Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Moderately and Poorly Differentiated Appendiceal Adenocarcinoma: Survival Outcomes and Patient Selection.

Abstract

Moderately and poorly differentiated adenocarcinoma of the appendix represents an aggressive histological variant with a high risk of recurrence and death. Overall, 178 patients with moderately and poorly differentiated appendiceal adenocarcinoma were identified from a prospective database. Clinical, pathologic, and treatment factors were analyzed for outcomes. Diagnostic laparoscopy (DL) identified radiographic occult peritoneal metastasis in 25 (42%) patients. These patients had a significantly lower peritoneal carcinomatosis index (PCI) and improved overall survival (OS) compared with those with radiographic disease. Twenty-seven (41%) patients were excluded from cytoreductive surgery (CRS) because of findings on DL, while 116 (65%) patients underwent CRS and hyperthermic intraperitoneal chemotherapy (HIPEC), with a median disease-free survival (DFS) of 23months. Mucinous histology (hazard ratio [HR] 0.52, p=0.04) and PCI (HR 1.054, p=0.02) were independent predictors of DFS. The median OS following CRS and HIPEC was 48months. Mucinous histology (HR 0.352, p=0.018), signet ring cells (HR 3.34, p=0.02), positive peritoneal cytology (HR 0.081, p=0.04), and PCI (HR 1.076, p=0.004) were independently associated with OS. Eight-five (73.3%) patients received neoadjuvant chemotherapy, and 40 (47.1%) patients achieved a radiographic response; 36 (42.3%) had stable disease, while 9 (10.6%) had progressive disease. Stable or responsive disease was associated with improved median OS of 44months, compared with 21months for those with progressive disease (p=0.011). In selected patients, long-term survival can be obtained. Mucinous histology, absence of signet ring cells, negative peritoneal cytology, PCI≤20, and response/stable disease after neoadjuvant chemotherapy are important selection criteria for CRS and HIPEC.