Citations

243 Background: The risk factors for gallbladder cancer (GBC) are poorly understood and preventive therapeutic options have not been identified. The use of aspirin (ASA) and/or statin has been associated with reduced risk of several gastrointestinal cancers. In this study, we explore if the use of ASA or statin is associated with a reduced risk of GBC. Methods: We identified patients with GBC diagnosed between the years 2000 and 2016 at Mayo Clinic. We identified matched controls in 2:1 fashion for age, gender and country of residence from patients who underwent cholecystectomy at Mayo Clinic. We collected information on co-morbidities and use of statins or ASA by retrospective chart review. We compared baseline characteristics between cases and controls using Fisher’s exact test for categorical variables and Mann-Whitney U test for continuous variables. We used binomial logistic regression to calculate the odds ratio (OR) and 95% confidence intervals (CI) to estimate the association of ASA or statin use with GBC. The logistic regression model included history of cholelithiasis, diabetes, hypercholesterolemia (HCL), hypertension (HTN), hyperthyroidism, hypothyroidism, primary sclerosing cholangitis (PSC), inflammatory bowel disease (IBD), cirrhosis and statin or ASA use as covariates. Results: 633 cases and 1,266 controls were included in our final analysis. The median age at diagnosis of cases and controls was 67 years. The control group had a significantly (p < 0.05) higher proportion of patients with cholelithiasis, HCL, HTN, hypothyroidism and liver cirrhosis compared to the cases. The case group,contrarily, had a significantly higher proportion of patients with PSC and IBD. In univariate analysis, ASA (OR: 0.41; 95% CI: 0.33-0.52) or statin (OR: 0.48; 95% CI: 0.38-0.60) use was associated with a lower risk of GBC (p < 0.001). However, in multivariate analysis, ASA use was associated with a lower risk of GBC (OR: 0.52; 95% CI: 0.41-0.67, p < 0.001) whereas statin use was not (OR: 0.76; 95% CI: 0.56-1.03, p = 0.08). Conclusions: Our study demonstrates that aspirin use is associated with a reduced risk of GBC, whereas statin use is not. Further studies on GBC are needed to confirm these results and to elucidate mechanisms that explain the risk reduction with aspirin.

728 Background: Adjuvant FOLFOX therapy for stage II patients remains controversial, and selection criteria are imprecise. We examined the trend of disease-free survival (DFS: time to recurrence or death, whichever occurs first); time to recurrence (TTR: time to recurrence, censored at death without recurrence); survival after recurrence (SAR); and overall survival (OS) of pts treated with FOLFOX over a ten-year period. Methods: Outcomes of pts with stage II colon cancer enrolled in 6 adjuvant trials receiving FOLFOX alone were analyzed. Pt enrollment period was dichotomized as old (1998 – 2003) vs. new era (2004 – 2009) based on the FDA approval date of bevacizumab. 3/5yr event-free rates were estimated using adjusted Kaplan-Meier methods. Outcomes were compared between the two eras by multivariate Cox model. To control for potential confounding effects, all analyses were adjusted for age, gender, performance score, T stage, number of lymph nodes (LNs) examined, tumor side, and histologic grade. Results: In total, 1,122 pts with stage II were identified; 71% and 29% were treated in the old and new era, respectively. Pts enrolled in the new era were significantly younger and more likely to have higher tumor-grade and right-sided tumors compared to old era. More pts in the new era (71%) had ≥12 LNs examined compared to the old era (53%). After adjusting for potential confounding effects, no difference in DFS, TTR, SAR or OS between old and new eras was found (Table). Although median SAR increased from 13.6 to 26 months over time, this was not statistically significant, likely due to lack of power. An increased TTR over time (HRadj. 0.41, padj.= 0.002) was observed in pts with ≥12 LNs examined (3-yr TTR: 92% in old era vs. 96% in new era), but not pts with <12 LNs examined (pinteraction = 0.04). Conclusions: In stage II colon cancer pts who received adjuvant FOLFOX, no significant increase of DFS or OS was observed over time. However TTR was longer only in pts with ≥12 LNs examined. [Table: see text]

724 Background: Adjuvant FOLFOX is the standard of care for pts with stage III colon cancer and a platform to test new agents. Improvements in supportive care and development of newer treatments for metastatic disease impact the overall outcome of pts treated with adjuvant therapy. We examined the trend of disease-free survival (DFS), survival after recurrence (SAR), and overall survival (OS) of pts treated with FOLFOX over a ten-year period. Methods: Outcomes of colon cancer pts enrolled in 6 adjuvant trials receiving FOLFOX alone were analyzed. Pt enrollment period was dichotomized as old (1998 – 2003) vs. new era (2004 – 2009) based on the FDA approval date of bevacizumab. 3/5yr event-free rates were estimated by adjusted Kaplan-Meier methods. Outcomes were compared between the two eras by Cox model. To control for potential confounding effects, all analyses were adjusted for age, gender, performance score, T/N stage, tumor sidedness and histologic grade. Results: In total, 7,230 pts (stage II [n = 1122]; stage III [n = 6,108]) were identified; 32% and 68% were treated in the old and new era, respectively. Stage III pts enrolled in the new era were significantly younger, more likely to have T4/N2 disease, higher tumor grade, and left-sided tumors. After adjusting for pt characteristics, no difference in DFS was seen over time. However prolonged SAR and OS were observed in pts treated in the new era (Table). 5yr OS increased from 76% to 80% over time. Median SAR improved from 14.8 to 26.4 months. Conclusions: Stage III colon cancer pts who received adjuvant FOLFOX experienced significant improvements in SAR and OS—but not DFS—over time. In view of the improvements in OS and nearly doubled SAR, the optimal duration of OS follow-up to evaluate the benefits of adjuvant therapy (currently 5 years) should be reassessed, and ACCENT investigators are planning to conduct these additional analyses using their large pooled-trial database. [Table: see text]

452 Background: Surgical resection is the only curative treatment for patients with gallbladder cancer, despite surgical advances many patients ultimately develop recurrent disease. Management of resected gallbladder cancer mostly relies on single-arm trials and retrospective observations. The purpose of our study is to assess the role of adjuvant therapy in stage I-III gallbladder cancer patients who have undergone surgical resection. Methods: Clinical data were collected on 251 patients who underwent surgical resection for stage I-III gallbladder cancer and presented to Mayo clinic from January 2000-December 2015. Patients were then classified into adjuvant treatment group and surveillance only group. Overall survival and recurrence were compared between the two groups. Results: 78 (31.1%) patients received adjuvant therapy while 173 patients were observed only. Patients who received adjuvant tended to be younger (63.0[SD 11] vs 66.2 [SD 13.1]), have higher stage, and underwent extended surgery. Most patients received chemoradiotherapy (55) with 5-Fluorouracil (67.3%) and capecitabine (25.5%) as radiosensitizing agents. 21 patients received additional adjuvant chemotherapy. 27% of patients received chemotherapy as the sole adjuvant treatment. The most common chemo regimens included gemcitabine (52.3%) and gemcitabine plus cisplatin combination (23.8%). On multivariate analysis patients > 65 years(HR 1.53 [1.07-2.19], p = 0.02), males (HR 1.7 [1.2-2.4], p = 0.003), positive margins (2.77 [1.69-4.38], p < 0.01), and stage III (HR 1.91 [1.35-2.70], p < 0.01) had worse overall survival. Patients who underwent extended radical resection (HR 0.73 [0.51-1.05], p = 0.09) had better overall survival. Adjuvant therapy had no statistical significant effect on overall survival (HR 1.10 [0.75-1.59], p = 0.63 or disease free survival (HR 1.05 [0.69-1.59], p = 0.81) on overall population. However, in stage IIIB, patients receiving adjuvant therapy had better overall survival (HR 0.51 [0.25-1.01], p = 0.05) and disease free survival (HR 0.45 [0.19-1.09], p = 0.06). Conclusions: In our study, adjuvant treatment, especially chemoradiation therapy, was only beneficial in patients with stage IIIb gallbladder cancer patients.

450 Background: The standard treatment for patients with gallbladder cancer is a combination of gemcitabine and cisplatin based on ABC-02 trial. However, there are no guidelines regarding treatment after first-line therapy. We retrospectively analyzed the efficacy and overall survival of different second-line regimens. Methods: We identified 203 patients with advanced gallbladder cancer who received palliative treatment between January 2000 and December 2015 at Mayo Clinic, Rochester. RECIST criteria was used to assess response. Results: 68 patients received second-line chemotherapy. Median age was 63 years (range: 32-86) and majority were males (60.6%). The median time from the diagnosis to the start of the second line chemotherapy was 8 (1-120) months. The most common used second-line chemotherapy were FOLFOX (14), gemcitabine alone (10), single agent fluoropyrimidine (11), gemcitabine with capecitabine (5), and capecitabine with oxaliplatin (4). There were 30 patients that received 5-fluorouracil based regimens, 20 patients received gemcitabine-based regimen, 3 patients received taxane-based regimen, and 15 patients received other types of chemotherapy. Median progression free survival and overall survival was 2.1 (1.8-2.7) and 16.7 (13.2-21.3) months respectively. There were 10 (52%), 11 (37%), 2 (67%), 5 (33%) with partial response and stable disease in 5-fluorouracil-based, gemcitabine-based, taxane-based, and others, respectively. There were no difference in PFS, with median PFS of 2.5, 2.0, 2.8 and 2.3 months, respectively (p=0.43). The overall survival were 15.7 (8.9-40.2), 15.0 (10.7-21.3), 40.3 (22.0-47.0), and 20.4 (9.2-30.7) months, respectively (p=0.83). There were 27 patients that received single agent chemotherapy and 41 patients that received combined regimen. There were 17 (42%) patients and 13 (48%) patients with partial response or stable disease in single and combined regimen. There were no differences in progression free survival and overall survival between single and multi agent chemotherapy. Conclusions: In this largest single institution study, second-line chemotherapy regimens for gallbladder cancer provided benefit in select patients and there is an urgent need to develop more active therapeutic regimens.

Background: Various vascular pedicles have been used to supply the proximal fibula for vascularized epiphyseal transfer. The optimal pedicle has, however, not been agreed on. This study aimed to describe the detailed vascular anatomy of the proximal fibula to assist the surgeon in choosing the optimal pedicle. Methods: Twenty-eight lower extremities were injected with latex or a mixture of latex and barium sulfate. Vessels supplying the proximal fibula were identified and dissected, and the course, diameter, anatomical relations, length, and branches were documented. In the barium group, high-resolution computed tomographic scanning was conducted before dissection. In seven specimens, branches of the deep peroneal nerve to the tibialis anterior muscle were carefully preserved, and their relation to the proximal fibular vascularity was noted. Results: An anastomotic vascular network supplied the proximal fibula. This was formed superiorly by branches of the inferior lateral genicular artery, and inferiorly by branches of the anterior tibial artery, the most important of which were the first and second recurrent epiphyseal arteries. One or more deep peroneal nerve branches passed deep to the first recurrent epiphyseal artery in all specimens examined. In five specimens, all of the branches were superficial to the second recurrent epiphyseal artery, whereas two had branches deep to it. Conclusions: The proximal fibula can be transferred using the inferior lateral genicular or anterior tibial artery because of the existing anastomosis. Factors including length of pedicle, potential for nerve injury, and diaphyseal portion to be harvested should be considered in the pedicle choice.