Hemorrhoids and Rectal Cancer: A Systematic Review of Clinical Overlap, Diagnostic Misclassification, and Early Detection Strategies for Primary Care.

Hemorrhoidal disease (HD) and rectal cancer (RC) are common anorectal disorders with overlapping clinical symptoms, including rectal bleeding, altered bowel habits, and anorectal discomfort. This similarity leads to frequent misdiagnosis of RC as HD, and early diagnosis is essential for improving survival and quality of life in patients with RC. This systematic review aimed to summarize overlapping features, analyze causes of misdiagnosis, and review advances in early detection to provide practical guidance for primary care. A literature search was performed in PubMed, Embase, and Web of Science, covering publications from January 2018 to February 2026. We included systematic reviews, meta-analyses, randomized controlled trials, cohort studies, case-control studies, and clinical guidelines that addressed clinical association, differential diagnosis, or early detection of HD and RC, with case series requiring ≥10 participants; single case reports, conference abstracts, animal studies, and low-quality non-core journals were excluded. Two reviewers independently extracted data and assessed study quality using AMSTAR 2, Cochrane RoB, Newcastle-Ottawa Scale, and AGREE II, with disagreements resolved by consensus. Due to substantial heterogeneity across studies, a narrative qualitative synthesis was performed, grouping findings by the three review questions. Forty-six moderate- to high-quality studies were included in the analysis. Rectal bleeding was the most frequent overlapping symptom, followed by altered bowel habits and anorectal discomfort. Warning signs suggestive of RC included dark red blood per rectum, persistent anorectal pain, and unexplained weight loss. Major causes of misdiagnosis include clinical inertia, insufficient use of digital rectal examination, and limited access to endoscopy, especially in primary care settings. Limitations include scarcity of randomized controlled trials in diagnostic research, limited primary care data, and preliminary evidence for emerging technologies. Overlapping symptoms remain the main cause of misdiagnosis of RC. Increased clinical awareness, standardized diagnostic procedures, and proper screening tools can significantly reduce diagnostic errors. This review offers evidence-based support for differential diagnosis and early detection of RC in routine clinical practice.