Hajjar, Adnan Humam

e19543 Background: Multiple myeloma (MM) is a plasma cell malignancy characterized by immune dysfunction and end-organ damage. Emerging preclinical evidence suggests vitamin D is implicated in MM biology through effects on plasma cell differentiation and immune regulation. Vitamin D deficiency is common among patients with MM, yet its prognostic significance remains unclear. Clarifying its role may inform risk stratification and supportive management in MM. Methods: We conducted a retrospective cohort study using the multicenter TriNetX research network. Adults aged ≥20 years diagnosed with MM between 2011 and 2024 were included. Vitamin D status was defined using serum 25-hydroxyvitamin D levels, with deficiency defined as ≤30 ng/mL and normal levels defined as 31–80 ng/mL. Patients were stratified into two groups based on vitamin D status at the time of MM diagnosis. Propensity score matching (1:1) was performed to balance age, sex, race, baseline laboratory values, and clinically relevant comorbidities between groups. Kaplan–Meier survival analyses and Cox proportional hazards models were performed for outcome analyses. Results: A total of 36,273 patients with MM were included, of whom 42% (n = 15,262) had vitamin D deficiency. After propensity score matching, 14,023 vitamin D–deficient patients were well balanced with 14,006 non-deficient patients across baseline characteristics. In the matched cohort, the mean age was 64 years, 49% were female, and 64% were White. At five years, vitamin D deficiency was associated with a significantly higher risk of mortality (hazard ratio [HR] 1.63, 95% CI 1.54–1.72), with lower five-year overall survival (OS) compared with non-deficient patients (71.1% vs 80.8%, p<0.05). Vitamin D deficiency was also associated with increased risks of pneumonia (risk ratio [RR] 1.11), bacteremia (RR 1.22), and critical care admission (RR 1.30) (all p<0.05). Additionally, deficient patients had higher risks of acute kidney injury (AKI) (RR 1.19) and venous thromboembolism (RR 1.18) (both p<0.05). Notably, the risk of MM relapse was modestly increased among vitamin D-deficient patients (RR 1.07, 95% CI 1.01–1.13). No significant associations were observed between vitamin D deficiency and amyloidosis or pathologic fractures. In multivariable Cox regression, vitamin D deficiency remained independently associated with worse five-year OS (adjusted HR 1.60, 95% CI 1.52–1.67). Conclusions: This study highlights the negative impact of vitamin D deficiency in patients with MM. It identifies a high-risk subgroup of patients characterized by worse five-year OS, higher rates of serious infections, AKI, critical care utilization, and an increased risk of MM relapse. These findings suggest vitamin D deficiency as a clinically relevant prognostic marker in MM. Prospective studies are warranted to determine whether vitamin D level optimization can improve MM outcomes.

800 Background: Primary squamous cell carcinoma (SCC) of the small intestine is exceedingly rare and associated with poor prognosis. Literature is currently limited to a few case reports, and, to our knowledge, this is the first population-based analysis of patients with small intestine SCC. This study aimed to identify patient demographics and predictors of survival outcomes. Methods: Patients with histologically confirmed primary SCC of the small intestine diagnosed between 2000 and 2022 were identified from the SEER database; autopsy-only cases were excluded. Patient demographics, tumor site, stage (SEER summary stage), and initial treatments were summarized. Overall survival (OS) was defined from diagnosis to death, with one-year OS estimated by Kaplan–Meier methods. Multivariate Cox proportional hazards models evaluated associations between patient variables (age, sex, race, residence, year of diagnosis, surgery, and chemotherapy) and mortality. All statistical analyses were performed using R version 4.4.2. Results: A total of 89 patients diagnosed with primary small intestine SCC were identified. The median age at diagnosis was 68 years; 43 % were female, and 67 % were non-Hispanic White. Most patients (82 %) resided in urban counties. Tumor site was mostly the duodenum (37 %), followed by ileum (16 %) and jejunum (10 %); 33 % were not otherwise specified. Among patients with a recorded stage, 45 % had localized disease, 38 % regional disease, and 17 % distant metastases. Initial treatment comprised surgery in 60 % of patients, chemotherapy in 25 %, and radiation in 10%. The median OS was approximately six months, and the one-year OS was 36.7 % (95 % CI 27.9–48.3). Women had a higher one-year OS (42 %) than men (33 %), although this difference was not statistically significant. In multivariable analysis, surgical resection was associated with a markedly lower hazard of death (HR = 0.43, 95 % CI 0.25–0.74). Chemotherapy was associated with an insignificantly improved survival (HR 0.54, 95 % CI 0.27–1.09). Additionally, rural residence (HR ≈ 2.9) and older age (HR ≈ 1.03) were independently associated with worse survival (p<0.05). Conclusions: This population-based study highlights the rarity and aggressiveness of primary small bowel SCC, with a median OS of six months. Surgical resection was strongly associated with improved survival (adjusted HR ≈ 0.43), reinforcing its role as the cornerstone of management. Chemotherapy showed a nonsignificant survival benefit, highlighting the need for prospective studies. The association of rural residence with higher mortality suggests disparities in access to care and underscores the need for strategies to improve early detection and referral. Overall, these findings support a multimodal approach centered on surgery and warrant further studies to elucidate pathogenesis and optimize systemic therapy.

Abstract Introduction Hodgkin's lymphoma is known to have favorable survival outcomes; however, limited data exist regarding survival disparities between rural and urban populations. In this study, we aimed to investigate the differences in survival outcomes between the two populations. Methods Data for patients diagnosed with Hodgkin lymphoma (HL) between 2000 and 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Rurality was identified using the Rural-Urban Continuum Codes (RUCC). Patients aged ≥ 20 years with HL as the only primary malignancy were included. Individuals with unknown race or those diagnosed at autopsy were excluded. The Ann Arbor Staging system was utilized for HL staging at diagnosis. HL-specific survival was defined as the time from diagnosis to death attributable to HL and was censored at the time of death from other causes or at last follow-up. Meanwhile, overall survival (OS) was defined as the time from diagnosis to death from any cause and was censored if the patient was still alive. A Cox proportional hazards model was performed to analyze the predictors for 10-year overall and HL-specific mortality. All statistical analyses were conducted using RStudio (version 2024.12.0). Results Between 2000 and 2015, a total of 22,505 patients diagnosed with Hodgkin lymphoma (HL) were included in the analysis. Among them, 13,657 (61%) were aged between 20 and 44 years. Overall, 10,137 patients (47%) were female, 14,885 (66%) were White, 2,672 (12%) were Black, and 3,724 (17%) were Hispanic. The majority of patients resided in urban counties, while only 2,266 (10.1%) lived in rural areas. Among rural patients, 845 (37%) were diagnosed with stage II disease, followed by 475 (21%) with stage III at the time of diagnosis. Notably, both the 10-year overall survival (69.5%) and Hodgkin lymphoma–specific survival (79.7%) were significantly lower among rural patients compared with urban patients (75.3% and 83.5%, respectively; p &lt; 0.001). In the multivariable model for 10-year HL-specific survival, older age (&gt; 65 years) was associated with the highest risk of mortality (HR 10.32; 95% CI 9.42–11.32). Although survival improved over the study period, male patients remained at increased risk of mortality (HR 1.26; 95% CI 1.18–1.35). Urban residence, diagnosis in more recent years, early stage, female sex, White race, and married status were independently associated with improved overall survival (p &lt; 0.01). Conclusion In this population-based study, both the 10-year overall and HL-specific survival were consistently lower among rural vs. urban patients. Male sex, older age, and unmarried status were particularly associated with worse survival outcomes. Further research is warranted to identify possible strategies for improving healthcare access and reducing survival disparities among rural patients.