Important considerations in treating children, adolescents and young adults with colorectal carcinoma

An Unusual Presentation of Rectal Carcinoma in a Child

Colorectal carcinoma is a well-known malignancy in adults. However, it is rare in children. Besides, it also has different behaviour in paediatric age-group and usually presents with non-specific symptoms like abdominal pain, weight loss, and anaemia. This usually leads to delay in diagnosis. Adenocarcinoma in children has unfavourable tumour histology (mucinous subtype) and advanced disease stage at presentation which lead to poorer prognosis in children. Family history, genetic typing and sibling screening are essential components of management as this malignancy is frequently seen associated with hereditary syndromes. We describe a case of unusual presentation of rectal carcinoma in a 12-year-old girl.

Increased incidence of FBXW7 and POLE proofreading domain mutations in young adult colorectal cancers

BACKGROUND

The incidence and outcomes of patients with colorectal cancer (CRC) varies by age. Younger patients tend to have sporadic cancers that are not detected by screening and worse survival. To understand whether genetic differences exist between age cohorts, the authors sought to characterize unique genetic alterations in patients with CRC.

METHODS

In total, 283 patients who were diagnosed with sporadic CRC between 1998 and 2010 were identified and divided by age into 2 cohorts-ages ≤45 years (the younger cohort) and ≥65 years (the older cohort)-and targeted exome sequencing was performed. The Fisher exact test was used to detect differences in mutation frequencies between the 2 groups. Whole exome sequencing was performed on 21 additional younger patient samples for validation. Findings were confirmed in The Cancer Genome Atlas CRC data set.

RESULTS

In total, 246 samples were included for final analysis (195 from the older cohort and 51 from the younger cohort). Mutations in the FBXW7 gene were more common in the younger cohort (27.5% vs 9.7%; P = .0022) as were mutations in the proofreading domain of polymerase ε catalytic subunit (POLE) (9.8% vs 1%; P = .0048). There were similar mutation rates between cohorts with regard to TP53 (64.7% vs 61.5%), KRAS (43.1% vs 46.2%), and APC (60.8% vs 73.8%). BRAF mutations were numerically more common in the older cohort, although the difference did not reach statistical significance (2% vs 9.7%; P = .082).

CONCLUSIONS

In this retrospective study, a unique genetic profile was identified for younger patients who have CRC compared with patients who are diagnosed at an older age. These findings should be validated in a larger study and could have an impact on future screening and treatment modalities for younger patients with CRC. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2828-2835. © 2016 American Cancer Society.

Metastatic Colon Cancer in an 18-Year-Old without Predisposing Factors

While colorectal carcinoma is a common gastrointestinal cancer in adults, it is rare in pediatrics with an incidence of 1 : 1,000,000 and represents a fraction of neoplasms encountered in children. Malignant neoplasms represent a major cause of mortality in the pediatric age group. While presenting with weight loss, iron deficiency, rectal bleeding, abdominal pain, and change in bowel habits, or symptoms similar to acute appendicitis, the working diagnosis may be considered to be anorexia. This case illustrates the importance of considering colon cancer among other disease entities as a cause of unintentional weight loss in adolescents. While this is a rare occurrence in the pediatric population, significant unintentional weight loss with altered bowel habits should prompt a search for underlying malignancy—even in the absence of a positive family history or predisposing cancer syndromes.