Instruments for determining clinically relevant fatigue in breast cancer patients during radiotherapy
This study aimed to determine radiotherapy (RT)-related changes in cancer-related fatigue (CRF), using Multidimensional Fatigue Inventory-20 (MFI-20), and fatigue-intensity rating (FIR) instruments at three different timepoints and to identify the optimal thresholds of MFI-20 scores which would correlate with moderate-to-severe fatigue warranting an intervention in breast cancer patients treated with RT.
Eighty-eight breast cancer patients treated with surgery followed by RT were included in the study. CRF was assessed with both FIR and MFI-20 tools at three different timepoints: within the week prior to RT (pre-RT), last week of RT, and 6 weeks after RT completion (post-RT). Changes in measurements, correlations between measurements and optimal cutpoints of MFI-20 scores were analyzed.
While FIR scores significantly changed over time (η2: 0.179), changes in MFI-20 scores were relatively small (η2: 0.076). Comparisons of the last week of RT versus post-RT scores showed small-to-moderate decrease for MFI-20 and FIR. FIR and MFI-20 scores were correlated at all timepoints and most correlated during and after RT (r = 0.525 95%CI 0.346–0.667, r = 0.791 95%CI 0.692–0.860 and r = 0.716 95%CI 0.589–0.808, respectively). Furthermore, the most correlated MFI-20 subscale with FIR was general fatigue (r = 0.603 95%CI 0.442–0.725, r = 0.821 95%CI 0.734–0.881 and r = 0.754 95%CI 0.641–0.835, respectively). Optimal cutpoints of the MFI-20 total scores corresponding to FIR scores ≥ 4 was 43.5 for all timepoints and the MFI total scores corresponding to FIR score ≥ 7 were 53.5, 52.5 and 60.5, respectively.
MFI-20 and FIR scores are highly correlated measures of CRF among breast cancer patients treated with RT. An MFI-20 score of ≥ 43.5 is suggested as a clinically significant score indicating moderate-to-severe fatigue, while an MFI score of ≥ 52.5 is indicative of severe fatigue.
KeywordsCancer-related fatigue Multidimensional fatigue inventory Fatigue-intensity rating Breast cancer Radiotherapy
This work was supported by National Institutes of Health, National Cancer Institute Grants R21CA155511, R03CA173770, R03CA183006, and P30CA138292. A seed Grant was also provided by the Radiation Therapy Oncology Group Community Clinical Oncology and Symptom Management Group. Funding was also provided by the Fred Cooper Family Foundation Breast Cancer Initiative and Robbins Scholar Award from the Winship Cancer Institute of Emory University.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no potential conflict of interest.
All procedures performed in our study were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
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