Overall cancer risk for TNFi-treated PsA patients is not increased

[Fred]

This study investigated the risk of cancer in TNFi treated psoriatic arthritis (PsA) patients compared with standardized rates from the general population in Denmark, Finland, Iceland and Sweden.

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Background: Tumour necrosis factor inhibitors (TNFi) effectively reduce inflammation in Psoriatic arthritis (PsA). However, a possible association between treatment with TNFi and an increased cancer risk has previously been suggested.

Objectives: To investigate the risk of cancer in TNFi treated PsA patients compared with standardized rates from the general population in Denmark, Finland, Iceland and Sweden.

Methods: TNFi-treated PsA patients were followed from first registration with TNFi-treatment in ARTIS (Sweden), DANBIO (Denmark), ICEBIO (Iceland) or ROB-FIN (Finland) and linked to the national Cancer Registry in each country. Patients with a cancer history prior to start of follow-up were excluded. We investigated the risk of primary cancer among TNFi-treated PsA patients compared with general population cancer rates standardized to age, sex and calendar period within each country. Standardized incidence ratios (SIRs) were estimated for each country and pooled SIRs were subsequently calculated for both any cancer and site-specific cancers of interest.

Results: A total of 5218, 2039, 270 and 526 patients were registered as ever TNFi-treated in ARTIS, DANBIO, ICEBIO and ROB-FIN, respectively, contributing a total of 44 041 patient years of follow-up across all 4 countries.

For all cancers, the SIRs of TNFi-treated patients from ARTIS, DANBIO, ICEBIO and ROB-FIN were 0.94 (0.80 to 1.10), 0.99 (0.77 to 1.26), 1.71 (0.88 to 2.99) and 1.28 (0.82 to 1.90), respectively. The number of observed and expected cancers and the SIRs of any and selected site-specific cancers are listed in table 1

Table 1
Standardized incidence ratios (SIR) of TNFi-treated patients from 4 Nordic countries compared with the general population.

Observed cancers  Expected cancers SIR (95% confidence interval) All cancers
282                           281.6                      1.00 (0.89 to 1.13)
Colorectal
32                             26.5                        1.21 (0.85 to 1.71)
Hodgkin’s and non-Hodgkin’s lymphoma
21                             11.4                        1.84 (1.20 to 2.82)
Lung
20                             25.4                        0.79 (0.51 to 1.22)
Malignant melanoma
20                             18.6                        1.07 (0.69 to 1.66)
Pancreas
8                               6.6                          1.21 (0.60 to 2.41)
Brain
7                              7.4                           0.95 (0.45 to 1.99)
Female breast
58                            48.4                         1.20 (0.93 to 1.55)
Corpus uteri
6                              9.0                           0.67 (0.30 to 1.49)
Prostate
34                            48.8                         0.70 (0.50 to 0.98)
Only included sites with >5 cancer outcomes.

Conclusion: Our results suggest that the overall cancer risk for TNFi-treated PsA patients is not increased compared to the general population. Further analysis of the risk of malignant lymphomas will inform on whether the increased risk we observed is attributed to the PsA disease or treatment with TNFi.

Source: EULAR: Annual European Congress of Rheumatology OD0005

*Funding: FOREUM and NordForsk