Epidemiological evidence confirms that obesity is a risk factor for the onset of a variety of cancers [14-15]. To determine obesity, BMI is typically used, and patients with a BMI of ≥30 kg/m² are defined as obese. However, BMI does not reflect the whole-body fat distribution . Traditionally, intra-abdominal fat is indirectly measured by waist circumference, hip circumference or waist-to-hip ratio . Whereas, these parameters do not reflect the distribution of body fat either. In the present study, CT was used to measure the visceral fat area directly. Our results showed that patients could have visceral obesity even with a normal BMI. Nevertheless, an appropriate range of CT values for adipose tissue segmentation has not yet been determined. In a recent study, visceral obesity in females was defined as > 80.1 cm², using metabolic syndrome (MetSyn) as an indicator of obesity-associated dysmetabolism in obesity-associated cancer [18-19]. Heus et al. found that the visceral fat area threshold was 100 cm² and 130 cm², and 100 cm² had a better correlation with postoperative complications . In the present study, We use ROC curve to define the best cutoff value. The incidence of complications after cytoreductive surgery increased significantly in patients with visceral obesity. This suggests that providers should design strategies to reduce complications and be more aware of the possibility of complications.
The occurrence of postoperative complications is an important unfavorable factor for the rapid recovery of patients . It is particularly critical to identify the factors predicting postoperative complications. Severe complications can be the result of complex procedures. These complications can result in delays of the start of adjuvant therapy, which can worsen the condition. In a study of 369 patients who had an abdominal or laparoscopic procedure for proven or suspected gynecological cancer, Kondalsamy-Chennakesavan et al. demonstrated that surgical complexity was one of the independently predictive factors of an adverse events . In our study, the complexity of the operation was scored by SCS. Univariate analysis also showed that SCS weas significantly associated with postoperative complications, while result of multivariate analysis was not. The reason for this inconsistency may be due to small size of enrolled patients.
Whether visceral obesity can be used to predict postoperative complications in patients has been controversial. C. Heus et al. found that patients with visceral obesity had an increased risk of postoperative complications . In contrast, the study by Rutten et al. showed that there was no correlation between visceral obesity and postoperative complications . It is worth noting that the characteristics of the patients included in these two studies were not consistent. Moreover, the operation period was also inconsistent, and the selected CT scan images and method of measurement were also different. In this study, VFA was manually traced on a single transverse slice at the level of L3–L4. Importantly, visceral obesity defined as a VFA of ≥ 86.7 cm2 was identified as an independent prognostic factor associated with postoperative complications. In addition, Boutin et al. found that there was no significant relationship between adipose tissue distribution and postoperative complications in patients with soft tissue sarcoma . The results from three studies on complications of radical resection of gastrointestinal tumors revealed that an increase in visceral fat could lead to a prolonged operation time, poor recovery and postoperative complications [26-28]. These studies suggest that visceral obesity may only have predictive value in certain types of tumors.
Postoperative fever is common in patients undergoing cytoreductive surgery. A postoperative body temperature rise (<38.0 °C) does not require special treatment . In this study, we found that patients with visceral obesity were more likely to have postoperative fever and a postoperative body temperature ≥38.0 °C. Adipose tissue is the primary site for storing and mobilizing lipids: it is also associated with endocrine and metabolic functions and contains multiple immune cells . Weisberg et al. demonstrated that the number of macrophages increases during obesity, and the expression of TNF-α and IL-6 are induced, which activate the inflammatory pathway . Similarly, the low levels of adiponectin in obese patients may increase postoperative insulin resistance and induce inflammation . Therefore, the increase in postoperative fever in patients with visceral obesity may be related to the greater release of these inflammatory factors, but this needs further study.
In this study, preoperative CT images were used to assess the incidence of postoperative complications. Visceral obesity was defined as > 86.7 cm2, which improved the applicability in clinical practice. Our study confirmed that BMI is a weak indicator for short-term surgical and recovery outcomes after cytoreductive surgery. However, this study also has some limitations. First, it was a single-center and retrospective study that produced inherent and unavoidable biases. Second, In China, due to the lack of rehabilitation institutions to assist in the management of postoperative patients, most patients need to recover in the hospital after surgery, which leading to a relatively long hospital stay. At the same time, the length of hospital stay is prolonged also because of the immediate postoperative chemotherapy. Meanwhile, it may help us observe mild complications. Last, the sample size was small. The number of samples needs to be increased to further prove that visceral obesity is an independent predictor of short-term complications of cytoreductive surgery for ovarian cancer.