Importance of complete pathologic response to prehepatectomy chemotherapy in treating colorectal cancer metastases.

OBJECTIVE

We studied the influence of complete pathologic response of colorectal cancer liver metastases to prehepatectomy chemotherapy on longterm survival after hepatectomy.

SUMMARY BACKGROUND DATA

Although complete response seen on imaging may be a useful criterion for evaluating efficacy of chemotherapy, complete clinical response by imaging has shown limited predictive value for complete pathologic response in treating colorectal liver metastases.

METHODS

We retrospectively analyzed data from 63 patients who received preoperative chemotherapy and underwent hepatectomy.

RESULTS

Of 472 liver metastases evaluated, 86 were no more visible from images after chemotherapy. We excluded 14 of these metastasis treated with local ablation. Of the remaining 72 metastasis, 22 (30.6%) were microscopically persistent metastases or recurrences in situ. Liver metastases with complete pathologic response had smaller diameters at diagnosis than others (P < 0.001), and microscopic cancer deposits surrounding macroscopic tumors were less frequent in patients with complete pathologic response than others (P < 0.05). Outcomes were favorable in patients whose liver metastases all showed a complete pathologic response. Even patients with complete pathologic response in only some metastases showed higher overall and disease-free survival rates than pathologic nonresponders (P = 0.001 and P = 0.002, respectively). Presence or absence of metastases showing complete pathologic response was an independent prognostic factor (relative risk, 4.464; P = 0.0099).

CONCLUSIONS

Little correlation was observed between imaging response of colorectal cancer liver metastases to chemotherapy and pathologic response. Liver surgery should be undertaken even after a complete response by imaging. Outcome after hepatectomy was favorable in patients showing complete pathologic response of least one metastasis.