Prognostic value of mucinous histology depends on microsatellite instability status in patients with stage III colon cancer treated with adjuvant FOLFOX chemotherapy: a retrospective cohort study.
BACKGROUND
The close association between mucinous histology and microsatellite instability (MSI) may have hindered the evaluation of prognostic significance of mucinous histology. The aim of this retrospective study was to investigate whether mucinous histology was associated with a worse prognosis, independent of MSI status, compared to nonmucinous histology in patients with stage III colon cancer.


METHODS
This study enrolled 394 consecutive patients with stage III colorectal cancer treated with adjuvant FOLFOX after curative resection (R0). Clinicopathological information was retrospectively reviewed. Tumors were analyzed for MSI by polymerase chain reaction to determine MSI status. Kaplan-Meier method, log-rank test, and Cox proportional hazard regression models were used.


RESULTS
The estimated rate of 3-year disease-free survival (DFS) in patients with nonmucinous adenocarcinoma (NMA 79.2 %) was significantly greater than that in patients with mucinous adenocarcinoma (MA) and adenocarcinoma with mucinous component (MC) (56.9 %; log-rank, P = 0.002). In univariate analysis, histology (NMA vs. MA/MC), American Joint Committee on Cancer stage (IIIA, IIIB, and IIIC), and lymphovascular invasion (present vs. absent) were significantly associated with DFS. In multivariate analysis, mucinous histology (MA/MC) was associated with decreased DFS in all patients (hazard ratio 1.82, 95 % confidence interval 1.03-3.23, P = 0.0403). In patients with MA/MC, no difference in DFS was observed between MSI and microsatellite stability (log-rank, P = 0.732).


CONCLUSIONS
Mucinous histology is an independent poor prognostic factor for DFS in patients with stage III colon cancer after adjuvant FOLFOX chemotherapy.
Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
Se Hyun
SH
Kim
Sang Joon
SJ
Shin
Kang Young
KY
Lee
Hyunki
H
Kim
Tae Il
TI
Kim
Dae Ryong
DR
Kang
Hyuk
H
Hur
Byung So
BS
Min
Nam Kyu
NK
Kim
Hyun Chul
HC
Chung
Jae Kyung
JK
Roh
Joong Bae
JB
Ahn
D002288:Adenocarcinoma, Mucinous / Q000188:drug therapy / Q000235:genetics / Q000401:mortality* / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000401:mortality* / Q000473:pathology; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D002955:Leucovorin / Q000627:therapeutic use; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000235:genetics / Q000401:mortality* / Q000473:pathology; D009367:Neoplasm Staging; D009944:Organoplatinum Compounds / Q000627:therapeutic use; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult
D009944:Organoplatinum Compounds; D002955:Leucovorin; D005472:Fluorouracil