The Natural Disease Course of Pancreatic Cyst-Associated Neoplasia, Dysplasia, and Ductal Adenocarcinoma: Results of a Microsimulation Model.

BACKGROUND & AIMS: Estimates on the progression of precursor lesions to pancreatic cancer (PC) are scarce. We used microsimulation modeling to gain insight into the natural disease course of PC and its precursors. This information is pivotal to explore the efficacy of PC screening. METHODS: A Microsimulation Screening Analysis model was developed in which pancreatic intraepithelial neoplasms and cysts can evolve from low-grade dysplasia (LGD) to high-grade dysplasia (HGD) to PC. The model was calibrated to Dutch PC incidence data and Japanese precursor prevalence data (autopsy cases without PC) and provides estimates of PC progression (precursor lesion onset and stage duration). RESULTS: Mean LGD state durations of cysts and pancreatic intraepithelial neoplasms were 15.8 years and 17.1 years, respectively. Mean HGD state duration was 5.8 years. For lesions that progress to PC, the mean duration was 4.8-4.9 years for LGD lesions and 4.0-4.1 years for HGD lesions. In 13.7% of individuals who developed PC, the HGD state lasted less than 1 year. The probability that an individual at age 50 years developed PC in the next 20 years was estimated to be 1.8% in the presence of any cyst and 6.1% in case of an LGD mucinous cyst. This 20-year PC risk was estimated to be 5.1% for individuals with an LGD pancreatic intraepithelial neoplasm. CONCLUSIONS: Mean duration of HGD lesions before development of PC was estimated to be 4.0 years. This implies a window of opportunity for screening, presuming the availability of a reliable diagnostic test. The probability that an LGD cyst will progress to cancer was predicted to be low.

Impact of COVID-19-related care disruptions on cervical cancer screening in the United States.

OBJECTIVES: To quantify the secondary impacts of the COVID-19 pandemic disruptions to cervical cancer screening in the United States, stratified by step in the screening process and primary test modality, on cervical cancer burden. METHODS: We conducted a comparative model-based analysis using three independent NCI Cancer Intervention and Surveillance Modeling Network cervical models to quantify the impact of eight alternative COVID-19-related screening disruption scenarios compared to a scenario of no disruptions. Scenarios varied by the duration of the disruption (6 or 24 months), steps in the screening process being disrupted (primary screening, surveillance, colposcopy, excisional treatment), and primary screening modality (cytology alone or cytology plus human papillomavirus "cotesting"). RESULTS: The models consistently showed that COVID-19-related disruptions yield small net increases in cervical cancer cases by 2027, which are greater for women previously screened with cytology compared with cotesting. When disruptions affected all four steps in the screening process under cytology-based screening, there were an additional 5-7 and 38-45 cases per one million screened for 6- and 24-month disruptions, respectively. In contrast, under cotesting, there were additional 4-5 and 35-45 cases per one million screened for 6- and 24-month disruptions, respectively. The majority (58-79%) of the projected increases in cases under cotesting were due to disruptions to surveillance, colposcopies, or excisional treatment, rather than to primary screening. CONCLUSIONS: Women in need of surveillance, colposcopies, or excisional treatment, or whose last primary screen did not involve human papillomavirus testing, may comprise priority groups for reintroductions.