Prognostic markers of recurrence and survival in rectal cancer treated with neoadjuvant chemoradiotherapy and surgery

Abstract

• In our cohort of patients with locally advanced rectal cancer who received neoadjuvant chemoradiotherapy and surgery.• The rate of pathological complete response (pCR) was 18.9%.• The 5-year rate of recurrence was 33.2%.• The 5-year overall survival rate was 77%.• Lymphovascular invasion in pathological specimen was associated with recurrence.• pCR was associated with less recurrence and better survival and should be considered as an oncological end point.• Aduvant chemotherapy was associated with better survival.• The patients who achieved pCR may not benefit from aduvant chemotherapy. Aim:To identify markers of recurrence and survival in patients with locally advanced rectal cancer who received neoadjuvant chemoradiotherapy and surgery. Materials & methods: A total of 280 patients were identified in Manitoba between 2007 and 2012. Demographics and clinical data were collected. Cox regression models were used to identify outcome predictors. Results: A total of 53 patients achieved pathological complete response (pCR) and 160 patients received adjuvant chemotherapy (ACT). The median follow-up duration was 2.06 years. Recurrence and survival rates at 5 years were 33.2 and 77.0%, respectively. pCR and lymphovascular invasion predicted recurrence. pCR and ACT predicted better survival. Conclusion: pCR is a significant predictor of recurrence and survival and may be considered as an oncological end point. The patients who achieve pCR may not derive additional survival benefit from ACT. Locally advanced rectal cancer (LARC) is defined as the presence of either T3-4 and/or node-positive disease in absence of distant metastases. Neoadjuvant chemoradiotherapy (NACRT) followed by radical surgery that includes total mesorectal excision is standard treatment for these patients [1,2]. The estimated 5-year overall survival (OS) and local recurrence (LR) rates were 76% and 6%, respectively, with the distant recurrence (DR) rate at 36% in CAO/ARO/AIO-94 study [2]. Similar results were reported by the European Organization for Research and Treatment of Cancer (EORTC) Radiotherapy Group Trial 22921 [1] with a 5-year cumulative incidence of LR at 7.6% and DR at 34.4%.

Clinical study of colorectal cancer operation: Survival analysis

“…Various factors such as tumor stage, preoperative CEA, cell differentiation, vascular invasion, intestinal obstruction, intestinal perforation, age, and sex have been reported as predictive factors on survival rate following curative resection for colorectal cancer [14][15][16]. In our study, there was significant difference in survival rate according to tumor stage, preoperative CEA, age, and sex.…”

Impact of KRAS status on tumor response and survival after neoadjuvant treatment of locally advanced rectal cancer

“…As a result, the identification of biologic markers associated with pCR and tumor downstaging have become an increasing focus of research. [8][9][10] The Kirsten rat sarcoma (KRAS) gene is one of the most common mutations found in colorectal cancer, which is seen in approximately 30%-50% of cases.…”

“…Although several disease‐ and treatment‐related factors including histopathologic stage, tumor size, radiation therapy dosing, and timing of surgery 3 have been associated with pCR and low NAR scores, tumor biology appears to be the most important factor in determining response to treatment. As a result, the identification of biologic markers associated with pCR and tumor downstaging have become an increasing focus of research 8–10 . The Kirsten rat sarcoma ( KRAS ) gene is one of the most common mutations found in colorectal cancer, which is seen in approximately 30%–50% of cases.…”