Res (2017) 26(Suppl 1): ab105.5.