Antimuscarinics and lung cancer survival: A Norwegian population-based cohort study

Epidemiological studies have reported an association between antimuscarinics and reduced risk of cancer, including lung cancer (LC). However, the potential association between antimuscarinic use and LC prognosis has not previously been assessed. In a large population-based cohort, we aimed to investigate the association between the use of antimuscarinics and LC-specific survival.

Norwegian residents, aged ≥ 50 years, and diagnosed with LC between 2005 and 2018, were identified in the Cancer Registry of Norway, and information on filled prescriptions was obtained from the Norwegian Prescription Database. We used Cox proportional hazard models to estimate hazard ratios (HR) and 95 % confidence intervals (CI) for the association between peri-diagnostic and post-diagnostic use of antimuscarinics and LC-specific survival.

We included 26,693 patients with incident primary invasive LC. Of these, 466 (1.7 %) were peri-diagnostic users, and 877 (3.3 %) were post-diagnostic users of antimuscarinics, respectively. During a median follow-up of nine months, 18,088 (67.8 %) patients died due to LC. In the overall LC population, the HRs for the association between the use of antimuscarinics, compared to no use, were estimated at 1.01 (95 %CI: 0.90-1.12) for peri-diagnostic use, and 0.84 (95 %CI: 0.77-0.92) for post-diagnostic use. The association with post-diagnostic use was observed in many subgroups defined by sex, age, smoking status, histopathology, and stage, except for patients with unspecified or other histopathology than small cell LC and non-small cell LC, and for patients with local disease. The association was observed in patients treated with chemotherapy (HR = 0.75, 95 %CI: 0.64-0.88), but not in those not treated with chemotherapy (HR = 1.00, 95 %CI: 0.86-1.17; p for interaction: 0.007).

Our results suggest a possible association between use of antimuscarinics and longer LC-specific survival. More studies are warranted to investigate the use of antimuscarinics to possibly prolong LC prognosis.