Utility of Chemoresponse Assay in Patients Undergoing Cytoreductive Surgery Plus Hyperthermic Intraperitoneal...

Our aim was to evaluate the utility of in vitro drug sensitivity testing in patients with peritoneal surface malignancies undergoing cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC).

We found data for 27 patients who underwent CRS plus HIPEC from September 2009 to May 2012 and whose tumors were submitted for in vitro drug sensitivity (ChemoFx(®)). Intraperitoneal chemotherapy agents included mitomycin C, cisplatin + doxorubicin, or cisplatin alone.

There were 12 (44.4 %) appendiceal adenocarcinomas, 5 (18.5 %) colon cancers, 4 (14.8 %) sarcomas, 3 (11.1 %) ovarian cancers, 2 (7.4 %) mesotheliomas, and one (3.7 %) gastric cancer. In all, 15 patients (55.5 %) underwent complete cytoreduction (CC ≤ 1). Seventeen tumors (63 %) displayed in vitro sensitivity to the agents used. Mean overall (OS) and progression-free (PFS) survivals for the entire group were 34.4 ± 4.5 months (median 41 months) and 12.5 ± 2.1 months (median 8 months), respectively. There were no significant differences in OS and PFS for patients whose tumors displayed in vitro drug sensitivity versus those whose tumors did not (p = 0.101 and p = 0.403, respectively). These results also did not differ when evaluating only the patients who underwent complete cytoreduction. In vitro, the drug sensitivity did not correlate with primary tumor pathology or preoperative systemic chemotherapy administration. In vitro drug sensitivity correlated with the drug used at the time of HIPEC (p = 0.003). None of the tumors tested showed in vitro sensitivity to cisplatin and/or doxorubicin. Eight nonresponsive tumors, however, showed in vitro activity to other agents.

Data indicate a high rate of in vitro resistance to the intraperitoneal chemotherapeutic agents used. In vitro drug sensitivity is not useful in patients undergoing CRS plus HIPEC.