Citations

e19532 Background: The diagnosis of amyloidosis requires histological confirmation of Congo-red (CR) deposits. The tissue source is preferably fat and/or bone marrow biopsy, but at times organ biopsy is required. Methods: We studied 612 patients with systemic light chain amyloidosis to characterize the tissues used to establish the diagnosis Results: The median number of tissue samples biopsied for CR staining was 3. Ninety-five percent of bone marrow (BM) biopsies were stained for CR, while 79% of patients had fat aspiration performed for CR staining. Overall, 76% of patients underwent both procedures. CR stain sensitivity was 69% in BM samples, 75% in fat aspiration and in 89% for both sources combined. CR stain sensitivity was 97-100% for heart, renal and liver biopsies. 42% of patients with renal involvement, 21% of patients with liver involvement and 13% of patients with heart involvement underwent organ biopsy, when a less invasive safer biopsy would have established the diagnosis. Predictors of need for organ biopsy were male sex, limited organ involvement and lack of fat aspiration (Table). Conclusions: Fat aspiration is underutilized for histologic confirmation of amyloidosis. Organ biopsies (particularly renal biopsies) were performed at a high rate, which represents a failure to recognize the disease (i.e. failure to screen with a light chain assay etc.). Early awareness of amyloidosis in the differential diagnosis of patients with organ dysfunction may lead to fewer unnecessary organ biopsies [Table: see text]

e19530 Background: Neuropathy is a universal symptom of patients with POEMS syndrome, which makes the use of bortezomib less appealing. However, proteasome inhibitors (PIs) can provide rapid and deep hematologic responses in plasma cell disorders. Because there is very little data regarding the use PIs in POEMS syndrome, we performed a study of patients with POEMS syndrome treated with PIs. Methods: Among the 167 patients with POEMS syndrome seen at our institution between 2001-2016, we identified 12 patients who received a PI. One patient receiving < 1 cycle of bortezomib because of worsening neuropathy was included but was excluded from response analyses. One patient received 2 different PIs at separate points during the disease course and each course was considered separately. Four response categories were considered: hematologic, PET, VEGF and clinical as previously described (Dispenzieri et. al AJH 2015). Results: Among the 12 patients who received 13 courses of therapy, the median age at PI initiation was 59; 8 patients were male. Median number of prior therapies was 1 (0-4) and median time from diagnosis to initiation of PI was 75 months. Excluding steroids, regimens were as follows: bortezomib, n=3; bortezomib and cyclophosphamide, n=4; carfilzomib, n=1; and ixazomib, n=1. With a median follow-up from PI initiation of 18 months, the median duration of treatment was 7 months (1-18). Three patients achieved a hematologic CR. Of 6 patients with an abnormal baseline VEGF, 3 achieved normalization VEGF levels. Of 5 patients with an abnormal baseline PET, 2 achieved normalization of their PET. Two patients had improvement of their neuropathy, with the rest having stable symptoms. Of 9 patients with fluid overload, 8 improved. Only 2 patients stopped therapy due to worsening neuropathy related to PIs. Median PFS and OS from initiation of PI were 50 months and 53 months, respectively. Conclusions: We show that PI use in patients with POEMS syndrome can be safe and effective. Nearly 75% of patients treated with bortezomib had no exacerbation of their neuropathy. Clinical improvement in severe fluid overload symptoms (edema, ascites, pleural effusions) is almost universal, making PI-based therapy an attractive potential option in these patients.

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]