Abstract
Background: CRC in young patients is uncommon and a phenotypically more aggressive disease. We completed a retrospective descriptive study to determine epidemiological and pathological characteristics of young patients seen by medical oncology within the Sydney West Cancer Network between 2006 and 2015.
Methods: Patients less than 30 years of age with histologically proven CRC were included. Demographic and pathological factors were identified. Extended RAS and BRAF mutation testing was performed for all available tumors.
Results: Thirty patients were included in this study with median age of diagnosis at 26 years (range 15–29). The majority of primary tumors were left sided (63%) with rectum and splenic flexure being the most common sites (30% and 33%, respectively). Twenty-four patients (80%) presented with stage 3 and 4 disease and the most common tumor histopathology was adenocarcinoma no special type (26%). Nine patients had MMR staining patterns suggestive of microsatellite instability and eight of these underwent further genetic testing. Of those tested, four were positive for a genetic predisposing condition (three with Lynch syndrome and one with sessile serrated polyposis syndrome). There were no familial adenomatous polyposis cases identified. KRAS testing was performed on 29 tumor samples, of which seven were KRAS mutant (24%). NRAS and BRAF testing was performed on 27 samples and two returned mutant for NRAS (7%). No BRAF mutations were identified.
Conclusion: This Australian cohort of patients with CRC is one of the youngest described in the literature. They demonstrated similar clinicopathological characteristics compared to previous studies, including a low incidence of RAS mutations. These features are distinctly different to those seen in classic CRC seen in older patients. The aggressive behavior of these tumors warrants further exploration of causative factors and therapeutic options.
Disclosures: RAS testing funded by Merck Serono research grant.
Methods: Patients less than 30 years of age with histologically proven CRC were included. Demographic and pathological factors were identified. Extended RAS and BRAF mutation testing was performed for all available tumors.
Results: Thirty patients were included in this study with median age of diagnosis at 26 years (range 15–29). The majority of primary tumors were left sided (63%) with rectum and splenic flexure being the most common sites (30% and 33%, respectively). Twenty-four patients (80%) presented with stage 3 and 4 disease and the most common tumor histopathology was adenocarcinoma no special type (26%). Nine patients had MMR staining patterns suggestive of microsatellite instability and eight of these underwent further genetic testing. Of those tested, four were positive for a genetic predisposing condition (three with Lynch syndrome and one with sessile serrated polyposis syndrome). There were no familial adenomatous polyposis cases identified. KRAS testing was performed on 29 tumor samples, of which seven were KRAS mutant (24%). NRAS and BRAF testing was performed on 27 samples and two returned mutant for NRAS (7%). No BRAF mutations were identified.
Conclusion: This Australian cohort of patients with CRC is one of the youngest described in the literature. They demonstrated similar clinicopathological characteristics compared to previous studies, including a low incidence of RAS mutations. These features are distinctly different to those seen in classic CRC seen in older patients. The aggressive behavior of these tumors warrants further exploration of causative factors and therapeutic options.
Disclosures: RAS testing funded by Merck Serono research grant.
| Original language | English |
|---|---|
| Article number | 243 |
| Pages (from-to) | 127 |
| Number of pages | 1 |
| Journal | Asia-Pacific Journal of Clinical Oncology |
| Volume | 12 |
| Issue number | S5 |
| Publication status | Published - Nov 2016 |
| Externally published | Yes |
| Event | COSA's 43rd and ANZBCTG's 38th Annual Scientific Meetings. Partners for Progress in Breast Cancer Research and Care (2016) - Gold Coast , Australia Duration: 15 Nov 2016 → 17 Nov 2016 |