Progression-free survival as a predictor of long-term prognosis

This study examined whether progression-free survival time could be used to predict long-term prognosis in non-resectable, locally advanced non-small cell lung cancer patients following chemotherapy and/or radiation therapy.

Non-small cell lung cancer is the most common form of lung cancer, and roughly 30% of tumors cannot be surgically removed, or resected. A combination of chemotherapy and radiation therapy is the standard treatment for advanced non-small cell lung cancer patients, and has been shown to lead to a tumor response, such as tumor shrinkage, in 60-70% of cases. Overall, multiple trials have demonstrated the combination of chemoradiotherapy to significantly extend disease-free periods before the eventual progression of the disease (referred to as progression-free survival). However, chemoradiotherapy is not curative, as studies have shown that up to two-thirds of patients treated will experience a recurrence of their disease, most relapses occurring within 2 to 3 years of treatments. The current study compared the effectiveness of response rates and progression-free survival times as predictors of long-term survival among non-resectable, locally advanced non-small cell lung cancer patients.

This study examined the medical records of 159 non-small cell lung cancer patients who received both chemotherapy and radiation therapy. For each patient, tumor response was measured following every two rounds of chemotherapy. Cancer progression was assessed following treatments using CT scans every 2 to 3 months during the first year, and every 3 to 6 months during subsequent years.

The overall response rate to treatments was 72%, with the majority of patients experiencing a partial response. At an average follow-up of 57 months, 72% of patients showed disease progression. The average progression-free survival time was 12 months, and the average overall survival time was 39 months. 5-year survival rates were shown to increase steadily according to progression-free survival times. Among all patients who were progression-free at 9 month, 5-year survival rate was 53%. In comparison, a 5-year survival rate of 82% was seen among patients who were progression-free at 18 months, and a 5-year survival rate of 89% was seen among patients who were progression-free at 24 months. Patients achieving a progression-free period greater than 24 months showed a 5-year survival rate of 90%. 

This study concluded that the progression-free survival following non-small cell lung cancer treatments can be used to estimate 5-year survival rates.

The patients included in this retrospective analysis received different chemotherapy and radiotherapy regimens, which could have influenced survival and response rates.