| Objective: Effects of different doses of prophylactic cranial irradiation ( PCI ) for limited stage small cell lung cancer ( SCLC ) brain metastasis and survival rates in effect. To determine appropriate prophylactic cranial irradiation dose can be increased without increasing the brain tissue reactions is reduced below the premise of brain metastasis rate, improve the survival rate .In order to guide the clinical selection of optimal prophylactic cranial irradiation dose.Materials and Methods: 2008 July to 2010 July in our hospital were put up after chemotherapy by the limitations of the CR SCLC patients, PCI 48 patients were randomly divided into two groups: 25GY / 10 fractions radiotherapy group (23 cases ) as a conventional dose group, 30GY / 10 fractions group (n = 25 ) is set to high dose group. Case selection criteria: ( 1) all patients entered by histopathology ( electronic bronchoscopy or lung biopsy pathology or cytology ( sputum ), exfoliated cells in pleural fluid or pulmonary aspiration cytology ) confirmed; according to the Veteran's Administration Lung Cancer Study Group (VALG) clinical staging criteria are limited SCLC. ( 2)age 30 to 68 years old, KPS scores≥70. ( 3) receiving chemotherapy and radiotherapy in the treatment of tumor of the limitations of the CR SCLC PCI patients. Tumor CR refers to all the tumors treated with operation, chemotherapy and radiotherapy after all subsided, methods of evaluation included chest CT, head MRI and abdominal ultrasound examination. Tumor size and tumor diameter before treatment. Two groups of patients were given chemotherapy and radiotherapy, two courses of chemotherapy after radiotherapy, and received two cycles of chemotherapy, radiotherapy target area includes chemotherapy after primary lesion, ipsilateral hilar lymph nodes, chemotherapy before the invasion area, total dose of 56 chemotherapy regimens for EP ( Gy; E: etoposide, P: cisplatin ), in the treatment of tumor of CR after the start of PCI. PCI method of tumor CR after 30 ~ 45 days (mean 40 days ) to PCI. Using whole brain levels of two wild isocenter irradiation, irradiation field lower bound upper bound, flat cranial base line, before and after bounded open, with multiple blade grating eye protection and other important organs. Using conventional radiotherapy, 2.5 of A group Gy / fractions, 1 fractions / day, 5 fractions / week, total dose of 25 Gy; 3of Bgroup Gy / fractions, 1 fractions / day, 5 fractions / week, total dose of 30Gy.Result: 2 groups of patients with clinical data such as age, gender, tumor size, there was no significant difference between the treatment time interval. Brain metastasis: all the 48 patients, 9 patients (18.8% ) occurs in patients with brain metastases, of which the high dose group of 2 patients showed brain metastases, brain metastasis rate was 8%, significantly lower than conventional dose group ( 30.4% x 2 = 3.958, P = 0.047 ). The conventional group of cerebral metastases occurred on average time : 13.5 months ( 7-25 months ), where as the high dose group was 13 months ( 8-18 months ). All brain metastases occurred after MRI confirmed. Survival: conventional dose group of 1 years, 2 years, 3 year survival rates were 87%, 46.8% and 22.3%. Where as the high dose group were: 84%, 52.0% and 20.0%, the two groups showed no statistical differences ( x 2 = 0.020, P = 0.887 ). Conventional dose group, the median survival time was 23 months ( 95%CI 19.08-26.71), high dose group was 23 months ( 95%CI 20.18 - 26.31). Brain radiation toxicity: the whole group in all 48 patients, a total of 20 patients ( 41.7%) with varying degrees of acute radiation toxicity reaction. The conventional dose group 7 cases ( 30.4% ), high dose group 13 cases ( 52%). There was no significant difference between the two groups and (x 2 = 2.292, P = 0.130 ). But visible in high dose group of early adverse reaction was significantly higher than that of conventional dose group. As late side effects, high dose group in 2 cases with a survival time of more than 2 years of patients showed loss of memory and intermittent symptoms of dizziness, and conventional dose group had no obvious toxic and side effects of the late. Only 1 patients 60 years of age undergoing brain MRI showed cortical atrophy mild.Conclusion:Moderately improve the selectivity of PCI dose can be significantly increased in patients with neurotoxic while reducing the probability of occurrence of cerebral metastases, but failed to improve the survival rate of the patients with. The data analysis a few, short duration of follow up. But confirmed moderately selective prophylactic cranial irradiation dose can be significantly increased in patients with neurotoxic while reducing the probability of occurrence of cerebral metastases, but failed to improve the survival rate of the patients with. Of course, selective optimal dose of PCI need large sample studies further confirm center. |
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