Repeat cytoreduction with Hyperthermic Intraperitoneal chemotherapy in patients with peritoneal disease: A 5-year retrospective analysis

Background: Cytoreductive surgery with Hyperthermic Intraperitoneal Chemotherapy (CR-HIPEC) is a locorregional surgical therapy applied in patients with peritoneal-only metastatic disease of primary abdominal malignancies. Integrated in a multimodal treatment, CR-HIPEC is associated with increased overall survival. In cases of peritoneal-site only relapse, it may be carried out more than once. Methods: Patients who received a CR-HIPEC between January 2016 and December 2020 at Instituto Portugues de Oncologia do Porto, Portugal were included in a unicentric, retrospective, observational study. Short- and longterm outcomes after surgery were analyzed. Results: In this period, 259 CR-HIPEC were performed on 248 patients. Of these, 31 were CR-HIPEC repeats, with 6 being the third HIPEC in the same patient. Of the 31 cases, 15 (48.4 %) had an appendicular origin. Mean PCI in re-HIPEC group was 10.6 (SD +/- 7.1). No significant differences in baseline characteristics between the first and re-HIPEC groups were found, except for mean PCI, higher in the 1st HIPEC group (p = 0.047). In re-HIPEC group, major complications rate (CT-CAE 3-4) was 12.9 % (n = 4), without postoperative mortality. The 1st and re-HIPEC group had similar morbidity rates and hospitalization time. With a median follow-up time of 44 months, relapse rate after repeat CR-HIPEC was 45.2 % (n = 14), with a mean overall survival (OS) of 68.7 months and 5-year OS of 78 %. Conclusions: Repeat CR-HIPEC is a safe approach with an acceptable complication rate for its complexity, associated with a survival benefit in selected patients. It should be presented as a valid therapeutic option in recurrent peritoneal disease.