BACKGROUND: Salivary duct carcinoma (SDC) and adenocarcinoma, not otherwise specified (adeno-NOS), are rare salivary gland cancers. Data on the efficacy of systemic therapy for these diseases are limited. METHODS: Data were retrospectively collected from patients seen at The University of Texas MD Anderson Cancer Center during 1990 to 2020. Objective response rate (ORR) was assessed per RECIST v1.1. Recurrence-free survival (RFS), progression-free survival (PFS), and overall survival (OS) were assessed by Kaplan-Meier method. Cox regression model was performed to identify predictors of survival. RESULTS: The analysis included 200 patients (110 with SDC and 90 with adeno-NOS); 77% had androgen-receptor-positive tumors and 47% had HER2-positive (2+-3+) tumors. Most patients without metastasis at diagnosis underwent surgery (98%) and postoperative radiotherapy (87%). Recurrence rate was 55%, and the median RFS was 2 years. Nodal involvement and positive surgical margins were associated with recurrence (P < .005). Among patients with stage IVA-B disease, addition of systemic therapy to local therapy increased OS (P = .049). The most-used palliative-systemic-therapy regimen was platinum doublet ± trastuzumab. For first-line therapy, the ORR and median PFS were 33% and 5.76 months, respectively, and for second-line therapy the ORR and median PFS were 25% and 5.3 months, respectively. ORR and PFS were higher with HER2targeting agents. Median OS was 5 years overall and 2 years for metastatic disease. Older age and higher stage were associated with worse OS. CONCLUSION: Adding systemic therapy to local therapy may improve outcomes of patients with locoregionally advanced SDC or adeno-NOS. Except for HER2-targeted therapy, response to palliative systemic therapy is limited. These findings may be used as a benchmark for future drug development.

Objective: Methicillin-resistant Staphylococcus aureus (MRSA) nasal swabs are utilized to guide the discontinuation of empiric MRSA therapy. In multiple studies, MRSA nasal swabs have been shown to have a negative predictive value (NPV) of ~99% in non-oncology patients with pneumonia and other infections. We evaluated the performance characteristics of a negative MRSA nasal swab in the acute myeloid leukemia (AML) populaion to determine its NPV. Design: Retrospective chart review. Patients: This study included adult AML patients with a suspected infection and a MRSA nasal swab collected between 2013 and 2018. Methods: MRSA nasal swab and culture-documented infections were identified to determine the sensitivity, specificity, NPV, and positive predictive value of the MRSA nasal swabs. Results: In total, 194 patients were identified, and 484 discrete encounters were analyzed. Overall, 468 (97%) encounters had a negative MRSA nasal swab upon admission with no cultured documented MRSA infection during their hospitalization. However, 3 encounters (0.6%) had a negative MRSA nasal swab with a subsequent cultured documented MRSA infection during their admission. Identified infections were bacteremia (n = 2) and confirmed pneumonia (n = 1). MRSA nasal swab had a sensitivity of 62% (95% CI, 0.24–0.91), specificity of 98% (95% CI, 0.96–0.99), positive predictive value of 38% (95% CI, 0.21–0.6), and NPV of 99% (95% CI, 0.98–1). Conclusions: A negative MRSA nasal swab has a 99% NPV for subsequent MRSA infections in AML patients with no prior history of MRSA colonization or infection. Based on these findings, a negative MRSA nasal swab can help guide de-escalation of empiric MRSA antibiotic therapy.

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6084 Background: Salivary duct carcinoma (SDC) and adenocarcinoma, not otherwise specified (Adeno-NOS) are rare and aggressive subtypes of salivary gland cancers. Biomarker studies revealed targetable alterations such as androgen receptor (AR) and HER2 overexpression; nevertheless, chemotherapy (CT) remains the cornerstone treatment of patients (pts) with locally advanced or metastatic disease based on limited efficacy data. We sought to describe the treatment patterns and outcomes of SDC and Adeno-NOS pts. Methods: We retrospectively collected clinicopathological, treatment, and outcomes data of SDC or Adeno-NOS pts that were seen at MD Anderson from 1990-2020. AR positivity was defined by IHC staining in ≥ 10% of tumor cells, and HER2 by IHC 2+ or 3+ scores. Overall response rate (ORR) was assessed by an independent radiologist per RECIST v1.1. Recurrence-free survival (RFS) and overall survival (OS) from diagnosis were estimated using log-rank test. A multivariable cox regression model was performed to estimate the hazard-ratio (HR) of risk factors on pts outcomes. Results: 200 pts were included, 110 had SDC and 90 Adeno-NOS. Most pts (61%) presented with locoregional disease (stage III-IVB), while 13% had distant metastasis (IVC). AR was positive in 77% of cases, and HER2 in 47%. In the curative setting (N=174), 98% pts underwent surgery and 90% radiotherapy (RT); 15 pts with stage IVA-B disease had aggressive trimodality therapy including surgery, RT, and systemic therapy. Overall, 55% pts recurred. The mRFS and 5-y RFS rate were 24 mos (95%CI, 16-43) and 34.5%, respectively. For pts with IV-A-B stage, trimodality therapy was associated with an improved OS in comparison to surgery and/or RT (39 mos vs NA, p=0.04). In the metastatic setting, 82 pts received ≥1 line of systemic therapy; the preferred 1st line regimen was platinum/taxane with or without trastuzumab (50%). Table summarizes the ORR and mPFS to each therapy line. ORR and PFS was higher for HER2-targeted therapy (1st line: 47% and 11 mos; 2nd line 29% and 6 mos; respectively); only 10 pts received androgen blockage. At a median follow-up of 7.5 y, the mOS was 5 ys and the 5-y OS rate was 50%. In multivariate analysis, higher T and N stages (HR 2.1 and 3.8, p<0.05), and positive margins (HR 2.0, p=0.003) were associated with worse RFS; older age (HR 1.03, p=0.003), and higher TNM stage (HR 1.78, p=0.006) were associated with worse OS. HER2 expression was not prognostic. Conclusions: This study validates prognostic factors in SDC and adeno-NOS and is the largest series to report outcomes to palliative systemic therapy per treatment line, providing a benchmark for future studies in these diseases. Aggressive trimodality therapy may improve outcomes of pts with stage IVA-B disease.[Table: see text]

BackgroundMethicillin-Resistant Staphylococcus aureus (MRSA) nasal swabs are utilized to guide discontinuation of empiric MRSA therapy. In multiple studies, MRSA nasal swabs has been shown to have a negative predictive value (NPV) of ~99% in non-oncology patients with pneumonia and other infections. At Yale New Haven Hospital (YNHH), a negative MRSA nasal swab is utilized in acute myeloid leukemia (AML) patients to de-escalate empiric MRSA antibiotic therapy. The primary endpoint was to assess the percentage of patients with a negative MRSA nasal swab who developed a culture documented (CD) MRSA infection during their admission. Secondary endpoints included the number of MRSA nasal swabs that were initially negative but converted to positive, and the types of MRSA infections.MethodsThis was a retrospective chart review of AML patients with a suspected infection and a MRSA nasal swab collected at YNHH between 2013 and 2018. Patients were excluded if < 18 years old, prior confirmed MRSA infection or positive MRSA nasal swab within the past year.Results194 patients were identified with 484 discrete encounters analyzed. Hematopoietic stem cell transplantation occurred in 83 (43%) patients. A total of 468 (97%) encounters had a negative MRSA nasal swab upon admission with no CD MRSA infection during their hospitalization. Three encounters (0.6%) had a negative MRSA nasal swab with a subsequent CD MRSA infection during their admission. Identified infections were bacteremia (2) and pneumonia (1). Median duration from the negative MRSA nasal swab to CD infection was 16 days. Thirteen encounters (3%) had a positive MRSA nasal swab, 5 of which had a CD MRSA infection. Infections included bacteremia (3), pneumonia (2), and sputum with negative chest X-ray (1). MRSA nasal swab had a sensitivity of 57% (CI 0.56–0.58), specificity of 98% (CI 0.98–0.98) positive predictive value of 31% (CI 0.3–0.32), and NPV of 99% (CI 0.99–0.99).ConclusionThe results of this retrospective study demonstrate that a negative MRSA nasal swab has a 99% NPV for subsequent MRSA infections in AML patients with no prior history of MRSA colonization or infection. Based on these findings, a negative MRSA nasal swab can help guide de-escalation of empiric MRSA antibiotic therapy in this immunosuppressed population.Disclosures All authors: No reported disclosures.