Use of interval-censored survival data as an alternative to Kaplan-Meier survival curves: studies of oral lesion occurrence in liver transplants and cancer recurrence

After undergoing liver transplantation, children are susceptible to oral lesions due to immunosuppressant drugs that are needed to maintain the transplant. In this context, it is important to understand how disease characteristics and age at transplantation influence the development of these lesions. Monitoring of lesions begins after transplantation and children are usually observed by a specialist in stomatology at periodic visits. Consequently, lesion development is estimated to occur between two observed times, and this is characterized as interval-censored data. However, in clinical practice, it is common to assume the moment of observation as the time of event occurrence, thereby excluding interval-censored data. Here, we discuss the impact of excluding interval-censored mechanisms in statistical analyses by using simulation studies to consider differences in sample sizes and amplitudes between observed intervals. Then, application studies are presented which use a data set from a prospective study that was conducted to investigate oral lesions in patients after liver transplantation at the A.C.Camargo Cancer Center in Brazil between 2013 and 2016 and a data set involving recurrent ovarian cancer in patients diagnosed with high-grade serous carcinoma at the A.C.Camargo Cancer Center between 2003 and 2016 (AU)