OBJECTIVE: To provide equipercentile equating of physical function (PF) scores from frequently used PROMs in cancer patients to facilitate data pooling and comparisons.

STUDY DESIGN AND SETTING: Adult cancer patients from five European countries completed the EORTC CAT Core, EORTC QLQ-C30, FACT-G, SF-36, and the PROMIS Physical Function 20a short form. The R package "equate" was used to establish conversion tables of PF scores on those measures with a bivariate rank correlation of at least 0.75.

RESULTS: In total, 953 patients with cancer (mean age 58.9 years, 54.7% men) participated. Bivariate rank correlations between PF scores from the EORTC CAT Core, EORTC QLQ-C30, SF-36, and PROMIS were all above 0.85, but below 0.69 for the FACT-G. Conversion tables were established for all measures but the FACT-G. These tables indicate which score from one PROM best matches the score from another PROM and provide standard errors of converted scores.

CONCLUSION: Our analysis indicates that linking of PF scores from both EORTC measures (CAT and QLQ-C30) with PROMIS and SF-36 is possible whereas the physical domain of the FACT-G seems to be different. The established conversion tables may be used for comparing results or pooling data from clinical studies using different PROMs.