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

Objective: To explore the expression of phosphatase and tensin homolog deleted on chromosome ten (PTEN) in low rectal cancer on neoadjuvant chemoradiotherapy with capecitabine plus radiotherapy.

Methods: Sixty-six patients with low rectal cancer on therapy with capecitabine (1650 mg×m(-2)×d(-1) in 2 divided doses) for two course and concurrent radiotherapy (50 Gy, 2 Gy/day, 5 days a 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 anal edge 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, up-regulating PTEN expression, promoting the apoptosis of cancer cell and achieving a better survival rate. Thus preoperative neoadjuvant chemoradiotherapy is an effective adjuvant measure.