Colorectal carcinoma in young adults: a retrospective study on Indian patients: 2000-2008

Clinical profile of 1208 newly diagnosed colorectal cancer patients in Tamil Nadu-A multi-centric survey

BACKGROUND

An increasing incidence of colorectal cancer (CRC) is being reported in developing countries, including India. Most Indian studies on CRC are retrospective and single-centered. The present study is an attempt to understand the current clinical profile and stage of newly diagnosed CRCs across multiple centers in Tamil Nadu, India.

METHODS

A multi-centric observational survey was conducted between September 1, 2021, and August 31, 2022, under the aegis of the Indian Society of Gastroenterology - Tamil Nadu chapter. Patients 18 years of age and older with a recent diagnosis of CRC fulfilling the inclusion criteria were prospectively recruited at the participating centers. Their demographic, clinical, biochemical, endoscopic, histopathologic, radiologic and risk factor details were systematically collected and analyzed.

RESULTS

Across 23 centers in Tamil Nadu, 1208 patients were recruited. The male:female ratio was 1.49:1, while mean (SD) age was 57.7 (13.5) years. A majority (81.9%) were Tamils and 78.5% belonged to lower socioeconomic classes. The predominant symptoms were hematochezia (30.2%) and a change in bowel habits (27.5%). The most common locations were the rectum (34.3%) and rectosigmoid (15.1%). Synchronous CRCs were seen in 3.3% and synchronous colorectal polyps in 12.8%. Predisposing factors for CRC were seen in 2%. A past history of any cancer among CRC patients was obtained in 3.1% and a family history of any cancer was found in 7.6%. Patients who were either overweight or obese constituted 46.4% of the study population. At presentation, the predominant stages were stage III (44.7%) and stage IV (20.8%).

CONCLUSIONS

A majority of patients with newly diagnosed CRC in Tamil Nadu belonged to the lower socioeconomic classes. About 60% had CRCs located within the reach of the flexible sigmoidoscope. Two-thirds of the patients exceeded stage II disease at presentation.

TRIAL REGISTRATION

Not applicable.

Clinico-epidemiological profile and treatment outcome in adolescents and young patients of rectal cancer attending a tertiary cancer center

INTRODUCTION

The incidence of colorectal cancer in young adults is on an increasing trend. It is observed that this subgroup of patients has an aggressive disease and carries a poorer prognosis compared to its older counterpart. This study aimed to analyze the incidence, treatment outcome, and prognostic factors in adolescents and young adults with rectal cancer attending a tertiary cancer center in North India.

MATERIALS AND METHODS

We retrospectively analyzed 50 patients of histologically proven rectal cancer, aged up to 30 years, treated at our center between 2015 and 2019. The clinical, demographic, and pathological parameters were studied in all these patients. Kaplan-Meier survival analysis was used to find out survival. Univariate analysis was performed to assess prognostic factors.

RESULTS

The incidence was 26.4% at our center with a median age of 28 years. Bleeding per rectum was the commonest complaint. Most of them had signet ring cell histology (26%). The median overall survival was 16 months. Survival was significantly better in patients having bleeding per rectum as an initial complaint (P = 0.009), absence of lymphovascular invasion (LVI) (P = 0.005), and perineural invasion (PNI) (P = 0.002), who received complete planned treatment compared to patients who could not receive either of the modality (P < 0.001). Patients who did not receive radiotherapy (RT) had the worst outcomes compared to those who received RT in any form. RT dose of 50.4 Gy was found to be superior as compared to other schedules. There was no significant difference in survival with gender, tumor stage, grade, type of surgery, or chemotherapy regimen.

CONCLUSION

The majority of patients presented in an advanced stage. Therefore, bleeding per rectum should be properly and timely investigated in all these young patients. Early detection and complete treatment are paramount to improving the outcome.

Unraveling anticancer potential of a novel serine protease inhibitor from marine yeast Candida parapsilosis ABS1 against colorectal and breast cancer cells

The study was planned to isolate a serine protease inhibitor compound with anticancer potential against colorectal and breast cancer cells from marine yeast. Protease enzymes play a crucial role in the mechanism of life-threatening diseases like cancer, malaria and AIDS. Hence, blocking these enzymes with potential inhibitors can be an efficient approach in drug therapy for these diseases. A total of 12 marine yeast isolates, recovered from mangrove swamps of Sundarbans, India, showed inhibition activity against trypsin. The yeast isolate ABS1 showed highest inhibition activity (89%). The optimum conditions for protease inhibitor production were found to be glucose, ammonium phosphate, pH 7.0, 30 °C and 2 M NaCl. The PI protein from yeast isolate ABS1 was purified using ethyl acetate extraction and anion exchange chromatography. The purified protein was characterized using denaturing SDS-PAGE, Liquid Chromatography Electrospray Ionization Mass Spectrometry (LC-ESI-MS), Reverse Phase High Pressure Liquid Chromatography (RP-HPLC) and Fourier Transform Infra-red Spectroscopy (FTIR) analysis. The intact molecular weight of the PI protein was determined to be 25.584 kDa. The PI protein was further studied for in vitro anticancer activities. The IC₅₀ value for MTT cell proliferation assay was found to be 43 µg/ml against colorectal cancer HCT15 cells and 48 µg/ml against breast cancer MCF7 cells. Hoechst staining, DAPI staining and DNA fragmentation assay were performed to check the apoptotic cells. The marine yeast was identified as Candida parapsilosis ABS1 (Accession No. MH782231) using 18s rRNA sequencing.

Molecular genetics of early-onset colorectal cancer

Early-onset colorectal cancer (EOCRC) has been rising in global prevalence and incidence over the past several decades. Environmental influences, including generational lifestyle changes and rising obesity, contribute to these increased rates. While the rise in EOCRC is best documented in western countries, it is seen throughout the world, although EOCRC may have distinct genetic mutations in patients of different ethnic backgrounds. Pathological and molecular characterizations show that EOCRC has a distinct presentation compared with later-onset colorectal cancer (LOCRC). Recent studies have identified DNA, RNA, and protein-level alterations unique to EOCRC, revealing much-needed biomarkers and potential novel therapeutic targets. Many molecular EOCRC studies have been performed with Caucasian and Asian EOCRC cohorts, however, studies of other ethnic backgrounds are limited. In addition, certain molecular characterizations that have been conducted for LOCRC have not yet been repeated in EOCRC, including high-throughput analyses of histone modifications, mRNA splicing, and proteomics on large cohorts. We propose that the complex relationship between cancer and aging should be considered when studying the molecular underpinnings of EOCRC. In this review, we summarize current EOCRC literature, focusing on sporadic molecular alterations in tumors, and their clinical implications. We conclude by discussing current challenges and future directions of EOCRC research efforts.

Analysing 11 years of incidence trends, clinicopathological characteristics, and forecasts of colorectal cancer in young and old patients: a retrospective cross-sectional study in an Indonesian national referral hospital

OBJECTIVE

To obtain annual incidence trends, understand clinicopathological characteristics, and forecast the future burden of colorectal cancer (CRC) in Indonesia.

DESIGN

11-year retrospective cross-sectional study.

SETTING

A national referral hospital in Jakarta, Indonesia.

PARTICIPANTS

Data from 1584 eligible cases were recorded for trends and forecasting analyses; 433 samples were analysed to determine clinicopathological differences between young (<50 years) and old (≥50 years) patients.

METHODS

Trend analyses were done using Joinpoint software, expressed in annual percentage change (APC), and a regression analysis was executed to generate a forecasting model. Patients' characteristics were compared using χ2 or non-parametric tests.

MAIN OUTCOMES

Analysis of trends, forecasting model, and clinicopathological features between the age groups.

RESULTS

A significant increase in APC was observed among old patients (+2.38%) for CRC cases. Colon cancer increased remarkably (+9.24%) among young patients; rectal cancer trends were either stable or declining. The trend for right-sided CRC increased in the general population (+6.52%) and old patients (+6.57%), while the trend for left-sided CRC was stable. These cases are expected to be a significant health burden within the next 10 years. Patients had a mean age of 53.17±13.94, 38.1% were young, and the sex ratio was 1.21. Prominent characteristics were left-sided CRC, tumour size ≥5 cm, exophytic growth, adenocarcinoma, histologically low grade, pT3, pN0, inadequately dissected lymph nodes (LNs), LN ratio <0.05, no distant metastasis, early-stage cancer, no lymphovascular invasion, and no perineural invasion (PNI). Distinct features between young and old patients were found in the histological subtype, number of dissected LN, and PNI of the tumour.

CONCLUSIONS

Epidemiological trends and forecasting analyses of CRC cases in Indonesian patients showed an enormous increase in colon cancer in young patients, a particularly concerning trend. Additionally, young patients exhibited particular clinicopathological characteristics that contributed to disease severity.

Worrisome Trends in Young-Onset Colorectal Cancer: Now Is the Time for Action

Colorectal cancer (CRC) in the young adult population is of increasing incidence and concern. Since 1994, CRC incidence in individuals younger than 50 years has been increasing by 2% per year. The surge of CRC incidence in young adults is particularly alarming as the overall CRC frequency has been decreasing. Young-onset CRCs are characterized by more advanced stage at diagnosis, poorer cell differentiation, higher prevalence of signet ring cell histology, and left-colon sided location of the primary tumor. Genetic predisposition and heritable syndromes contribute to this trend, but perhaps more concerning is the majority of new diagnoses that involve no traceable genetic risk factors are sporadic. This review provides a summary of key aspects related to colorectal cancer in young adults, including epidemiology, etiology, genetics, clinical difficulties, early diagnosis, and prevention with emphasis on screening age.

Clinicopathological patterns and survival outcomes of colorectal cancer among young adults in Malaysia: an institutional cohort study

INTRODUCTION

This study aimed to investigate the clinicopathological patterns and survival outcomes of young-onset colorectal cancer (CRC) in Malaysia.

METHODS

The study consisted of 206 patients with young-onset CRC (age < 50 years at diagnosis) and 1,921 patients with late-onset CRC (age ≥ 50 years at diagnosis) diagnosed during 2002-2016. The clinicopathological characteristics of patients with young-onset CRC were compared with those of patients with late-onset CRC during 2009-2013. Kaplan-Meier survival analysis was performed to determine the overall survival (OS) and disease-specific survival (DSS) in these patients.

RESULTS

The overall proportion of young-onset CRC was 10.7%. Mean age for young-onset CRC was 39.5 ± 7.4 years, with male-to-female ratio of 1.2:1.0. There were more Malay patients with young-onset CRC than late-onset CRC (44.0% vs. 19.9%, p = 0.004). Most CRC were diagnosed at advanced stage in both groups. However, young-onset CRC showed more aggressive tumour characteristics, such as poorer differentiation and mucinous subtype. Despite such differences, OS and DSS in both groups were similar (five-year OS for young-onset CRC vs. late-onset CRC: 44.2% vs. 49.0%, p = 0.40; five-year DSS for young-onset CRC vs. late-onset CRC: 48.8% vs. 57.6%, p = 0.53; mean survival of young-onset CRC vs. late-onset CRC: 4.9 years vs. 5.4 years, p = 0.15). Advanced stage at diagnosis and treatment modality were independent prognostic factors.

CONCLUSION

The unique ethnic and histological differences between patients with young- and late-onset CRC suggest that young-onset CRC may represent a distinct entity. However, despite such differences, prognosis between both groups were equivalent.

Clinical characteristics and survival profile of young versus old colorectal cancer patients at a tertiary cancer center in North India over a period of 5 years

Background

Colorectal cancer (CRC) is mostly considered a disease of the elderly. But the rate is increasing among young adults and is associated with different clinical patterns. The objective was to study the frequency of CRC in young patients and compare the clinicopathological profile and survival with the older cohort.

Methods

Five-year (2012-2016) data of the 912 consecutive CRC cases treated at the center were analyzed. Clinical and histopathological characteristics were compared in young (≤40) and older (>40) patients. Descriptive statistics were used for data presentation. Categorical data were compared by the Chi-square test; survival analyses were performed by Kaplan-Meier method.

Results

In total, 231 (25.3%) and 681 (74.7%) cases were in the young and older age groups, respectively. Male predominance was noted. Young patients presented predominantly in stage III (46%). Majority of the young patients harbored left-sided tumors (75.8% vs 63.7% in old patients, P = 0.001) and rectum was the favored site in young patients (53.7% vs 37%; P < 0.001). Poorly differentiated adenocarcinoma was more common in the young age group (46.88% vs 24.16% in old patients, P < 0.001), also signet-ring cell morphology occurred more often in young patients (11.7% vs 4%, P < 0.001). Survival was inferior in the patients presenting at an advanced stage or with adverse histology or poor tumor grade. However, stage-specific survival showed no significant difference between both groups.

Conclusion

This study shows that though young CRC patients present with higher stage, aggressive morphology, and predominantly rectal localization, the overall survival and stage-specific survival did not differ significantly from the older patients.

Systemic chemotherapy and short-course radiation in metastatic rectal cancers: A feasible paradigm in unresectable and potentially resectable cancers

Background:

The optimal use and sequencing of short-course radiotherapy (SCRT) in metastatic rectal cancers (mRCs) are not well established.

Materials and Methods:

We retrospectively reviewed the records of mRC patients receiving SCRT followed by palliative chemotherapy between January 1, 2013, and December 31, 2016, in Tata Memorial Hospital. Patients were classified as having “potentially resectable” disease (local and metastatic) or “unresectable” disease at baseline based on prespecified criteria.

Results:

A total of 105 consecutive patients were available for analysis. The median age of patients was 48 years (range: 16–62 years), and 57.1% were male patients. Signet ring histology was seen in 13.3% of patients. The most common site of metastases was liver limited (29.5%), nonloco-regional nodes (12.4%), and lung limited metastases (9.5%). Chemotherapeutic regimens administered were capecitabine-oxaliplatin (70.5%), modified 5 fluorouracil (5 FU)-leucovorin-irinotecan-oxaliplatin (10.5%), and modified 5 FU-leucovorin-irinotecan (8.6%). Targeted therapy accompanying chemotherapy was administered in 27.6% of patients. About 42.1% of patients with potentially resectable disease and 11.1% with the unresectable disease at baseline underwent curative-intent resection of the primary and address of metastatic sites. With a median follow-up 18.2 months, median overall survival (OS) was 15.7 months (95% confidence interval: 10.42–20.99). Patients classified as potentially resectable had a median OS of 32.62 months while patients initially classified as unresectable had a median OS of 13.04 months (P = 0.016). The presence of signet ring morphology predicted for inferior mOS (P = 0.021).

Conclusions:

SCRT followed by systemic therapy in mRC is a feasible, efficacious paradigm for maximizing palliation, and achieving objective responses. The classification of patients based on resectability was predictive of actual resection rates as well as outcomes. Signet ring mRC show inferior outcomes in this cohort of patients.

The association of age with the clinicopathological characteristics and prognosis of colorectal cancer: a UK single-centre retrospective study

INTRODUCTION

Colorectal cancer (CRC) is uncommon in patients under the age of 40 years and its association with poor histological features and survival is uncertain. This study aimed to evaluate age-related differences in clinicopathological features and prognosis in patients diagnosed with CRC.

METHOD

A single-centre retrospective review of all patients diagnosed with CRC between 2004 and 2013 was performed. Patients were stratified into three age groups: (1) 18-40 years, (2) 41-60 years and (3)> 60 years. Clinicopathological characteristics and outcomes were compared between the three groups.

RESULTS

A total of 1328 patients were included, of whom 57.2% were men. There were 28 (2.1%) patients in group 1, 287 (21.6%) in group 2 and 1013 (76.3%) in group 3. Group 1 had the highest proportion of rectal tumours (57.1% in group 1, 50.2% in group 2 and 31.9% in group 3; P < 0.001). Tumour histology and disease stage were comparable between the groups. Group 1 had significantly worse disease-free survival (DFS) than the two older groups (44%, 78% and 77%, respectively; P = 0.022). Multivariate analysis demonstrated that age was not an independent prognostic factor whereas Stage III disease [hazard ratio (HR) 4.42; 95% CI 2.81-6.94; P < 0.001] and neoadjuvant chemotherapy (HR 1.65; 95% CI 1.06-2.58; P = 0.026) were associated with increased risk of recurrence.

CONCLUSION

Patients under the age of 40 are more likely to present with rectal cancer and have comparable histological features than the older groups. Despite higher rates of adjuvant and neoadjuvant treatment, the young group were found to have worse DFS.

CDH1 gene mutation in early-onset, colorectal signet-ring cell carcinoma

AIM

Colorectal signet-ring cell carcinomas (SRCC) are highly malignant tumours with poor prognosis that disproportionately affect younger patients. There is growing evidence of a unique set of molecular features that separate SRCC from conventional colorectal adenocarcinoma. Identification of these distinct features may have diagnostic and prognostic significance for patients and families. CDH1, which encodes E-cadherin, a cell adhesion protein, is commonly mutated in gastric SRCC and our study aimed to identify whether CDH1 mutation was also a common phenomenon in colorectal SRCC.

METHODS

DNA was extracted from formalin-fixed paraffin embedded tumour tissue, the CDH1 gene was analysed by next generation sequencing and the pathogenicity of mutations assessed in silico. Sections cut from the same blocks were immunostained to identify the presence of the E-cadherin protein.

RESULTS

We found 8 CDH1 mutations that meet our inclusion criteria in seven of 11 samples. Of these, five (from four patients), were likely to be germline mutations. E-cadherin staining was absent or markedly reduced in all of the seven samples with CDH1 mutation.

CONCLUSION

Our finding of CDH1 mutations in a proportion of signet-ring cell carcinomas and associated reduction in E-cadherin in these tumours supports previous findings of a role for mutation of this gene in the development of this disease. In addition, the finding of likely germline mutations suggests that a subset of these tumours may be familial. Loss of E-cadherin staining in the absence of CDH1 mutations however also suggests a role for environmental factors in a subset of these tumours.

Is colorectal cancer a more aggressive disease in young patients? A population-based study from the Czech Republic

INTRODUCTION

The incidence of colorectal cancer in young patients is increasing. The goal of this study was to investigate whether clinicopathological features and survival differed between young, middle-aged and elderly patients.

METHODS

The Czech National Cancer Registry was searched to identify all cases of colorectal cancer between 1982 and 2014. Three subgroups of patients were created: young patients, defined as being between 18 and 40 years of age, middle-aged patients, defined as being between 41 and 74 years of age, and elderly patients, defined as being over the age of 75 years.

RESULTS

A total of 192,241 patients diagnosed with colorectal cancer between the years 1982 and 2014 were included in the study. Out of these, 3,287 patients (1.7%) were between 18 and 40 years of age, 134,139 patients (69.8%) were between 41 and 74 years of age and 54,815 patients (28.5%) were 75 years of age or older. The young patients had a higher incidence of mucinous adenocarcinoma and signet ring cell carcinoma, more advanced disease and more rectal tumours than elderly patients. Nonetheless, young patients received treatment more frequently and had better cancer-specific survival than the older patients.

CONCLUSION

The better prognosis in young patients is presumably due to their better physiological reserve and lower incidence of comorbidities. Efforts should be made in younger patients to diagnose early and treat aggressively.

Microsatellite instability in young patients with mucinous colorectal cancers - characterization using molecular testing, immunohistochemistry, and histological features

CONTEXT

The incidence of colorectal cancers (CRCs) in young Indian patients is higher than the international average. CRCs in young patients are commonly of mucinous type and show microsatellite instability (MSI).

AIMS

To ascertain the MSI status of mucinous CRCs in patients ≤40 years of age by molecular testing and to correlate this with immunohistochemical (IHC) analysis and tumor histology.

SUBJECTS AND METHODS

Archived formalin-fixed paraffin embedded tissue blocks of 30 young mucinous CRC patients were retrieved. MSI testing was done using two mononucleotide markers - BAT26 and NR24. IHC analysis was done using MLH1, MSH2, and MSH6. Histological features of all cases were studied. Data were analyzed using the SPSS software and the Pearson's chi-square test and Fisher's exact test.

RESULTS

Eight out of 30 cases (26.7%) showed MSI by molecular testing. IHC identified seven of these cases. Histological features showing a statistically significant association with MSI were the presence of a well-differentiated adenocarcinoma component (P = 0.003), peritumoral lymphocytes (P = 0.002) and tumor budding (P = 0.021).

CONCLUSION

The detection of defective mismatch repair (MMR) proteins using IHC for MLH1, MSH2, and MSH6 and molecular testing using BAT26 and NR24 appears to be a good protocol to detect CRCs with MSI. Histology could be useful in identifying cases that require screening for presence of MMR protein defects.

Adjuvant chemotherapy in stage II-III operated colon cancer patients from a nontrial cohort in a low colon cancer prevalence country with predominant use of modified CAPOX

BACKGROUND

Data regarding the practice of adjuvant chemotherapy, specifically with modified CAPOX, and survival outcomes in operated colon cancer patients from a nontrial cohort in a lower-middle income and low prevalence nation like India is scarce.

MATERIALS AND METHODS

Patients who underwent upfront curative resection for colon cancer from January 2013 to December 2016 were analyzed for baseline variables and outcomes.

RESULTS

A total of 491 patients underwent curative resection in the predefined time period. The median age of the patients was 53 years (range: 17-87). Patients with Stage I, Stage II, and Stage III disease comprised 7.9%, 44.8%, and 45.4% of the entire cohort, respectively. Patients with Stage I cancer were observed. Adjuvant chemotherapy was planned for 384 patients (78.2%), with the doublet regimens (capecitabine-oxaliplatin, or 5-fluorouracil-oxaliplatin) being used commonly (77.6%). Common toxicities were Hand-foot syndrome (Grade 2/3 - 21.4%) and peripheral neuropathy (Grade 2/3 - 20.1%). About 85% of patients receiving monotherapy (capecitabine or 5 fluorouracil) and 81.2% of patients receiving doublet chemotherapy (mCAPOX or modified FOLFOX-7) completed their planned adjuvant treatment. With a median follow-up of 22 months, estimated 3 years event-free survival was 86%, and overall survival (OS) was 93.6%. Stage, younger age (<50 years), underlying cardiovascular abnormalities, need for dose reductions and noncompletion of planned chemotherapy predicted for inferior estimated 3-year OS on multivariate analysis.

CONCLUSIONS

Adjuvant chemotherapy especially with modified CAPOX appears well tolerated in the Indian population and early survival outcomes appear to be comparable to published literature.

Augmented CD133 expression in distal margin correlates with poor prognosis in colorectal cancer

Pathological assessment of excised tumour and surgical margins in colorectal cancer (CRC) play crucial role in prognosis after surgery. Molecular assessment of margins could be more sensitive and informative than conventional histopathological analysis. Considering this view, we evaluated the distal surgical margins for expression of cancer stem cell (CSC) markers. Cellular and molecular assessment of normal, tumour and distal margin tissues were performed by flow cytometry, real-time q-PCR and immuno-histochemical analysis for CRC patients after tumour excision. CRC patients were evaluated for expression of CSC markers in their normal, tumour and distal tissues. Flow cytometry assay revealed CD133 and CD44 enriched cells in distal margin and tumour compared to normal colorectal tissues, which was further confirmed by immunohistochemistry. Most importantly, immunohistochemistry also revealed the enrichment of CSC markers expression in pathologically negative distal margins. Patients with distal margin enriched for CD133 expression showed an increased recurrence rate and decreased disease-free survival. This study proposes that although distal margin seems to be tumour free in conventional histopathological analysis, it could harbour cells enriched for CSC markers. Further CD133 could be a promising molecule to be used in molecular pathology for disease prognosis after surgery in CRC patients.

Clinical Utility of Staging Laparoscopy for Advanced Obstructing Rectal Adenocarcinoma: Emerging Tool

The multimodal treatment for advanced rectal adenocarcinoma mandates accurate preoperative staging with contrast-enhanced computed tomography (CECT) of the thorax, abdomen, and pelvis, and magnetic resonance imaging (MRI) of the pelvis. Unlike gastric cancer, the role of staging laparoscopy (SL) in advanced colorectal cancer has not been evaluated. This study aims to evaluate the clinical value of SL in treatment decision-making for advanced rectal cancer (RC) with near or complete obstructing tumors. Observational review of colorectal database at Tata Memorial Hospital from January 2013 to December 2016 identified 562 patients diagnosed and treated for advanced RC. Of the 562 cases, 48.7% (274) were clinically and radiologically diagnosed of near or complete obstructing advanced RC. Medical records of 34% (94/274) who underwent SL with diversion stoma (DS) were analyzed. In the absence of ascites, extensive peritoneal deposits, and unresectable liver metastases on SL, a curative treatment was offered, which entailed neoadjuvant chemoradiation (NACTRT), whereas the cohort of patients with extensive peritoneal disease received palliative therapy. Of the 94 patients with advanced RC, conventional imaging studies staged 73.5% (69/94) cohort as non-metastatic locally advanced and 26.5% (25/94) had potentially resectable metastatic RC. Pre-therapeutic SL upstaged the disease by 26% (18/69) and 8% (2/25) in locally advanced and potentially resectable metastatic RC cohorts, respectively. Treatment decision changed in 21.2% (20/94) of the patients, and midline laparotomy was thus avoided. In our observational study, SL was found to be a safe and effective staging modality in RC; it detected occult peritoneal disease and prevented midline laparotomy in 21.2% of the cohort, which was of value to determine treatment strategy in patients with advanced RC before initiating NACTRT. SL and laparoscopic-assisted de-functioning stoma were associated with minimal morbidity and led to early initiation of NACTRT.

Early onset sporadic colorectal cancer: Worrisome trends and oncogenic features

Early onset colorectal cancers, defined as arising before 50 years of age, are a growing health hazard in western and eastern countries alike. The incidence of colon and rectal cancers in young individuals is projected to increase by as much as 90% and 140%, respectively, by 2030. Although several known cancer risk factors (e.g. smoking, alcohol, dietary habits) have been investigated, there is no single compelling explanation for this epidemiological trend. While some early onset colorectal cancers have been associated with germline mutations in cancer predisposition genes, genetic syndromes are implicated in only a fraction of these cancers (20%) and do not explain the rising incidence. Colorectal neoplasms develop through microsatellite instability or chromosomal instability pathways, with most of the early onset colorectal cancers exhibiting microsatellite stable phenotypes. Genome-wide hypomethylation is a feature of a subgroup of early onset cancers, which appears to be correlated with chromosomal instability and poor prognosis.

18F-FDG-PET/CT Imaging to Diagnose Septic Emboli and Mycotic Aneurysms in Patients with Endocarditis and Cardiac Device Infections

PURPOSE OF REVIEW

This review analyzes recent studies evaluating the diagnostic value of ¹⁸F-FDG-PET/CT for the detection of peripheral emboli and secondary infectious foci in patients with infective endocarditis and cardiac device infections.

RECENT FINDINGS

Detection of extracardiac septic localizations in patients with infective endocarditis and cardiac device infections is crucial, as it may impact the diagnosis, prognosis, and therapeutic management. Recent literature substantiated the clinical usefulness of ¹⁸F-FDG-PET/CT in this setting. ¹⁸F-FDG-PET/CT has proven its high diagnostic value for the detection of peripheral emboli in patients with infective endocarditis and cardiac device infections, substantially affecting patients' outcome and treatment. A multimodal approach, combining the high sensitivity of ¹⁸F-FDG-PET/CT with morphological imaging seems promising.

Colorectal cancer in the young: a possible role for immune surveillance?

BACKGROUND

Younger patients with colorectal cancer (CRC) generally have better survival in spite of worse clinical and pathological features.

METHODS

Twenty-six patients under 50 years operated for primary CRC were enrolled and matched 1:2:2 according to stage, tumor site and gender with 52 patients from 50 to 70 years and 52 patients over 70 years old.

RESULTS

Patients under 50 years had a significantly longer overall, cancer specific and disease free survival (p = .001, p = .007 and p = .05, respectively). However, they had more frequently lymphovascular invasion (p = .006) and they more frequently developed metachronous CRC at follow-up (p = .03). Nevertheless, preoperative lymphocytes blood count/white blood count (LBC/WBC) ratio inversely correlated with age at operation (rho = -.21, p = .04) and it predicted CRC recurrence with an accuracy of 70%, p < .001 (threshold value LBC/WBC = 0.21%) and better overall, cancer specific and disease free survival (p < .0001 for all). At multivariate analysis, stage and LBC/WBC ratio resulted independent predictors of disease free survival (p = .0001 and p = .01, respectively).

CONCLUSIONS

Patients under 50 years had a significantly longer survival with a higher LBC/WBC ratio. These results could suggest a possible role of immunosurveillance in neoplastic control.

Low prevalence of deficient mismatch repair (dMMR) protein in locally advanced rectal cancers (LARC) and treatment outcomes

Background

The available evidence in locally advanced rectal cancer (LARC) suggests a low prevalence of deficient mismatch repair (dMMR) protein status, approximating 1-3%.

Methods

Patients with LARC who were offered long course chemoradiation (LCRT), as per institution protocol during the period of 1st January 2014 to 31st December 2015 at Tata Memorial Hospital (TMH) in Mumbai were evaluated for outcomes and assessment of MMR status.

Results

A total of 419 patients were evaluated for LARC in TMH, of whom 354 were treated with LCRT. Of these 354 patients, 296 were assessable for MMR status based on tissue adequacy for testing. Three patients (1.01%) has dMMR status, while the remaining 293 patients had proficient MMR status. A total of 240 patients (67.8%) underwent curative intent resections. With a median follow-up of 32 months, estimated 3-year recurrence free survival (RFS) and overall survival (OS) for the resected group was 63.5% and 85.2%, respectively, while 3-year event free survival and OS for the unresected cohort was 15.2% and 15.8%, respectively. Signet ring histology, higher ypT stage, involved margin status post resection, and delays (>1 week) in LCRT were associated with inferior OS on multivariate analysis.

Conclusions

In a large LARC cohort, a majority of tumors had proficient MMR status, suggesting that MSI as a biomarker may have limited applicability in the management of rectal cancers. Signet ring histology, CRM involvement post resection, higher ypT stage and interruptions in LCRT predicted for inferior OS.

Colorectal cancer in patients under the age of 40 years: experience from a tertiary care centre in the Czech Republic

INTRODUCTION

Colorectal cancer (CRC) in young patients is not an uncommon disease. Reports on its behaviour in young patients are conflicting. The aim of this study was to investigate patient and tumour characteristics, treatment and prognosis of this disease.

METHODS

Our study group comprised all patients under the age of 40 years treated with CRC at the Department of Surgery at Motol University Hospital in Prague between the years 2005 and 2015.

RESULTS

Thirty-eight patients under 40 years of age diagnosed with CRC were included in the study. Five patients had Lynch syndrome and six had first-degree relatives with CRC. There were 22 rectal tumours. All but four patients underwent resection of the primary tumour, all patients received chemotherapy and 13 patients received biological therapy. Disease recurrence occurred in 25.8%. Five-year survival was 47.9%. Advanced disease and adverse histological subtypes were identified as poor prognostic factors.

CONCLUSIONS

Colorectal cancer in young patients has a high incidence of predisposing conditions, aggressive histological features and advanced disease. Young patients are of a good state of health and thus should receive aggressive therapy. Clinicians should pay more attention to symptoms of CRC in young patients to be able to initiate early treatment.

Ca2+/nuclear factor of activated T cells signaling is enriched in early-onset rectal tumors devoid of canonical Wnt activation

Our previous extensive analysis revealed a significant proportion of early-onset colorectal tumors from India to be localized to the rectum in younger individuals and devoid of deregulated Wnt/β-catenin signaling. In the current study, we performed a comprehensive genome-wide analysis of clinically well-annotated microsatellite stable early-onset sporadic rectal cancer (EOSRC) samples. Results revealed extensive DNA copy number alterations in rectal tumors in the absence of deregulated Wnt/β-catenin signaling. More importantly, transcriptome profiling revealed a (non-Wnt/β-catenin, non-MSI) genetic signature that could efficiently and specifically identify Wnt- rectal cancer. The genetic signature included a significant representation of genes belonging to Ca²⁺/NFAT signaling pathways that were validated in additional samples. The validated NFAT target genes exhibited significantly higher expression levels than canonical Wnt/β-catenin targets in Wnt- samples, an observation confirmed in other CRC expression data sets as well. We confirmed the validated genes to be transcriptionally regulated by NFATc1 by (a) evaluating their respective transcript levels and (b) performing promoter-luciferase and chromatin immunoprecipitation assays following ectopic expression as well as knockdown of NFATc1 in CRC cells. NFATc1 and its targets RUNX2 and GSN could drive increased migration in CRC cells. Finally, the validated genes were associated with poor survival in the cancer genome atlas CRC expression data set. This study is the first comprehensive molecular characterization of EOSRC that appears to be driven by noncanonical tumorigenesis pathways.

KEY MESSAGES

Early-onset sporadic rectal cancer exhibits DNA gain and loss without Wnt activation. Ca²⁺/NFAT signaling appears to be activated in the absence of Wnt activation. An eight-gene genetic signature distinguishes Wnt+ and Wnt- rectal tumors. NFAT and its target genes regulate tumorigenic properties in CRC cells.

Young Vs Old Colorectal Cancer in Indian Subcontinent: a Tertiary Care Center Experience

This study aims to compare patient, tumor, treatment-related factors and survival between young (<45 years) and old (>45 years) Indian colorectal cancer (CRC) patients. Total 778 patients of CRC were registered at tertiary cancer center in India between 1 August 2013 and 31 July 2014. Patients were followed up for median period of 27.73 months. Data regarding patient, tumor, treatment and survival-related factors were collected. Patients were divided in young (≤45 years) and old (>45 years) age groups. Statistical analysis was done with SPSS software version 23. Young age group patients presented more commonly with poor histology, node-positive disease, and rectal site. Younger age group patients received multiple lines of neoadjuvant treatment. There was no significant overall survival difference in both groups of patients. On stratified stage-wise analysis, no significant overall survival (OS) difference was found between two groups (young vs old-1- and 3-year OS: 85.2 and 61.5% vs 81.5 and 64.5%, respectively; P = 0.881). On univariate analysis, gender, performance status, site, stage, differentiation, TRG, CRM status, signet ring type, and CEA level were significant prognostic factors. In disease-free survival (DFS) analysis, it is found that there is statistically significant difference in DFS (young vs old: 1 and 3 years; 77.6 and 62.8% vs 85.8 and 74.1%, respectively; P value, 0.02), but when OS was analyzed for same group of patient, there was no statistical difference (P = 0.302). This study confirms the high incidence rates of CRC in young Indian patients. There is no OS difference between two age groups. In operated group of patients, there is higher DFS in older patients but no OS advantage at 3 years follow-up. Further long-term follow-up is required to see any OS difference.

Targeted sequencing-based analyses of candidate gene variants in ulcerative colitis-associated colorectal neoplasia

BACKGROUND

Long-standing ulcerative colitis (UC) leading to colorectal cancer (CRC) is one of the most serious and life-threatening consequences acknowledged globally. Ulcerative colitis-associated colorectal carcinogenesis showed distinct molecular alterations when compared with sporadic colorectal carcinoma.

METHODS

Targeted sequencing of 409 genes in tissue samples of 18 long-standing UC subjects at high risk of colorectal carcinoma (UCHR) was performed to identify somatic driver mutations, which may be involved in the molecular changes during the transformation of non-dysplastic mucosa to high-grade dysplasia. Findings from the study are also compared with previously published genome wide and exome sequencing data in inflammatory bowel disease-associated and sporadic colorectal carcinoma.

RESULTS

Next-generation sequencing analysis identified 1107 mutations in 275 genes in UCHR subjects. In addition to TP53 (17%) and KRAS (22%) mutations, recurrent mutations in APC (33%), ACVR2A (61%), ARID1A (44%), RAF1 (39%) and MTOR (61%) were observed in UCHR subjects. In addition, APC, FGFR3, FGFR2 and PIK3CA driver mutations were identified in UCHR subjects. Recurrent mutations in ARID1A (44%), SMARCA4 (17%), MLL2 (44%), MLL3 (67%), SETD2 (17%) and TET2 (50%) genes involved in histone modification and chromatin remodelling were identified in UCHR subjects.

CONCLUSIONS

Our study identifies new oncogenic driver mutations which may be involved in the transition of non-dysplastic cells to dysplastic phenotype in the subjects with long-standing UC with high risk of progression into colorectal neoplasia.

Colorectal cancer-global burden, trends, and geographical variations

BACKGROUND

The aim of this study is to describe the trends and variations in the global burden of colorectal cancer (CRC).

METHODS

Data (2012-2030) relating to CRC was extracted from GLOBOCAN 2012 database and analyzed.

RESULTS

The results of our study demonstrate a rising global burden of colorectal cancer which persists until the year 2035 and likely beyond. The rise in the global burden is not uniform with significant variations influenced by geographic location, socio-economic status, age, and gender. Although the EURO region has the highest burden, Asia as a continent continues to bear the heaviest brunt of the disease. Although the burden of disease is higher in more developed regions, mortality is considerably higher in less developed regions and this gap widens over the next two decades. The disease predominantly affects the male gender across all regions of the world. Age has a complex relation with the burden of CRC and is affected by the cross-influences relating to socio-economic status.

CONCLUSIONS

The results of our study demonstrate a rising global burden of CRC with some unique variations. Knowledge of this data can increase awareness and help strategic targeting of efforts and resources.

High nodal positivity rates even in good clinical responders after chemoradiation of rectal cancer: is organ preservation feasible?

AIM

Local excision (LE) is emerging as a treatment option for rectal cancer responding well to chemoradiation. However, it does not address the mesorectal nodal burden. We aimed to identify the factors influencing nodal positivity and subsequently defined a low-risk group by including only patients at low risk.

METHOD

A single-centre, retrospective database analysis was carried out of patients with radically resected rectal cancer after neoadjuvant chemoradiation.

RESULTS

This study included 524 patients with predominantly low rectal tumours. Nodal positivity among ypT0, T1 and T2 groups was 14.7%, 28% and 30%, respectively. Multivariate analysis with stepwise logistic regression identified the following low-risk features: age ≥ 40 years, nonsignet ring cell carcinoma (SRCC) histology and pathological complete response (pCR). Sixty-nine patients fulfilling all three criteria were analysed and the nodal positivity was found to be 10.1%, which implies that, if these patients had been selected for LE, one in 10 would have had positive mesorectal nodes.

CONCLUSION

Even in patients with low-risk criteria (pCR, non-SRCC histology and age ≥ 40 years), the residual positive nodal disease burden is 10%. Whether this high incidence of residual nodal disease translates into a similar risk of locoregional recurrence if an organ-preservation strategy is adopted is unclear.

Colorectal cancer in the young, many questions, few answers

At a time where the incidence of colorectal cancer, a disease predominantly of developed nations, is showing a decline in those 50 years of age and older, data from the West is showing a rising incidence of this cancer in young individuals. Central to this has been the 75% increase in rectal cancer incidence in the last four decades. Furthermore, predictive data based on mathematical modelling indicates a 124 percent rise in the incidence of rectal cancer by the year 2030 - a statistic that calls for collective global thought and action. While predominance of colorectal cancer (CRC) is likely to be in that part of the large bowel distal to the splenic flexure, which makes flexible sigmoidoscopic examination an ideal screening tool, the cost and benefit of mass screening in young people remain unknown. In countries where the incidence of young CRC is as high as 35% to 50%, the available data do not seem to indicate that the disease in young people is one of high red meat consuming nations only. Improvement in our understanding of genetic pathways in the aetiology of CRC, chiefly of the MSI, CIN and CIMP pathway, supports the notion that up to 30% of CRC is genetic, and may reflect a familial trait or environmentally induced changes. However, a number of other germline and somatic mutations, some of which remain unidentified, may play a role in the genesis of this cancer and stand in the way of a clear understanding of CRC in the young. Clinically, a proportion of young persons with CRC die early after curative surgery, presumably from aggressive tumour biology, compared with the majority in whom survival after operation will remain unchanged for five years or greater. The challenge in the future will be to determine, by genetic fingerprinting or otherwise, those at risk of developing CRC and the determinants of survival in those who develop CRC. Ultimately, prevention and early detection, just like for those over 50 years with CRC, will determine the outcome of CRC in young persons. At present, aside from those with an established familial tendency, there is no consensus on screening young persons who may be at risk. However, increasing awareness of this cancer in the young and the established benefit of prevention in older persons, must be a message that should be communicated with medical students, primary health care personnel and first contact doctors. The latter constitutes a formidable challenge.

Adenocarcinoma of the Rectum-A Composite of Three Different Subtypes With Varying Outcomes?

INTRODUCTION

Adenocarcinoma of the rectum has been classified by the World Health Organization into various histologic subtypes. We analyzed the effect of the histologic subtype (classic, signet ring cell, and mucinous) on the clinical outcomes of patients with rectal cancer. We hypothesized that clinicopathologic outcome measures such as tumor margins, tumor regression grade, recurrence rate, and survival would vary with the histologic subtype.

MATERIALS AND METHODS

We conducted a retrospective analysis of a prospectively maintained database. All patients with stage I-III rectal adenocarcinoma were included.

RESULTS

From May 2010 to August 2013, 273 patients underwent curative resection. Both mucin-secreting variants were more common in younger patients and presented at a more advanced stage. Also, 54% and 48% of those with signet ring cell carcinoma (SRCC) and mucinous adenocarcinoma (MAC) had node-positive disease compared with the rate in the classic variant (30%). Circumferential resection margin positivity was 24% with MAC and 19% with SRCC compared with 4% with the classic variant. Disease-free survival for those with the classic and mucinous variants was 38.5 and 37.4 months, respectively. In contrast, it was 28.6 months in the SRCC group. The overall survival did not differ significantly.

CONCLUSION

Rectal adenocarcinoma presents as a spectrum of disease, with progressively worsening outcomes from classic to MAC to SRCC. These aggressive variants might warrant more aggressive resection. These data from the Indian subcontinent differ from the published data from Western countries.

Colorectal cancer in young patients: is it a distinct clinical entity?

BACKGROUND

The incidence of colorectal cancer in young patients is increasing. It remains unclear if the disease has unique features in this age group.

METHODS

This was a single-center, retrospective cohort study which included patients diagnosed with colorectal cancer at age ≤40 years in 1997-2013 matched 1:2 by year of diagnosis with consecutive colorectal cancer patients diagnosed at age >50 years during the same period. Patients aged 41-50 years were not included in the study, to accentuate potential age-related differences. Clinicopathological characteristics, treatment, and outcome were compared between groups.

RESULTS

The cohort included 330 patients, followed for a median time of 65.9 months (range 4.7-211). Several significant differences were noted. The younger group had a different ethnic composition. They had higher rates of family history of colorectal cancer (p = 0.003), hereditary colorectal cancer syndromes (p < 0.0001), and inflammatory bowel disease (p = 0.007), and a lower rate of polyps (p < 0.0001). They were more likely to present with stage III or IV disease (p = 0.001), angiolymphatic invasion, signet cell ring adenocarcinoma, and rectal tumors (p = 0.02). Younger patients more frequently received treatment. Young patients had a worse estimated 5-year disease-free survival rate (57.6  vs. 70 %, p = 0.039), but this did not retain significance when analyzed by stage (p = 0.092). Estimated 5-year overall survival rates were 59.1 and 62.1 % in the younger and the control group, respectively (p = 0.565).

CONCLUSIONS

Colorectal cancer among young patients may constitute a distinct clinical entity. Further research is needed to validate our findings and define the optimal approach in this population.

Pathological stage significantly predicts survival in colorectal cancer patients: a study from two tertiary care centers in India

SUMMARY

Aims: An increase in incidence of early-onset colorectal cancer (EOCRC) in developing countries, including India, is reported recently; however, systematic analyses of clinico-pathological features and disease prognosis has seldom been undertaken. Materials & methods: We studied clinical data pertaining to 1259 colorectal adenocarcinoma patients from two tertiary cancer centers in south India. Results: Approximately 45% of patients were aged below 50 years and poor grade and late-stage tumors were significantly associated with early disease onset. Although tumor grade and stage significantly influenced disease-free survival independently, significant association between survival and age of onset or tumor location was not detected unlike previous observations. Conclusion: Given the sizeable proportion of EOCRC, implementation of the revised Bethesda guidelines may not be tenable in India. More importantly, the previous observation of EOCRC being significantly associated with poor survival could, in part, be due to a higher proportion of advanced-stage tumors.

Clinical features and outcome of sporadic colorectal carcinoma in young patients: a cross-sectional analysis from a developing country

Background. Early onset colorectal carcinoma (CRC) is rare and has been hypothesized to be a biologically and clinically distinct entity personifying aggressive disease and worse survival. Methods. Data for 131 patients was collected by retrospective chart review. Cox proportional hazard model was used to compute prevalence ratios and 95% confidence intervals. Results. Early onset sporadic CRC accounted for 32% of all CRC treated in the specified time period. The mean age was 33.3 ± 7.9 years and the male to female ratio was 2 : 1. Colon and rectal cancers accounted for 55% and 45% of patients, respectively. 96% of rectal carcinoma patients received appropriate therapy as opposed to 65% of colon cancers. On multivariable analysis, appropriate reception of therapy (PR 4.99; 95% CI, 1.21–20.6) and signet ring morphology (PR 2.40; 95% CI, 1.33–4.32) were significantly associated with rectal cancers as opposed to colon cancer. Kaplan-Meier analysis revealed a trend towards inferior survival for rectal carcinoma 2 years after diagnosis. Conclusion.A high prevalence of early onset CRC was noted in the study. A trend towards inferior survival was seen in patients with rectal cancer. This finding raises the possibility of rectal carcinoma being an aggressive subset of young CRC.

Rectal cancer in young Indians--are these cancers different compared to their older counterparts?

BACKGROUND

The incidence of rectal cancer in young Indians is increasing. Recent evidence suggests a probable existence of noncanonical tumorigenesis pathways in early-onset colorectal cancer patients in India. The aim of the study was to evaluate rectal cancer outcomes in patients ≤40 years with those >40 years.

METHODS

An analysis of a prospective database of surgically treated rectal cancer patients ≤40 years (group 1) and those >40 years (group 2) over 2 years was performed. Clinicopathological features, perioperative outcomes, and disease-free survival (DFS) were analyzed.

RESULTS

Of the 512 patients with colorectal cancer treated surgically, 237 patients (group 1-57 patients; group 2-180 patients) were diagnosed with nonmetastatic rectal adenocarcinoma. Patients in group 1 were more likely to present with locally advanced (stage III) disease (p < 0.005) resulting in a higher proportion of them receiving neoadjuvant chemoradiotherapy (NACT-RT). There was no difference in morbidity and mortality between the two groups. Younger patients had a significantly higher median total and positive lymph node yield (p < 0.003). Patients in group 1 had a significantly lower overall DFS (p < 0.005). Stage-specific DFS also demonstrated a significantly lower trend in stage III patients in group 1.

CONCLUSIONS

Young rectal cancer patients in India tended to present more frequently with locally advanced tumors resulting in a higher proportion being treated with NACT-RT. Stapled rectal anastomoses could be performed safely in young patients even after NACT-RT. The significantly poorer DFS in young Indian patients with stage III disease was a novel finding and merits further investigation into tumor biology.

Changing trends of colorectal carcinoma in Nepalese young adults

INTRODUCTION

Colorectal carcinoma (CRC) is the most common gastrointestinal malignancy in the older population, but it is also quite frequent among young adults in developing countries. The aim of this study was to update the trends of clinicopathological features of CRC in young Nepalese.

METHODS

A retrospective comparative study on the data retrieved from the surgical records of all patients between 20 to 39 years of age with CRC was carried out for periods of 5 years each from 1999 to 2003 (early) and 2004 to 2008 (recent), treated at Tribhuvan University Teaching Hospital, Kathmandu, Nepal.

RESULTS

The number of young adults with CRC increased from 28 to 34. However, the proportion of young patients in both groups was 28% of all CRC patients. The mean ages were 34±4.7 and 31.8±5.1 years in early and recent 5 years, respectively, and the male female ratio changed from 2:3 to 4:3. Abdominal pain as the most common presenting symptom was replaced by bleeding per rectum in recent years. The mean duration from onset of symptoms to seeking medical advice decreased from 7.8 months to 5.6 months in recent years. More patients (85.3%) were subjected to endoscopic examination in recent years than early years (60.7%) and right colonic cancer increased from 10.7% to 26.5%. However, the rectum was the commonest site in both early (71.4%) and recent (50%) groups. CRC was detected significantly at an earlier stage (7.1% vs 32.4%) in recent years with large proportion of modified Dukes B stage. Poorly differentiated adenocarcinoma was the predominant histology in both groups (50% vs 60.7%). Curative resection had risen in recent years (39.3% vs 73.6%).

CONCLUSION

CRC among Nepalese young adults accounts for a high incidence (28%) of all CRC cases. Although right sided colonic cancer has been increasing, rectum is the commonest site. There is also an increasing trend for diagnosis at earlier stages of the disease which can be treated with curative intent.

Evidence for possible non-canonical pathway(s) driven early-onset colorectal cancer in India

Two genetic instability pathways viz. chromosomal instability, driven primarily by APC mutation induced deregulated Wnt signaling, and microsatellite instability (MSI) caused by mismatch repair (MMR) inactivation, together account for >90% of late-onset colorectal cancer (CRC). Our understanding of early-onset sporadic CRC is however comparatively limited. In addition, most seminal studies have been performed in the western population and analyses of tumorigenesis pathway(s) causing CRC in developing nations have been rare. We performed a comparative analysis of early and late-onset CRC from India with respect to common genetic aberrations including Wnt, KRAS, and p53 (constituting the classical CRC progression sequence) in addition to MSI. Our results revealed the absence of Wnt and MSI in a significant proportion of early-onset as against late-onset CRC in India. In addition, KRAS mutation frequency was significantly lower in early-onset CRC indicating that a significant proportion of CRC in India may follow tumorigenesis pathways distinct from the classical CRC progression sequence. Our study has therefore revealed the possible existence of non-canonical tumorigenesis pathways in early-onset CRC in India.