Smith, Andrew D.

432 Background: In clinical trials and clinical practice, tumor response assessment with computed tomography (CT) defines critical end points in patients with metastatic disease treated with systemic agents. Methods to reduce errors and improve efficiency in tumor response assessment could improve patient care. Methods: Eleven readers from 10 different institutions independently categorized tumor response according to three different therapeutic response criteria using paired baseline and initial post-therapy CT studies from 20 randomly selected patients with metastatic renal cell carcinoma treated with sunitinib as part of a completed phase III multi-institutional study. Images were evaluated with a manual tumor response evaluation method (standard-of-care) and with computer-assisted response evaluation (CARE) that included stepwise guidance, interactive error-identification and correction methods, automated tumor metric extraction, calculations, response categorization, and data/image archival. A cross-over design, patient randomization, and two-week washout period were used to reduce recall bias. Comparative effectiveness metrics included error rate and mean patient evaluation time. Results: The standard-of-care method was on average associated with one or more errors in 30.5% (6.1/20) of patients while CARE had a 0.0% (0.0/20) error rate (p<0.001). The most common errors were related to data transfer and arithmetic calculation. In patients with errors, the median number of error types was 1 (range 1-3). Mean patient evaluation time with CARE was twice as fast as the standard-of-care method (6.4 vs. 13.1 minutes, p<0.001). Conclusions: Computer-assisted tumor response evaluation reduced errors and time of evaluation, indicating better overall effectiveness than manual tumor response evaluation methods that are the current standard-of-care.

238 Background: To compare post-transplant recurrence rates of hepatocellular carcinoma (HCC) and differences in percent tumor necrosis in patients with pre-operative superselective chemoembolization (CE) vs. non-superselective CE. Methods: Retrospective review of 147 patients with liver transplant (LT) for HCC treated with pre-operative CE. Those transplanted less than 24 hours after CE and those who had other concomitant treatments were excluded. The angiographic studies and written reports were reviewed to categorize patients into superselective and non-superselective groups. CE was done with an emulsion of lipiodol, cisplatin, doxorubicin, mitomycin C, and contrast, with or without embolization particles. Superselective CE was defined as treatment directly into the vessel(s) feeding the tumor. Treatment from more proximal vessels was considered non-superselective. Data gathered included age, gender, date of CE, date of LT, tumor size and number, tumor stage, MELD score, Child-Pugh class, alpha fetoprotein, percent tumor necrosis at explant, date of recurrence, date and cause of death, and date of last follow-up. Patient and disease characteristics and percent tumor necrosis were analyzed with a Wilcoxon rank sum test or Fisher’s exact test. The Kaplan-Meier method was used to estimate the cumulative incidences of death due to recurrent disease after LT. Results: 99 patients were included, 53 had superselective CE and 46 non-superselective. HCC recurrence rates at 1, 3, 5, and 8 years were all significantly less for superselective CE compared to non-superselective CE (p = 0.039 single, p = 0.011 multivariable). Using multivariable analysis, superselective CE had a lower risk of death due to recurrent HCC at 1, 3, 5, and 8 years (p = 0.046). There was a trend toward more percent tumor necrosis after superselective CE, but it did not reach significance (p = 0.057). Conclusions: This study provides evidence that HCC recurrence after LT and death due to recurrent HCC is lower after pre-LT superselective CE versus non-superselective CE. The strong trend for greater percent tumor necrosis with superselective CE may explain the differences in recurrence rate.