Neuropathic Pain After Breast Cancer Treatment: Characterization and Risk Factors.

Context: Neuropathic pain (NP) may be an important contributor to the morbidity burden of breast cancer.

Objectives: We aimed to quantify the incidence of NP in the first year after diagnosis of breast cancer and to identify its main determinants.

Methods: We performed a prospective cohort study including 506 patients with incident breast cancer, recruited at the Portuguese Institute of Oncology of Porto, and followed for one year; patients with incident NP were additionally evaluated when this condition was diagnosed and after six months, to identify chronic NP.

Results: During the first year, 156 patients were diagnosed with NP (30.8%, 95% CI 27.0-35.0). Anxiety (relative risk [RR] 1.50; 95% CI 1.06-2.13), arm symptoms (RR 1.44; 95% CI 1.02-2.05), cancer Stage III/IV (RR 2.47; 95% CI 1.66-3.66), breast-conserving surgery with axillary lymph node dissection (RR 3.13; 95% CI 1.51-6.48), mastectomy with axillary lymph node dissection (RR 2.52; 95% CI 1.25-5.11), and damaging of the intercostobrachial nerve (RR 2.05; 95% CI 1.25-3.37) were predictors of a higher risk of NP. A total of 97 patients (62.2%, 95% CI 54.4-69.4) diagnosed with NP remained symptomatic after six months.

Conclusion: NP and chronic NP were frequent in this population, being associated with anxiety and arm symptoms before breast cancer treatments and type of surgical management. These results highlight the need for monitoring the occurrence of this neurologic side effect of treatments and to develop strategies for reducing the morbidity burden of breast cancer.