Recent Trends in the Incidence and Survival of Stage 1A Pancreatic Cancer: A Surveillance, Epidemiology, and End Results Analysis

A Surveillance, Epidemiology, and End Results Analysis

Amanda L. Blackford; Marcia Irene Canto; Alison P. Klein; Ralph H. Hruban; Michael Goggins

Disclosures

J Natl Cancer Inst. 2020;112(11):1162-1169. 

In This Article

Abstract and Introduction

Abstract

Background: Rapid access to pancreatic imaging and regular pancreatic surveillance may help identify stage I pancreatic cancer. We investigated recent trends in the stage of newly diagnosed pancreatic ductal adenocarcinoma (PDACs), age at diagnosis, and survival.

Methods: Trends in age-adjusted incidence of stage IA PDAC between 2004 and 2016 were determined from the National Cancer Institute's Surveillance, Epidemiology and End Results database. All tests were two-sided.

Results: The incidence of stage IA PDAC cases diagnosed increased statistically significantly from 2004 to 2016 (annual percent change = 14.5, 95% confidence interval [CI] = 11.4 to 17.7; P < .001). During the study period, average age at diagnosis for stage IA and IB casesAQ3 declined by 3.5 years (95% CI = 1.2 to 5.9; P = .004) and 5.5 years (95% CI = 3.4 to 7.6; P < .001), whereas average age increased for higher-stage cases (by 0.6 to 1.4 years). Among stage IA cases, the proportion of blacks was smaller (10.2% vs 12.5%), and the proportion of other non-Caucasians was higher compared with higher-stage cases (11.9% vs 8.4%; P < .001). Stage IA cases were more likely to carry insurance (vs Medicaid or none) than higher-stage cases (cases aged younger than 65 years; odds ratio = 2.45, 95% CI = 1.96 to 3.06; P < .001). The 5-year overall survival for stage IA PDAC improved from 44.7% (95% CI = 31.4 to 63.7) in 2004 to 83.7% (95% CI = 78.6% to 89.2%) in 2012; 10-year survival improved from 36.7% (95% CI = 24.1 to 55.8) in 2004 to 49.0% (95% CI = 37.2% to 64.6%) in 2007.

Conclusions: In recent years, the proportion of patients diagnosed with stage IA PDAC has increased, their average age at diagnosis has decreased, and their overall survival has improved. These trends may be the result of improved early diagnosis and early detection.

Introduction

Pancreatic ductal adenocarcinoma (PDAC) has very poor survival, but 5-year survival rates have improved recently (currently approximately 9%).[1,2] The reasons for this improved survival are uncertain. Most patients with PDAC develop symptoms after the cancer has spread beyond the gland.[3,4] Patients diagnosed with stage I PDAC while undergoing pancreatic surveillance with imaging are usually asymptomatic.[5] Opportunities to diagnose an asymptomatic stage I PDAC occur when patients undertake regular pancreatic surveillance either for their familial and/or genetic susceptibility[6] or for incidentally detected pancreatic cyst(s). Asymptomatic stage I PDACs can be detected incidentally when individuals undergo abdominal imaging for other indications. The risk of developing pancreatic cancer is generally highest among carriers of pathogenic pancreatic cancer susceptibility gene variants and in those with a significant family history of PDAC[7,8] and intermediate in those with incidentally detected pancreatic cysts[9] and other risk factors, such as smoking (average approximately twofold elevated risk), obesity or metabolic syndrome (approximately 1.5-fold elevated),[10,11] and increasing age (approximately tenfold increase between ages 40 and 80 years).[12] The magnitude of risk depends on many factors, including the extent of PDAC family history (eg, having two first-degree relatives with PDAC confers approximately sixfold elevated risk),[13] which pathogenic susceptibility gene and variant is affected (if any), and the number of pack-years smoked.[14]

Most incidentally detected neoplastic pancreatic cysts are intraductal papillary mucinous neoplasms (IPMNs), and most of these have very low risk of progressing to invasive carcinoma.[15,16] Pancreatic cysts are commonly found during abdominal imaging for nonpancreatic indications, with an incidence that increases with age [approximately 10% by age 70 years[9,17,18]]. Invasive carcinomas diagnosed in association with IPMNs can be usual PDACs or colloid carcinomas, which are often low-stage with better outcome.[19]

PDACs are not commonly detected at stage IA in the absence of regular surveillance because they usually do not cause symptoms and may progress relatively quickly to higher stages.[20] Regular pancreatic surveillance of individuals with familial/genetic susceptibility has been reported to result in the downstaging of PDAC, with improved 5-year survival compared with PDAC diagnosed after symptomatic presentation.[5,21] Median 5-year survival for patients with localized PDAC who undergo pancreatic resection and (neo)-adjuvant chemotherapy is approximately 20% and higher for stage I cases.[22–25] With the emergence of pancreatic surveillance programs for individuals with familial/genetic risk, and improvements in the detection and management of pancreatic cystic neoplasms, we suspected better early detection could be contributing to the improvement in PDAC survival. If so, this would be reflected in a downward stage shift, with an increase in the incidence of stage IA PDAC being diagnosed. We analyzed data from the Surveillance, Epidemiology and End Results (SEER) registry, representative of the US population, to assess recent trends in the stage of newly diagnosed PDACs, age at diagnosis, and survival.

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