| BackgroundLung cancer is the most common type in brain metastatic tumors,small cell lung cancer(SCLC) accounts for about 15% of all lung cancer cases, it is the most common type of lung cancer which is prone to brain metastasis. Occurrence of brain metastases have a bad effect on the prognosis of cancer patients,which can reduce the median survival to 4-6 months. The probability of brain metastases in patients with SCLC in 2 years can reach 50%, so the prevention of brain metastases of SCLC is very important. Study on the factors affecting the brain metastasis has been a hot spot.However, at present, in addition to the clinical stage and prophylactic cranial irradiation(PCI),other risk factors concerning SCLC for clinical research of brain metastases are rare.ObjectivesFully utilize the clinical and laboratory parameters, to analyze the clinical risk factors which can predict brain metastasis of SCLC. The aim of this study is to provide foundation to the best population who are more likely to benefit from PCI.Methods215 patients who were diagnosed as primary SCLC were analyzed retrospectively.Clinical and laboratory factors were tested for their risk factors of brain metastases.Kaplan—Meier method was used to calculate PFS and the rate of brain metastasis at1 and 2 years,Log-rank test was used to compare brain metastasis rate,univariate analysis and multivariate Cox regression model were used to analysis the risk factors for brain metastases.Results215 patients were included in this study and a total of 75 cases of patients had brain metastases(34.9%), the median brain metastases time is 10.5 months. For the 171 patients who did not receive PCI, 67 cases of the patients had brain metastases(39.2%), the median brain metastases time is 10.1 months.For the 44 patients who received PCI, 8 cases of the patients had brain metastases(18.2%), the median brain metastases time is 18.3 months. Progression Free Survival of the group is 9.1 months.Progression Free Survival rate at 1 and 2 years is 43% and 15%,respectively. Univariate analysis and Multivariate Cox regression model analysis indicate that KPS score(P=0.066,P=0.022),the patterns of tumor progression before brain metastases(P<0.0001,P<0.0001),receive PCI or not(P=0.003, P=0.01) were the clinical risk factors of brain metastases. Sex, age, weight loss or not, tumor family history, TNM stage, first- line chemotherapy regimen, first- line chemotherapy cycles, thoracic radiotherapy-time before brain metastases, anemia or not, low sodium, neutrophil to lymphocyte ratio(NLR), platelet to lymphocyte ratio(PLR),CEA, NSE, CYFRA211 have no statistical differences. Both Kaplan-Meier analysis and Multivariate analyses of patients who have not recevived PCI showed that KPS score(p=0.023,p=0.005) and the patterns of tumor progression before brain metastases(p<0.0001,p<0.0001) are the risk factors of brain metastases. The occurrence of brain metastases between the progression-free group and intrathoracic replase group is significantly different(P<0.0001), the occurrence of brain metastases between the progression-free group and intrathoracic replase plus extrathoracic and extracranial progression group have statistical differences( P < 0.0001), the occurrence of brain metastases between the extrathoracic and extracranial progression group and the intrathoracic replase plus the extrathoracic and extracranial progression group(P=0.018) have statistical differences.ConclusionsPCI can reduce the incidence of brain metastases. Analysis of PCI group and without PCI group showed that KPS score, intrathoracic and extracranial progression in the distance are the factors of SCLC patients which were prone to brain metastasis.Thus, for the patients whose KPS <80(between 50 and 80) or who have better control situation of intrathoracic and extracranial lesions(no progression or with extracranial or extrathoracic metastasis as the first progression),they should pay attention to the prevention of brain metastases. |
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