Long-term course of pain in breast cancer survivors: a 4-year longitudinal study.

After successful treatment of early breast cancer, many women still report pain symptoms, and attribute them to the previous illness or its treatment. However, knowledge about the long-term course of pain in breast cancer is limited. Baseline assessment included 3,088 women who received a breast cancer diagnosis on average 2 years prior to enrollment, and who completed typical medical treatments. After 4 years, a subsample of 2,160 recurrence-free women (70%) was re-assessed. The major outcome variable was the composite index for general pain symptoms. Over the 4-year course, a slight but significant increase in pain was reported. If only medical variables were examined, a triple interaction between surgery type, breast cancer stage, and time indicated that pain scores increased in most subgroups, while they decreased in stage II women after mastectomy and stage III women after lumpectomy. Using a regression analytical approach, psychological and other variables added significantly to the prediction of pain persistence. Regression analysis revealed that pain symptoms increased in those women taking tamoxifen at baseline, in those reporting depression at baseline or stressful life events during the first 12 months after enrollment. Exercise at baseline had a beneficial effect on pain recovery. The persistence or increase of pain symptoms in women surviving breast cancer is associated with some medical factors (surgery type, tamoxifen use), but also with psychological factors. Pain should be a standard outcome variable in the evaluation of cancer treatment programs.