Pancreatic Cancer Is Caught Sooner When Regular Screening Done
A recent study shows that most patients who underwent such screening were diagnosed at an earlier stage than those who did not.
Given the number of people affected by pancreatic cancer, and the fact it is projected to become the second leading cause of cancer deaths by 2026, early diagnosis could save many lives.
Now, a new study shows just how important regular screening for pancreatic cancer could be to finding the disease as early as possible in high-risk individuals, as well as increasing survival rates. The study, led by researchers from Johns Hopkins Kimmel Cancer Center and published June 15 in the Journal of Clinical Oncology, shows that those who underwent regular screening for the disease were diagnosed at the earliest stage and therefore had higher survival rates than those who were not regularly screened.
The Diagnostic Challenge
Though pancreatic cancer accounts for only about three percent of all cancers diagnosed each year in the US, it will be responsible for an estimated 49,830 deaths this year—the fourth most among all cancers—according to the American Society of Clinical Oncology’s (ASCO’s) Cancer.Net patient information website. The society adds that this form of cancer is the eighth most common cancer in women and the tenth most common in men.
However, the disease is tough to diagnose as people don’t usually show symptoms until the later stages of pancreatic cancer, when survival is less likely, and “there are no validated, specific screening tests that can easily and reliably find early-stage pancreatic cancer in people who do not show symptoms,” according to Cancer.Net.
The new study provides evidence that regular screening using certain imaging methods can detect the disease earlier than when regular surveillance is not done.
The multicenter Cancer of Pancreas Screening-5 (CAPS5) study involved 1,461 high-risk individuals who were enrolled in one of eight study centers between 2014 and 2021. Nearly half of the participants (48.5%) had a pathogenic variant in a gene making them susceptible to pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer. Participants were screened each year using endoscopic ultrasound (EUS) and/or magnetic resonance imaging/magnetic resonance cholangiopancreatography (MRI/MRCP), though screening was done more frequently if signs of disease were detected. The study also provided an update on findings of earlier CAPS studies.
Over the course of the study, 10 of the participants were diagnosed with PDAC, with one individual being diagnosed with a metastatic form of the disease four years after dropping out of the regular screenings. Of the remaining nine people who maintained regular screenings:
- Seven had a stage I PDAC detected via regular screening
- One person had stage II detected via screening
- One patient had stage III detected through screening
In addition to those nine patients, seven of whom were still alive after a 2.6-year-follow-up, eight other patients had surgery to remove “worrisome lesions,” five of which had high-grade and three of which had low-grade abnormalities in their removed specimens, according to the study abstract. Across the entire CAPS cohort so far, 26 cases of PDAC have been diagnosed, with:
- 19 cases detected within surveillance (57.9% of those cases were stage I and 5.2% were stage IV)
- 7 cases detected outside surveillance, with 6 (85.7%) of those being stage IV
Of the entire group of CAPS participants whose cancer was detected through screening, the five-year survival was just over 73 percent, and the median overall survival was almost 10 years, compared to just 1.5 years for those diagnosed outside regular screening.
“Many of those diagnosed with pancreatic cancer under surveillance can be potentially cured. By contrast, people who dropped off their surveillance had poor survival rates,” said senior study author Michael Goggins, M.B.B.Ch., MD, in a recent press release on the study. “Our results support the CAPS surveillance recommendation that those who meet the criteria should undergo regular screenings.”
Recommendations for Pancreatic Cancer Screening
Current guidelines for pancreatic cancer screening are similar among various organizations. The American Gastroenterological Association (AGA) recommends that screening for this form of cancer should start at age 50 for those at high risk, though, depending on the specific genetic risk or condition the patient has, screening could start as early as age 35, or 10 years younger than their youngest family member diagnosed with the disease. However, if concerning lesions are found, the AGA suggests shorter screening intervals of as often as every six months, depending on the exact findings.
The association does not recommend screening for “average-risk” individuals. Similarly, the U.S. Preventive Services Task Force recommends against screening “asymptomatic adults” (those not known to be at risk) for pancreatic cancer.
The latest American Society for Gastrointestinal Endoscopy (ASGE) guidelines recommend pancreatic annual cancer screening for those with a genetic susceptibility, regardless of family history. Earlier guidelines recommended that those with the BRCA1/2 pathogenic variant only be screened if they had a family history of pancreatic cancer. As with the AGA guidelines, the ASGE recommends screening start at age 50, but depending on the specific genetic risk and family history of pancreatic cancer, that recommendation changes to as early as age 35, or “10 years earlier than the youngest relative with pancreatic cancer.”
The authors of the recent Journal of Clinical Oncology study say their findings support the recommendation that screening should not be limited to those with certain genetic risk factors who have a family history of pancreatic cancer, but should include all patients with BRCA2 and ATM mutations.
As noted by the study authors, their work confirms the findings of many other studies that show regular screening for pancreatic cancer catches the disease sooner, when it is more treatable, but also reveals the limitations of current screening methods. For example, the fact that regular screening resulted in the diagnosis of only nine of 1,461 participants “highlights the need to develop more refined estimates of pancreatic cancer risk,” to better determine who should be screened and when screening should start, the authors say. They also point out that there has been little research on how cost-effective pancreatic cancer screening is.
In addition, the authors note some limitations to their study:
- Relatively short follow-up of the study cohort (though they note they have long-term data from the other CAPS studies)
- The small number of individuals who were diagnosed after screening
- The small number of PDAC cases diagnosed so far in the CAPS program
To “generate better precision estimates for the proportion of stage I PDACs diagnosable with surveillance” via EUS and MRI-based methods in high-risk patients, the team recommends further research with a larger cohort and longer follow-up. A 2021 commentary piece evaluating the state of pancreatic cancer screening also highlights “the importance of well-organized, large-scale, long-term, longitudinal follow-up studies of a population with sufficiently high risk for cancer” in evaluating the success of pancreatic cancer screening in decreasing mortality. That commentary also points out the importance of standardization of data collection in all studies assessing screening techniques.
Despite the limitations to the CAPS5 study as well as other research on the effectiveness of pancreatic cancer screening, what has been done so far shows that it has promise is detecting the disease early and improving survival rates. Specifically, the CAPS5 study shows that “pancreatic surveillance of [high-risk-individuals] can dramatically downstage PDACs diagnosed; most of the patients with PDACs diagnosed in the multicenter CAPS5 study to date had stage I disease,” the authors conclude, adding, “[t]he long-term survival among patients in the CAPS cohort is excellent.” Further research will reveal whether these results hold true on a larger scale, as well as determine the effectiveness of newly-emerging biomarker tests in detecting pancreatic cancer early, they add.
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