In Colombia, there is a lack of studies comparing survival differences between EOCRC and LOCRC. To address this gap, we conducted a cohort study of CRC patients in Medellín, Colombia, with the aim of analysing their OS disparities. Our study indicates that EOCRC is associated with a higher 5-year OS, whereas advanced stages and higher tumor grading are linked to lower 5-year OS among all CRC patients. Specifically, the differences in the 5-year OS rates were statistically significant, with 54% for EOCRC and 32% for LOCRC. This suggests that among Colombian adults with CRC, a higher proportion of EOCRC cases survive five years post-diagnosis compared to LOCRC cases.
Supporting this finding, a study from Brazil reported a 5-year OS rate of 70.0% for adults with EOCRC (< 50 years), while those aged 50–74 and ≥ 75 years had lower rates of 66.9% and 43.8%, respectively (Aguiar-Junior et al. 2020). In contrast, a study conducted with Chilean patients showed that younger adults (≤ 50 years) had a lower 5-year OS rate (73.6%) than adults in the 51–69 years group (80%). However, the late-onset group (≥ 70 years) had the lowest survival rate (48.5%) (Alvarez et al. 2021). These regional disparities are particularly interesting given the geographical proximity of the study populations.
After adjusting for tumor site and grading, the differences in 5-year OS rates remained higher for younger individuals in our sample. For example, EOCRC patients with right-sided tumours experienced better OS rates than their counterparts with the same tumor location (Fig. 3A). Our findings suggest that age is associated with a better prognosis, regardless of tumor site. However, it is important to note that tumor site was not an independent prognostic factor for OS after Cox regression analyses in our study. Other investigations have reported conflicting results. For instance, one study found that tumor sidedness is not an independent prognostic factor for OS among stage I-III EOCRC patients (Azar et al. 2021). Conversely, some authors have stated that right-sided tumours are associated with poorer overall and CRC-specific survival due to their histopathological profile, regardless of age (Akimoto et al. 2021; Di Leo et al. 2021; REACCT Collaborative et al. 2021; Dharwadkar et al. 2022).
Our study also demonstrated that advanced staging at diagnosis is associated with poorer oncological outcomes among CRC patients. Within our sample, individuals with stage IV were approximately 12 times more likely to die within the first five years than those diagnosed at stage I. Metastatic disease is strongly associated with higher morbidity and mortality rates, as well as an increased incidence of both local and distant recurrences (Hernandez-Dominguez et al. 2023). Although we did not find significant differences in tumor staging between EOCRC and LOCRC, it has been reported that EOCRC is frequently diagnosed at more advanced stages (REACCT Collaborative et al. 2021). This is thought to be due to a higher prevalence of genetic or underlying familial factors that contribute to faster cancer progression, bypassing the traditional adenoma-carcinoma sequence, which can take up to 15 years to develop (Muller et al. 2021). Interestingly, observational studies have shown that, despite presenting at advanced stages, younger CRC patients exhibit higher survival rates compared to older patients (Di Leo et al. 2021). One plausible explanation for this discrepancy is that EOCRC may behave differently from LOCRC in several ways. For instance, younger patients might have a better response to treatment regimens and greater physiological reserves, which could contribute to their improved survival outcomes (REACCT Collaborative et al. 2021).
Furthermore, our study found that tumor grading is an independent prognostic factor for worse OS among all individuals. This linkage has been reported previously (REACCT Collaborative et al. 2021). However, evidence on age-related differences suggests no clear association. EOCRC often presents with poorly differentiated tumours and non-adenocarcinoma not otherwise specified (NOS) histology (e.g., signet-ring cell, mucinous), which are associated with a more treatment-resistant disease and higher rates of local and distant recurrences (REACCT Collaborative et al. 2021). Despite this, younger patients are more likely to receive aggressive surgical and systemic therapies earlier and with longer duration, despite the increased incidence of toxic side effects (Done and Fang 2021; Dharwadkar et al. 2022).
Our study highlights the role of younger age as a prognostic factor for OS in CRC patients. In our sample, patients with EOCRC were approximately 37% less likely to die from any cause within the first five years compared to those with LOCRC. After adjusting for tumor characteristics and staging, this increased to 52%. Supporting our findings, researchers reported that patients aged 50–74 and ≥ 75 years had a significantly higher risk of death (HR: 1.24; 95% CI: 1.02–1.51 and HR: 3.02; 95% CI: 2.42–3.78, respectively) compared to younger adults (< 50 years) (Aguiar-Junior et al. 2020). Furthermore, in Colombia, three studies have concluded that younger CRC patients experience better survival outcomes than older CRC patients. A population-based study conducted in Manizales, Colombia found that patients > 75 years old had lower CRC-specific survival than adults < 50 years of age (HR: 1.97, 95%CI: 1.44–2.69) (Guzmán-Gallego et al. 2023). Similar results were found in CRC patients from Cali, Colombia, as older persons (≥ 70 years) had around a 145% increment in their risk of dying from CRC than younger individuals (< 50 years) (HR: 2.45, standard error: 0.23, p = 0.00) (Cortés et al. 2014). Moreover, another study reported that adults with CRC in Pasto, Colombia aged 35–54 years were 60% less likely to die from CRC than older (≥ 55 years) individuals (HR: 0.404, 95%CI: 0.171–0.953) (Jurado-Fajardo et al. 2011).
CRC survival can be influenced by numerous factors that affect disease outcomes at the individual level. These factors range from body weight (Jayasekara et al. 2018) and race/ethnicity (Acuna-Villaorduna et al. 2021) to even socioeconomic status (Zhang et al. 2017). Lifestyle choices such as diet, physical activity, and smoking habits also play a crucial role (Jayasekara et al. 2018). Access to quality healthcare services are significant determinants as well (Muller et al. 2021). Additionally, psychological factors, including stress and mental disorders, can impact survival rates too (Lloyd et al. 2019). Therefore, understanding the interplay of these diverse elements is essential for interpreting studies’ findings and developing evidence-based comprehensive and effective treatment plans tailored to individual patient needs, regardless of age.
This study has some limitations. First, the data source for the survival analyses could represent a bias as it is possible that health insurance companies did not update the required information weekly as mandated by the government. And second, the database used for the vital status review includes records only for persons affiliated through two types of health insurance companies (public/subsidized and private/contributive), excluding individuals with other types of affiliations. Nevertheless, some strengths can be noted. To the best of our knowledge, this is the first study conducted in the city of Medellín, Colombia that compared survival outcomes between EOCRC and LOCRC and some related prognostic factors. Additionally, the large sample used in this study adds to the statistical significance of our findings.