New nomogram predicts conditional probability of survival after gastric cancer surgery

Last Updated: 2018-05-18

By Will Boggs MD

NEW YORK (Reuters Health) - A new nomogram can predict the probability of surviving a certain number of years after gastric cancer surgery based on the duration of time that has already passed (the "conditional" probability), researchers from China report.

Most studies of gastric cancer survival evaluate only the risk of death starting from the time of diagnosis or gastric resection. Conditional probability, on the other hand, can provide a more accurate assessment of changes in the risk of death as patients live longer after gastrectomy.

To develop the nomogram, Dr. Chang-Ming Huang and colleagues from Fujian Medical University, in Fuzhou, China, used information on more than 11,500 patients from the most recent Surveillance, Epidemiology, and End Results (SEER) database and from China (as representative of the Asian population). The tool predicts the conditional probability of overall survival and disease-specific survival in patients at any point after curative-intent gastrectomy for gastric cancer.

The five-year conditional probability of overall survival improved with increasing postoperative survival time for all patients, from 41.6% immediately after gastrectomy to 52.8% at one year, 68.2% at two years, 80.4% at three years, and 90.1% at four years after gastrectomy, the team reports in Surgery, online April 20.

Similarly, the five-year conditional probability of disease-specific survival increased from 48.9% at the time of gastrectomy to 59.8%, 74.7%, 85.5%, and 93.3% for patients surviving one, two, three and four years after gastrectomy, respectively.

Factors used in the nomogram included sex, race, age, depth of invasion, number of metastatic lymph nodes, tumor size, primary tumor site and tumor grade.

The accuracy of the conditional probability of overall survival nomogram ranged from 76% to 82%, and the accuracy of the conditional probability of disease-specific survival ranged from 75% to 82%, depending on the population (U.S. or Chinese) and the time since gastrectomy.

"This study presents the first tool capable of providing an individualized assessment of the conditional probability of survival for patients with gastric cancer on a global scale, allowing adjustment of the predicted durations of survival after gastrectomy," the researchers conclude. "This tool may prove to be useful for patients, physicians, and researchers and will guide dynamic and personalized clinical management decisions."

Dr. Marino Venerito from Otto-von-Guericke University Hospital, in Magdeburg, Germany, who has investigated clinical and epidemiological aspects of gastric cancer, told Reuters Health by email, "This may represent a tool for clinical decisions, but it should be integrated into an algorithm including many other medical and ethical aspects."

He expressed uncertainty about how he would use the nomogram with his patients. "If I know a patient is not going to live very long," he said, "should I tell him? What is the value of a life without hope? But nomograms express only a probability, anyway."

Dr. Venerito, who was not involved in the study, added, "Chemosensitivity testing may represent a further tool in the future (not yet) to improve results of patients undergoing surgery for gastric cancer. New therapeutic strategies may completely reverse these nomograms."

Dr. Huang and co-corresponding author Dr. Chao-Hui Zheng did not respond to requests for comments.

SOURCE: https://bit.ly/2rCPyT8

Surgery 2018.