Dimensions of fatigue during radiotherapy - An application of the Swedish Occupational Fatigue Inventory (SOFI) on cancer patients

The aims of this study were primarily to evaluate the applicability of the Swedish Occupational Fatigue Inventory (SOFI) on cancer patients, secondly to describe the development of fatigue in patients, receiving full dose rad iotherapy with a curative intent. A questionnaire was completed by 81 cance r patients at Four occasions; before treatment, during the last week of tre atment, 1 and 3 months, respectively, after treatment. The fatigue increase d significantly at the end of treatment, as compared to pretreatment, and d ecreased after treatment. The highest fatigue ratings concerned lack of ene rgy, lack of motivation and sleepiness. The five SOFI-dimensions explained more than half of the variance in the overall rating of fatigue, and the in ternal consistency of the dimensions were good. However, the ratings were o n the lower part of the scale and the dimensions correlated more than expec ted. Thus, the relevance of the SOFI for use also among patients is only pa rtially supported, and studies with larger samples are needed for further t esting of the inventory.