Low Tumor Metabolic Activity May Help Guide Therapy in NSCLC Patients

Preoperative Fluorodeoxyglucose (FDG) uptake in the primary tumor in patients with stage I non-small cell lung cancer (NSCLC) appears to be associated with overall survival (OS) and time to recurrence, according to a new retrospective study published in the Journal of Thoracic Oncology. The researchers report that using this marker of metabolic activity may be useful in identifying early-stage patients who may benefit from more aggressive therapy following surgical resection.

FDG is a radiolabeled analogue of glucose whose concentration within a tumor can be measured with a positron emission tomography (PET). Researchers found that a low presurgery uptake of the labeled glucose analogue was associated with increased OS and a longer time before tumor recurrence. The investigators report that NSCLC patients with high labeled glucose uptake may benefit from additional therapy following surgical resection.

Researchers from Duke University Medical Center reviewed 336 patients (176 women, 160 men) diagnosed between 2005 and 2010 with stage I NSCLC. All the patients underwent FDG/PET within 90 days of surgery to determine if FDG uptake, as measured by maximum standard uptake value (SUVmax) with PET, was associated with OS or time to recurrence. The median follow-up was 5.1 years.

The results showed that the risk of dying and recurrence decreased significantly as SUVmax decreased. It was 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, the researchers found that 41% of the patients in the third quartile of SUVmax will be alive compared to 77% in the lowest SUVmax group.

"FDG/PET SUVmax of stage I NSCLC at diagnosis is predictive of survival and time of recurrence. This parameter may serve as a biomarker to guide selection of patients for postsurgical chemotherapy or other more aggressive therapies," concluded the authors.

Senior study author Edward Patz, MD, who is with Duke University Medical Center, Durham, NC, said currently there is a need for prospective clinical trials to further examine the prognostic utility of tumor SUVmax in early-stage lung cancer.

The researchers noted that patients with stage I NSCLC have a wide variation in outcomes. They theorized that it is most likely due to undetected metastases at presentation. While surgical resection is the standard of care for patients with stage I NSCLC, it is often far from a cure, as demonstrated by 5-year survival rates of less than 60%. There is a clear need for a diagnostic test to identify which patients should receive postsurgical therapy. In some cases, patients may not need further treatment and can avoid unnecessary treatment-related toxicity and complications.

References:

• Wynes MW. (2015). Early stage NSCLC patients with low tumor metabolic activity have longer survival. The International Association for the Study of Lung Cancer.