Deciding which treatments to try and determining whether they are working are two of the biggest challenges for patients with malignant pleural mesothelioma. But a team of researchers in the UK is trying to make the process a little easier. They have identified three markers the say can help doctors predict prognosis in mesothelioma patients and monitor their response to treatment.
The South West Area Mesothelioma and Pemetrexed trial, based in the Southwestern part of England, recruited 73 pleural mesothelioma patients between 2008 and 2011. Fifty-eight of the patients elected to undergo chemotherapy with pemetrexed (Alimta) for their mesothelioma and 15 opted only for best supportive care, without chemotherapy.
Before treatment began, the researchers used PET-CT to test each patient’s baseline total glycolytic volume (TGV), a measure of metabolic activity within the mesothelioma tumor. They also measured several serum markers including mesothelin, fibulin-3, and neutrophil-to-lymphocyte ratio. Patients were followed for a minimum of one year. Median survival in the chemotherapy group was 368 days and in the best-supportive care group it was 325.
The study results suggest that neutrophil-to-lymphocyte ratio (a measure of immune response) and baseline TGV may be the best predictors of overall survival in patients with mesothelioma. A baseline neutrophil-to-lymphocyte ratio (NLR) of less than 4 was “an independent predictor of better overall survival” and increased survival by a median of about 200 days over patients with a higher NLR.
But not all of the prognostic factors tested were valuable for the same things. Mesothelin, for example, turned out not be a good predictor of overall survival but was valuable for monitoring treatment response. Patients whose mesothelin levels fell at 8 weeks, regardless of what the initial level was, were more likely to have a longer time before their mesothelioma progressed. And while baseline TGV (measured by PET-CT) was valuable for predicting survival, it turned out not to be useful for monitoring chemotherapy response.
“There appears to be no role for routine interval PET-CT scanning in patients undergoing chemotherapy,” writes lead author Dr. Claire Hooper of the North Bristol Lung Centre. “However, change in serum mesothelin could be an indicator of treatment response and warrants further study.”
The article appears in a recent issue of the British Journal of Cancer.
Hooper, CE, “The South West Area Mesothelioma and Pemetrexed Trial: a multicenter prospective observational study evaluating novel markers of chemotherapy response and prognostication”, March 10, 2015, British Journal of Center, Epub ahead of print