术前新辅助放化疗对低位直肠癌患者PTEN表达的影响

Expression of phosphatase and tensin homolog in lower rectal cancer on neoadjuvant chemoradiotherapy

目的 探讨术前口服卡培他滨与放疗联合治疗对低位直肠癌的疗效及磷酸酶与张力蛋白同源物（PTEN）蛋白在此过程中的表达变化.方法 66例低位直肠癌患者均给予术前新辅助放化疗：口服卡培他滨1650 mg·m-2·d-1分两次服用,总服药2个疗程;化疗同时开始体外放疗,2 Gy/d,每周治疗5 d,总剂量为50 Gy.观察术前新辅助放化疗的疗效,并应用反转录-聚合酶链反应（RT-PCR）和Western印迹技术检测患者PTEN的表达变化.结果 92.4%（61/66）的患者按计划完成新辅助放化疗.87.9%（58/66）的患者肿瘤分期降级,癌灶范围缩小距肛缘的距离增大.所有患者均施行根治性切除术,保肛率达90.9%（60/66）,85.5%的患者肛门括约肌功能良好.随访发现患者术后2年生存率为87.9%（58/66）,仍然健在患者的生存期25～60个月,平均35.3个月;PTEN mRNA和蛋白在新辅助治疗前直肠癌组织中表达量均明显低于手术后直肠癌组织（P=0.0079、0.0269）.结论 低位直肠癌术前采用术前新辅助放化疗确实能达到肿瘤降期、提高手术切除率和保肛成功率等目的,增加PTEN表达、促进癌细胞凋亡、取得了较高的生存率,是治疗低立直肠癌的一种有效辅助措施.

Objective To explore the expression of phosphatase and tensin homolog deleted on chromosometen （PTEN） in low rectal cancer on neoadjuvant chemoradiotherapy with capecitabine plus week）. Then the investigators analyzed the relationship between the preoperative neoadjuvant chemoradiotherapy and prognosis and measured the expression of PTEN during neoadjuvant chemoradiotherapy. Results 92.4% （61/66） of patients received neoadjuvant chemoradiotherapy as planned. 87.9% （58/66）tumor stages were down-staged, tumor size decreased while the distance from analedge increased. And curative resection with sphincter-sparing was carried out in all patients. The rate of sphincter preservation was 90.9% （60/66）. Among which, 85.5% patients showed an excellent function of sphincter. The 2-year survival rate was 87.9% （58/66）. The survival period was an average of 35.3 months （range： 25 -60）. The PTEN mRNA and protein expression in cancer tissues on neoadjuvant chemoradiotherapy were significantly higher than those before neoadjuvant chemoradiotherapy （P= 0.0079,0.0269）. Conclusions The preoperative neoadjuvant chemoradiotherapy in lower rectal cancer patients has shown its efficacy in down-staging cancer, enhancing resectability, offering sphincter preservation, upregulating PTEN expression, promoting the apoptosis of cancer cell and achieving a better survival rate. Thus preoperative neoadjuvant chemoradiotherapy is an effective adjuvant measure.