Baseline pain scores are the strongest predictor of pain following radiotherapy in patients with breast cancer, according to a presentation at the American Association for Cancer Research (AACR) 2019 Annual Meeting in Atlanta, Georgia. Other factors associated with postradiotherapy pain included age, body mass index (BMI), current smoking status, radiotherapy fractionation, and use of pain medication.

In this prospective, longitudinal study of 1000 patients with breast cancer enrolled between 2011 and 2013, researchers assessed risk factors for developing pain in women undergoing adjuvant radiotherapy. The Brief Pain Inventory, with an 11-point numeric rating scale between 0 and 10, was used to determine the average of 4 different pain severity items at baseline and after radiotherapy.

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Baseline characteristics included 62% white patients (n = 623), 28% African American patients (n = 280), 6.4% Hispanic patients (n = 64), and 3.3% patients from other races/ethnicities (n = 33). The mean age was 58.1 years (±10.8 years). The mean BMI was 30.7 kg/m2 (±7.0 kg/m2).

At baseline, the average pain score was 1.5 (±1.0), and it rose to 2.5 (±1.8) following radiotherapy.

Multivariable linear regression analysis on data from 863 patients indicated postradiotherapy pain scores associated with baseline pain score (β = 0.39 per 1 point increment; P <.0001), age (β = –0.03 per 1 year increment; P <.001), BMI (β = 0.03 per 1 kg/m2 increment, P =.004), current smoking status (β = 0.57, P =.022), conventional radiotherapy fractionation (β = 0.48, P =.033), and use of pain medication (β = 1.85, P <.0001).

Additional stratification of analyses showed that radiotherapy fractionation is a significant risk factor for postradiotherapy pain only in patients who experienced more pain. Identification of risk factors for postradiotherapy pain could help identify patients at high risk and guide decisions on treatment regimens and approaches, particularly as cancer- and treatment-related pain can affect quality of life in cancer survivors.

Reference

Lee E, Snyder S, Ip E, Wright JL, Hu JJ. Risk factors for post-radiotherapy pain in a multi-racial ethnic population of breast cancer patients: a prospective study. Poster presented at: American Association for Cancer Research 2019 Annual Meeting; March 29-April 3, 2019; Atlanta, GA. Abstract 3290/10.