Retrospectively Analysis of Factors Influencing the Relapse (or Progression) of Newly Diagnosed Nonoperative Small Cell Lung Cancer

Background and objective Most small cell lung cancer (SCLC) patients relapse or progress and have low survival rate although they have significant response to initial chemotherapy and radiotherapy. This study intends to explore the factors affecting the relapse (or progression) of nonoperative SCLC and to explore the correlations between progression-free survival (PFS) and overall survival (OS). Methods Clinical data of 182 patients diagnosed with SCLC between January 2009 and December 2011 at Shanghai Chest Hospital has been reviewed and retrospectively analyzed. All of these patients accepted chemotherapy combined (or not combined) with radiotherapy, and relapsed or progressed after first-line therapy. Univariate Kaplan-Meier survival estimates as well as multivariate Cox regression survival analysis were used to locate the potential factors affecting PFS. The correlation between PFS and OS was analyzed via Bivariate Correlation Analysis method. Results The univariate estimates showed that the TNM stage, liver metastasis or not, brain metastasis or not, first-line chemotherapy cycles, effect of initial chemotherapy, and thoracic radiotherapy combined or not were the significant contributive factors to PFS. In the subgroup of the patients without brain metastases, those received prophylactic cranial irradiation (PCI) had longer PFS. Cox regression indicated that the three independent variables of first-line chemotherapy cycles, effect of initial chemotherapy and thoracic radiotherapy combined or not were closely related to PFS. In addition, significant positive correlation between PFS and OS had been observed. Conclusion PFS could be prolonged by having more first-line chemotherapy cycles (>4 cycles), obtaining better effect of initial chemotherapy (partial response or complete response), combining with thoracic radiotherapy and implementing PCI for patients without brain metastasis.