PET-Assessed Tumor Response Does Not Predict Gastric Adenocarcinoma Outcomes

Submitted by admin5 on Wed, 08/16/2017 - 16:45

By Reuters Staff

NEW YORK (Reuters Health) - Post-treatment/preoperative tumor response, as measured on positron emission tomography (PET), does not predict outcomes in patients with gastric and gastroesophageal junction (GEJ) adenocarcinoma, according to a database review.

PET is commonly used to evaluate tumor responses to therapy, and some have suggested that repeat PET/CT imaging is prognostic in patients with GEJ cancer and gastric cancer.

To investigate, Dr. Daniel G. Coit and colleagues from Memorial Sloan Kettering Cancer Center, New York City, analyzed the relationship between changes in standardized uptake value (SUV) on PET imaging and histopathologic response and survival after neoadjuvant therapy.

Maximum SUV responses showed small but statistically significant correlations with histologic tumor responses for patients with GEJ cancers (rho=0.19) and those with gastric cancers (rho=0.44).

None of the SUV variables, however, was significantly associated with disease-specific survival (DSS) in patients with GEJ or gastric cancers, the researchers report in Annals of Surgery, online August 1.

In bivariate models, histologic tumor response, but not maximum SUV response, significantly predicted outcomes for patients with GEJ and gastric cancers.

In multivariable analyses, only N stage and lymphovascular invasion were significant predictors of DSS in patients with GEJ cancers, whereas only T stage and N stage were significant predictors of DSS in patients with gastric cancers.

SUV responses did not show any significant relationship with DSS for patients with either cancer.

“We therefore conclude that the routine use of repeat preoperative PET imaging following neoadjuvant therapy for locoregionally advanced adenocarcinoma of the stomach and GEJ is of limited prognostic value, and should be abandoned, unless being performed in the context of a research setting to assess its value in redirecting neoadjuvant therapy for nonresponders,” the researchers write.

Dr. Coit did not respond to a request for comment.

SOURCE: http://bit.ly/2wau6JJ

Ann Surg 2017.

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