Study Supports Routine Omentectomy in Absence of Metastasis During CRS-HIPEC

Almost one-third of patients undergoing omentectomy for peritoneal metastases had occult omental metastases, supporting routine omentectomy prior to cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC), authors of a retrospective review concluded.

Among 72 patients with a grossly normal omentum, 23 had occult metastases. More than half of patients who did not undergo omentectomy had peritoneal recurrences, including omental recurrences in more than 20% of cases.

“Patients undergoing CRS-HIPEC with greater omentectomy, who had a grossly normal omentum, had a high rate of occult histologic omental metastasis,” stated Joel Baumgartner, MD, of the University of California San Diego, and colleagues, in the Annals of Surgical Oncology. “Omentectomy was not associated with higher morbidity than patients who did not have an omentectomy. Additionally, one fifth of patients who did not have an omentectomy had omental recurrence.

“Routine omentectomy in the absence of gross metastasis therefore is recommended during CRS-HIPEC procedures.”

The study provides guidance regarding the potential value of routine omentectomy during CRS-HIPEC, said Daniel Joyce, MBBCh, of the Cleveland Clinic, who was not involved in the study.

“Personally, I always perform a greater omentectomy since the omentum can be a nuisance for the outflow catheters when using closed HIPEC technique,” Joyce told MedPage Today via email. “This paper strengthens the oncologic argument for CRS-HIPEC. Interestingly, there has been much written about the role of omentectomy in curative gastric cancer surgery, and there may not be a significant benefit for that patient population. But of course that is a different disease and different stage of disease compared to this patient population.”

CRS-HIPEC has gained support as treatment for peritoneal mesothelioma and isolated peritoneal metastases associated with multiple types of cancer, including gastric, appendiceal, colorectal, and ovarian malignancies. No standard CRS-HIPEC protocol exists for different malignancies, and approaches vary from one center to another, Baumgartner’s group noted.

Peritoneal recurrence rates also vary by histology and disease burden but generally depend on the completeness of cytoreduction, they added.

Greater omentectomy during CRS has traditionally been performed even in the absence of visible omental metastases. Rates of omental metastases in the absence of visible disease are generally unknown. Given the physiologically uncertain role of the omentum and potential risks of omentectomy, some specialists have questioned the need for omentectomy with other surgical oncology procedures.

Baumgartner and colleagues performed a retrospective review of omentectomy cases to determine the rate of occult omental metastases in patients undergoing CRS-HIPEC for peritoneal malignancies. Data analyses included 683 CRS-HIPEC procedures performed in 654 patients from August 2007 to August 2020. Greater omentectomy was performed in 580 (84.9%) cases.

The most common types of cancer were appendiceal (61.6% of cases), colorectal (20.8%), and mesothelioma (9.1%). Patients who underwent greater omentectomy had higher rates of complete cytoreduction (97.3% vs 92.2%) and splenectomy (36.4% vs 10.7%, P<0.001) and longer hospitalization (9 vs 7 days).

Time to return of bowel function, postoperative ileus rate, and 60-day comprehensive complication index were similar between patients who had omentectomy and those who did not.

In the omentectomy group, 452 patients (77.9%) had gross intraoperative evidence of omental metastases and 72 (12.4%) had a grossly normal omentum. In the remaining 56 (9.7%) cases, gross omental appearance was not documented.

Pathology confirmed omental metastasis in 421 of 452 (93.1%) patients with gross intraoperative omental metastasis. Of the 72 patients with a grossly normal omentum, pathologic assessment showed benign histology in 49 (68.1%) cases and occult omental metastasis in 31.9%. Patients with occult omental metastasis had a significantly higher peritoneal cancer index as compared with patients who did not have occult metastasis (9 vs 6, P=0.013).

The authors identified 43 cases without greater omentectomy that had residual omentum described in the operative notes. During a median follow-up of 25.9 months, 24 (55.8%) of the patients developed recurrent disease, which was omental in nine (37.5%) cases and extra-omental in 15 (62.5%).