Evaluation of prognostic value and stage migration effect using positive lymph node ratio in gastric cancer.
OBJECTIVE
To detect the best cut-off value of the positive lymph node ratio (PLNR) for stratifying the prognosis and analyzing its value with regard to stage migration effect using PLNR in gastric cancer.


METHODS
We retrospectively analyzed 1069 consecutive gastric cancer patients, who underwent curative gastrectomy with radical lymphadenectomy from 1997 through 2009.


RESULTS
1) The mean number of dissected lymph nodes was 42.6 in pStage I, 32.4 in pStage II and 37.1 in pStage III. The PLNR of 0.2 was proved to be the best cut-off value to stratify the prognosis of patients into two groups (P < 0.0001; PLNR <0.2 vs. PLNR ≥0.2), and patients were correctly classified into four groups: PLNR 0, PLNR 0-<0.2, PLNR 0.2-<0.4 and PLNR ≥0.4 by the Kaplan-Meier method. 2) Compared patients with the PLNR <0.2, those with the PLNR ≥0.2 had a significantly higher incidence of pT3 or greater, pN2 or greater, lymphatic invasion, vascular invasion and undifferentiated cancer. Multivariate analysis showed that the PLNR ≥0.2 was an independent prognostic factor [P < 0.0001, HR 2.77 (95% CI: 1.87-4.09)]. 2) The PLNR cut-off value of 0.2 could discriminate a stage migration effect in pN2-N3 and pStage II-III, which patients with PLNR ≥0.2 might be potentially diagnosed as a lower stage after gastrectomy.


CONCLUSIONS
The PLNR contributes to evaluating prognosis and stage migration effect even in a single institute and enable to identify those who need meticulous treatments and follow-up in patients with gastric cancer.
Division of Digestive Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan. Electronic address: skomatsu@koto.kpu-m.ac.jp.
S
S
Komatsu
Division of Digestive Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan.
D
D
Ichikawa
Division of Digestive Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan.
M
M
Nishimura
Division of Digestive Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan.
T
T
Kosuga
Division of Digestive Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan.
K
K
Okamoto
Division of Digestive Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan.
H
H
Konishi
Division of Digestive Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan.
A
A
Shiozaki
Division of Digestive Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan.
H
H
Fujiwara
Division of Digestive Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan.
E
E
Otsuji
D000368:Aged; D005260:Female; D005743:Gastrectomy; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery*
Gastric cancer; Lymph node metastasis; Positive lymph node ratio; Prognosis; Stage migration