Citations

672 Background: Rectal squamous cell carcinoma (RSCC) is a rare form of gastrointestinal malignancy. Using the NCDB, we determined the prognostic factors and survival outcomes of RSCC in the United States. Methods: We identified histologically confirmed cases of RSCC from the National Cancer Data Base (2004-2015). Univariate and multivariable methods were used to assess factors associated with survival. Kaplan-Meier method and log-rank test were used to perform overall survival (OS) analysis. Results: Of the 5,527 cases included in our analysis, 67% were female. Median age at diagnosis was 61 years and did not differ by sex. The proportion of patients with stage 1, 2, 3 and 4 diseases were 22%, 16%, 20%, and 11%, respectively (30% unknown stage). Among the ones who received surgical resection of primary tumor, 41%, 30%, 20% and 8% are of stages 1, 2, 3 and 4 respectively. The rate of R0 resection was 54%, 63%, 55% and 38% in stage 1, 2, 3 and 4, respectively. The R0 resection rate was much higher in patients who received neoadjuvant chemo or radiation therapy or both (87%, 78%, 74%, and 57% in stages I, 2, 3 and 4, respectively) as compared to that of their counterparts. On stage wise sub-group OS analysis, stage 1-3 patients had OS benefit from surgery (as compared to no-surgery) (145 vs 90 months, p<0.001) as opposed to 4 disease (16 vs 11 months, p=0.06). Adjuvant radiation therapy improved the median OS in stage 1-3 patients (as compared to no-adjuvant radiation) in patients with positive surgical margins (not reached vs 40 months, p<0.0001). Patients with stage 4 disease treated with radiation therapy had a better median OS than those without (16 vs 6 months, p<0.0001). On therapy wise sub-group analysis, the patients who received surgery only had a median OS of 145 months; surgery + chemoradiation (adjuvant and neoadjuvant) = not reached; whereas patients with chemoradiation only had median OS of 80 months. Conclusions: This is the largest registry-based study on RSCC to date. RSCC had a diverse OS varied significantly according to stage of the disease at presentation and therapy received. Surgical resection of primary tumor was associated with improved OS as compared to that of patients who received chemoradiation.

399 Background: PSCC is a rare form of exocrine pancreatic malignancy with a dismal prognosis. Using the NCDB, we determined the prognostic factors and survival outcomes of PSCC in the United States. Methods: We performed a retrospective analysis of patients with histologically confirmed PSCC from 2004-2015 using NCDB. Kaplan-Meier method and log-rank test were used to perform overall survival (OS) analysis. Hazard Ratios were calculated using the Cox-proportional hazard method. Results: Of the 654 cases included in our analysis, 46% were female. Median age at diagnosis was 70 years and did not differ by sex (p = 0.19). The proportion of patients with stage I, II, III and IV diseases were 5%, 18%, 12%, and 54%, respectively (10%, unknown stage). Among these, 23% (35 of 150) of stage I and II disease, 10% (8 of 78) of stage III, and 2% (7 of 353) received surgical resection of the primary tumor. The rate of R0 resection was 74% in stage I and II; 38% in stage III; 29% in stage IV disease. Median OS for the entire cohort was 4 months and was significantly higher in patients who received surgical resection of the primary tumor (17 vs. 4 months, p < 0.001). On stage wise sub-group analysis, stage I-II patients had OS benefit from surgery (21 vs. 5 months, p < 0.001) as opposed to stage III (7 vs. 6 months, p = 0.31) and IV disease (5 vs. 3 months, p = 0.17). Adjuvant chemotherapy had no role in prolonging survival in stage I-II disease (20 vs 24 months, p = 0.6). Stage IV patients treated with chemotherapy had a better median OS than those without (5 vs. 2 months, p < 0.0001). On Cox multivariable analysis, stage IV disease (HR: 1.92 CI: 1.46-2.52, p < 0.001) and advanced patient age (HR: 1.02; CI:1.01-1.03, p < 0.001 were associated with poor OS, whereas OS was not dependent on the sex, race, grade, insurance status, surgery, and chemotherapy. Conclusions: This is the largest registry-based study on PSCC to date. PSCC had a diverse OS varied significantly according to increasing age and stage of the disease at presentation. Surgical resection of primary tumor was associated with improved OS in stages I-II, whereas chemotherapy improved OS in stage IV disease. The results of our study may aid the prognostication of patients and in treatment decision making.

393 Background: Clinicopathological features and the outcomes of patients with fibrolamellar hepatocellular carcinoma (FLHCC) are not clearly defined. Methods: Data were collected by retrospective chart review on 42 patients with FLHCC treated between 1990 and 2017 at the Mayo Clinic. Clinicopathological characteristics, response to treatment, recurrence pattern and survival were analyzed. Results: Of 42 patients (17 males and 25 females; median age at diagnosis 22 years, range 15 to 39), 10 patients (23%) had stage I disease and 32 patients (77%) had stage II to IVB disease. All 10 patients with stage I disease and 21 of 32 patients with stage II-IVB disease underwent resection at presentation. In stage I patient group, 6 patients experienced recurrence with a median time to recurrence of 30.5 months, resulting in a 5 year overall survival (OS) of 86%. Patients with stage II to IVB disease who underwent resection (n=21) at presentation had a median OS of 32.5 months and 5 year OS of 44%. In the upfront surgery group, 71% of the patients experienced recurrent disease. The median OS of patients with unresectable disease (n=11) was 10 months. Systemic therapy was given to 17 patients which included sorafenib, FOLFOX (5-fluorouracil/leucovorin and oxaliplatin), gemcitabine plus oxaliplatin, single agent adriamycin or gemcitabine, capecitabine plus interferon alfa, gemcitabine plus cisplatin, cisplatin plus adriamycin and nivolumab . Sorafenib was given to 9 patients and 4 patients achieved stable disease (SD) with duration ranging from 5 months to 5 years. One programmed cell death receptor positive-1 patient had a durable complete response after 2 months of therapy with nivolumab. Conclusions: In FLHCC, surgical resection was associated with prolonged OS. However, recurrences were common after the surgery. Limited benefit was derived from the systemic treatment. In rare cases, therapy with a checkpoint inhibitor may provide a viable treatment option.

Abstract Erdheim-Chester disease (ECD) is a rare histiocytosis of the “L” (Langerhans) group with multisystem involvement that can affect the large and medium-sized arteries mimicking vasculitis. Aortic involvement is common but the frequency and outcome of aortic branch vessel abnormalities are less well described. Patients with ECD were retrospectively identified. Images containing information of arterial involvement within 6 months of diagnosis were considered baseline and compared to last follow-up studies. Two physicians independently reviewed the studies to evaluate for presence of abnormalities attributable to ECD. Age and sex-adjusted logistic regression models were used to examine associations between patient characteristics and vessel involvement at baseline. Among a cohort of 64 patients with ECD, 63 had baseline imaging of vascular structures. ECD involvement of at least 1 segment of the aorta was observed in 56%. Abnormalities were also observed in aortic arch branches (26%), visceral branch arteries (40%), iliofemoral arteries (31%), coronary (5%), and pulmonary (3%) arteries. Perinephric fibrosis was strongly associated with the identification of abnormalities in the thoracic aorta (OR 4.92 [1.54, 15.75]; P = .007), abdominal aorta (OR 7.57 [2.28, 25.07]; P = .001) and visceral branch arteries (OR 6.05 [1.52, 24.03]; P = .01) but not pelvic/lower extremity arteries. Complete normalization of arterial abnormalities at follow-up was only observed in 9% or less of arterial segments involved at baseline. Aortic and aortic branch vessel abnormalities are frequently observed in patients with ECD and are often asymptomatic. Partial and/or complete resolution of arterial findings is uncommon.

9044 Background: Prior studies have shown superior surgical outcomes of stage I-III non-small cell lung cancer (NSCLC) in centers with higher patient volumes. However, there is a lack of such information in stage IV NSCLC. In this study, we aim to determine the association between the number of patients with stage IV NSCLC treated annually at a treatment facility (volume) and all-cause mortality (outcome). Methods: Using the National Cancer Database, we identified patients diagnosed with stage IV NSCLC between 2004 and 2013. We classified the facilities by quartiles (Q; mean patients with NSCLC treated per year): Q1: < 13.8; Q2: 13.8 to 23.6, Q3: 23.6 to 30.3, and Q4: > 30.3. We used sandwich variance estimators to account for clustering of patients within facilities and Cox regression to determine the volume-outcome relationship, adjusting for demographic (sex, age, race), socioeconomic (insurance type), receipt of chemotherapy, and comorbid (Charlson-Deyo score) factors and year of diagnosis. Results: There were 281,654 patients with stage IV NSCLC treated at 1,275 facilities. The median age at diagnosis was 66 years, and 55.7% were men. The median annual facility volume was 23.6 patients per year (range, 1.0 to 301.4). The distribution of patients according to facility volume was: Q1: 6.6%, Q2: 14.9%, Q3: 25.4%, and Q4: 53.1%. The unadjusted median overall survival by facility volume was: Q1: 4.4 months, Q2: 4.5 months, Q3: 4.7 months, and Q4: 5.3 months ( P< .001). Multivariable analysis showed that facility volume was independently associated with all-cause mortality. Compared with patients treated at Q4 facilities, patients treated at lower-quartile facilities had a small but significantly higher risk of death (Q3 hazard ratio [HR], 1.05 [95% CI, 1.03 to 1.07]; Q2 HR, 1.06 [95% CI, 1.03 to 1.09]; Q1 HR, 1.09 [95% CI, 1.06 to 1.13]). Conclusions: Patients who were treated for stage IV NSCLC at lower-volume facilities had a significantly higher risk of all-cause mortality compared with those who were treated at lower-volume facilities. [Table: see text]

8050 Background: There is a lack of contemporary studies analyzing the optimum radiation dose and prognostic factors for outcomes of extramedullary plasmacytomas. In this study, we aim to answer these questions by utilizing the National Cancer Data Base (NCDB). Methods: This is a retrospective study of patients with histologically confirmed diagnosis of plasmacytoma from 2000-2011 using NCDB. Patients who had bone marrow involvement were excluded from the analysis. Hazard ratios were calculated using the Cox-proportional hazard method. In addition, we utilized survival trees as a novel tool for assessing prognostic effect of factors among four age quartiles (Q): Q1: 18-52, Q2:52-62, Q3:62-72, and Q4: ≥72 years. Results: A total of 5,056 patients were included in the study (median age 62 years; range, 52-72 years). Of these, 63% were males. Radiation therapy was received by 3,905 patients, with a median radiation dose of 45 Gy. A radiation dose of ≥40 Gy was associated with improved overall survival (OS) as compared to <40 Gy. Factors associated with worse OS included older age (≥65 years) and bone disease (Table). In survival tree analysis, radiation dose ≥44.5 Gy was associated with better OS in Q1 as compared to lower dose. For Q2 and Q3, disease location played a major role, with improved survival seen in upper aero-digestive and lymph node disease as compared to bone and soft tissue. In Q3, among the bone and soft tissue disease, radiation dose ≥ 43.5 Gy was associated with the better survival as compared to ≤43.5 Gy. In Q4, soft tissue and upper aerodigestive plasmacytomas had better outcomes as compared to bone and lymph node disease. Among the latter group, a radiation dose ≥30.3 Gy was associated with improved OS as compared to lower dose. Conclusions: This is the largest study of extramedullary plasmacytomas in the United States. This study shows that dose of radiation has a significant impact on outcomes, in addition to disease location and age. [Table: see text]