Effect of Neoadjuvant Chemoradiotherapy on Perineural Invasion in Colorectal Cancer
Posted: Monday, September 10, 2018
Neoadjuvant chemoradiotherapy seems to decrease lymphovascular invasion but does not appear to affect perineural invasion in patients with invasive colorectal cancer. These findings were reported by Chang Hyun Kim, PhD, and colleagues, of Chonnam National University Hospital and Medical School, Gwangju, South Korea, in the World Journal of Surgery. The authors concluded that the presence of lymphovascular invasion and perineural invasion after neoadjuvant chemoradiotherapy were prognostic for disease-free and overall survival.
In this single-center observational study of 1,411 patients with colorectal cancer, 446 patients were treated with neoadjuvant chemoradiotherapy, and patterns of metastasis were followed for a median of 33.4 months. Detection rates of lymphovascular invasion in patients treated with neoadjuvant chemoradiotherapy were 8.1%, compared with 20.6% in patients not treated with neoadjuvant chemoradiotherapy (P < .001), and perineural invasion rates were 28.3% in patients treated with neoadjuvant chemoradiotherapy compared with 29.1% in those not so treated (P = .786). Accurate determination of 5-year disease-free and overall survival rates using the T stage with lymphovascular invasion and the T stage with perineural invasion systems was improved over the TNM system, particularly for patients who had fewer than 8 lymph nodes harvested for pathologic examination.
“The neural structures in the rectum may be more radioresistant than the lymphovascular structures,” the authors posited. They noted that little is known about radiation sensitivity of tumor cells metastasizing to lymphatic and peripheral nervous system, but “the presence of perineural invasion in rectal cancer specimens following neoadjuvant chemoradiotherapy is helpful to identify candidates for more intensive adjuvant treatment.”