Unusual Cancers of Childhood Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Abdominal Cancers
There is a higher incidence of mucinous adenocarcinoma in the pediatric and adolescent age group (40%–50%), with many lesions being the signet ring cell type,[76,79,88] whereas only about 15% of adult lesions are of this histology. The tumors of younger patients with this histologic variant may be less responsive to chemotherapy. In the adolescent and young adult population with the mucinous histology, there is a higher incidence of signet ring cells, microsatellite instability, and mutations in the mismatch repair genes. These tumors arise from the surface of the bowel, usually at the site of an adenomatous polyp. The tumor may extend into the muscle layer surrounding the bowel, or the tumor may perforate the bowel entirely and seed through the spaces around the bowel, including intra-abdominal fat, lymph nodes, liver, ovaries, and the surface of other loops of bowel. A high incidence of metastasis involving the pelvis, ovaries, or both may be present in girls. Colorectal cancers in younger patients with noninherited sporadic tumors often lack KRAS mutations and other cytogenetic anomalies seen in older patients.
Treatment and survival
Most patients present with evidence of metastatic disease, either as gross tumor or as microscopic deposits in lymph nodes, on the surface of the bowel, or on intra-abdominal organs.[86,88] Complete surgical excision is the most important prognostic factor and should be the primary aim of the surgeon, but in most instances this is impossible; removal of large portions of tumor provides little benefit for those with extensive metastatic disease. Most patients with microscopic metastatic disease generally develop gross metastatic disease, and few individuals with metastatic disease at diagnosis become long-term survivors.
Current therapy includes the use of radiation for rectal and lower colon tumors, in conjunction with chemotherapy using 5-FU with leucovorin. Other agents, including irinotecan, may be of value.[Level of evidence: 3iiiA] No significant benefit has been determined for interferon-alpha given in conjunction with 5-FU/leucovorin. A recent review of nine clinical trials comprising 138 patients younger than 40 years demonstrated that the use of combination chemotherapy improved progression-free survival and overall survival (OS) in these patients. Furthermore, OS and response rates to chemotherapy were similar to those observed in older patients.