P0009 - Concerning Trend in Increasing Pancreatic Cancer (PC) Incidence Among Young Women: A Population-Based Time-Trend Analysis Using the Surveillance, Epidemiology, and End Results (SEER) Database

Yazan Abboud, MD, Janice E. Oh, MD, MS, Jamil Samaan, MD, Nicholas Nissen, MD, Simon Lo, MD, Srinivas Gaddam, MD
Cedars-Sinai Medical Center, Los Angeles, CA

Introduction: PC is a highly fatal disease with limited data on gender-based time-trends. The aim of this study was to perform a time-trend analysis of PC incidence rates (IRs) in a large population-based cohort.

Methods: IRs of PC per 100,000 population (age-adjusted to the 2000 US population) from 2000-2018 were calculated from the SEER 21 database using SEER*Stat software (v8.3.9) and were stratified by gender. Time-trends were quantified using Joinpoint Regression Program (v4.9), using Monte Carlo permutation analysis to identify the best fit. Annual percentage change (APC) and the average APC (AAPC) were calculated and evaluated using parametric estimations. Pairwise comparison between the segmented-linear trends was performed to assess identicalness and parallelism. Further age and gender-specific analysis was conducted to evaluate for variations in IRs and time-trends.

Results: From 2000-2018, a total of 284,150 cases of PC (51% women; 81% Caucasian) were reported. Overall, the AAPCs of the total PC cases were significantly increasing in women (0.72) and men (0.87) over the past two decades. The trends were parallel (p=0.28) suggesting that gender-specific IRs are increasing at the same rate. However, stratified analysis of different age groups showed variation of trends in women and men. In the ≥50 years age group, gender-specific trends were not parallel (p=0.04) with higher increase of IR in men than in women with a modest absolute AAPC difference (0.26) (table). In < 50 years, the trends were again not parallel (p< 0.01); however, in this age group, gender-based trends were reversed. Women showed a significantly higher increase in incidence when compared to men (absolute AAPC difference = 1.40). To evaluate the subgroup contributing to this reversal of trend, 15-34 year-old PC patients were analyzed. Younger women were found to have a much higher increase than men (p=0.01) and the magnitude of absolute AAPC difference was 3.48 suggesting a rapid increase in incidence (figure). If current trends persist, the IR of PC in women aged 15-34 is projected to be 400% that of counterpart men by 2040.

Discussion: SEER population-based data indicates that pancreatic cancer incidence has been increasing at a modest rate among both genders over the past 2 decades and is likely to continue. However, we observed a potentially alarming trend in increasing incidence in young women and is estimated to be 400% that of men by 2040. Future studies should validate this finding in other population-based cohorts.


Figure: Figure: Pancreatic cancer gender-specific trends and age-adjusted incidence rates per 100,000 population among multiple age-specific groups.
A: The average annual percentage rate (AAPC) in men is increasing at the same rate as women (0.87 vs 0.72, p=0.281 indicating parallel trends) among people of all ages.
B: The AAPC in men is increasing at a higher rate than in women (0.87 vs 0.60, p=0.04 indicating non-parallel trends) among people aged ≥50.
C: The AAPC in women is increasing at a higher rate than in men (2.28 vs 0.88, p=0.001 indicating non-parallel trends) among people aged 15-49.
D: The AAPC in women is increasing at a higher rate than in men (7.56 vs 4.08, p=0.01 indicating non-parallel trends) among people aged 15-34.

Age range, y	Trends				AAPC		Pairwise comparison between gender-specific trends
	Time period	APC (95% CI)	Time period	APC (95% CI)	Value	Difference between gender-specific AAPCs#	Test of Coincidence p-value***	Test of Parallelism p-value****
All ages
Men	2000-2008	1.19* (0.89-1.48)	2008-2018	0.62* (0.44-0.80)	0.87*	0.15	0.0002	0.281
Women	2000-2018	0.72* (0.60-0.83)			0.72*
Aged ≥50
Men	2000-2008	1.21* (0.92-1.49)	2008-2018	0.60* (0.43-0.77)	0.87*	0.26**	0.0002	0.04
Women	2000-2018	0.60* (0.48-0.73)			0.60*
Aged 15-49
Men	2000-2018	0.88* (0.58-1.18)			0.88*	-1.40*	0.0002	0.001
Women	2000-2018	2.28* (1.83-2.74)			2.28*
Aged 15-34
Men	2000-2018	4.08* (2.44-5.75)			4.08*	-3.48*	0.0002	0.01
Women	2000-2018	7.56* (6.09-9.04)			7.56*

Table: Table: Pancreatic cancer gender-specific trends among multiple age-specific groups.
* Indicates that the annual percentage change (APC) or the average APC (AAPC) is significantly different from zero at the alpha=0.05 (p < 0.001). The trends were described as increasing.
** Indicates that the AAPC difference is significantly different from zero at the alpha=0.05.
*** Tests whether gender-specific trends are identical. A significant p-value indicates that the trends are not identical, i.e., they have different incidence rates (coincidence is rejected).
**** Tests whether gender-specific trends are parallel. A significant p-value indicates that the trends are not parallel (parallelism is rejected).
# A negative value is associated with higher AAPC in women.



Disclosures:
Yazan Abboud indicated no relevant financial relationships.
Janice Oh indicated no relevant financial relationships.
Jamil Samaan indicated no relevant financial relationships.
Nicholas Nissen indicated no relevant financial relationships.
Simon Lo indicated no relevant financial relationships.
Srinivas Gaddam indicated no relevant financial relationships.


Yazan Abboud, MD, Janice E. Oh, MD, MS, Jamil Samaan, MD, Nicholas Nissen, MD, Simon Lo, MD, Srinivas Gaddam, MD. P0009 - Concerning Trend in Increasing Pancreatic Cancer (PC) Incidence Among Young Women: A Population-Based Time-Trend Analysis Using the Surveillance, Epidemiology, and End Results (SEER) Database, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.