SHBC1044

CG.CHUA¹, WY.LIM¹, JZ.LOW¹, M.MANGHANI¹

Tan Tock Seng Hospital¹

Anti-TIF-1gamma Ab associated dermatomyositis (DM) is strongly associated with the occurrence of malignancies. The objective of this study was to determine the clinical profile and outcomes of anti-TIF-1gamma positive DM patients in Singapore.

A chart review was undertaken of 84 DM patients with positive myositis specific antibodies diagnosed between January 2015 and July 2019 at Tan Tock Seng Hospital.

Of the 84 DM patients, 32 were anti-TIF-1gamma Ab positive, of which 71.9% were female, 15.6% were smokers, and the median age of DM diagnosis was 61 years.  A higher proportion of the anti-TIF-1gamma Ab positive group (59.4%) developed cancer compared to the anti-TIF-1gamma Ab negative group (5.8%).

The median time interval of diagnosis in the cancer associated anti-TIF-1gamma Ab positive DM group was 12 months prior to or 12 months following the onset of DM. In this group, nasopharyngeal carcinoma (NPC) was the commonest cancer (31.6%) followed by breast (21.1%), bowel (15.8%), lung (10.5%), cervical/ovarian (5.3%), lymphoma (5.3%), thyroid (5.3%), and kidney (5.3%). Of those anti-TIF-1gamma Ab positive NPC, 66.6% presented with advanced stage (Stage III or more) and all had undifferentiated histology.

Our results show the strong association of anti-TIF-1gamma Ab DM and increased risk of malignancy, particularly nasopharyngeal cancer in our Singaporean population. The clinical profile revealed is be useful in guiding the targeted cancer surveillance this group of patients to reduce morbidity and mortality.