Catechol-O-methyltransferase genotype (Val158met) modulates cancer-related fatigue and pain sensitivity in breast cancer survivors

Cancer-related fatigue and pain after surgery are the most frequent and most incapacitating cancer-related symptoms after breast cancer treatment. Genetic influence of cancer-related fatigue and pain has not been previously investigated. Our aim was to examine the influence of catechol- O -methyltransferase (COMT) Val158Met genotypes on cancer-related fatigue, post-mastectomy pain, and pressure pain hypersensitivity in breast cancer survivors. One-hundred and twenty-eight ( n = 128) breast cancer survivors who were treated with radiotherapy and chemotherapy participated in this study. After amplifying Val158Met polymorphisms by polymerase chain reaction, COMT genotype was divided into Val/Val, valine/methionine (Val/Met), or Met/Met. The Piper fatigue scale (PFS) was used to assess cancer-related fatigue. Neck and shoulder/axillary pain intensity was assessed with a numerical pain rate scale (0–10). Finally, pressure pain thresholds (PPT) were assessed bilaterally over the C5–C6 zygapophyseal joints, deltoid muscles, second metacarpal, and tibialis anterior muscles. Breast cancer survivors carrying the Met/Met genotype reported higher levels of fatigue (all subscales, P