In:
American Journal of Surgical Pathology, Ovid Technologies (Wolters Kluwer Health), Vol. 44, No. 12 ( 2020-12), p. 1685-1698
Abstract:
Grade 3 (G3, poorly differentiated) is an important treatment-decision factor in stage II colon cancer, but no unified diagnostic criteria are established. According to previous studies, an intratumoural poorly differentiated area with no glandular formation (POR) that fills the microscopic field of a ×40 objective lens was an essential factor that defined G3. We aimed to prospectively validate this in a randomized controlled study of adjuvant chemotherapy (SACURA trial). We enrolled 991 patients with stage II colon cancer. POR was graded according to the ×40 objective lens rule and the intensity of poorly differentiated clusters (Grade POR ), and its prognostic power was compared with that of the conventional tumor grade on the basis of predominant histology rule (Grade conv ). According to Grade POR , 313, 526, and 152 tumors were classified as G1 POR , G2 POR , and G3 POR , respectively, and the 5-year relapse-free survival (RFS) rates were 91.1%, 82.9%, and 74.7%, respectively ( P 〈 0.0001). When G3 POR and G3 conv were alternatively added to the prognostic model consisting of 8 conventional factors, only G3 POR was a significant factor for RFS ( P =0.040, Wald test). The adverse impact of G3 POR on RFS was greater in the microsatellite stable/microsatellite instability–low subset than that in the full analysis set. In the microsatellite stable/microsatellite instability–low subset, the 5-year RFS rate of patients with G3 POR tumors in the chemotherapy group achieved greater improvement (9.1%) than the surgery-alone group. The least differentiation policy with the ×40 objective lens rule may be highlighted as the diagnostic criterion for G3 because of its validated prognostic value.
Type of Medium:
Online Resource
ISSN:
0147-5185
DOI:
10.1097/PAS.0000000000001570
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2020
detail.hit.zdb_id:
2029143-7
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