Introduction: Cancer pain is chronic pain resulting from various mechanisms related to the natural history of the disease, the course of therapy, and psychosocial factors.

Aim of the research: To assess the relationship between the intensity of cancer pain in women at the final stage of chemotherapy following radical surgery of breast cancer, and the intensity of negative emotional reactions.

Material and methods: The study was conducted in a population of 118 women after radical surgical treatment of breast cancer and undergoing chemotherapy at the Chemotherapy Unit of the Holycross Cancer Centre in Kielce in 2011. The research methodology consisted of a diagnostic survey and medical documentation review.

Results: Strong emotional stress manifested by anxiety and depression was experienced by 48.3% and 29.7% of patients, respectively. Aggression was experienced by 15.2%. Intensification of pain was associated with the intensification of anxiety (r = 0.37; p < 0.0001), depression (r = 0.35; p < 0.01), and aggression (r = 0.30; p < 0.01).

Conclusions: Adherence to the WHO-recommended analgesic ladder regimen is an effective means to treat chronic cancer pain in women in the final stage of chemotherapy following radical surgical treatment. Effective pharmacotherapy of cancer pain significantly contributes to a reduction in the intensity of negative emotional reactions, i.e. anxiety, depression, and aggression in patients undergoing chemotherapy following mastectomy. Breast cancer chemotherapy is associated with high levels of anxiety, pain, and aggression being experienced by the patients. Pain is an important determinant of the emotional state of women undergoing chemotherapy following radical cancer surgery.