Latest pancreatic cancer staging system "slightly" more prognostic

Last Updated: 2018-10-11

By Marilynn Larkin

NEW YORK (Reuters Health) - Compared to the previous edition, the recently released eighth edition of the TNM staging system shows a modest increase in prognostic accuracy for patients with resected pancreatic ductal cancer, researchers say.

"In (our) international validation study, the eighth edition...demonstrated a slightly improved prognostic accuracy," Dr. Marc Besselink of the University of Amsterdam, in the Netherlands, told Reuters Health by email. "Although the new size-based T category offered limited incremental value to the predictive ability, the new N category was highly prognostic for overall survival."

As reported online October 3 in JAMA Surgery, Dr. Besselink and colleagues studied 1,525 patients (median age, 66; 52.6% men) at five tertiary centers in Europe and the U.S. from 2000 to 2015. Participants underwent pancreatoduodenectomy for nonmetastatic pancreatic ductal adenocarcinoma and were retrospectively staged according to the seventh and eighth edition of the TNM staging system.

Distribution among the stages differed between the two editions. With the eighth edition, 50.8% of patients migrated to a different stage; 12.0% were reclassified to a lower stage; and 38.8% to a higher stage.

In the seventh and eighth editions, respectively, distributions were 2.7% and 7.7% in stage IA; 2.8% and 9.4% in stage IB; 13.1% and 1.4% in stage IIA; 80.6% and 42.2% in stage IIB; and 0.8% and 39.2% in stage III.

Median overall survival for the entire cohort was 24.4 months.

Five-year survival rates with the seventh and eighth editions, respectively, were 38.2% and 39.2% for patients in stage IA; 34.7% and 33.9% in stage IB; 35.3% and 27.6% in stage IIA; 16.5% and 21.0% in stage IIB; and 0% and 10.8% in stage III.

For node-negative patients, the T stage was not associated with prognostication of survival in either edition.

However, in the eighth edition, the N stage was associated with five-year survival rates of 35.6% in N0; 20.8% in N1; and 10.9% in N2. The concordance statistic improved from 0.55 for the seventh edition to 0.57 for the eighth edition.

"These findings, in line with previously published studies, confirm that it remains extremely difficult to discriminate patients with early-stage pancreatic cancer (e.g., stage IA, IB and II) in terms of survival," Dr. Besselink said.

"Novel biomarkers and information on tumor microenvironment and/or the immune system might offer a solution for this particular subgroup," he noted, "although promising results need to be awaited and thoroughly studied prior to incorporation in any staging system."

"This study also shows the added value of international collaboration," he said. "Enhancing patient volumes allows for more accurate predictions in oncological outcome and increases the generalizability of the results."

"Meanwhile," he concluded, "endeavors should be made on the uniformity of definitions to warrant valid conclusions."

Dr. Joe Hines of the David Geffen School of Medicine at the University of California, Los Angeles, coauthor of a related editorial, told Reuters Health, "Although this study aids in stratifying patient survival, the field eagerly awaits a broader range of effective treatments to improve survival."

"We hope the management and outcomes for patients with pancreatic cancer moves toward a paradigm like breast cancer, where substantial survival improvements have been realized," he said by email. "Treatment advances will be underpinned by improved understanding of pancreatic cancer biology."

"Ultimately," he added, "computer algorithms will be used with the input of a multitude of factors about the tumor and patient to classify pancreatic patients and assist in selecting a yet to be discovered broader range of effective treatments."

SOURCE: http://bit.ly/2OUWoRn and http://bit.ly/2ORCFC8

JAMA Surg 2018.