Background: The degree of histopathological response after neoadjuvant therapy in locally advanced gastric cancer (GC) is a key determinant of patients' long-term outcome. We aimed to assess the pattern of histopathological regression after two neoadjuvant approaches and its impact on survival times.
Methods: Regression grade of the primary tumour (Becker criteria) and the degree of nodal response by a 4-point scale (grades A-D) were assessed. Grade A-true negative lymph nodes (LNs); grade B and C-infiltrated LNs with any or little evidence of nodal response; and grade D-complete pathological response in a previously infiltrated LN. A favourable pathological response was defined as Becker Ia-b and grade D.
Results: From 2004 to 2014, 80 patients with GC (cT3-4/N + by CT-scan/EUS) were treated with either preoperative chemotherapy (ChT, n = 34) or chemoradiation (CRT, n = 46). Patients in the CRT group had a higher likelihood of achieving a Becker Ia-b response (58 vs 32%, P = 0.001), a grade D nodal regression (30 vs 6%, P = 0.009) and a favourable pathological response (23 vs 3%; P = 0.019). Patients with a grade D nodal response had a longer 5-year PFS and OS compared with those with a grade B or C response. Patients with a baseline negative LN status had similar outcomes irrespective of the preoperative therapy received (5-year OS; ChT vs CRT, 58 vs 51%, P = 0.92).
Conclusions: Preoperative chemoradiation increases the likelihood of achieving favourable ...