RESUMO
PURPOSE: Radiotherapy-induced dysfunction of the gastrointestinal tract is common in cancer patients and has a significant impact on their quality of life. In this study, we investigated the prevalence of breakthrough cancer pain (BTcP) in patients undergoing 3D pelvic radiotherapy and who had proctalgia. METHODS: This observational, multicenter, cross-sectional epidemiological study was performed in 13 Spanish hospitals. Data were obtained on the presence and characteristics of BTcP, demographics, common comorbidities, and treatments prescribed to the patients. RESULTS: The prevalence of BTcP in patients undergoing pelvic 3D external radiotherapy with proctalgia (N = 105) was 48.6% (95% CI 39.0-58.1%). BTcP was further characterized in 59 patients. The mean (± SD) intensity of the BTcP episodes was 7.45 ± 1.47 in a visual analog scale. We found several statistically significant associations between the descriptive variables of BTcP with demographic and clinical variables associated with the tumor or the patient, such as an increased number of BTcP episodes per day depending on the presence or absence of diabetes (p = 0.001, Chi-square) or time to the onset of pain relief depending on the location of the tumor (p = 0.019, Chi-square). Fentanyl was the drug of choice in BTcP episodes for 95% of the patients. CONCLUSIONS: This study demonstrated a high prevalence of BTcP prevalence in cancer patients undergoing pelvic 3D radiotherapy and with proctalgia. Although the variables determining the onset of BTcP are still unclear, our results could help in the design of future clinical studies addressing the treatment of BTcP in these patients.