Patients with Early-Onset Colorectal Cancer Have an Increased Risk of Second Primary Malignancy

Focusing on colorectal cancer in young adults (Review)

Colorectal cancer (CRC) ranks as the third leading cause of cancer-related mortality worldwide. Recent years have witnessed an increase in the incidence of CRC among adults <50 years old on a global scale. The increased incidence is associated with several modifiable risk factors, including obesity, type II diabetes, physical inactivity and frequent antibiotic use. In younger individuals, haematochezia and abdominal pain are the most common symptoms, predominantly affecting the left-side colon. While certain cases of early-onset CRC (eoCRC) are associated with a genetic predisposition, the majority result from sporadic mutations in the genes APC, KRAS, BRAF and TP53, which trigger uncontrolled cell proliferation and tumour formation. Colorectal carcinogenesis involves three major pathways: The chromosomal instability (CIN), microsatellite instability and CpG island methylator phenotype pathways. Dysregulation of the CIN pathway accounts for 85% of sporadic cases of eoCRC. Notably, eoCRC exhibits a distinctive molecular profile, characterized by a decreased prevalence of BRAF mutations, an increased prevalence of KRAS mutations and LINE-1 hypomethylation, and involvement of the Microsatellite and Chromosomal Stable pathway. Prevention strategies for eoCRC primarily centre on lifestyle modifications and the development of screening programs targeting younger populations. Further exploration into the molecular mechanisms involved in the identification of novel risk factors associated with eoCRC is imperative. These efforts, in conjunction with the development of specific screening strategies, hold the potential to reduce morbidity and mortality in the future.

Second primary cancer among 217702 colorectal cancer survivors: An analysis of national German cancer registry data

With improvements in survival after colorectal cancer (CRC), more survivors are at risk of developing a second cancer, particularly in younger populations where CRC incidence is increasing. We estimated the incidence of second primary cancer (SPC) in CRC survivors and its potential risk factors. We identified CRC cases diagnosed between 1990 and 2011 and SPCs until 2013 from nine German cancer registries. Standardized incidence ratios (SIR) and absolute excess risk (AER) per 10 000 person-years were calculated and were stratified by index site: colon cancer (CC) and rectal cancer (RC), age and sex. Cox regression assessed potential SPC risk factors, including primary tumor-related therapy considering death as a competing risk. We included 217 202 primary CRC cases. SPC occurred in 18 751 CRC survivors (8.6%; median age: 69 years). Risk of cancer was significantly higher in CRC survivors than in the general population (SIR males 1.14, 95% confidence interval [CI] 1.12-1.17, AER = 24.7; SIR females 1.20, 95% CI 1.17-1.23, AER = 22.8). Increased risks of SPCs were observed for the digestive system, urinary system and female and male reproductive organs. CRC incidence increased in younger persons (<50 years) and SPC incidence was 4-fold in this group (SIR males 4.51, 95% CI 4.04-5.01, AER = 64.2; SIR females 4.03, 95% CI 3.62-4.48, AER = 77.0). Primary tumor-related factors associated with SPC risk were right-sided cancer and smaller primary tumor size. Treatment and risk of SPC differed for CC (no effect) and RC (lower risk after chemotherapy). CRC survivors have excess risk of developing SPC, with particular characteristics that could guide targeted surveillance.

Correlation between lymphoma and second primary malignant tumor

Although studies have investigated the risk of second primary malignancies (SPMs) associated with lymphoma of various sites, limited studies have investigated risk of lymphoma with different SPMs and risk factors related to different SPMs. We conducted a retrospective cohort study to evaluate the cumulative incidence and risk factors of different secondary SPMs in patients previously diagnosed as lymphoma, and to compare the survival rates of SPMs and primary malignant tumors. Retrospective analysis was performed on data obtained from Surveillance, Epidemiology, and End Results database. Patients with an initial primary malignancy diagnosis of lymphoma between 2000 and 2019 were included in the study. The statistical analysis was conducted from March 2022 to January 2023. The development of an SPM defined as any type of malignant tumor 292,210 patients remained in final cohort, including 35,220 patients with secondary primary malignant tumor. The cumulative incidence of SPMs during 20 years of follow-up is 1.95% in combined respiratory system, 0.14% in central nervous system, is 0.82% hepatobiliary pancreatic system, is 1.31% in urinary system, is 1.92% digestive tract. Multivariate competitive risk model analysis showed that Different characteristics of lymphoma patients were associated with secondary different types of SPMS. The risk of secondary SPMs in lymphoma patients after radiotherapy and chemotherapy varies with the change of diagnosis time, diagnosis age and incubation period. Propensity score matching and Kaplan-Meier analysis showed that the survival rate of secondary tumor was significantly lower than that of matched primary malignant tumor. This study reminds us to consider the possibility of SPMs in the initial treatment of lymphoma patients, and develop a follow-up plan according to the characteristics of patients to reduce the risk of SPMs. Occurring more than 6 months after the diagnosis of lymphoma. The cumulative incidence of SPMs was estimated by Fine-Gray competing risk regression. Poisson regression was used to evaluate the therapeutic factors associated risk for SPMs in patients undergoing radiotherapy or chemotherapy. The Kaplan-Meier method was used to assess the survival outcomes of patients with SPMs.

Incidence and risk outcomes of second primary malignancy of patients with post-operative colorectal cancer

BACKGROUND AND AIMS

This study aimed to investigate the incidence and the risk factors of incidence for second primary malignancies (SPMs) onset among survivors diagnosed with colorectal cancer (CRC).

METHODS

A large population-based cohort study was performed. Data of patients diagnosed with CRC was identified and extracted from 8 cancer registries of Surveillance, Epidemiology, and End Results database from January 1990 to December 2017. The outcome of interest was percentage and common sites of SPM onset after primary CRC diagnosis. The cumulative incidence and standardize incidence rates (SIRs) were also reported. Afterwards, we estimated sub-distribution hazards ratios (SHRs) and relative risks (RRs) for SPM occurrence using multivariable competing-risk and Poisson regression models, respectively.

RESULTS

A total of 152,402 patients with CRC were included to analyze. Overall, 23,816 patients of all CRC survivors (15.6%) were reported SPM occurrence. The highest proportion of SPMs development after primary CRC diagnosis was second CRC, followed by lung and bronchus cancer among all survivors. Also, CRC survivors were more susceptible to develop second gastrointestinal cancers (GICs). Besides, pelvic cancers were analyzed with a relative high proportion among patients who received RT in comparison to those without RT. The cumulative incidence of all SPMs onset was 22.16% (95% CI: 21.82-22.49%) after near 30-year follow-up. Several factors including older age, male, married status, and localized stage of CRC were related to the high risk of SPMs onset. In treatment-specific analyses, RT was related to a higher cumulative incidence of SPMs occurrence (all SPMs: 14.08% vs. 8.72%; GICs: 2.67% vs. 2.04%; CRC: 1.01% vs. 1.57%; all p < 0.01). Furthermore, the increased risk of SPMs onset was found among patients who received RT than patients within the NRT group (SHR: 1.50, 95% CI: 1.32-1.71), p < 0.01; RR: 1.61, 95% CI: 1.45-1.79, p < 0.01).

CONCLUSION

The present study described the incidence pattern of SPM among CRC survivors and identified the risk factors of the SPM onset. RT treatment for patients diagnosed with CRC may increase the risk of SPMs occurrence. The findings suggest the need for long-term follow-up surveillance for these patients.

A Proposed Link Between Acute Thymic Involution and Late Adverse Effects of Chemotherapy

Epidemiologic data suggest that cancer survivors tend to develop a protuberant number of adverse late effects, including second primary malignancies (SPM), as a result of cytotoxic chemotherapy. Besides the genotoxic potential of these drugs that directly inflict mutational burden on genomic DNA, the precise mechanisms contributing to SPM development are poorly understood. Cancer is nowadays perceived as a complex process that goes beyond the concept of genetic disease and includes tumor cell interactions with complex stromal and immune cell microenvironments. The cancer immunoediting theory offers an explanation for the development of nascent neoplastic cells. Briefly, the theory suggests that newly emerging tumor cells are mostly eliminated by an effective tissue immunosurveillance, but certain tumor variants may occasionally escape innate and adaptive mechanisms of immunological destruction, entering an equilibrium phase, where immunologic tumor cell death "equals" new tumor cell birth. Subsequent microenvironmental pressures and accumulation of helpful mutations in certain variants may lead to escape from the equilibrium phase, and eventually cause an overt neoplasm. Cancer immunoediting functions as a dedicated sentinel under the auspice of a highly competent immune system. This perspective offers the fresh insight that chemotherapy-induced thymic involution, which is characterized by the extensive obliteration of the sensitive thymic epithelial cell (TEC) compartment, can cause long-term defects in thymopoiesis and in establishment of diverse T cell receptor repertoires and peripheral T cell pools of cancer survivors. Such delayed recovery of T cell adaptive immunity may result in prolonged hijacking of the cancer immunoediting mechanisms, and lead to development of persistent and mortal infections, inflammatory disorders, organ-specific autoimmunity lesions, and SPMs. Acknowledging that chemotherapy-induced thymic involution is a potential risk factor for the emergence of SPM demarcates new avenues for the rationalized development of pharmacologic interventions to promote thymic regeneration in patients receiving cytoreductive chemotherapies.

Epidemiology and biology of early onset colorectal cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related mortality in men or women in the United States. Average-risk screening that begins at age 50 years has reduced incidence and mortality of CRC in those over 50 years of age, whereas CRC incidence in those under age 50 years (early onset colorectal cancer (eoCRC)) has recently and dramatically increased. In this review, we summarize the recent literature including risk factors for eoCRC, differences in clinicopathologic presentation and outcomes in eoCRC, and emerging evidence regarding the molecular pathways that are altered in eoCRC compared to later onset CRC (loCRC). Epidemiologic studies of eoCRC show predominance in distal colon and rectum, and association with several modifiable risk factors, including diabetes, obesity, diet, sedentary time, alcohol consumption and smoking. Data regarding potential risk factors of prior antibiotic exposure and microbiome alterations or direct carcinogen exposure are still emerging. Aggressive clinicopathologic features of eoCRC at presentation may be due to delay in diagnosis or more aggressive tumor biology. EoCRC outcomes are similar to loCRC when matched for stage, but overall mortality is greater due to higher frequency of advanced disease at a younger presentation, with more life-years lost. There are only few molecular evaluations of eoCRC to date, with findings of potential increase in TP53 and CTNNB1 somatic mutation and decrease in APC, KRAS and BRAF somatic mutation, compared to loCRC. Other findings include LINE-1 hypomethylation, absence of microsatellite instability (MSI-H), presence of chromosomal instability (CIN) or microsatellite and chromosomal stability (MACS). These studies are only now emerging and have not yet identified a specific molecular signature defining eoCRC. Further research evaluating genetic and molecular differences as well as environmental triggers for eoCRCs should provide a clearer understanding to inform targeted screening for pre-symptomatic at-risk younger individuals.