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

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.