Incidence and origin of histologically confirmed liver metastases: an explorative case-study of 23,154 patients

Abstract

Background: The liver is a common metastatic site for a large variety of primary tumors. For both patients with known and unknown primary tumors it is important to understand metastatic patterns to provide tailored therapies.

Objective: To perform a nationwide exploration of the origins of histological confirmed liver metastases.

Results: A total of 23,154 patients were identified. The majority of liver metastases were carcinomas (n=21,400; 92%) of which adenocarcinoma was the most frequent subtype (n=17,349; 75%). Most common primary tumors in patients with adenocarcinoma were from colorectal (n=8,004), pancreatic (n=1,755) or breast origin (n=1,415). In women of 50 years and younger, metastatic adenocarcinoma originated more frequently from breast cancer, while in women older than 70 years liver metastases originated more frequently from gastrointestinal tumors. Liver metastases in men older than 70 years originated often from squamous cell lung carcinoma. An unknown primary tumor was detected in 4,209 (18%) patients, although tumor type could be determined in 3,855 (92%) of them.

Methods: Data were collected using the nationwide network and registry of histo- and cytopathology in the Netherlands (PALGA). All histological confirmed liver metastases between January 2001 and December 2010 were evaluated for tumor type, origin of the primary tumor and were correlated with patient characteristics (age, gender).

Conclusion: The current study provides an overview of the origins of liver metastases in a series of 23,154 patients.

Keywords: colorectal liver metastases; histology; incidences; liver metastases; non-colorectal liver metastases.

Figure 1. Origins of liver metastases of the carcinoma type

Each clock plot shows the origins of liver metastases per carcinoma subtype (adenocarcinoma, small cell carcinoma, neuroendocrine carcinoma, large cell carcinoma, squamous cell carcinoma). Outer circles represent the location of the primary tumor. Circle size is proportional to the number of metastases.

Figure 2. Differences in gender between tumor types A

and the most important carcinoma subtypes B. #: no significant difference between women and men.

Figure 3A. Relative incidences of primary tumor locations in women and men with metastatic adenocarcinoma

In young women, metastatic breast cancer was more frequently observed (p<0.0001). Liver metastases from urological tumors were more frequently observed in men older than 50 years (p<0.0001).

Figure 3B. Relative incidences of primary tumor locations in women and men with metastatic neuroendocrine tumor

In young women (≤50 years), the primary tumor was significantly more often located in the gynecological tract (p=0.034).

Figure 3C. Relative incidences of primary tumor locations in women and men with metastatic squamous cell carcinoma

Liver metastases from the gynecological tract were more frequently observed in women ≤ 50 years (p=0.007). Primary tumor location in the lung was observed significantly more frequent in men older than 50 years (p=0.41).