Computed Tomography Characteristics of Unresectable Primary Renal Cell Carcinoma Treated With Neoadjuvant Sunitinib

IntroductionIn patients with locally advanced and metastatic RCC, selection criteria for nephrectomy are imprecise. Neoadjuvant sunitinib might downsize unresectable tumors and enable nephrectomy. CT scans of unresectable primary RCCs before and after neoadjuvant sunitinib were retrospectively reviewed to identify radiographic features associated with patient selection for surgery.Patients and MethodsCT scans of 27 patients with RCC (31 tumors) treated with neoadjuvant sunitinib were performed as part of a prospective clinical trial. After neoadjuvant sunitinib, tumors were surgically resected in 13 patients (17 tumors) and not resected in 14 patients (14 tumors). Response to treatment with sunitinib was assessed with Response Evaluation Criteria in Solid Tumors and MASS criteria.ResultsOn the contrast-enhanced CT scan before nephrectomy compared with the baseline CT scan, 88% of resected tumors demonstrated decreased size (median decrease 26%; −2.0 cm; P < .001), 88% had decreased attenuation (median decrease 30%; −27 Hounsfield units; P = .004), and 76% had increased necrosis (P < .001). Response to sunitinib was significantly more favorable (according to MASS criteria) in resected than in nonresected tumors (P = .005). In addition, the degree of baseline necrosis was less in tumors subsequently resected than in nonresected tumors (P = .05). Multivariate analysis showed that higher tumor attenuation after 2 cycles of sunitinib therapy and a favorable response (MASS criteria) after 2 cycles of sunitinib therapy were independent predictors of subsequent tumor resection.ConclusionIn unresectable primary RCC tumors, changes in select CT parameters after 2 cycles of neoadjuvant sunitinib might be associated with the potential for surgical resection.