title: Is the T1/2N1 (≤3 nodes) category actually stage IIIA (TNM)/IIIa (Japanese classification) in patients with primary colorectal cancer?
abstract: The 5-year relapse-free survival rate (5Y-RFS) and the 5-year overall survival rate (5Y-OS) were calculated for 972 patients (stage I, 206 patients; stage II, 396 patients; stage III, 370 patients). We divided the stage III group into 259 patients with IIIa/N1 disease (≤3 positive nodes) and 111 patients with IIIb/N2 disease (≥4 positive nodes) according to the Japanese classification. The IIIa/N1 and IIIb/N2 categories were each subdivided into T1/2 (stage IIIa, 45 cases; IIIb, 9 cases) and ≥T3 (stage IIIa, 214 cases; IIIb, 102 cases) according to the TNM classification, and 5Y-RFS and 5Y-OS were compared between each subcategory and each group. The 5Y-RFS/5Y-OS values calculated for each stage were as follows: stage I, 94.0/90.7%; stage II, 80.5/81.1%; stage III, 63.5/65.7%. When stage IIIa was compared with IIIb, we obtained 67.9/72.0% for stage IIIa and 53.6% (p=0.001)/50.4% (p<0.001) for stage IIIb. For stage IIIa vs. IIIb in the ≥T3 category, we obtained 63.1/68.5% for stage IIIa and 51.9% (p=0.010)/49.0% (p=0.008) for stage IIIb. For stage IIIa vs. IIIb in the T1/2 category, we obtained 92.1/92.0% for stage IIIa and 72.9% (p=0.040)/63.5% (p=0.003) for stage IIIb. There were significant differences between T1/2 and ≥T3 within stage IIIa (p=0.001/p=0.009), but not within stage IIIb. These results suggest that the T1/2N1 category of colorectal cancer should be classified as a subcategory of stage IB/Ib rather than stage IIIA (TNM)/IIIa (Japanese classification).
authors.affiliation: Department of Surgery, Tokai University Hachioji Hospital, Ishikawa-cho 1838, Hachioji, Tokyo 192-0032, Japan. mukai.masaya@hachioji-hosp.tokai.ac.jp
authors.forename: Masaya
authors.initials: M
authors.lastname: Mukai
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kishima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukumitsu
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Sekido
authors.forename: Hideki
authors.initials: H
authors.lastname: Izumi
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Hoshikawa
authors.forename: Takayuki
authors.initials: T
authors.lastname: Tajima
authors.forename: Kousuke
authors.initials: K
authors.lastname: Tobita
authors.forename: Sotaro
authors.initials: S
authors.lastname: Sadahiro
authors.forename: Seiei
authors.initials: S
authors.lastname: Yasuda
authors.forename: Kyoji
authors.initials: K
authors.lastname: Ogoshi
mesh_terms: D015179:Colorectal Neoplasms / Q000145:classification* / Q000175:diagnosis*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007564:Japan; D008207:Lymphatic Metastasis; D008297:Male; D008495:Medical Oncology / Q000379:methods; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging / Q000379:methods*; D012008:Recurrence; D013997:Time Factors; D016896:Treatment Outcome