Positive findings at preoperative PET in the mediastinum appear to have prognostic implications for non-small-cell lung cancer despite histologically negative mediastinal lymph nodes, according to a single-center study published in the October issue of Radiology.
In the study, Liyi Xie, MD, of the department of radiation oncology at the University of North Carolina School of Medicine in Chapel Hill, and colleagues sought to assess the prognostic implications of mediastinal PET findings in patients undergoing curative resection of non-small-cell lung cancer (NSCLC), who have histologically negative mediastinal lymph nodes, with the hypothesis that positive findings at PET are prognostic even in patients with negative histologic findings in the lymph nodes.
The researchers reviewed records of patients with a preoperative PET exam undergoing curative surgery, without adjuvant radiation, for pathologic T1-3N0-1 non-small-cell lung cancer at the University of North Carolina between 2000 and 2006.
According to the study authors, 90 patients were evaluable (all histologically negative in mediastinum; 44 with both mediastinoscopy and surgery); 13 patients had positive mediastinal PET findings and 77 had negative mediastinal PET findings. Local-regional and distant failure rates in patients with and those without mediastinal abnormalities at preoperative PET were compared by using logistic regression and log-rank tests. The median follow-up was 54.3 months.
There were higher rates of local-regional and distant failure as well as death in patients with positive PET findings than in patients with negative findings. In multivariable analysis (adjusting for other prognostic factors), positive PET findings in the mediastinum remained prognostic for distant failure and were marginally prognostic for local-regional failure, the researchers reported.
“The high rate of local-regional and distant failure suggests that postoperative radiation therapy and/or chemotherapy may be particularly helpful in patients with positive mediastinal findings at preoperative PET,” Xie and colleagues wrote. “In conclusion, our findings suggest that, in patients with NSCLC, preoperative evaluation of the mediastinum with PET may complement the surgical and histologic findings. Among patients with a negative pathologic assessment of the mediastinum, those with an abnormality in the mediastinum at PET have a higher rate of local-regional and distant failure than do those without.”