Relationship between catechol-o-methyltransferase gene polymorphism and pain syndrome in breast cancer patients

The goal of the study was to explore the influence of single-nucleotide polymorphisms of the COMT gene on the formation and features of pain syndrome, the level of anxiety, and the need for narcotic analgesics in patients with breast cancer. Materials and methods. The intensity of pain and opioid consumption in the postoperative period were evaluated in 58 patients who met the inclusion criteria of the study and were operated for breast cancer. The frequency of chronic pain syndrome after mastectomy was studied in the same group of patients after a year by using short pain questionnaires, McGill Pain Questionnaire and PainDetect. The anxiety level was assessed by using the HADS questionnaire. Genotyping was performed for single-nucleotide polymorphisms, rs4680, rs740603, rs2097603 = rs2070577, rs4633, of the COMT gene localized in the 22q11.21 region in the studied group of patients. The relationship between the carrier of different genotypes and the intensity of acute and chronic pain, the severity of the pain rating index for sensory and affective characteristics, the presence of a neuropathic component of pain, and the severity of anxiety were studied in the entire sample. The use of narcotic analgesics was evaluated in the postoperative period (IU/day and IU/course) and for the relief of chronic pain. Results. It is shown that the intensity of postoperative pain and the severity of anxiety do not depend on the presence of a mutant allele for the studied polymorphisms of the COMT gene, while the postoperative consumption of opioids in patients with the rs4680 missense mutation in the exon of this gene is significantly less. The dependence of the intensity of chronic pain syndrome and the severity of anxiety on the presence of a mutant allele for the polymorphic locus rs4680 localized in the exon of the COMT gene was established. No significant relationship was observed between the mutant alleles and the use of opioids for chronic pain relief after mastectomy. Conclusion. Genotyping for the COMT gene polymorphisms can be useful for choosing the optimal tactics of pain management in patients with breast cancer.