Analysis of thousands of hospital records from the UK suggests an increased cancer risk for patients with PMR, but only within six months after diagnosis and only for certain malignancies.
Muller S, Hider SL; Belcher J, et al. Is cancer associated with polymyalgia rheumatica? A cohort study in the General Practice Research DatabaseAnn Rheum Dis. (2013) [Epub ahead of print July 18] DOI: 10.1136/annrheumdis-2013-203465
A large community-based comparative study of possible links between polymyalgia rheumatica (PMR) and cancer finds a 69% increased risk of cancer within the first 6 months after a PMR diagnosis. But researchers can’t say whether beyond that time period the risk is any different from that in controls.
The study follows concerns raised by a discovery reported in 2010 that there was a 19% increased cancer risk among of 36,918 Swedish patients hospitalized with PMR or giant cell arteritis compared with the general population. That associated increase declined to 6% after the first year.
In the current study, after almost 8 years of follow-up, hospital records for 2,877 PMR patients from England and Wales (73% female, mean age 71.6) and 9,942 matched controls showed almost equal rates of cancer. All subjects in the analysis had no previous diagnoses of cancer or vascular disease.
Overall, 23.2% of the PMR patents (n=667) and 19.5% (n=1,938) of controls developed cancer over a median of 7.8 years. Beyond 6 months, although rates among PMR patients were often higher at certain time periods the difference was never significant at any other time point. Cancer risk among the PMR patients appears unrelated to age, sex or smoking status, or even to treatment with corticosteroids. The data suggest excesses only in risk for cancers of the genitourinary, lymphatic, hematological, nervous system, and female reproductive tract among those with PMR.
Some previous studies of the question have focused on the risk for cancer among patients with the related condition giant cell arteritis, although no significant distinction could be established in this analysis. Given the non-specific symptoms and the absence of a definitive test for PMR, is it often difficult to make an accurate diagnosis. So the researchers advise clinicians to be careful to exclude cancer as a cause of PMR-like symptoms, and to monitor PMR patients closely in the early months after their diagnosis.