Increased overall survival and a longer time before tumor recurrence is associated with low presurgery uptake of a labeled glucose analogue, a marker of metabolic activity, in the primary tumor of patients with stage I non-small cell lung cancer (NSCLC). Patients with high uptake of labeled glucose may benefit from additional therapy following surgery.
Surgery is the standard of care for patients with stage I NSCLC but not all patients are cured, as demonstrated by a 5-year survival rate of less than 60% in these patients. There is a clear need for a diagnostic test to identify which patients should receive postsurgical therapy, such as chemotherapy, and which patients do not need further treatment, thus avoiding unnecessary treatment-related toxicity and complications.
Fluorodeoxyglucose (FDG) is radiolabeled analogue of glucose whose concentration within a tumor can be measured with a positron emission tomography (PET) imaging scanner.
Researchers from Duke University Medical Center in Durham, North Carolina, reviewed 336 patients with stage I NSCLC diagnosed between 2005 and 2010 who underwent FDG/PET within 90 days of surgery.
They sought to determine if FDG uptake, as measured by maximum standard uptake value (SUVmax) with PET, was associated with overall survival or time to recurrence. The median follow-up was 5.1 years.
The results, published in the Journal of Thoracic Oncology (2015; doi:10.1097/JTO.0000000000000534), show that the risk of dying and recurrence decreased significantly as SUVmax decreased (P=.0008 and P=.24, respectively).
The study estimated that 22.5% of the patients with SUVmax above the median will have recurrent disease at 2 years, compared to 8% in the lowest SUVmax quartile. At 5 years, 41% of the patients in the third quartile of SUVmax will be alive compared with 77% in the lowest SUVmax group.
“FDG/PET SUVmax of stage I NSCLC at diagnosis is predictive of survival and time of recurrence,” concluded the authors. “This parameter may serve as a biomarker to guide selection of patients for postsurgical chemotherapy or other more aggressive therapies.”
However, senior author Edward Patz, MD, pointed out “there is a need for prospective clinical trials to further examine the prognostic utility of tumor SUVmax in early stage lung cancer.”