Cancer-Related Neuropathic Pain in Socially Vulnerable Patients in Brazil.

PURPOSE: To estimate the prevalence and 6-month incidence of cancer-related neuropathic pain and to identify associated clinical and psychosocial factors in a socially vulnerable oncology population in Northeastern Brazil.

DESIGN

Population-based cross-sectional study with a 6-month follow-up subcohort.

METHODS

This hospital-based observational study combined a baseline cross-sectional assessment with a 6-month follow-up subcohort. Adults with histologically confirmed cancer were recruited from two public oncology referral hospitals in São Luís, Maranhão, Northeastern Brazil. At baseline, 1,020 participants were assessed; 224 participants from the incidence arm were reassessed after 6 months. Neuropathic pain was screened using the Douleur Neuropathique 4 questionnaire, and functional status, anxiety/depression symptoms, and sleep quality were assessed using the Karnofsky Performance Status scale, the Hospital Anxiety and Depression Scale, and the Mini-Sleep Questionnaire, respectively. Multivariable logistic regression was used to identify factors independently associated with cancer-related neuropathic pain.

RESULTS

Among 1,020 participants, 35.3% reported chronic pain, and cancer-related neuropathic pain accounted for 62.5% of chronic pain cases. In the follow-up subcohort reassessed at 6 months (n = 224), 12.5% developed chronic pain (n = 28), and 6 participants met criteria for cancer-related neuropathic pain (21.4% of incident chronic pain cases). Cancer-related neuropathic pain was associated with female sex, age 40-59 years, breast or cervical cancer, metastases, prior radiotherapy, and pain localized to the chest or lower limbs. Functional impairment (Karnofsky Performance Status 50-80), anxiety, depression, and disturbed sleep were also independent correlates. Most affected participants were low-income women with limited education, many living in rural areas; use of adjuvant analgesics was low.

CONCLUSIONS

Cancer-related neuropathic pain was highly prevalent and was linked to clinical and social factors associated with worse function and well-being.

CLINICAL IMPLICATIONS: Routine, repeated screening for neuropathic pain features, together with assessment of function, mood, and sleep, may help nurses and oncology teams identify high-risk patients earlier and facilitate timely access to multidisciplinary pain care in vulnerable populations.