Rising trends in the incidence and mortality of early-onset CRC in those who are ages less than 50 years have been well-established. These trends have spurred intense investigation focused on elucidating the epidemiology and characteristics of early-onset CRC, as well on identifying strategies for early detection and prevention. In this review, we provide a contemporary update on early-onset CRC with a particular focus on epidemiology, molecular characterization, red flag signs and symptoms, and screening for early-onset CRC.

Risk Factors for Early-Onset Colorectal Cancer Study GroupResults Clini al FindingVeterans 18 -49 years of age undergoing colonoscopy loss may be an early clinical sign of early-onset colorectal cancer

Background: Mailed outreach promoting colorectal cancer (CRC) screening with a stool blood test kit may increase participation, but magnitude and consistency of benefit of this intervention strategy is uncertain. Aim: Conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing mailed outreach offering stool tests to usual care, clinic-based screening offers on CRC screening uptake in the United States. Methods: We performed a systematic literature search of 5 databases for RCTs of mailed outreach January 1980 through June 2017. Primary outcome was screening completion, summarized using random-effects meta-analysis as pooled differences in proportion completing screening and relative risk of achieving screening compared to control. Subgroup analyses by test type offered-fecal immunochemical test (FIT) or guaiac fecal occult blood test (gFOBT)-, presence of telephone reminders, and presence of predominant underserved/minority population within study were performed. Quality of evidence was evaluated using the GRADE framework. Results: 7 RCTs which enrolled 12,501 subjects were included (n=5,703 assigned mailed outreach and n=6,798 usual care). Mailed outreach resulted in a 28% absolute (95%CI: 25-30%; I2=47%), and a 2.8-fold relative (RR 2.65, 95%CI: 2.03-3.45; I2=92%) increase in screening completion compared to usual care, with a number needed to invite of 3.6. Similar outcomes were observed across subgroups. Overall body of evidence was moderate quality. Conclusions: Mailed outreach offering a gFOBT or FIT is associated with a large and consistent increase in CRC screening completion and should be considered for more widespread implementation for improving screening rates nationwide.

BACKGROUND AND AIMS: The optimal time interval for diagnostic colonoscopy completion after an abnormal stoolbased colorectal cancer (CRC) screening test is uncertain. We examined the association between time to colonoscopy and CRC outcomes among individuals who underwent diagnostic colonoscopy after abnormal stool-based screening. METHODS: We performed a retrospective cohort study of veterans age 50 to 75 years with an abnormal fecal occult blood test (FOBT) or fecal immunochemical test (FIT) between 1999 and 2010. We used multivariable Cox proportional hazards to generate CRCspecific incidence and mortality hazard ratios (HRs) and 95% confidence intervals (CI) for 3-month colonoscopy intervals, with 1 to 3 months as the reference group. Association of time to colonoscopy with late-stage CRC diagnosis was also examined. RESULTS: Our cohort included 204,733 patients. Mean age was 61 years (SD 6.9). Compared with patients who received a colonoscopy at 1 to 3 months, there was an increased CRC risk for patients who received a colonoscopy at 13 to 15 months (

ObjectiveTo conduct an anatomic site-specific case–control study of candidate colorectal cancer (CRC) risk factors.DesignCase–control study of US veterans with >1 colonoscopy during 1999–2011. Cases had cancer registry-identified CRC at colonoscopy, while controls were CRC free at colonoscopy and within 3 years of colonoscopy. Primary outcome was CRC, stratified by anatomic site: proximal, distal, or rectal. Candidate risk factors included age, sex, race/ethnicity, body mass index, height, diabetes, smoking status, and aspirin exposure summarised by adjusted ORs and 95% CIs.Results21 744 CRC cases (n=7017 rectal; n=7039 distal; n=7688 proximal) and 612 646 controls were included. Males had significantly higher odds relative to females for rectal cancer (OR=2.84, 95% CI 2.25 to 3.58) than distal cancer (OR=1.84, 95% CI 1.50 to 2.24). Relative to whites, blacks had significantly lower rectal cancer odds (OR=0.88, 95% CI 0.82 to 0.95), but increased distal (OR=1.27, 95% CI 1.19 to 1.37) and proximal odds (OR=1.62, 95% CI 1.52 to 1.72). Diabetes prevalence was more strongly associated with proximal (OR=1.29, 95% CI 1.22 to 1.36) than distal (OR=1.15, 95% CI 1.08 to 1.22) or rectal cancer (OR=1.12, 95% CI 1.06 to 1.19). Current smoking was more strongly associated with rectal cancer (OR=1.81, 95% CI 1.68 to 1.95) than proximal cancer (OR=1.53, 95% CI 1.43 to 1.65) or distal cancer (OR=1.46, 95% CI 1.35 to 1.57) compared with never smoking. Aspirin use was significantly more strongly associated with reduced rectal cancer odds (OR=0.71, 95% CI 0.67 to 0.76) than distal (OR=0.85, 95% CI 0.81 to 0.90) or proximal (OR=0.91, 95% CI 0.86 to 0.95).ConclusionCandidate CRC risk factor associations vary significantly by anatomic site. Accounting for site may enable better insights into CRC pathogenesis and cancer control strategies.

Background Potential benefits of screening mammography among women ages 75 years and older remain unclear. Methods We evaluated 10-year cumulative incidence of breast cancer and death from breast cancer and other causes by Charlson Comorbidity Index (CCI) and age in the Medicare-linked Breast Cancer Surveillance Consortium (1999–2010) cohort of 222 088 women with no less than 1 screening mammogram between ages 66 and 94 years. Results During median follow-up of 107 months, 7583 were diagnosed with invasive breast cancer and 1742 with ductal carcinoma in situ; 471 died from breast cancer and 42 229 from other causes. The 10-year cumulative incidence of invasive breast cancer did not change with increasing CCI but decreased slightly with age: ages 66–74 years (CCI0 = 4.0% [95% CI = 3.9% to 4.2%] vs CCI  ≥ 2 = 3.9% [95% CI = 3.5% to 4.3%]); ages 75–84 years (CCI0 = 3.7% [95% CI = 3.5% to 3.9%] vs CCI  ≥ 2 = 3.4% [95% CI = 2.9% to 3.9%]); and ages 85–94 years (CCI0 = 2.7% [95% CI = 2.3% to 3.1%] vs CCI  ≥ 2 = 2.1% [95% CI = 1.3% to 3.0%]). The 10-year cumulative incidence of other-cause death increased with increasing CCI and age: ages 66–74 years (CCI0 = 10.4% [95% CI = 10.3 to 10.7%] vs CCI ≥ 2 = 43.4% [95% CI = 42.2% to 44.4%]), ages 75–84 years (CCI0 = 29.8% [95% CI = 29.3% to 30.2%] vs CCI ≥ 2 = 61.7% [95% CI = 60.2% to 63.3%]), and ages 85 to 94 years (CCI0 = 60.3% [95% CI = 59.1% to 61.5%] vs CCI  ≥ 2 = 84.8% [95% CI = 82.5% to 86.9%]). The 10-year cumulative incidence of breast cancer death was small and did not vary by age: ages 66–74 years = 0.2% (95% CI = 0.2% to 0.3%), ages 75–84 years = 0.29% (95% CI = 0.25% to 0.34%), and ages 85 to 94 years = 0.3% (95% CI = 0.2% to 0.4%). Conclusions Cumulative incidence of other-cause death was many times higher than breast cancer incidence and death, depending on comorbidity and age. Hence, older women with increased comorbidity may experience diminished benefit from continued screening.

Breast cancer is a major cause of cancer-related deaths among older women, aged 65 years or older. Screening mammography has been shown to be effective in reducing breast cancer mortality in women aged 50–74 years but not among those aged 75 years or older. Given the large heterogeneity in comorbidity status and life expectancy among older women, controversy remains over screening mammography in this population. Diminished life expectancy with aging may decrease the potential screening benefit and increase the risk of harms. In this review, we summarize the evidence on screening mammography utilization, performance, and outcomes and highlight evidence gaps. Optimizing the screening strategy will involve separating older women who will benefit from screening from those who will not benefit by using information on comorbidity status and life expectancy. This review has identified areas related to screening mammography in older women that warrant additional research, including the need to evaluate emerging screening technologies, such as tomosynthesis among older women and precision cancer screening. In the absence of randomized controlled trials, the benefits and harms of continued screening mammography in older women need to be estimated using both population-based cohort data and simulation models.

IMPORTANCE Radiation doses for computed tomography (CT) vary substantially across institutions. OBJECTIVE To assess the impact of institutional-level audit and collaborative efforts to share best practices on CT radiation doses across 5 University of California (UC) medical centers. DESIGN, SETTING, AND PARTICIPANTS In this before/after interventional study, we prospectively collected radiation dose metrics on all diagnostic CT examinations performed between October 1, 2013, and December 31, 2014, at 5 medical centers. Using data from January to March (baseline), we created audit reports detailing the distribution of radiation dose metrics for chest, abdomen, and head CT scans. In April, we shared reports with the medical centers and invited radiology professionals from the centers to a 1.5-day in-person meeting to review reports and share best practices. MAIN OUTCOMES AND MEASURES We calculated changes in mean effective dose 12 weeks before and after the audits and meeting, excluding a 12-week implementation period when medical centers could make changes. We compared proportions of examinations exceeding previously published benchmarks at baseline and following the audit and meeting, and calculated changes in proportion of examinations exceeding benchmarks. RESULTS Of 158 274 diagnostic CT scans performed in the study period, 29 594 CT scans were performed in the 3 months before and 32 839 CT scans were performed 12 to 24 weeks after the audit and meeting. Reductions in mean effective dose were considerable for chest and abdomen. Mean effective dose for chest CT decreased from 13.2 to 10.7 mSv (18.9% reduction; 95% CI, 18.0%-19.8%). Reductions at individual medical centers ranged from 3.8% to 23.5%. The mean effective dose for abdominal CT decreased from 20.0 to 15.0 mSv (25.0% reduction; 95% CI, 24.3%-25.8%). Reductions at individual medical centers ranged from 10.8% to 34.7%. The number of CT scans that had an effective dose measurement that exceeded benchmarks was reduced considerably by 48% and 54% for chest and abdomen, respectively. After the audit and meeting, head CT doses varied less, although some institutions increased and some decreased mean head CT doses and the proportion above benchmarks. CONCLUSIONS AND RELEVANCE Reviewing institutional doses and sharing dose-optimization best practices resulted in lower radiation doses for chest and abdominal CT and more consistent doses for head CT.