Conditional relative survival of cervical cancer: a Korean National Cancer Registry Study

OBJECTIVE: Conditional relative survival (CRS) considers changes in prognosis over time and may offer more useful estimates for survivors. We aimed to investigate CRS among patients with cervical cancer stratified by various factors that influence survival probability. METHODS: This nationwide retrospective study used data from the Korean Central Cancer Registry. We included 78,606 patients diagnosed with cervical cancer as their first cancer between January 1, 1996 and December 31, 2015, and who were followed until December 31, 2016. CRS and the conditional probabilities of death for the following 1 year were stratified by age at diagnosis, histology, cancer stage, treatment, year of diagnosis, and social deprivation index. RESULTS: The 5-year relative survival rate at the time of diagnosis was 80.6% for all cases. The probability of surviving an additional 5 years conditioned on having already survived 1, 2, 3, 4, and 5 years after diagnosis was 85.7%, 90.6%, 93.5%, 95.3%, and 94.3%, respectively. Patients with poorer initial survival estimates (older, advanced stage, non-squamous cell histology) generally showed the largest increases in CRS over time. Patients aged ≥70 years had the highest probability of death in the first year after diagnosis (24.5%), but the conditional probability of death in the 2nd, 3rd, 4th, and 5th years declined abruptly to 13.1%, 7.5%, 5.4%, and 3.9%, respectively. CONCLUSIONS: The CRS rates for patients with cervical cancer improved over time, particularly among patients with poorer initial prognoses. Our estimates enable patients to make better informed decisions regarding follow-up care and their personal life.