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ObjectiveTo investigate the application of non-contrast and contrast-enhanced 18FDG PET/CT in the delineation of gross tumor volume ( GTV ) of pancreatic cancer.MethodsBetween Jan.2008 and Dec.2009,twenty-one patients with unresectable locally advanced pancreatic cancer or recurrent pancreatic cancer after surgery in our hospital had both non-contrast CT and PET images acquired at the same body position.Among the whole group,eleven patients also had contrast CT images.The image data sets were transferred to the treatment planning workstation for registration.Then gross tumor volumes ( GTV )were delineated independently using the information of PET images,contrast/non-contrast CT scan and contrast/non-contrast PET-CT fusion images.The differences of mean volume in these different sets of GTV were analyzed.Results For the whole group,the mean volume of non-contrast GTVCT,GTVPET,noncontrast GTVPET-CT were 76.9 cm3,47.0 cm3 and 44.5 cm3,respectively.The mean volume of non-contrast GTVPET-CT was significantly smaller than non-contrast GTVCT ( z =-3.91,P =0.000 ).For the eleven patients with contrast CT,the mean volume of contrast GTVCT,GTVPET,contrast GTVPET-CT were 64.1 cm3,45.1 cm3 and 49.3 cm3,respectively.The mean volume of contrast GTVPET-CT was significantly smaller than contrast GTVCT (z =-2.13,P =0.033 ).No significant differences were found between contrast PET-CT and non-contrast PET-CT (z =-0.80,P =0.424).ConclusionsCo-registration of PET and contrast/noncontrast CT information in pancreatic cancer may improve the accuracy of GTV delineation,and possibly reduce the adverse effect of irradiation.
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Objective To evaluate clinical risk factors that can predict brain metastasis after complete resection of small cell lung cancer (SCLC) and to assess the role of prophylactic cranial irradiation (PCI) in such kind of patients.Methods Eighty-eight patients with completely resected stage Ⅰ - Ⅲ SCLC from Jan.2000 to Dec.2009 in our hospital were retrospectively analyzed.Kaplan-Meier was used to compare the differences in the incidence of metastasis free survival in different groups.Logistic model was used to assess the independent risk factors for brain metastasis.Results The follow-up rate is 100％,and 37 patients were followed up for more than three years.None of the 3 patients who received PCI developed brain metastasis,while for patients without receiving PCI,24％ developed brain metastases.The incidence of brain metastasis for stage Ⅰ,Ⅱ and Ⅲ SCLC after surgery were 4％,26％ and 29％ ( x2 =7.57,P =0.023),respectively.The median survival time and the 3-year survival rate were 18 months and 25％ for patients who developed brain metastasis,and 48 months and 59％ for those without brain metastasis ( x2 =10.63,P =0.001 ).Both univariate and multivariate analyses showed that pre-treatment disease stage wasindependent risk factor for brain metastasis ( x2 =7.57,8.52 ; P =0.023,0.004 ).Age,sex,tumor location,pathological type,induction chemotherapy,and postoperative chemotherapy/radiotherapy were not significantly correlated with the incidence of brain metastasis ( x2 =0.03,0.00,0.00,2.58,0.01,1.23,0.84;P =0.869,0.998,0.992,0.109,0.936,0.266,0.361,respectively).Conclusions Pre-treatment disease stage was independent risk factor for brain metastasis in SCLC.PCI may be important for stage Ⅱ -Ⅲ SCLC but not for stage Ⅰ disease.=Carcinoma,small cell lung/surgery; Neoplasm metastasis,brain/prophylactic irradiation; Factors analysis
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Objective To explore the reasonable radiotherapy range by analyzing the patterns and characteristics of intra-thoracic lymph node metastasis in small cell lung cancer (SCLC).Methods One hundred and fifty patients with limited-stage SCLC who received radical resection of primary tumor and systemic intra-thoracic lymph node dissection were included in the study.All the lymph nodes in each area were recorded and examined pathologically to analyze the patterns and characteristics of intra-thoracic lymph node metastasis.Results A total of 2372 lymph nodes were found in 631 areas,and a total of 413 positive lymph nodes (17.4％) were found in 188 lymph node areas (29.8％ ).Intra-thoracic lymph node metastasis were found in 88 patients,with a positive rate of 58.7％.The frequencies of metastasis in the area 11,10,7,5,4 were much higher than those in the other areas,and central located lesions and the higher T-stage lung tumors were more likely to develop intra-thoracic lymph node metastasis (x2 =15.32,39.72;P =0.000,0.000,respectively).Tumors located in the right upper lobe and right middle/lower lobe had a higher tendency of metastasis to the areas 4,7,10 and 4,7,10,11,respectively.Tumors located in the left upper lobe and left lower lobe had a higher tendency of metastasis to the areas 4,5,6,10 and 4,7,9,10,11,respectively.Mediastinal lymph node metastasis (N2 ) were found in 72 patients,among whom 29 patients (40.3％ ) had skipping N2 metastasis without hilar metastasis.Tumors located in the upper lobe had a tendency of skipping metastasis to the upper mediastinum,while tumors located in the middle/lower lobe had a tendency of skipping metastasis to the upper and lower mediastinum.Conclusions The lymph node metastases in SCLC follow the lymphatic drainage routes,that is,from intrapulmonary to the hilar and then to the mediastinum,but with some skipping metastases.Tumors located in different lobes have different high risk lymph node areas for metastasis,and elective irradiation to these lymph node areas maybe increase radiotherapy gain ratio in SCLC.