Improved keratinocyte carcinoma outcomes with annual dermatology assessment after solid organ transplantation: population-based cohort study

Solid organ transplant recipients have a high risk of keratinocyte carcinoma (non-melanoma skin cancer). Consensus-based transplant guidelines recommend annual dermatological examination but the impact on skin cancer-related outcomes is unclear. We conducted a population-based, retrospective, inception cohort study using administrative health databases in Ontario, Canada to evaluate the association between adherence to annual dermatology assessments (time-varying exposure) and keratinocyte carcinoma-related morbidity and mortality after transplantation. The primary outcome was the time to first advanced (highly morbid or fatal) keratinocyte carcinoma. Among 10 183 adults receiving their first transplant from 1994 to 2012 and followed for a median of 5.44 years, 4.9% developed an advanced keratinocyte carcinoma after transplant. Adherence to annual dermatology assessments for at least 75% of the observation time after transplant was associated with a 34% reduction in keratinocyte carcinoma-related morbidity or death compared with adherence levels below 75% (adjusted hazard ratio 0.66, 95% CI 0.48-0.92). Adherence levels were universally low (median proportion of time spent in adherence 0%, inter-quartile range 0-27%). Only 45% of transplant recipients had ever seen a dermatologist and 2.1% were fully adherent during the entire observation period. Strategies are needed to improve adherence rates in order to help decrease long-term morbidity after transplant.