Reassuring findings may positively impact current clinical guidelines.
The results of two studies presented at the Annual European Congress of Rheumatology (EULAR) 2017 press conference should reassure rheumatologists regarding the risk of cancer from the use of biological disease modifying anti–rheumatic drugs (bDMARDs), including anti–TNF treatment, in patients with rheumatoid arthritis (RA).

Although current clinical guidelines caution against the use of anti–TNF drugs in individuals with a recent history of cancer (in the last 5–10 years), the only evidence to date that there isn’t any increased risk of cancer recurrence has been limited to women with breast cancer. New data has now shown that, among patients with RA and a previous history of solid, non–skin cancer, those selected to receive anti–TNF treatment did not experience any more cancer recurrences than RA patients treated with other classes of anti–rheumatic drug.

Also, the risk didn’t vary depending on the timing of the start of anti–TNF in relation to the original cancer diagnosis.

To investigate the risk of recurrence of solid non–skin cancer in RA patients receiving anti–TNF treatment, 446 patients with at least one diagnosis of solid cancer prior to the start of anti–TNF treatment, were compared with 1,278 matched controls with a history of equally recent cancer of the same type and stage who were not being prescribed biologic treatment.

Thirty individuals (7%) among these 446 anti–TNF treatment RA patients developed a cancer recurrence (crude incidence rate 14/1000 person–years), compared with 89 (7%) among the 1,278 matched biologics–naive controls (crude incidence rate 17/1000 person–years).

“Because TNF is one of the cytokines involved in the immunosurveillance of tumours, its inhibition may theoretically increase the risk of new tumour formation or cancer recurrence. However, current guidelines do not provide clear guidance regarding the use of anti–TNF treatment in patients with recent malignancies,” said lead author Professor Johan Askling from Karolinska Institute, Stockholm, Sweden. “Rheumatologists should find our data reassuring. However, it is not possible to extrapolate these new findings to individuals with a very recent cancer, or a poor prognosis,” he added.

Statistical analysis accounting for matching variables: sex, birth year, year of diagnosis of the index cancer and index cancer type and stage, and adjusting for education level and comorbidities indicated no increased risk associated with any specific cancer type with the possible exception of uterine cancer where the hazard ratio for recurrence was 14.8, but this was based on only 1 event among the anti–TNF treated patients.

Study participants were required to be in cancer remission for a period of 6 months prior to start of follow–up. The primary outcome was first recurrence or second primary of the same cancer type, identified through the cancer registry up until December 2014.

The mean time from index cancer diagnosis until anti–TNF treatment / start of follow–up was 9.9 and 9.5 years among the anti–TNF treated patients and their matched biologic–naïve controls, respectively. The mean follow–up from the start of anti–TNF treatment was 4.9 and 4.1 years, respectively. The cancer stage distribution was similar between the two groups, apart from stage IV (0.6 % among the anti–TNF treated patients and 1.6% among the biologic–naïve controls).