Predicting preoperatively which patients can be optimally cytoreduced may be challenging. Limited data exist addressing the efficacy of computed tomographic (CT) scanning to predict optimal resectability, and no solitary feature has been consistently associated with unresectability.
Funt and associates37 attempted to correlate CT findings with surgical outcome in patients undergoing secondary cytoreduction. Two radiologists unaware of surgical outcomes retrospectively reviewed CT images and tried to assess for resectability. Peritoneal carcinomatosis, ascites, nodal disease, perihepatic metastasis, and involvement of bladder, rectum, sigmoid, or vagina were not indicators of tumor resectabil-ity. Pelvic sidewall invasion and hydronephrosis were significant independent predictors of suboptimal cytoreduction. It is not entirely clear why pelvic sidewall invasion would be unresectable in the recurrent setting because it is often not found to be unresectable in the primary setting. However, this may be explained by the hypothesis that tumor cells become fibrin-entrapped on previously traumatized peritoneal surfaces.38 This was a small study of only 36 cases; therefore, the true significance and accuracy of these findings need further evaluation. Currently, there are no reliable CT findings that predict suboptimal cytoreduction, since even extensive hepatic tumors have been demonstrated to be resectable in this setting in experienced centers.39
Another imaging modality frequently used in preoperative evaluation is integrated 18fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT). This modality has been shown to be a sensitive post-therapy surveillance modality for the detection of recurrent ovarian cancer and can be useful for the detection of tumor recurrence when conventional imaging is inconclusive or negative.40,41
Lenhard and colleagues42 assessed the predictive value of PET/CT imaging compared with AGO-scoring in patients planned for cytoreductive surgery with recurrent ovarian cancer. The investigators concluded that PET/CT and the AGO score offer good tools for determining candidates for full resectability in recurrent ovarian cancer. PET/CT was found to have a higher negative predictive value and the AGO score a higher positive predictive value; the combination of both improved the diagnostic accuracy.
Bristow and associates43 used integrated PET/CT to evaluate patients with clinically occult recurrent ovarian cancer before secondary cytoreduction. The overall accuracy of PET/CT for discriminating recurrent disease larger than 1 cm was 81.8%. PET/CT demonstrated high sensitivity (83.3%) as well as a positive predictive value (PPV; 93.8%) for surgically documented recurrent ovarian cancer measuring more than 1 cm. Despite negative or equivocal findings on conventional CT imaging, localized nonphysiologic uptake of FDG on combined PET/CT was a strong predictor of suboptimal-volume recurrent tumor. In addition, lesion-based analysis showed a high PPV (96.1%) for surgically documented macroscopic recurrent tumor. However, PET/CT had only modest lesion-based sensitivity (60.5%), owing primarily to the inability to detect small-volume (less than 7 mm) disease.
This observation raises concerns regarding the clinical impact of PET imaging techniques for patients with suspected recurrent ovarian cancer. As previously discussed, carcinomatosis, usually defined as multiple small lesions, is an important factor in determining prognosis after secondary cytoreduction. A reliable preopera-tive diagnosis of carcinomatosis would thus be of tremendous importance. If carci-nomatosis will not be detected by PET/CT, this modality may not assist in patient selection. Understanding these limitations, currently PET/CT is the most reliable, noninvasive method of identifying larger lesions, which are often not identified on conventional imaging, and can therefore serve as a useful adjunct in the preoperative evaluation and operative planning in patients being considered for secondary cytoreduction.
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