Reporting of propranolol use in studies of beta-blockers in colorectal cancer.

Abstract

e23378 Background: Beta-adrenergic blockers have been investigated for potential therapeutic and prognostic effects across multiple malignancies, including colorectal cancer (CRC). Propranolol, a non-selective beta-blocker with proposed anti-tumour and anti-angiogenic properties, has received growing interest in oncology. However, the extent to which propranolol use has been specifically reported in studies of beta-blockers in CRC is unclear. Methods: A structured search of PubMed was conducted for the terms beta-adrenergic blockers and colon cancer, identifying publications from 1 January 1970 to 31 December 2025. Only full-length original research articles were included; reviews, abstracts, and letters were excluded. In studies reporting multiple cancer types, data from CRC-specific cohorts were extracted if these were identifiable. Extracted variables included total study population, number of beta-blocker users, and number of propranolol users. Studies were grouped according to whether propranolol use was explicitly reported. Descriptive statistics (medians, interquartile ranges [IQRs], and proportions) were calculated. No inferential analyses were performed. Results: The search (conducted 24 January 2026) yielded 66 publications; 38 were excluded as non-relevant or secondary literature. One target-trial emulation study in colorectal polyps was excluded. Two additional eligible studies were identified through reference screening, resulting in 30 included publications. Only 27% (8/30) reported data on propranolol exposure. Among these studies, the median number of propranolol users was 10 (IQR, 5–49). Studies reporting propranolol use were generally smaller than those that did not report drug-specific exposure, despite broadly similar reporting of beta-blocker use. Conclusions: Although several decades of published research have examined beta-blockers in CRC, explicit reporting of propranolol exposure is uncommon. The limited and inconsistent capture of propranolol use may constrain interpretation of existing evidence and hinders evaluation of this agent’s specific oncologic relevance. Improved granularity in reporting individual beta-blockers is needed to inform future repurposing studies and clinical trial design. Summary of propranolol use in papers of beta blocker use in colorectal cancer. Type of paper Number of papers (%) Number of people in study, median [IQR] Number of people taking beta blockers, median [IQR] Number of people taking propranolol, median [IQR] Propranolol users counted 8 (27%) 1001 [51 to 3801] 286 [15 to 1159] 10 [5 to 49] Propranolol users not counted 22 (73%) 3770 [1213 to 22891] 1236 [468 to 8663]* Not specified Total 30 (100%) 3329 [584 to 20248] 840 [194 to 8049] - *in three studies the number of people taking beta blockers was not specified.