Oral Presentation NSW State Cancer Conference 2023

Increased risk of rectal cancer and aggressive disease in sporadic early-onset colorectal cancer: a single site study of 3609 consecutive cases in NSW over 26 years from 1995 to 2020 (#47)

Ehsan Alvandi 1 , Kerry Hitos 2 , James WT Toh 3 , Kheng-Seong Ng 4 , Matthew JFX Rickard 4 , Stephanie H Lim 1 , Wilson W Wong 5 , Anandwardhan A Hardikar 5 , Pierre Chapuis 3 , Kevin J Spring 1
  1. Medical Oncology Group, Liverpool Clinical School, School of Medicine, Western Sydney University and Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
  2. Westmead Clinical School, Faculty of Medicine and Health Sciences, University of Sydney, Sydney, NSW, Australia
  3. Department of Colorectal Surgery, Westmead Hospital, Westmead, NSW, Australia
  4. Colorectal Surgical Unit, Concord Repatriation General Hospital, Sydney, NSW, Australia
  5. Diabetes & Islet Biology Group, School of Medicine, Western Sydney University, Campbelltown, NSW, Australia

Objective: An increasing incidence of early-onset colorectal cancer (EOCRC) diagnosed before the age of 50 years has been reported globally, yet the current screening program in Australia does not address this phenomenon. We investigated the EOCRC incidence, trend, clinicopathological and survival features over a 26-year period.

Methods: The study cohort comprised 3609 consecutive CRC patients who had undergone tumour resection between 1995-2020. Data were retrieved from Concord Colorectal Cancer Surgical Registry in Sydney, Australia, and categorized into EOCRC and late-onset CRC (LOCRC) subgroups based on a threshold of 50 years of age. Familial CRC was excluded from analyses.

Results: Within the examined cohort 7.4% of patients were found to have EOCRC. Overall, no increasing trend in EOCRC incidence was observed, however, rectal cancer was significantly more associated with EOCRC (P<0.001), as well as distal compared to proximal colon cancer (P<0.001). The percentage of lymph node and distant metastasis was significantly greater in patients with EOCRC than LOCRC (P=0.005, and P=0.025, respectively) with an almost two-fold increased risk of metastasis (OR=1.7; 95% CI: 1.32-2.18; P<0.001). Further, EOCRC tumours were more likely to be poorly differentiated (P=0.026). Despite EOCRC patients having better five-year survival (72% for EOCRC vs 62% for LOCRC), the estimated mean cancer-specific survival time was approximately only one year more for EOCRC [3.79±0.84 (95% CI, 2.16-5.43) vs 2.66±0.23 (95% CI, 2.22-3.1)].

Conclusion: A significantly greater percentage of EOCRC patients were diagnosed with lymph node and distant metastasis. Although an increasing incidence trend for EOCRC was not observed in this study, our results provide additional supportive evidence for reducing the current commencing age of the National Bowel Cancer Screening Program in Australia to 45 or even 40 years of age to better identify younger individuals at risk of harbouring advanced EOCRC.