Purpose This study was designed to evaluate the relationship between the minimal margin size and local tumor progression (LTP) following CT-guided radiofrequency ablation (RFA) of colorectal cancer liver metastases (CLM). Methods An institutional review board-approved, HIP-PA-compliant review identified 73 patients with 94 previously untreated CLM that underwent RFA between March 2003 and May 2010, resulting in an ablation zone completely covering the tumor 4–8 weeks after RFA dynamic CT. Comparing the pre- with the post-RFA CT, the minimal margin size was categorized to 0, 1–5, 6–10, and 11–15 mm. Follow-up included CT every 2–4 months. Kaplan–Meier methodology and Cox regression analysis were used to evaluate the effect of the minimal margin size, tumor location, size, and proximity to a vessel on LTP. Results Forty-five of 94 (47.9 %) CLM progressed locally. Median LTP-free survival (LPFS) was 16 months. Two-year LPFS rates for ablated CLM with minimal margin of 0, 1–5 mm, 6–10 mm, 11–15 mm were 26, 46, 74, and 80 % (p < 0.011). Minimal margin (p = 0.002) and tumor size (p = 0.028) were independent risk factors for LTP. The risk for LTP decreased by 46 % for each 5-mm increase in minimal margin size, whereas each additional 5-mm increase in tumor size increased the risk of LTP by 22 %. Conclusions An ablation zone with a minimal margin uniformly larger than 5 mm 4–8 weeks postablation CT is associated with the best local tumor control.

Purpose: Conventional noncontrast CT (NCCT) is insensitive to hyperacute cerebral infarction in the first 3 h. Our aim was to determine if CT perfusion (CTP) can improve diagnostic accuracy over NCCT for patients presenting with stroke symptoms in the 3-hour window. Methods: Consecutive patients presenting to our emergency department with symptoms of ischemic stroke <3 h old and receiving NCCT and CTP as part of their triage evaluation were retrospectively reviewed. Patients with follow-up diffusion-weighted MRI (DWI) <7 days from ictus were included. Two readers rated the NCCT and CTP for evidence of acute infarct and its vascular territory. CTP selectively covered 24 mm of brain centered at the basal ganglia with low relative cerebral blood volume in a region of low cerebral blood flow or elevated time to peak as the operational definition for infarction. A third reader rated all follow-up DWI for acute infarct and its vascular territory as the reference standard. Sensitivity, specificity, and predictive values were calculated. An exact McNemar test and generalized estimating equations from a binary logistic regression model were used to assess the difference in detection rates between modalities. A two-sided p value <0.05 was considered significant. Results: 100 patients were included. Sixty-five (65%) patients had follow-up DWI confirmation of acute infarct. NCCT revealed 17 (26.2%) acute infarcts without false positives. CTP revealed 42 (64.6%) acute infarcts with one false positive. Of the 23 infarcts missed on CTP, 10 (43.5%) were outside the volume of coverage while the remaining 13 (56.5%) were small cortical or lacunar type infarcts (≤15 mm in size). CTP was significantly more sensitive (64.6 vs. 26.2%, p < 0.0001) and accurate (76.0 vs. 52%, p < 0.0001) and had a better negative predictive value (59.6 vs. 42.2%, p = 0.032) than NCCT. Conclusion: In a retrospective cohort of 100 patients with symptoms of hyperacute stroke in the 3-hour window, CTP provided improved sensitivity and accuracy over NCCT.

On CTP, ASPECTS mismatch showed strong correlation to volumetric mismatch. ASPECTS mismatch >or=1 was the optimal cut point for volumetric mismatch >or=20%.

358 Background: BRCA1, BRCA2, and PALB2 germline mutations are associated with an increased risk of PC. Other BRCA-associated cancers have demonstrated increased sensitivity to PARP inhibitors (PARPi) and early trials have shown activity of PARPi in untreated BRCAmut PC. We evaluated theactivity of V in patients with previously treated BRCA/PALB2mutPC. Methods: Eligibility: BRCA1/2, or PALB2mutPC, at least 1 and up to 2 prior treatment regimens, measurable stage III/IVPC; ECOG 0-1. Treatment Plan: V 300mg BID (N= 3 pts), then V 400mg BID day1- 28. Primary endpoint: RECIST 1.1 response rate (RR). Statistical plan: Single-arm, non-randomized, open-label, phase II, two-stage design, unacceptable RR 10%, promising 28%, type I, II error rates 10%. Secondary endpoints: progression-free survival (PFS), duration of response, overall survival, safety, tolerability and archival tumor analyses. Results: Between 05/12 and 12/13, N= 16 enrolled. Male= 8, Female= 8. Median age= 52 years (range 43- 77). BRCA1 mut=5. BRCA2 mut=11. N= 1AJCC stage III PC, N= 15 AJCC stage IV PC. N= 8 and N= 8 (50%) had 1 and 2 prior lines of therapy respectively. N= 13 (81%) received prior platinum therapy. Response: N= 1 unconfirmed PR (PR at 4 months (mo), POD at 6 mo), N= 4 stable disease (SD), N= 10 progressive disease (PD); N= 1 inevaluable (12 days of V only due to disease-related complications). Median PFS was 52 days (range 12 to 423). Three pts treated at 400mg V were dose-reduced for toxicity. Six pts had V related grade 3 toxicity including fatigue (N=3), hematologic (N=2) and nausea (N=1). No therapy-related grade 4-5 toxicities were observed. Conclusions: V was well tolerated. While no confirmed partial responses were observed, single-agent activity of V in previously treated PC was noted, and N= 4 (25%) remained on study with SD for ≥ 4mo (4, 6, 6, 9 mo). A randomized phase II trial evaluating cisplatin,gemcitabine +/- V is underway in untreated BRCA/PALB2mutPC (NCT01585805). Results of correlative studies will be presented. Acknowledgements: Lustgarten Foundation. NCI.AbbVie. Clinical trial information: NCT01585805.