Incomplete cytoreductive surgery for appendiceal and colorectal peritoneal carcinomatosis: Characteristics and outcomes of an overlooked group.

Background Ond Objectives: Complete cytoreductive surgery (CRS) may prolong survival for selected patients with peritoneal carcinomatosis from colorectal cancer (CRC). However, there is a paucity of data on outcomes following incomplete procedures.
Methods: Patients with incomplete CRS for well-differentiated (WD) and moderate/poorly-differentiated (M/PD) appendiceal cancer, right and left CRC were identified at a single tertiary center (2008-2021).
Results: Of 109 patients, 10% were WD and 51% M/PD appendiceal cancers, and 16% right and 23% left CRC. There were no differences in gender, BMI (mean = 27), ASA score, previous abdominal surgery (72%), and extent of CRS. The PC Index differed between appendiceal and colorectal cancers (mean = 27 vs. 17, p < 0.01). Overall, the perioperative outcomes were similar among the groups, with 15% experiencing complications. Postoperatively, 61% received chemotherapy, and 51% required ≥1 subsequent procedure. The 1 and 3-year survival for the WD, M/PD, right and left CRC subgroups were 100%, 67%, 44%, 51%, and 88%, 17%, 12%, and 23%, respectively (p = 0.02).
Conclusions: Incomplete CRS was associated with significant morbidity and number of subsequent palliative procedures. Prognosis correlated with histologic subtype; WD appendiceal cancer patients having superior outcomes, while those with right sided CRC the worst survival. These data may help guiding expectations in the setting of incomplete procedures.
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