Calcification in colorectal hepatic metastases correlates with longer survival

Calcification occurs in 12-27% of hepatic colorectal metastases, but its clinical significance and its influence on prognosis are unknown.

All patients diagnosed with colorectal liver metastases at the Ottawa Regional Cancer Center in 1991 (n = 97), as well as those enrolled in chemotherapy trials in 1990-1992 (n = 51), were entered into a retrospective cohort study. Thirty-six patients were excluded due to inadequate follow-up. In the remaining 112, abdominal CT scans and/or ultrasound examinations were used to determine the presence of calcification. Charts were reviewed for variables, including primary tumour pathology, amount of liver involvement by tumour (< 25%, 25-50%, > 50%), and the chemotherapeutic agents received, and were subjected to multivariate and regression analysis. End point was survival in months or to December 1993 (median follow up 24 months).

Patients with calcification (n = 31) (28%) were compared to those who did not have calcifications (n = 81). The groups were comparable with respect to sex, age, time to calcification, time to metastases, and treatment type. Calcification occurred independent of the degree of tumour differentiation, the presence of mucinous adenocarcinoma, or the hepatic tumour burden. Nine patients with calcified metastases (30%) had calcification at presentation. Biopsies showed calcification next to viable tumour cells with an absence of an inflammatory reaction. Survival was improved with better primary tumour differentiation and less tumour burden. The presence of calcification had a statistically highly significant improvement in survival (P < 10(-6), relative risk = .19) independent of other variables.

The presence of calcification within a colorectal liver metastasis appears to imply a significantly better prognosis.