OP-0137 – Does Inflammation and Immune-Suppressive Treatment Affect Survival from Cancer? A Nation-Wide Population Based Study on Cancer Survival in Patients with RA in Sweden 1999-2006
Raaschou, Klareskog, Askling; Solna, Sweden
Objectives
The frequency of certain cancers, such as lymphoma, appear to be increased in RA patients in proportion to cumulative inflammation. How RA disease and treatment characterisitics influence outcomes after cancer diagnosis are less clear.
Methods
Through linkage to national cancer and death registries, all-cause and cancer specific mortality after cancer diagnosis was explored in two RA cohorts from Sweden, an early RA inception cohort (n=8,069) with detailed clinical information and a larger prevalence cohort (n=66,471) with less detail available, and compared to non-RA population-based cohort matched on demographics and time of cancer diagnosis. All subjects were alive in 1999. Cancer survival was explored for subgroups defined by specific cancer diagnoses, age groups, gender, and year of diagnosis, with adjustment for potentially confounding comorbid conditions.
Results
There were 386 first cancers in the inception cohort, resulting in death in 160, and 1725 first cancers in the prevalence cohort, resulting in death in 619. Compared to matched non-RA controls, the relative risk of death after any cancer diagnosis was not statistically significantly higher in the inception cohort (RR 1.09 (95%CI 0.91-1.32)). There was no association of RA severity, age at cancer diagnosis, rheumatoid factor status, or use immunomodulatory therapies with adverse survival outcomes. Findings in the prevalence cohort mirrored the inception cohort. For the combined RA groups, there was no significant increase in cancer related mortality for RA patients with lung, breast, or non-melanoma skin cancer. However, there was an increased risk of death due to prostate and colorectal cancer compared to the matched non-RA population (RR 1.10 (95% CI 1.04-1.17) and 1.36 (95% CI 1.06-1.75), respectively).
Conclusions
Survival after cancer diagnosis is not decreased in RA patients for most cancers. RA disease and treatment characterisitics were not predictive of mortality after cancer diagnosis.
Editorial Comment
These findings in general are reassuring for RA patients who develop cancer. Multiple studies have shown that colorectal cancer is decreased in RA patients, an association thought to be mediated, at least in part, by the ubiquitous use of NSAIDs in RA patients. But interestingly, the cancer with the largest mortality differential in this study is colorectal. Further study will be needed to identify the mechanisms underlying this possible association.
