Fatigue and psychological distress--exploring the relationship in women treated for breast cancer.

Disabling fatigue and psychological symptoms of depression or anxiety are commonly reported by women with treated breast cancer. However, most instruments designed to assess fatigue do not assess concurrent psychological symptoms. This study compared the characteristics of two conceptually different, self-report instruments assessing fatigue to determine the extent to which common psychological symptoms co-exist with the symptom of fatigue in women treated for breast cancer. Women attending an oncology day-care facility for adjuvant treatment of breast cancer or ongoing surveillance post-treatment, completed two self-report questionnaires. The Somatic and Psychological Health REport-34 items (SPHERE) and the Functional Assessment of Cancer Therapy-Fatigue (FACT-F subscale-13 items). One hundred and nine women (mean age 52.8 years) completed both questionnaires and total scores on both fatigue assessment scales, FACT-F and SOMA-6, were highly correlated (r = 0.72, P < 0.001). Using the SPHERE case criteria, prolonged fatigue (37% [40/109]) and psychological distress 31% (34/109) were common in women treated for breast cancer. However, those who reported fatigue were much more likely to also report psychological symptoms (22/40 vs. 12/69, X(2) = 16.7: degrees of freedom (df)=1; P < 0.001) and the levels of fatigue on the FACT-F were not significantly different between those who reported "fatigue only" and those who reported "psychological distress only" (18.8 vs. 17.8, P = 0.79). Thus the recent emphasis on recording fatigue during and following treatments for cancer needs to be accompanied by concurrent measurement of psychological symptoms.