Morphological consistency of desmoplastic reactions between the primary colorectal cancer lesion and associated metastatic lesions.

Some preceding studies show that a desmoplastic reaction (DR) at the invasive front of a primary tumor (DRprimary) is a promising prognostic indicator, and its histologic classification is an independent prognostic factor in patients with colorectal cancer (CRC). Although DR is observed in metastatic lesions, such as those in lymph nodes (DRLN) and the liver (DRliver), the association between DRprimary and DR of metastatic lesions is unclear. We investigated whether DRLN and DRliver could be categorized in the same manner as DRprimary and examined the features and prognostic implications of DRLN and DRliver. In this study, we evaluated 363 patients with metastases to lymph nodes and 45 patients with synchronous liver metastases who underwent curative resection. DRLN and DRliver statuses were classified as mature, intermediate, or immature, based on keloid-like collagen and myxoid stroma appearances in the metastatic lesions. Overall, 109, 106, and 148 patients had mature, intermediate, and immature DRLN, respectively; in total, 5, 21, and 19 patients had mature, intermediate, and immature DRliver, respectively. DRLN and DRprimary (spearman's rho = 0.43, P < 0.0001) and DRliver and DRprimary (spearman's rho = 0.40, P = 0.0069) were each significantly correlated. The 5-year relapse-free survival (RFS) after surgery was 67.7% for mature/intermediate DRLN and 52.9% for immature DRLN; the 5-year RFS after hepatectomy was 11.5% for mature/intermediate DRliver and 5.6% for immature DRliver. In conclusion, DRLN and DRliver may be classified in the same manner as DRprimary; morphological consistency of DR was observed between primary and metastatic lesions.