434 Background: Recently high rates of conversion (or adjuvant) surgery were reported after neoadjuvant chemo(radiation)therapy (NAC) for borderline or locally advanced pancreatic cancer (BR/LA PC) including our phase II trial of gemcitabine, S-1 and leucovorin (GSL) combination therapy for BR PC with arterial involvement (BR-A PC) and LA PC. In our phase II trial, a high recurrence rate of 78% was noted despite a high R0 resection of 76%. Herein, we conducted a retrospective analysis of BR-A PC who underwent NAC, upfront surgery and palliative chemotherapy to evaluate the long term outcomes of NAC. Methods: Consecutive patients with BR-A PC at the University of Tokyo Hospital were retrospectively studied. Clinical outcomes in patients who underwent (NAC group) were compared with those in patients who underwent upfront surgery or palliative chemotherapy (non-NAC group). NAC was introduced in our institution from January 2014. Results: A total of 45 patients (22 non-NAC and 23 NAC group) were diagnosed with BR-A PC between January 2008 and December 2016. There were no significant differences in patient characteristics between non-NAC group and NAC group: Median age of 63 vs. 64, male in 72% vs. 52%, Performance status of 0 in 63% vs. 65%, median pretreatment CA19-9 of 175 vs. 205 U/ml. In non-NAC group, 17 underwent palliative chemotherapy as follows 8 gemcitabine alone, 3 gemcitabine and S-1 combination chemotherapy and 6 other regimens. The remaining 5 patients underwent upfront surgery with an R0 resection rate of 80%. In NAC group, a median duration of neoadjuvant chemotherapy was 4 months. A total of 14 patients underwent surgical resection with an R0 resection rate of 76%. The remaining 9 patients had disease progression during NAC and received 2nd line chemotherapy. The median follow-up time was 16.5 months in non-NAC group and 15.3 months in NAC group. The median overall survival (OS) were 19.3 vs. 21.9 months (p = 0.25). Conclusions: Both R0 resection rate and the median OS were comparable between non-NAC group and NAC group. An ideal regimen of NAC or its duration needs further investigation to prolong OS in BR-A PC.
39: Long-Term Outcomes of a Phase II Trial of Moderate Hypofractionated Image-Guided Intensity Modulated Radiotherapy (IG-IMRT) for Localized Prostate Cancer
