Left-sided early onset colorectal carcinomas: A sporadic neoplasm with aggressive behavior

Rising Incidence and Mortality of Early-Onset Colorectal Cancer in Young Cohorts Associated with Delayed Diagnosis

Background and Aims: Prior data showed an increasing incidence of early-onset colorectal cancer (EO-CRC) in the US. However, there are limited comprehensive data on recent EO-CRC incidence and mortality per different age cohorts and tumor characteristics. We aimed to evaluate EO-CRC incidence and mortality in different populations. Methods: Age-adjusted EO-CRC incidence rates were calculated from the USCS database between 2001 and 2021. Age-adjusted EO-CRC mortality rates were calculated from the NCHS database between 2000 and 2022 and the SEER database between 2004 and 2021. The age groups were 20-44 years and 45-54 years. Tumors were categorized by anatomical location (right, transverse, left, and proximal) and stage at diagnosis (early and late). The annual and average annual percentage changes (AAPC) were estimated using joinpoint regression. Age-specific pairwise comparison was conducted. Results: A total of 474,601 patients were diagnosed with EO-CRC between 2001 and 2021. The EO-CRC incidence increased in patients aged 20-44 years faster than in those aged 45-54 years (AAPC = 1.51 vs. 0.73; AAPC difference = 0.78, p = 0.001). This was most notable in proximal colon tumors (AAPC difference = 0.88, p < 0.001). While the incidence of early-stage tumors decreased in recent years across all anatomical locations, late-stage tumors increased, mostly in the proximal colon (AAPC = 2.44). A total of 147,026 patients died from EO-CRC between 2000 and 2022. Mortality increased in patients aged 20-44 years faster than in patients aged 45-54 years, who had a stable trend (AAPC difference = 0.85, p < 0.001). The increase in mortality was noted in both early- and late-stage tumors. Conclusions: Our study provides epidemiologic evidence showing an alarming increase in EO-CRC incidence and mortality among patients aged 20-44 years compared to those aged 45-54 years, which is associated with delayed diagnosis, and mostly in proximal colon tumors. Expanding screening efforts to younger populations and addressing healthcare disparities are essential for improving early detection and outcomes for younger patients.

Early-Onset Colorectal Cancer: Current Insights

Over the past decade, the incidence of colorectal cancer has increased in individuals under the age of 50 years. Meanwhile, the incidence has gradually decreased in the older population. As described herein, we reviewed the available literature to summarize the current landscape of early-onset colorectal cancer, including risk factors, clinicopathological presentation, genetic makeup of patients, and management. Currently, early-onset colorectal cancer is treated similarly as late-onset colorectal cancer, yet the available literature shows that early-onset colorectal cancer is more aggressive and different, and this remains a significant unmet need. A detailed understanding of early-onset colorectal cancer is needed to identify risk factors for the increased incidence and tailor treatments accordingly.

Colorectal Cancer in North-Eastern Iran: a retrospective, comparative study of early-onset and late-onset cases based on data from the Iranian hereditary colorectal cancer registry

BACKGROUND

The incidence rate of colorectal cancer (CRC) is increasing among patients below 50 years of age. The reason for this is unclear, but could have to do with the fact that indicative variables, such as tumour location, gender preference and genetic preponderance have not been followed up in a consistent mann er. The current study was primarily conducted to improve the hereditary CRC screening programme by assessing the demographic and clinicopathological characteristics of early-onset CRC compared to late-onset CRC in northeast Iran.

METHODS

This retrospective study, carried out over a three-year follow-up period (2014-2017), included 562 consecutive CRCs diagnosed in three Mashhad city hospital laboratories in north-eastern Iran. We applied comparative analysis of pathological and hereditary features together with information on the presence of mismatch repair (MMR) gene deficiency with respect to recovery versus mortality. Patients with mutations resulting in absence of the MMR gene MLH1 protein product and normal BRAF status were considered to be at high risk of Lynch syndrome (LS). Analyses using R studio software were performed on early-onset CRC (n = 222) and late-onset CRC (n = 340), corresponding to patients ≤50 years of age and patients > 50 years.

RESULTS

From an age-of-onset point of view, the distribution between the genders differed with females showing a higher proportion of early-onset CRC than men (56% vs. 44%), while the late-onset CRC disparity was less pronounced (48% vs. 52%). The mean age of all participants was 55.6 ± 14.8 years, with 40.3 ± 7.3 years for early-onset CRC and 65.1 ± 9.3 years for late-onset CRC. With respect to anatomical tumour location (distal, rectal and proximal), the frequencies were 61, 28 and 11%, respectively, but the variation did not reach statistical significance. However, there was a dramatic difference with regard to the history of CRC in second-degree relatives between two age categories, with much higher numbers of family-related CRCs in the early-onset group. Expression of the MLH1 and PMS2 genes were significantly different between recovered and deceased, while this finding was not observed with regard to the MSH6 and the MSH2 genes. Mortality was significantly higher in those at high risk of LS.

CONCLUSION

The variation of demographic, pathological and genetic characteristics between early-onset and late-onset CRC emphasizes the need for a well-defined algorithm to identify high-risk patients.

Global variation in the long-term outcomes of ypT0 rectal cancers

BACKGROUND

Colorectal cancer mortality presents world-wide variation. In rectal cancers presenting a complete/nearly-complete tumor response (ypT0/ypTis) following neoadjuvant treatment, the features correlated to nodal metastases and relapses still need to be defined.

METHODS

An international cohort study enrolling ypT0/ypTis rectal cancers surgically treated from 2012 to 2017 was conducted. A propensity matching was used to balance nodal-positive and nodal-negative patients and statistical analyses were performed to investigate survivals, using a bootstrap model for internal validation. The features correlated with nodal metastasis were studied. Countries with participating centers were ranked using the World Bank (WBI), Human Development (HDI) and Global Gender Gap (GGG) indexes to compare survivals.

RESULTS

680 ypT0/ypTis from 52 European, Australian, Indian and American Institutions were analyzed. Mean follow-up was of 30.4 months. 96.5% were treated with total mesorectal excision, 7.2% were nodal-positive and 8.8% relapsed. Distal cancers (HR 0.71 95%CI: 0.56-0.91) and nodal metastasis and nodal metastasis (HR 3.85 95%CI:1.12-13.19) correlated with worse DFS, whereas a younger age was of borderline significance (HR 0.95 95%CI:0.91-0.99). The bootstrap analysis validated the model on 5000 repetitions. A short-course radiotherapy (OR 0.18 95%CI:0.09-0.37) correlated with the occurrence of nodal metastasis. Those countries classified in the low/medium-WBI, medium-HDI and lower-GGG ranks documented worse DFS curves (respectively p < 0.0001, p < 0.0001 and p 0.0002). However, the clinical stages were similar and patients from medium-HDI countries received more adjuvant chemotherapy than the others (p < 0.0001).

CONCLUSION

Sub-groups at risk for relapses and nodal metastasis were identified. A global variation exists also when benchmarking a rectal cancer complete regression.