Subsequent cancers, mortality, and causes of death in patients with mycosis fungoides and parapsoriasis: a Danish nationwide, population-based cohort study

Abstract

Background: Data on subsequent cancers, prognostic factors for mortality, and causes of death are limited in mycosis fungoides (MF) and parapsoriasis.

Objectives: To assess subsequent cancers, mortality, and causes of death in MF and parapsoriasis.

Methods: Using the Danish nationwide population-based registries, we identified 368 MF patients and 582 parapsoriasis patients and compared them with the general Danish population for subsequent cancers, mortality, and causes of death.

Results: Subsequent cancers were significantly increased in parapsoriasis patients (standardized incidence ratio [SIR], 2.0 [95% confidence interval {CI}, 1.6-2.5]), and a trend was observed in MF (SIR, 1.2 [95% CI, 0.9-1.5]). Mortality was significantly increased in MF (SIR, 2.0 [95% CI, 1.8-2.3]) and parapsoriasis (SIR, 1.3 [95% CI, 1.1-1.5]). Excess mortality from MF was highest during the first 5 years of follow-up, and causes of increased death included both malignant and nonmalignant diseases.

Limitations: We have no information regarding clinical stage, treatments, and patient lifestyles.

Conclusion: Patients with parapsoriasis had a significantly increased risk of subsequent cancers and increased mortality. In addition, the highest excess mortality in the MF group was observed during the first 5 years of follow-up, which suggests that MF exists in both an aggressive and a more indolent form.

Keywords: causes of death; cutaneous T-cell lymphoma; mortality; mycosis fungoides; parapsoriasis; subsequent cancers.