Pathological factors and prognosis of resected liver metastases of colorectal carcinoma: implications and proposal for a pathological reporting protocol

Abstract

Colorectal cancer is a leading cause of death worldwide. The liver is the most common site of distant metastases, and surgery is the only potentially curative treatment, although the recurrence rate following surgery is high. In order to define prognosis after surgery, many histopathological features have been identified in the primary tumour. In turn, pathologists routinely report specific findings to guide oncologists on the decision to recommend adjuvant therapy. In general, the pathological report of resected colorectal liver metastases is limited to confirmation of the malignancy and details regarding the margin status. Most pathological reports of a liver resection for colorectal liver metastasis lack information on other important features that have been reported to be independent prognostic factors. We herein review the evidence to support a more detailed pathological report of the resected liver specimen, with attention to: the number and size of liver metastases; margin size; the presence of lymphatic, vascular, perineural and biliary invasion; mucinous pattern; tumour growth pattern; the presence of a tumour pseudocapsule; and the pathological response to neoadjuvant chemotherapy. In addition, we propose a new protocol for the evaluation of colorectal liver metastasis resection specimens.

Prognostic significance of poorly differentiated clusters and tumor budding in colorectal liver metastases

“…As the liver is the most common metastatic site for CRC, many different histomorphological features have been examined and proposed to stratify patients with colorectal liver metastases (CLM) into distinct prognostic groups . The prognostic impact of a variety of factors including the presence of intrahepatic lymphatic vascular invasion, vascular invasion, infiltrative tumor border, the absence of tumor pseudocapsule, and peritumoral and intratumoral inflammatory infiltrate has been investigated .…”

“…3,[8][9][10][11][12][13][14][15] As the liver is the most common metastatic site for CRC, 16 many different histomorphological features have been examined and proposed to stratify patients with colorectal liver metastases (CLM) into distinct prognostic groups. 17,18 The prognostic impact of a variety of factors including the presence of intrahepatic lymphatic vascular invasion, vascular invasion, infiltrative tumor border, the absence of tumor pseudocapsule, and peritumoral and intratumoral inflammatory infiltrate has been investigated. 17,[19][20][21][22][23] In contrast, while examined in primary CRC tumors, only one study on TB has been reported among patients with CLM, 23 and the prognostic implications of PDC among patients with CLM has not been examined to date.…”

Gross and microscopic changes of liver neoplasms and background hepatic structures following neoadjuvant therapy

“…Successful documentation of these small deposits helps to avoid unnecessary imaging to confirm the lesions were removed during the liver resection. Several different methods for measuring viable tumour content have been proposed in an attempt to correlate histological response with prognosis after liver resection 72. Regardless of the scoring system used to represent histological response to treatment, it is important to flag lesions with complete response (ie, with absence of residual malignancy) as this finding has prognostic implications compared with lesions that show partial response only.…”

Surgery improves the prognosis of colon mucinous adenocarcinoma with liver metastases: A SEER-Based Study

“…One of important reason is M-CLM is frequently accompanied metastases of other sites, thus a large proportion of M-CLM are traditionally considered unresectable unless emergency circumstances, and many studies suggest that incomplete resection is associated with high recurrence, poorer survival, as well as tumor growth and progression [10,[21][22][23][24]. However, the relatively poor response to chemotherapy of metastatic MC indicates that surgery may occupy a more important role in treatment of these patients although recurrence is high [14,25,26]. Thus, some study found MC patients with completed resection of primary lesion and M-CLM had poorer survival than AC CLM patients (A-CLM), but other study found surgery for UICC stage IV MC could provide comparable survival as AC patients [17,18,20].…”