Peritoneal Involvement Is More Common Than Nodal Involvement in Patients With High-Grade Appendix Tumors Who Are Undergoing Prophylactic Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

BACKGROUND: Right hemicolectomy is routinely recommended in patients with histologic findings of high-grade appendix tumors after appendicectomy. Undetected peritoneal disease may be encountered at surgery. In high-grade appendix tumors with disease detected radiologically, complete cytoreduction may not be possible and outcomes poor. For these reasons, we adopted a policy of prophylactic cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. OBJECTIVE: The purpose of this study was to quantify the rates of peritoneal and nodal metastatic disease in patients with high-grade appendix tumors without obvious metastatic disease and to report the long-term outcomes of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in these patients. DESIGN: Data regarding peritoneal and nodal metastatic disease were extracted from surgical and histologic records. SETTINGS: The study was conducted at a high-volume tertiary referral center for peritoneal malignancy. PATIENTS: Patients referred with histologically high-grade appendix tumors at appendicectomy, without detectable metastatic spread, between January 1994 and September 2016 were included MAIN OUTCOME MEASURES: A total of 62 patients with high-grade pathology at appendicectomy, without clinical or radiological peritoneal disease, underwent complete cytoreduction with hyperthermic intraperitoneal chemotherapy. RESULTS: Thirty-five (57%) of 62 patients had peritoneal disease (median peritoneal cancer index 5 (range, 1-28)). Eleven (31%) of 35 had microscopic peritoneal disease. Overall, 23 (37%) of 62 had peritoneal disease beyond the confines of a standard right hemicolectomy. Nine (15%) of 62 had nodal involvement. Mean overall and disease-free survival were 110.9 (95% CI, 94.8-127.0 mo) and 102.1 months (95% CI, 84.3-119.9 mo), with 5-year overall and disease-free survival of 83.2% and 76.0%. LIMITATIONS: The retrospective nature limits the interpretation of these results. CONCLUSIONS: Complete cytoreduction was achieved in all of the patients, with excellent long-term survival. The incidence of peritoneal spread (57%) compared with nodal involvement (15%) supports cytoreductive surgery and hyperthermic intraperitoneal chemotherapy as definitive treatment rather than prophylaxis in patients with high-grade appendix tumors, even without radiologically detectable disease. High-grade appendix tumors benefit from early aggressive operative management to deal with potential peritoneal and nodal spread and should be considered for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.