The influence of time of radio-chemotherapy and other therapeutic factors on treatment results in patients with limited disease small cell lung cancer

PurposeThe evaluation of effect of therapeutic parameters such as time of starting thoracic radiotherapy in relation to chemotherapy, schedule of combination chemo- and radiotherapy and SER, on treatment results in patients with limited disease small cell lung cancer (LD SCLC).MethodsBetween 2000 and 2007, 212 patients with LD SCLC received combined therapy: chemotherapy and thoracic radiotherapy. All patients received chemotherapy according to PE schedule (4–6 cycles), in combination with thoracic radiotherapy. The total dose applied to GTV was 54 Gy given in 27–30 fractions using fraction dose of 1.8–2.0 Gy. The concurrent treatment was performed in 112 patients (52.8%): the conventional fractionation (once a day, every five days a week) in 35 patients while 77 patients received “moderate” accelerated fractionation (one fraction a day, every four days a week and two fractions within one day, a week apart, with 6 h gap). The remaining 100 patients (47.2%) received sequential treatment. The time from the first day of chemotherapy to the end of thoracic radiotherapy (SER) was evaluated in all patients. The SER ranged from 57 to 337 days with the median value of 121 days.ResultsThe complete response in the thorax was observed in 143 out of 212 patients (67.5%). Out of these, 82 patients received concurrent chemo-radiotherapy (given in 22 patients as conventional dose fractionation and in 60 patients according to “moderate” accelerated dose fractionation), and the remaining 61 patients were treated with sequential therapy. The 5-year survival rates were: 17.7% for overall survival (OS), and 19.3% for disease-free survival (DFS). The relationship of therapeutic factors to survival rates showed statistically significant improvement of survival ratios in relation to early starting of thoracic radiotherapy and application of concurrent chemo-radiotherapy. The results of logistic regression revealed significant relationship between the value of SER and OS and DFS. The analysis shows that each day of extension of the SER resulted in increased probability of death (decrease of OS) by 0.28% and in increased the risk of development failure (decrease of DFS) by 0.31%. The influence of SER on lowered probability of complete response frequency was not statistically significant.ConclusionsThe concurrent chemo-radiotherapy with early administration of thoracic radiotherapy, results in improved complete response in the thorax and increase of overall and disease-free survival rates. The 5-year survival rates were: 17.7% for overall survival and 19.3% for disease-free survival. Our analysis and data from the literature suggest that shorter SER may play prognostic role in patients with LD SCLC treated with combination chemo- and radiotherapy. However, these observations require the confirmation in following studies.