No correlation between early changes in NSCLC tumor size, survival

Researchers have found that there was no relationship between an early decrease in non–small cell lung cancer tumor size and survival, even for patients whose tumors shrank by as much as 30%.

The researchers measured the tumor size of 99 patients with advanced NSCLC at baseline and again at two to three months after treatment initiation.

No patient had complete response at follow-up. Among partial responders, 19 had a ≥30% decrease in tumor size, 38 patients had a ≥ 20% decrease and 46 patients had a ≥10% decrease. Seventy-one patients had no decrease and the remaining 28 patients had a >20% increase in tumor size or developed new lesions.

The median survival ranged from a high of 35.1 months for patients with a ≥30% decrease in tumor size to a low of 31.6 months for patients who had a ≥20% decrease. The researchers concluded that none of the response categories were predictive for survival.

The researchers wrote that they could find “no distinct percentage change value that correlated with survival that could be used to define” partial response.

“To predict outcome early in patients undergoing treatment of advanced NSCLC, response criteria beyond change in tumor size are needed,” they wrote. “The integration of new response criteria, such as PET and tumor biomarkers, may be useful in determining optimal response criteria.”

Cancer. 2009;115:581-586.