BMI Not Associated With Opioid Use Following Treatment for Abdominal Cancer

A study published in the Journal of Gastrointestinal Cancer investigated whether body mass index (BMI) is related to postoperative opioid use after pressurized intraperitoneal aerosol chemotherapy (PIPAC) for treatment of peritoneal carcinomatosis (PC).

PC is an abdominal cancer associated with poor prognosis. It is the most common malignant process of the peritoneal cavity and primarily originates from colorectal, gastric, and gynecological malignancies. PIPAC is a novel surgical technique for the treatment of PC that involves the delivery of normothermic chemotherapy into the patient’s abdominal cavity as a pressurized aerosol. It has been shown to enhance drug depth penetration, and it is currently used in the palliative setting in select patients with PC.

For this retrospective, observational study, the investigators analyzed pain scores following 100 PIPAC procedures conducted using either oxaliplatin or doxorubicin-cisplatin. In total, 49 patients who were treated between July 2016 and September 2020 were included. The researchers evaluated whether BMI was associated with postoperative pain and opioid consumption. Pain was self-rated using a visual analogue scale (VAS), ranging from 0 to 10. Patients were divided according to BMI: BMI <18.5, BMI ≥18.5 and <25, and BMI ≥25.

Using univariate regression analysis, the authors found that oxaliplatin and peritoneal cancer index (PCI) score were associated with moderate-to-severe postoperative pain, defined as VAS between 4 and 10 after adjustment for BMI. The odds ratio (OR) for moderate-to-severe pain for oxaliplatin was 3.26 (95% CI, 1.00-10.65; P=.05), and for PCI score the OR was 1.09 (95% CI, 1.01-1.17; P=.019). Pain was significantly different between the oxaliplatin and doxorubicin-cisplatin treatment groups, regardless of BMI (median, 2.5 vs 0; P=.0017).

Regarding opioid use, opioids were administered after 45% of procedures and rates of use were comparable between the treatment groups. Moderate-to-severe pain was significantly associated with greater use of opioids (OR, 3.91; 95% CI, 1.24-12.32), as was synchronous PC (OR, 5.16; 95% CI, 1.71-15.58). Overall, opioid administration and length of stay did not differ between the BMI-stratified groups.

In conclusion, the authors wrote, “BMI is not related to postoperative pain or opioid use; however, moderate-to-severe pain and synchronous PC are factors associated with requiring opioids.”