Relationship between pancreatic intraepithelial neoplasias, pancreatic ductal adenocarcinomas, and single nucleotide polymorphisms in autopsied elderly patients

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.

Genetic testing to guide screening for pancreatic ductal adenocarcinoma: Results of a microsimulation model

BACKGROUND

First-degree relatives (FDRs) of patients with pancreatic ductal adenocarcinoma (PDAC) have elevated PDAC risk, partially due to germline genetic variants. We evaluated the potential effectiveness of genetic testing to target MRI-based screening among FDRs.

METHODS

We used a microsimulation model of PDAC, calibrated to Surveillance, Epidemiology, and End Results (SEER) data, to estimate the potential life expectancy (LE) gain of screening for each of the following groups of FDRs: individuals who test positive for each of eight variants associated with elevated PDAC risk (e.g., BRCA2, CDKN2A); individuals who test negative; and individuals who do not test. Screening was assumed to take place if LE gains were achievable. We simulated multiple screening approaches, defined by starting age and frequency. Sensitivity analysis evaluated changes in results given varying model assumptions.

RESULTS

For women, 92% of mutation carriers had projected LE gains from screening for PDAC, if screening strategies (start age, frequency) were optimized. Among carriers, LE gains ranged from 0.1 days (ATM+ women screened once at age 70) to 510 days (STK11+ women screened annually from age 40). For men, LE gains were projected for all mutation carriers, ranging from 0.2 days (BRCA1+ men screened once at age 70) to 620 days (STK11+ men screened annually from age 40). For men and women who did not undergo genetic testing, or for whom testing showed no variant, screening yielded small LE benefit (0-2.1 days).

CONCLUSIONS

Genetic testing of FDRs can inform targeted PDAC screening by identifying which FDRs may benefit.

The stem cell-specific intermediate filament nestin missense variation p.A1199P is associated with pancreatic cancer

The intermediate filament nestin is upregulated in stem/progenitor cells and cancers, and regulates cell proliferation, migration, invasion and stemness. The present study comparatively analyzed serial autopsies of Japanese patients (n=2,206; males, 1,225; females, 981; median, 80.7 years old; range, 33-104 years old) with malignant tumors of whole organs, with respect to the clinical information, and 5 single nucleotide polymorphisms of the nestin gene. p.A1199P associated with pancreatic cancer (odds ratio, 4.4; 95% confidence interval, 1.9-10.0, P=0.001) while it did not associate with malignant neoplasms in other organs. p.A1199P did not associate with precancerous lesions of the pancreas. Single nucleotide polymorphisms of nestin were not associated with sex, drinking, smoking, or body weight. In conclusion, the amino acid 1,199 of nestin is localized in the tail structure of the filament and polymerizes with other intermediate filament proteins. The present results suggest that missense variations of nestin affect pancreatic carcinogenesis in Japanese patients.

Progression to pancreatic ductal adenocarcinoma from pancreatic intraepithelial neoplasia: Results of a simulation model

OBJECTIVES

To gain insight into the natural history and carcinogenesis pathway of Pancreatic Intraepithelial Neoplasia (PanIN) lesions by building a calibrated simulation model of PanIN progression to pancreatic ductal adenocarcinoma (PDAC) METHODS: We revised a previously validated simulation model of solid PDAC, calibrating the model to fit data from the National Cancer Institute's Surveillance, Epidemiology, and End Results program and published literature on PanIN prevalence by age. We estimated the likelihood of progression from PanIN states (1, 2, and 3) to PDAC and the time between PanIN onset and PDAC (dwell time). We evaluated a hypothetical intervention to test for and treat PanIN 3 lesions to estimate the potential benefits from PanIN detection.

RESULTS

We estimated the lifetime probability of progressing from PanIN 1 to PDAC to be 1.5% (men), 1.3% (women). Progression from PanIN 1 to PDAC took 33.6 years and 35.3 years, respectively, and from PanIN 3 to PDAC took 11.3 years and 12.3 years. A hypothetical test for PanIN 3 detection and treatment could provide a maximum, average life expectancy gain of 40 days.

CONCLUSIONS

Our modeling analysis estimates PanINs have a relatively indolent course to PDAC, supporting the feasibility of potential future early detection strategies.

Chemotherapy in elderly patients with pancreatic cancer: Efficacy, feasibility and future perspectives

By 2030 70% of newly diagnosed pancreatic ductal adenocarcinoma (PDAC) will occur in older adults. Elderly patients, defined by the World Health Organization (WHO) as people older than 65 years, represent a heterogeneous group with different biological and functional characteristics that need personalized anticancer treatments. Since older patients are under-represented in randomized phase III trials, their management is mostly extrapolated from studies performed in younger patients, without robust evidence-based recommendations. However, data from retrospective studies and case-control series show that elderly may benefit from chemotherapy in both the adjuvant and advanced disease settings. Although with discordant results, gemcitabine-based treatment and dose-adapted fluorouracil combination regimens seem to be effective and well tolerated in this subset of patients. A proper balance of potential treatment benefits and side effects represent the crucial point for managing elderly patients with PDAC. Therefore an appropriate patient selection is essential to maximize the therapeutic benefit in the older population: randomized studies aiming to better standardizing fitness parameters and implementing the routine use of comprehensive geriatric assessments are strongly warranted. In this light, the detection of molecular prognostic markers able to detect patients who may benefit more from oncological treatments should be a primary endpoint of age-focused clinical trials. Altogether, the field of geriatric oncology will expand in the next years, and the clinical management of elderly patients affected by PDAC will become a major public health issue.

Genome-Wide Somatic Copy Number Alterations and Mutations in High-Grade Pancreatic Intraepithelial Neoplasia

To obtain a better understanding of the genetic alterations of high-grade pancreatic intraepithelial neoplasia (HG-PanIN), we performed whole-genome copy number analysis by using single nucleotide polymorphism microarrays and targeted next-generation sequencing of 11 microdissected HG-PanIN and two low-grade PanIN lesions associated with HG-PanIN. HG-PanIN mutation profiles were compared with those of their associated invasive pancreatic ductal adenocarcinoma. All PanIN lesions harbored somatic KRAS mutations. The most common copy number losses in the HG-PanIN were at the CDKN2A (9p21), TP53 (17p13), and SMAD4 (18q21) loci. Chromosomal losses in HG-PanIN were also found at 6p25-p24, 6q11-q27, 12q24, and 17q23-q24. Biallelic inactivation of CDKN2A and TP53 was detected in five of eight and in three of eight evaluable PanIN lesions, respectively. None of the HG-PanIN lesions had SMAD4 mutations or homozygous deletion. Copy number gains were noted at the MYC (8q24) and CCNE1 (19q12) loci and at 1q25-q31. Four HG-PanINs and one low-grade PanIN harbored chromothripsis-like regions. Five of seven pancreatic ductal adenocarcinomas evaluated had additional mutations that were not found in their associated HG-PanIN. HG-PanIN harbors widespread copy number alterations and commonly shows evidence of biallelic inactivation of CDKN2A and TP53 but not SMAD4. Chromothripsis events contribute to the copy number alterations of HG-PanIN.