To define changes in sleep and subjective fatigue associated with localized radiation treatment, and to determine their relationship to interleukin-1B (IL-1), we prospectively followed 15 men, none of whom were depressed during 8 wk of radiation treatment for localized prostate cancer. Each patient rated fatigue daily on a visual analogue scale, recorded hours slept, and completed the Beck Depression Inventory weekly. Serum IL-1, taken at baseline and Fridays, was measured by quantitative enzyme immunoassay. Ranked weekly mean fatigue scores for each subject increased at week 4 (mean, 17 fractions, 1.8 Gy) then plateaued and rose in weeks 6 and 7. In week 6, the last week of full volume radiation, subjects slept most compared to all other weeks including week 7 when treatment was coned down. Ranked serum IL-1 tended to rise between weeks 1 and 4, as fatigue scores rose. These data suggest that localized radiation treatment is associated with increased fatigue and sleep requirement independent of depressive symptoms. Relative serum IL-1 changes may be one signal for the systemic reaction and subjective fatigue associated with the acute effects of radiation.

For cancer patients, fatigue is a disturbing symptom caused by many factors. Since fatigue is the most common side effect of localized radiation to the breast, this treatment provides a unique opportunity to follow patients prospectively as they develop one type of fatigue. We evaluated the effect of radiation treatment in 15 women with Stage I or II node-negative breast cancer who were otherwise healthy. Fatigue, contrary to our hypothesis, did not increase linearly with cumulative radiation dose over time. It dropped from the first to second week and rose in the third week. The cumulative effects reached a plateau in the fourth week (after an average of 17 fractions), which was maintained during the remaining weeks of treatment. Within 3 wk after treatment, fatigue had diminished. No patient had sustained depressive symptoms. Cardiopulmonary exercise capacity in 5 patients at 6 and 12 wk did not change from just before radiation. Other markers, including reverse triiodothyronine and pulse change with orthostatic stress, did not correlate with subjective fatigue nor cumulative radiation in 15 patients. The curve of the fatigue syndrome during treatment conforms to the adaptation of the organism to a continuing stress and begins to describe a mild fatigue syndrome associated with radiation.

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