不同肥胖测量指标对临床局限性前列腺癌术后病理特征的影响

Influence of obesity on clinicopathological characteristics in patients with clinically localized prostate cancer

目的 探讨不同肥胖测量指标包括体重指数、腹部皮下脂肪和腹部内脏肥胖对临床局限性前列腺癌患者术后病理特征的影响.方法 选择2006年1月至2013年3月413例在我院接受根治性前列腺切除术（RP）术治疗的临床局限性前列腺癌患者,回顾性分析其临床病理特征.本组中位年龄68岁（48 ～ 78岁）,术前均经病理诊断为前列腺腺癌,确诊Gleason评分4～10分,中位值7分.在MRI扫描T2WI、矢状位图像上测量前腹壁脂肪厚度、后腹壁脂肪厚度及前后径,计算腹部皮下脂肪厚度及腹部内脏脂肪比例.采用t检验或x2检验比较不同体重指数组患者的临床病理特征.Logistic回归分析评估各肥胖测量指标对RP术后病理特征的影响.结果 患者体重指数14.2～34.0 kg/m2,中位值23.8 kg/m2.皮下脂肪厚度为12.6～60.3 mm,中位值31.4 mm.内脏脂肪比例为71.1％ ～92.1％,中位值83.8％.RP术标本中,病理Gleason评分≥8分者141例（34.1％）.病理分期为pT3a期者69例（16.7％）,pT3b期者78例（18.9％）.413例患者中,71例（17.2％）患者RP术后病理标本切缘阳性,38例（9.2％）患者出现盆腔淋巴结转移.尽管在单因素分析中体重指数≥25 kg/m2可能与RP术后病理Gleason评分≥8相关（OR=1.413,P=0.035）,但多因素分析并未证实体重指数与术后病理Gleason评分相关（P =0.095）.多因素分析结果显示,经年龄、术前血清前列腺特异性抗原值、临床分期及确诊Gleason评分调整后,内脏脂肪比例为RP术后病理Gleason评分（OR =9.618,P=0.000）、包膜外侵犯（OR=6.750,P=0.002）和精囊腺侵犯（OR=4.419,P=0.007）的独立预测因素.结论 腹部肥胖测量指标比体重指数更能反映肥胖对前列腺癌病理特征的影响.腹部内脏脂肪比例为前列腺癌患者RP术后病理Gleason评分、包膜外侵犯和精囊腺侵犯的独立预测因素.

Objective To investigate the influence of anthropometric measures of obesity,including body mass index （BMI）,abdominal subcutaneous adipose tissue and visceral adipose tissue,on pathological characteristics in patients with clinically localized prostate cancer.Methods From January 2006 to March 2013,the 413 patients of prostate cancer who received radical prostatectomy （RP） and their clinical and pathological data had been collected.The median age for the entire cohort was 68 years,which ranged from 48 to 78 years.All patients were diagnosed with prostate cancer before surgery and the Gleason score ranged from 4 to 10 （median 7）.Anthropometric measures of abdominal adiposity including anterior abdominal fat,posterior abdominal fat and anteroposterior diameter were measured from the T2 weighted sagittal localization images of MRI scans and subcutaneous adipose tissue and the percentage of visceral adipose tissue were calculated.The patients＇ clinical and pathologic characteristics across BMI groups were compared used Student＇s t test for continuous variables or chi-squared test for categorical variables.Moreover,univariable and multivariable logistic regression models were used to address the influence of anthropometric measures of obesity on pathological outcomes.Results The BMI ranged from 14.2 to 34.0 kg/m2 and the median value was 23.8 kg/m2.The abdominal subcutaneous adipose tissue ranged from 12.6 to 60.3 mm and the median value was 31.4 mm.The percentage of visceral adipose tissue ranged from 71.1％ to 92.1％ and the median value was 83.8％.In RP specimens,Gleason score ≥ 8 was observed in 141 patients （34.1％）,pathological tumor stage was T3a in 69 patients （16.7％） and pathological tumor stage was T3b in 78 patients（18.9％）.Positive surgical margin and lymph node involvement were observed in 71 （17.2％） and 38 （9.2％） patients,respectively.Although univariate analysis showed that BMI ≥ 25 kg/m2 was associated with pathological Gleason score ≥ 8 （OR =1.413,P =0.035）,this positive correlation disappeared in multivariate analysis（P =0.095）.In multivariate analysis,the percentage of visceral adipose tissue was significantly associated with pathological Gleason score （OR =9.618,P =0.000）,extracapsular extension （OR =6.750,P =0.002） and seminal vesicle invasion （OR =4.419,P =0.007） after adjusting for patient age,PSA level,clinical stage and biopsy Gleason score.Conclusions Anthropometric measures of abdominal adiposity was more sophisticated than simple BMI to evaluate the risk of obesity with regard to the aggressiveness of prostate cancer.The percentage of visceral adipose tissue was an independent factor for pathological Gleason score,extracapsular extension and seminal vesicle invasion in RP specimens.