Indications for postchemotherapy surgery

Generally accepted indications for postchemo-therapy resection include patients who have residual radiographic disease and normalized serum tumor markers (a-fetoprotein and human chorionic gonadotropin). The added benefit of resection must be weighed against the morbidity of additional surgery. Removal of residual viable cancer offers therapeutic benefit and can be curative in a subset of patients. The excision of residual teratoma is also beneficial because teratoma possesses the potential to undergo malignant transformation, and to continue to grow, obstruct, and invade adjacent structures (growing teratoma syndrome). Because teratomas are chemoresistant, surgical extirpation is the only cure. Unfortunately clinicians cannot reliably predict the histology of residual masses within and outside of the retroper-itoneum. The studies presented above demonstrate a reasonable correlation between retroperitoneal and non-retroperitoneal histology, suggesting that perhaps necrosis discovered in the retroperitoneum obviates additional surgery [25]. Furthermore, certain subgroups of patients, such as those considered uncomplicated by Indiana University criteria, seem to demonstrate a stronger correlation between retroperitoneal and thoracic histology. Investigators have also used logistic regression models incorporating multiple variables to help predict the postchemotherapy histology of lesions outside the retroperitoneum [26]. On multivariate analysis, factors such as RPLND histology and pathology of the primary tumor proved to be strong predictors of thoracic histology. Remarkably, the size of the residual pulmonary nodules was not predictive ofhistology. This finding contrasted with an earlier study demonstrating that the size of post-chemotherapy retroperitoneal masses was a strong predictor of histology [32]. McGuire and colleagues [33] applied the logistic regression model described by Steyerberg and colleagues [26] to 70 patients who had no teratoma in the primary tumor and necrosis at RPLND and found teratoma or viable GCT in the thorax in 24% of patients.

Our interpretation of the above data is that no single variable or regression model can predict histology outside of the retroperitoneum with enough accuracy to safely preclude resection. Several studies have demonstrated that a significant proportion of patients who have necrosis in the retroperitoneum demonstrate teratoma or viable GCT at other sites [21,25]. Postchemotherapy resection of non-retroperitoneal residual masses provides important prognostic information and is curative in most patients who have teratoma and in a subset ofthose who have viable GCT. In an effort to maintain optimum survival, all sites ofresid-ual disease should be resected regardless of size. In patients who have multiple or bilateral residual pulmonary nodules, excision of all disease is still recommended if technically feasible.

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