A SINGLE-CENTER INVESTIGATION ON THE PREVALENCE OF MALIGNANCIES IN PATIENTS WITH POLYMYALGIA RHEUMATICA AND GIANT CELL ARTERITIS BY WAY OF 18F-FDG PET/CT: A PROSPECTIVE COHORT STUDY

Background: Several chronic inflammatory diseases are associated with a higher risk of cancer.[1] Whether, this is the case in Polymyalgia Rheumatica (PMR) and Giant Cell Arteritis (GCA) is still a matter of debate. Objectives: To identify the prevalence of newly diagnosed cancers in patients with PMR and GCA by means of 18F-FDG PET/CT. Moreover, to compare the characteristics of the patients with and without cancer. Methods: Eighty consecutive patients with newly diagnosed PMR/GCA were studied. Diagnosis of PMR/GCA was confirmed by a 40-weeks follow up. A unilateral temporal artery biopsy (TAB) was also performed at the time of diagnosis. All included patients underwent an 18F-FDG PET/CT before, or in case of GCA, within 3 days of initiation of high dose oral glucocorticoid (40-75mg). All cancer-suspicious 18F-FDG-PET/CT findings were assessed thoroughly and malignant diseases were confirmed by histology. Total PMR and GCA scores were defined as the sum of a 4-point visual grading scale in each articular/periarticular site as well as arterial segment. Results: Of the 80 patients, 64 (83.1%) were diagnosed with pure PMR, 10 (13.0%) with concomitant GCA with PMR and 3 (3.9%) with pure GCA. Three patients were diagnosed with rheumatoid arthritis during follow up and excluded from the study. Five types of cancer in 4 (5.2%;95% CI:1.4-12.8%) patients were found. Two patients had breast cancer, one patient had adenocarcinoma of colon and one patient had adenocarcinoma of colon together with skin cancer. Besides, 4 (5.2%;95% CI:1.4-12.8%) patients had Monoclonal Gammopathy of Unknown Significance (MGUS). Age and C-reactive protein were significantly higher among those with solid cancers (p:0.049) and MGUS (p:0.017), respectively (Table1). Table 1. Characteristics of the patients with and without solid cancer ae well as MGUS Variables Cancer –,n=73 Cancer +,n=4 P-value MGUS -, n =73 MGUS +,n =4 P-value Age, mean±SD 71.4±7.8 79.7±7.5 0.049 71.9±8.0 70.2±9.2 0.79 Gender, n(%) Female 46(59.7%) 3(3.9%) 0.99 47(61.0%) 2(2.6%) 0.62 Constitutional symptoms, n(%) 70(90.9%) 4(5.2%) 0.99 70(90.9%) 4(5.2%) 0.99 Shoulder girdle symptoms, n(%) 68(88.3%) 4(5.2%) 0.99 68(88.3%) 4(5.2%) 0.99 Hip girdle symptoms, n(%) 65(84.4%) 3(3.9%) 0.40 64(83.1%) 4(5.2%) 0.99 Cranial symptoms, n(%) 19(24.7%) 0(0%) 0.57 17(22.1%) 2(2.6%) 0.25 Patients pain VAS 75(50-85) 62.5(50-75) 0.53 72.5(50 -80) 87.5(77.5-95) 0.07 Patients global VAS 80(60-90) 62.5(50-75) 0.37 80(60-90) 89.5(79.5-95) 0.23 Physician global VAS 30(25-40) 24.5(20-29) 0.15 30(22.5-40) 37.5(32.5-45) 0.17 Erythrocyte sedimentation rate, mm[2-20] 54(38-79) 62.5(37.5-76) 0.93 54(38-77.5) 57.5(39 -73.5) 0.94 C-reactive protein, mg/L[<6.0] 37(17-64) 34(17.0-76) 0.80 33(17-60) 98(68 -115) 0.017 TAB positive 7(9.1%) 0(0%) 0.99 7(9.1%) 0(0%) 0.99 Total PMR score 14(10-17) 12(5-15) 0.39 14(10-17) 13(6-15.5) 0.64 Total GCA score 0(0-0) 0(0-0.5) 0.89 0(0-0) 0(0-0) 0.34 Clinical diagnosis, n(%) 0.99 0.53  Pure PMR 60(77.9%) 4(5.2%) 61(79.2%) 3(3.9%)  Pure GCA 3(3.9%) 0(0%) 3(3.9%) 0(0%)  Concomitant PMR and GCA 10(13.0%) 0(0%) 9(11.7%) 1(1.3%) VAS: Visual analogue scale Conclusion: The prevalence of cancers in this cohort was higher, compared to the 1-year prevalence of all cancer sites of 1.2% among age-, gender- and region-matched background population in 2016. Occult malignancies are important and relatively prevalent findings in newly diagnosed PMR/GCA patients. REFERENCES: [1]Hemminki K, et al. Cancer risk in hospitalized rheumatoid arthritis patients. Rheumatology (Oxford) 2008;47:698-701. Disclosure of Interests: None declared Citation: Ann Rheum Dis, volume 79, supplement 1, year 2020, page 681Session: Vasculitis (Poster Presentations)