Goyal, Gaurav

Abstract Background: Langerhans cell sarcoma (LCS) is a rare malignant neoplasm of Langerhans cells characterized by multi-organ involvement and an aggressive clinical course.Given the rarity of the disease, the true epidemiological data on LCS are lacking, and most of our knowledge is obtained from institutional case series. In this study, we utilized two national databases- the Surveillance, Epidemiology, and End Results (SEER) Program database (https://seer.cancer.gov/) and National Cancer Data Base (NCDB) to study the incidence, clinical presentation, and outcomes of LCS. Methods: We calculated LCS incidence (cases/10, 000, 000 individuals) from SEER database using SEER*Stat (v 8.3.4; https://seer.cancer.gov/seerstat/) statistical software. SEER is a population-based registry program of the United States National Cancer Institute that covers approximately 28% of the population. We identified LCS cases that were confirmed histologically using International Classification of Diseases for Oncology edition 3 (ICD-0-3) histology code 9756/3 from SEER 18 (2000-2014) registry. As the disease was mandatory reportable only after 2001, we included cases that were diagnosed after 2001 in the analysis. Demographic patterns, clinical presentation, and overall survival (OS) were calculated utilizing the patient level data from the NCDB Participant User File. NCDB is a joint program by the American College of Surgeons and American Cancer Society that represents approximately 70% of newly diagnosed cancer cases in the nation. All patients aged > 18 years with a diagnosis LCS (ICD-0-3 Code 9756/3) from 2004 to 2015 were included. To ensure accuracy of follow-up, we excluded the patients that were not treated at the same facility of diagnosis from survival analysis. Results: A total of 25 cases of LCS were reported to SEER between 2000 and 2014. The overall incidence of the disease was 0.2 per 10,000,000 [95% CI:0.1-0.3] and was similar among males and females (p=0.33). The incidence of the disease did not differ significantly among different races (whites, blacks and other races) (p=0.56). Between 2004 and 2015, 52 patients with newly diagnosed LCS were identified from NCDB and 60% were males. The median age of diagnosis was 62 (range, 19-90 years). The most common sites of the presentation were connective tissue (29%; n=15), reticuloendothelial system (RES) and hematopoietic system (25%; n=13), skin (19%, n=10), gastrointestinal (10%, n=5), bones and joints (8%, n=4), brain (2%, n=1) and breast (2%, n=1). Site specific details were missing in 27% (n=14) of cases. Out of the 52 patients, twenty patients (39%) received chemotherapy as first-line therapy, while 24 (46%) received surgery and 15 (29%) received radiation therapy. After a median follow up of 18 (range, 1-144) months, 27 patients (52%) had died. The one- year survival rate was 62%, and the median OS was 19 months (Fig. 1A). We also calculated the 1-year disease-specific survival and OS using SEER database, and was 74% and 63%, respectively. After censoring the patients with hematopoietic and RES involvement, the patients who were managed with radiation therapy (median dose 3960 cGy, range 750-6400) had a better OS as compared to those who received no radiation therapy (p=0.03, Fig. 1B). On the contrary, after excluding the patients with hematopoietic and RES as primary site, no significant difference in OS was noted between the patients who were managed with and without surgery (17 vs 21 months; p = 0.75; Fig. 1C). In addition, post-surgical radiation or chemotherapy had no significant benefit in median OS (p=0.25). Among patients with hematopoietic and RES involvement, there was no association between OS and receipt of chemotherapy (p = 0.16; Fig. 1D); however, the number of patients who received chemotherapy was small (n=6). Conclusion: This dual-national registry study shows that LCS is extremely rare, and has a poor prognosis. Although the data regarding optimal management of LCS are limited, our study demonstrates that radiation therapy may offer survival advantage in patients without hematopoietic and RES involvement. Disclosures No relevant conflicts of interest to declare.

Abstract Introduction Isolated myeloid sarcoma is a rare form (<1%) of acute myeloid leukemia presenting as extramedullary tumor. Contemporary clinical data are mostly limited to institutional case series. Using the National Cancer Database, the largest public cancer registry covering >70% of all newly diagnosed cancers in the United States, we determined the patterns of anatomical presentation and clinical outcome of myeloid sarcoma. Methods We identified patients with a histologically confirmed diagnosis of isolated myeloid sarcoma from 2004-2013 using International Classification of Diseases for Oncology version 3 (ICD-O-3) code: 9930. To allow at least 1 year of follow-up, only patients diagnosed from 2004-2012 were included in the survival analysis using Kaplan-Meier estimates. Results A total of 746 patients were included in the study. The median age of patients was 59 years (range, 41 to 73) and 56% were males. The anatomical distribution and median overall survival of patients are depicted in the Table. The top 3 most common sites of presentation were connective/soft tissues (31.3%), skin/breast (12.3%), and digestive system (10.3%). Compared to other races, Blacks were more likely to have presentation in bones/joints (11.8% vs 6.3% in others), lymph nodes/spleen (22.1% vs. 9%), and less likely in skin/breast (4.4% vs. 13.8%). Asians were more likely to present with cardiopulmonary/mediastinal disease as compared to other races (13.6% vs. 4.2%). According to outcomes, we can categorize the patients into 3 groups: good (median overall survival >30 months: reproductive and digestive systems), intermediate (median overall survival 15-30 months: head/neck and kidney/bladder/retroperitoneum/adrenal), and poor (median overall survival <15 months: nervous system, connective/soft tissue, and bones/joints). There was no significant difference in overall survival between males and females (P =0.06). Among the races, Blacks had the worst overall survival (P =0.02; Figure). Conclusions This is the largest registry-based study on isolated myeloid sarcoma in the United States. Isolated myeloid sarcoma has a diverse anatomic clinical presentation and the overall survival varied significantly according to sites of presentation and racial subgroups. The results of our study may aid the prognostication of patients for treatment decision making and in the understanding of the biological differences by anatomic sites of presentation. Table Anatomical distribution and median overall survival of isolated myeloid sarcoma Table. Anatomical distribution and median overall survival of isolated myeloid sarcoma Figure Overall survival by sex and race in isolated myeloid sarcoma Figure. Overall survival by sex and race in isolated myeloid sarcoma Disclosures Al-Kali: Onconova Therapeutics, Inc.: Research Funding; Celgene: Research Funding.

Abstract Introduction Plasmacytomas comprise approximately 3% of all plasma cell malignancies. There is a paucity of large studies assessing clinical features and outcomes of this relatively uncommon disease. Our objective was to describe the patterns of clinical presentation and survival of plasmacytomas using the National Cancer Data Base (NCDB). Methods This is a retrospective study of patients with histologically confirmed diagnosis of plasmacytoma from 2000-2011 using International Classification of Diseases for Oncology version 3 (ICD-0-3) code: 9930. Patients who had bone marrow involvement were excluded from the analysis. Plasmacytomas were grouped into two broad categories: extramedullary plasmacytoma (P-EM) and bone plasmacytoma (P-bone) based on their anatomical locations. Overall survival was analyzed using Kaplan-Meier estimates. Results A total of 6,939 patients were included in the study (median age 64 years; range 18-90 years). Approximately 62% of these patients were males and 46% patients were ≥ 70 years. Racial/ethnic distribution of the disease was as follows: 76% Whites, 13% Blacks, 7% Hispanics, and 4% others. The anatomical distribution and survival of patients is depicted in the Table. P-EM comprised 30% of the patients, with remaining 70% presenting as P-bone. Among P-EM, most common sites of presentation were upper aero-digestive tract (41%) and connective/soft tissue (20%). After a median follow up of 65 months, the overall survival of P-EM was significantly better than P-bone (113 vs. 78 months; Figure). Based on outcomes, we can categorize the P-EM patients into 3 groups: good (median overall survival > 120 months: upper aero-digestive tract, lymph nodes, endocrine and digestive system), intermediate (median overall survival 90-120 months: nervous system, eye/orbit, pulmonary), and poor (median overall survival <90 months: connective/soft tissue, cardiac/mediastinum, genitourinary, and hepatobiliary system). Males had better overall survival than females in P-bone (84 vs. 67 months; p<0.0001), but had no significant survival difference in P-EM (109 vs. 116 months; p=0.7). In the P-EM group, median overall survival was worst for Blacks (98 months vs. Whites- 108 months, Hispanics- not reached, others-145 months). Conversely, for P-bone, Blacks had a better overall survival than Whites (Blacks- 99 months, Whites- 72 months, Hispanics- 156, others-84 months). Patients who were treated at an academic center had better overall survival than patients treated at other/community centers both in case of P-EM (130 vs. 108 months) and P-bone (107 vs. 69 months). Conclusions This is the largest registry-based study on plasmacytoma in the United States. Plasmacytomas have varied clinical presentation, along with significantly different survival based on sites of presentation, race, sex, and treatment facility. Our study results point toward important differences in disease biology based on location and may aid in assessing prognosis for planning treatment. Table. Anatomical distribution and median overall survival of plasmacytomas. Table Overall survival based on location (P-EM: extramedullary plasmacytoma; P-bone: bone plasmacytoma) Table. Overall survival based on location (P-EM: extramedullary plasmacytoma; P-bone: bone plasmacytoma) Figure Figure. Disclosures Kumar: Noxxon Pharma: Consultancy, Research Funding; Kesios: Consultancy; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Consultancy, Research Funding; BMS: Consultancy; Array BioPharma: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Glycomimetics: Consultancy; AbbVie: Research Funding; Janssen: Consultancy, Research Funding.

6581 Background: While AC is recommended for all patients with stage IIA, IIB, and IIIA NSCLC, its use and benefit among the elderly population is unclear. Methods: We identified patients with stage IIA, IIB, or IIIA NSCLC using the National Cancer Database from 2006-2014. Patients were divided into age groups ≤65, 66-70, 71-75, 76-80, > 80 years. Trends in AC use, factors influencing AC administration, and outcomes associated with AC were studied. Results: Out of 27368 patients, 13464 received AC and 13904 did not. 11% had stage IIA disease, 50% had stage IIB disease and 39% had stage IIIA disease. AC use was lower with increasing age (49% age ≤65 vs. 3% age > 80 (P < 0.0001)). Temporal use of chemotherapy for each age group was unchanged from 2006-2014. In multivariate logistic regression analysis, factors predictive of lower AC use were older age, Medicare or Medicaid insurance, academic center, and higher Charlson Comorbidity Index (CCI). Stage IIIA (OR 1.4, 95% CI 1.3-1.6) and Stage IIB (OR 1.3, 95% CI 1.2-1.4) had a higher chance of receiving AC than stage IIA. In a Cox proportional hazard model, younger age, female sex, academic center, private insurance, higher income, lower CCI, West coast center and AC were associated with better outcomes. When stratified by age and stage, AC was still associated with better survival (Table). Conclusions: AC utilization in stages IIA, IIB and IIIA NSCLC remains low, despite its association with improved survival in the elderly. Future clinical trials may be needed focused on elderly patients to establish the best regimen to optimize outcomes. [Table: see text]

PURPOSE Time to event is an important aspect of clinical decision making. This is particularly true when diseases have highly heterogeneous presentations and prognoses, as in chronic lymphocytic lymphoma (CLL). Although machine learning methods can readily learn complex nonlinear relationships, many methods are criticized as inadequate because of limited interpretability. We propose using unsupervised clustering of the continuous output of machine learning models to provide discrete risk stratification for predicting time to first treatment in a cohort of patients with CLL. PATIENTS AND METHODS A total of 737 treatment-naïve patients with CLL diagnosed at Mayo Clinic were included in this study. We compared predictive abilities for two survival models (Cox proportional hazards and random survival forest) and four classification methods (logistic regression, support vector machines, random forest, and gradient boosting machine). Probability of treatment was then stratified. RESULTS Machine learning methods did not yield significantly more accurate predictions of time to first treatment. However, automated risk stratification provided by clustering was able to better differentiate patients who were at risk for treatment within 1 year than models developed using standard survival analysis techniques. CONCLUSION Clustering the posterior probabilities of machine learning models provides a way to better interpret machine learning models.

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.