The minimal clinically important difference in the treadmill six-minute walk test in active women with breast cancer during and after oncological treatments

Abstract

Purpose

To examine the minimal clinically important difference (MCID) in the treadmill 6-minute walk test (6MWT) in women with breast cancer.

Materials and methods

A secondary analysis of cross-sectional data from 112 women who were undergoing chemotherapy or had undergone anticancer treatment was conducted. Participants completed the 6MWT on a treadmill and the European Organization for Research and Treatment of Cancer Questionnaire (EORTC-QLQ-C30) twice, eight weeks apart. Change in the physical function domain of the EORTC-QLQ-C30 was used to classify the “positive change” subgroup (≥5 points difference) and the “unchanged” subgroup (<5 points difference). This was combined with the distance difference from the 6MWTs, determining the MCID as the cut-off from the area under the receiver operating characteristic (AUROC) curve (anchor-based determination). The MCID was also determined from (1) the effect size and (2) the difference in standard error (SEM) of the results of the first and second 6MWT (distribution-based determination).

Results

The MCIDs in the during-chemotherapy group was 66.5 and 41.5 m and those in the after-treatment group to be 41.4 and 40.5 m (SEM and effect size based respectively).

Conclusions

The MCID in the treadmill 6MWT distance could be used to interpret changes in the physical health status of women with breast cancer.

IMPLICATIONS FOR REHABILITATION

• The MCID for the 6MWT on treadmill in active women with breast cancer is of approximately 54 m during chemotherapy, and 41.6 m after treatment.

• The MCID on treadmill 6MWT distance could be used to interpret a decline in the physical health status of women with breast cancer.

• The 6MWT on treadmill could be an easy, feasible, performed under controlled conditions, alternative to the 6MWT to obtain valuable information in this population.

Keywords:

• 6MWT
• breast cancer
• minimal clinically important difference
• physical function
• rehabilitation professionals
• treadmill

Acknowledgments

The authors thank the patients who took part in the study. Thanks, are also due to Drs. Manuel Arroyo-Morales and Carmen Angélica Ariza-Garcia without whom this work would not have been possible.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors thank the Health Institute Carlos III (FIS PI10/02749-02764), the PNI + D + I2008–2011 FEDER funds, and the Andalusian Health Service, Junta de Andalucia, call for subsidies for the financing of biomedical research and health sciences in Andalusia (SAS-0457-2010), for funding this study.