Background and aim: Preoperative radiochemotherapy improves local control in locally advanced rectal cancer; however, its role in prolonging survival is still controversial. In order to better define the subset in patients who might benefit from this multimodal treatment, we have evaluated the correlation between grade of regression (GR) to preoperative treatment and disease-free survival (DFS).
Methods: We reviewed retrospectively the surgical specimens of 106 patients with locally advanced T3/T4 N0/ M0 rectal cancer. All patients were treated preoperatively with radiotherapy and 5-fluorouracil-based regimen chemotherapy. We evaluated ypTNM stage, and tumor regression was graded using the Dworak system that varies from GR 0 (absence of regression) to GR 4 (complete regression).
Results: GR was as follows: GR 4, 16 patients (15%); GR 3, 25 patients (23.6%), GR 2, 30 patients (28.4%), GR 1, 32 patients (30.2%) and GR 0, 3 patients (2.8%). A significant correlation was found between GR and DFS. Three-year DFS was 100, 85, 82, 66 and 33% in GR 4, 3, 2, 1 and 0, respectively (p=0.01). DFS was significantly lower in patients with advanced stages at diagnosis and in patients without down-staging. Moreover, in postoperative stage II and III cases, GR 3 correlated with a better DFS than GR 2-0 (p=0.2 and p=0.4, respectively).
Conclusions: The GR was a significant prognostic factor in locally advanced rectal carcinoma treated with preoperative chemoradiotherapy. The pathological stage and down-staging also have prognostic value. The use of a standardized system to evaluate GR in rectal cancer can allow for comparisons between different institutions and can identify patients at worse prognosis to be treated with adjuvant therapy.