CRC Subtype Predicts Metastatic Disease Pattern

Colorectal cancer histology may influence whether a patient will develop metastasis and, if so, at which site

medwireNews: The pattern of metastasis for patients with colorectal carcinoma (CRC) significantly varies with tumour subtype, suggest results from a large-scale autopsy study.

As published in the Annals of Oncology, metastasis was significantly more common in the 809 patients with mucinous adenocarcinoma (MC) and the 67 patients with signet-ring cell carcinoma (SRCC) than in the 4941 patients with adenocarcinoma (33.9 and 61.2 vs 27.6%).

And among patients with metastases, those with MC and SRCC were also more likely than those with adenocarcinoma to develop them at more than one site (58.6 and 70.7 vs 49.9%), say Niek Hugen, from Radboud University Medical Center in the Netherlands, and co-authors.

“These differences may have significant implications for clinical treatment, follow-up strategies and future clinical trials”, the team suggest.

Lung metastases occurred in around a third of patients regardless of CRC subtype. But patients with adenocarcinoma were more likely to experience metastases to the liver than those with MC or SRCC (73.0 vs 52.2 and 31.7%) and less likely to have spread to the peritoneal surface (20.1 vs 48.2 and 51.2%).

Lymph node metastases were significantly more common in SRCC patients than MC or adenocarcinoma patients (43.9 vs 22.3 and 19.9%), and SRCC was also associated with an increased risk for metastasis to rare locations such as the heart, bone, breast and pancreas.

When the researchers examined the pattern of metastases by primary CRC site, there was no significant difference in the likelihood of liver spread in patients with adenocarcinoma or MC tumours of the colon and the rectum.

However, adenocarcinoma and MC colon cancer patients were more likely to have intra-abdominal metastases, whereas rectal cancer patients were more likely to have extra-abdominal metastases, affecting sites such as the lung and the brain.
However, there was no significant difference in the pattern of metastases with colon and rectal cancer for those with the SRCC subtype.

Analysis of data from the Total Mesorectal Excision trial for rectal cancer patients confirmed that liver metastases most commonly affected the liver in adenocarcinoma patients whereas MC patients were more likely to develop peritoneal metastases.

“Based on profound differences in metastatic patterns between histological subtypes and localization of the primary tumor, we encourage [physicians] to take these factors into account during preoperative examination for metastases and during follow-up,” Niek Hugen et al conclude.

“Our results also indicate that these factors should be considered a stratification factor in future research initiatives focusing on advanced disease.”

Reference

N Hugen, van de Velde C, de Wilt J, et al. Metastatic pattern in colorectal cancer is strongly influenced by histological subtype. Ann Oncol; 6 February 2014. doi: 10.1093/annonc/mdt591

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