An assessment of left-digit bias in the treatment of older patients with potentially curable rectal cancer



      Patient age is associated with poorer rectal cancer treatment compliance. However, it is unknown whether left-digit bias (disproportionate influence of leftmost age digit) influences this association.


      The patients diagnosed with stage I–III rectal cancer between 2006 to 2017 in the National Cancer Database were identified. The association between age and receipt of guideline-adherent care was assessed using mixed-effects multivariable analyses.


      Among 97,960 patients, 46.2% received guideline-adherent overall treatment and 73.3% underwent guideline-adherent surgical resection. Of those who underwent guideline-adherent surgery, 86.4% received guideline-adherent radiotherapy and 56.6% received guideline-adherent chemotherapy. After risk-adjustment, each decade increase in age was associated with 36% decreased odds of guideline-adherent therapy (odds ratio = 0.64, 95% confidence interval = 0.63–0.65). Patients aged 58 to 59 (odds ratio = 1.15, 95% confidence interval = 1.02–1.27) and 78 to 79 (odds ratio = 1.28, 95% confidence interval = 1.08–1.51) had higher odds of guideline-adherent overall treatment compared with patients aged 60 and 80, respectively. However, there were no significant differences in the receipt of guideline-adherent treatment between patients aged 60 vs 61–62 and 80 vs 81–82.


      Older patients with rectal cancer are less likely to receive guideline-adherent care, and a left-digit bias is present. Geriatric assessment-guided treatment decisions could help mitigate this bias.
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        • Administration for Community Living (ADL)
        (profile of older americans)
        • Siegel R.L.
        • Miller K.D.
        • Goding Sauer A.
        • et al.
        Colorectal cancer statistics, 2020.
        CA Cancer J Clin. 2020; 70: 145-164
        • Loos M.
        • Quentmeier P.
        • Schuster T.
        • et al.
        Effect of preoperative radio(chemo)therapy on long-term functional outcome in rectal cancer patients: a systematic review and meta-analysis.
        Ann Surg Oncol. 2013; 20: 1816-1828
        • Ceelen W.
        • Pattyn P.
        Total mesorectal excision in the treatment of rectal cancer: a review.
        Acta Chir Belg. 2000; 100: 94-99
        • Ridgway P.F.
        • Darzi A.W.
        The role of total mesorectal excision in the management of rectal cancer.
        Cancer Control. 2003; 10: 205-211
        • Benson 3rd, A.B.
        • Bekaii-Saab T.
        • Chan E.
        • et al.
        Rectal cancer.
        J Natl Compr Canc Netw. 2012; 10: 1528-1564
        • Monson J.R.
        • Weiser M.R.
        • Buie W.D.
        • et al.
        Practice parameters for the management of rectal cancer (revised).
        Dis Colon Rectum. 2013; 56: 535-550
        • Tjandra J.J.
        • Kilkenny J.W.
        • Buie W.D.
        • et al.
        Practice parameters for the management of rectal cancer (revised).
        Dis Colon Rectum. 2005; 48: 411-423
        • Keikes L.
        • van Oijen M.G.H.
        • Lemmens V.
        • Koopman M.
        • Punt C.J.A.
        Evaluation of guideline adherence in colorectal cancer treatment in The Netherlands: a survey among medical oncologists by the Dutch Colorectal Cancer Group.
        Clin Colorectal Cancer. 2018; 17: 58-64
        • Minicozzi P.
        • Bouvier A.M.
        • Faivre J.
        • Sant M.
        Management of rectal cancers in relation to treatment guidelines: a population-based study comparing Italian and French patients.
        Dig Liver Dis. 2014; 46: 645-651
        • Kolarich A.
        • George Jr., T.J.
        • Hughes S.J.
        • et al.
        Rectal cancer patients younger than 50 years lack a survival benefit from NCCN guideline-directed treatment for stage II and III disease.
        Cancer. 2018; 124: 3510-3519
        • Dalmacy D.M.
        • Diaz A.
        • Hyer M.
        • Pawlik T.M.
        Age-based left-digit bias in the management of acute cholecystitis.
        J Gastrointest Surg. 2021; 25: 3239-3241
        • Olenski A.R.
        • Zimerman A.
        • Coussens S.
        • Jena A.B.
        Behavioral heuristics in coronary-artery bypass graft surgery.
        N Engl J Med. 2020; 382: 778-779
        • Foster J.A.
        • Salinas G.D.
        • Mansell D.
        • Williamson J.C.
        • Casebeer L.L.
        How does older age influence oncologists' cancer management?.
        Oncologist. 2010; 15: 584-592
        • Kunkel J.
        • Bohle W.
        • Henseling S.
        • Zoller W.
        Treatment intensity, not age, affects survival time of patients with advanced pancreatic cancer.
        J Gastrointestin Liver Dis. 2021; 30: 380-387
        • Wang Y.
        • Buchan J.
        • Deng J.
        • Raman V.
        • Yang C.
        MA03.11 cognitive bias in lung cancer surgery: the left digit effect.
        J Thorac Oncol. 2021; 16: S143
        • Xu Z.
        • Mohile S.G.
        • Tejani M.A.
        • et al.
        Poor compliance with adjuvant chemotherapy use associated with poorer survival in patients with rectal cancer: an NCDB analysis.
        Cancer. 2017; 123: 52-61
        • American Cancer Society
        Colorectal cancer: causes, risk factors, and prevention.
        • Boakye D.
        • Walter V.
        • Jansen L.
        • et al.
        Magnitude of the age-advancement effect of comorbidities in colorectal cancer prognosis.
        J Natl Compr Canc Netw. 2020; 18: 59-68
        • American College of Surgeons (ACS)
        National cancer database.
        • American College of Surgeons (ACS)
        Facility Oncology Registry Data Standards (FORDS): Revised for 2016.
        • National Comprehensive Cancer Network (NCCN)
        NCCN Guidelines, Rectal Cancer.
        • Mourad A.P.
        • De Robles M.S.
        • Putnis S.
        • Winn R.D.R.
        Current treatment approaches and outcomes in the management of rectal cancer above the age of 80.
        Curr Oncol. 2021; 28: 1388-1401
        • Chang G.J.
        • Skibber J.M.
        • Feig B.W.
        • Rodriguez-Bigas M.
        Are we undertreating rectal cancer in the elderly? An epidemiologic study.
        Ann Surg. 2007; 246: 215-221
        • Lemmens V.E.P.P.
        • Janssen-Heijnen M.L.G.
        • Verheij C.D.G.
        • Houterman S.
        • Repelaer van Driel O.J.
        • Coebergh J.W.W.
        Co-morbidity leads to altered treatment and worse survival of elderly patients with colorectal cancer.
        Br J Surg. 2005; 92: 615-623
        • Papamichael D.
        • Audisio R.A.
        • Glimelius B.
        • et al.
        Treatment of colorectal cancer in older patients: International Society of Geriatric Oncology (SIOG) consensus recommendations 2013.
        Ann Oncol. 2015; 26: 463-476
        • Mohile S.G.
        • Dale W.
        • Somerfield M.R.
        • et al.
        Practical assessment and management of vulnerabilities in older patients receiving chemotherapy: ASCO Guideline for Geriatric Oncology.
        J Clin Oncol. 2018; 36: 2326-2347
        • Husain S.A.
        • King K.L.
        • Mohan S.
        Left-digit bias and deceased donor kidney utilization.
        Clin Transplant. 2021; 35e14284
        • Morris A.M.
        • Billingsley K.G.
        • Baxter N.N.
        • Baldwin L.M.
        racial disparities in rectal cancer treatment: a population-based analysis.
        Arch Surg. 2004; 139: 151-155
        • Obrochta C.A.
        • Murphy J.D.
        • Tsou M.-H.
        • Thompson C.A.
        Disentangling racial, ethnic, and socioeconomic disparities in treatment for colorectal cancer.
        Cancer Epidemiol Biomarkers Preven. 2021; 30: 1546-1553