Rectosigmoid resection by gynecologic oncologists versus colorectal surgeons: as long as it catches the mouse, does the color of the cat matter?

Tumor-Bowel Fistula as a Rare Form of Recurrent Ovarian Cancer-Imaging and Treatment: Preliminary Report

BACKGROUND

The aim of this pilot study was to evaluate the value of imaging techniques, including computed tomography (CT) and magnetic resonance imaging (MRI), in the diagnosis of a tumor-bowel fistula as a rare form of epithelial ovarian cancer (EOC) relapse. We also performed an initial assessment of the effectiveness of the treatment of this form of relapse.

METHODS

The study group consisted of eight patients with suspected platinum-sensitive recurrence in the form of a tumor/bowel fistula. All patients finished their first line of chemotherapy and subsequently showed complete remission for 6 months or more. To qualify patients for further treatment, CT and MRI were performed, which suggested the presence of a fistula between the recurrent tumor and intestine. DESKTOP study criteria were used to qualify patients for secondary cytoreduction. Second-line chemotherapy was given after secondary debulking.

RESULTS

In all patients, fistulas formed between the tumor and large bowel. On CT, the fistulas were indirectly visible. In all cases, the fistula was visible on MR images, which showed hypointensity on the T2 and T1 post-contrast sequences but did not show restricted diffusion on the diffusion-weighted imaging (DWI) sequence. Patients who were qualified for the study underwent secondary debulking with bowel resection. In all eight cases, the fistula between the tumor and surrounding organs was confirmed. During surgery, seven intestinal anastomoses and one colostomy were performed. No residual macroscopic tumor remained in seven cases (resection R0-87.5%). The progression-free survival (PFS) was 8.4-22.6 months (median 13.4). In the group with cytoreduction R0, the median PFS was 15.5 months (12-22).

CONCLUSION

In patients with suspected EOC recurrence with clinically suspected fistula, CT scan is not sufficient. In CT, the presence of a fistula is suspected based on indirect symptoms. MRI, as a method with much greater tissue resolution, confirms the diagnosis. In addition, MRI can identify the point of the tumor/bowel junction. This is especially true with a large infiltration covering several intestinal parts. Bowel resection with simultaneous anastomosis is a good and safe solution for these patients. However, appropriate qualification for the procedure is necessary, which will allow for surgery without residual macroscopic disease (R0 surgery). Due to the small number of cases, our results cannot be generalized. We treat them as a hypothesis that can be verified in a larger study.

OVA-LEAK: Prognostic score for colo-rectal anastomotic leakage in patients undergoing ovarian cancer surgery

OBJECTIVE

The objective of the present study was to define and validate an anastomotic leak prognostic score based on previously described and reported anastomotic leak risk factors (OVA-LEAK: https://n9.cl/ova-leakscore) and to establish if the use of OVA-LEAK score is better than clinical criteria (surgeon's choice) selecting anastomosis to be protected with a diverting ileostomy.

MATERIAL & METHODS

This is a retrospective, multicentre cohort study that included patients who underwent cytoreductive surgery for primary advanced or relapsed ovarian cancer with colorectal resection and anastomosis between January 2011 and June 2021. Data from patients already included in the previous predictive model were not considered in the present analysis. To validate the performance of our logistic regression model, we used the OVA-LEAK formula (Annex I: https://n9.cl/ova-leakscore) for estimating leakage probabilities in a new independent cohort. Then, receiver operating characteristic (ROC) analysis was performed and area under the curve (AUC) was used to measure the performance of the model. Additionally, the Brier score was also estimated. 95% confidence intervals (CI) for each of the estimated performance measures were also calculated.

RESULTS

848 out of 1159 recruited patients were finally included in the multivariable logistic regression model validation. The AUC of the new cohort was 0.63 for predicting anastomotic leak. Considering a cut-off point of 22.1% to be 'positive' (to get a leak) this would provide a sensitivity of 0.45, specificity of 0.80, positive predictive value of 0.09 and negative predictive value of 0.97 for anastomotic leak. If we consider this cut-off point to select patients at risk of leak for bowel diversion, up to 22.5% of the sampled patients would undergo a diverting ileostomy and 47% (18/40) of the anastomotic leaks would be 'protected' with the stoma. Nevertheless, if we consider only the 'clinical criteria' for performing or not a diverting ileostomy, only 12.5% (5/40) of the leaks would be 'protected' with a stoma, with a rate of diverting ileostomy of up to 24.3%.

CONCLUSIONS

Compared with subjective clinical criteria, the use of a predictive model for anastomotic leak improves the selection of patients who would benefit from a diverting ileostomy without increasing the rate of stoma use.