Long-term follow-up needed for pancreatic cysts, regardless of stability

Last Updated: 2017-07-20

By Marilynn Larkin

NEW YORK (Reuters Health) - Patients with pancreatic cysts remain at risk for cyst growth, surgery and cancer for at least five years, even if the cyst is stable, researchers say.

The American Gastroenterological Association (AGA) recommends discontinuation of radiographic surveillance after five years for patients with stable pancreatic cysts. Studies on the outcomes of long-term surveillance of such cysts have been inconsistent, however.

To investigate, Dr. Peter Allen and colleagues at Memorial Sloan Kettering Cancer Center in New York City reviewed data on 2,473 patients (median age, 66; 63% women) evaluated for pancreatic cysts from 1995 to 2016 who initially underwent radiographic surveillance.

They divided patients into two groups: those followed for less than five years and those followed for five years or longer. For both groups, they analyzed data on cyst growth (>5 mm increase in diameter), crossover to surgery and development of cancer.

Because the AGA's recommendation mainly targets patients with stable cysts, the team focused on this group as well. Patients with five or more years of follow-up were further stratified by the detection of cyst progression at, or before, the five-year time point.

As reported online June 27 in Annals of Surgery, 596 patients were followed for five years or longer and 1,876 were followed for less than five years. In the group followed for five-plus years, cyst growth was more frequent (44% versus 20%; P<0.0001) but crossover to resection was less frequent (8% versus 11%; P=0.02). Progression to carcinoma was similar in the two groups (2% versus 3%; P=0.07).

Among those with longer follow-up, 412 (69%) had stable cysts at five years. This subgroup, when compared with those in the shorter follow-up group, had similar rates of cyst growth (19% versus 20%; P=0.95) and lower rates of crossover to resection (5% versus 11%; P< 0.0001) and development of cancer (1% versus 3%; P = 0.008).

However, the rate of cancer development in the stable cyst group was 31.3 per 100,000 per year, whereas the expected national age-adjusted incidence rate was 7.04 per 100,000 per year.

The authors suggest that surveillance not cease at five years, even for patients with stable cysts at that point.

Dr. Christopher DiMaio of the Icahn School of Medicine at Mount Sinai in New York City told Reuters Health, "Management of pancreatic cysts remains a controversial and frustrating topic among gastroenterologists and surgeons. The current study is a major step forward in shedding some light on this controversy."

"When applying these results to real-world patients, clinicians should recognize that not all patients can be managed the same," he said by email. "Patient age and comorbidities should play a large role in the decision-making process about whether to continue surveillance of a pancreatic cyst, or when or if to perform surgical resection on a particular lesion."

"A young fit patient with a long life expectancy who has significant growth in a low risk lesion may be managed differently than an elderly patient with comorbidities who has a large pancreatic cyst with worrisome but stable features," he said.

"It should be noted that while the study group exhibited a higher observed rate of developing cancer compared to the expected national age-adjusted incidence rate, the overall rate of malignancy in a patient with a pancreatic cyst remains relatively low - approximately 3%," he noted.

Dr. DiMaio concluded, "Optimal evaluation and management of these patients is best accomplished by an expert multidisciplinary team at high-volume centers."

Dr. Anton Bilchik, chief of gastrointestinal research at the John Wayne Cancer Institute in Santa Monica, California, told Reuters Health, "Pancreatic cysts are being detected more often because of significant improvements in body imaging. Most of them are benign."

"A small percentage can transform and turn into an aggressive cancer," he said by email. "There is therefore considerable debate as to how these patients should be followed and when, if ever, the cyst should be removed."

The AGA guidelines represented "an effort to reduce unnecessary pancreatic resections and the cost of frequent body imaging," he said.

"This very important study . . . refutes that . . . and supports the fact that better guidelines are needed for the management of patients with pancreatic cysts."

Dr. Allen did not respond to requests for a comment.

SOURCE: http://bit.ly/2gO0T0v

Ann Surg 2017.