510P - Prognostic impact of tumor (T) and lymph node (N) status in patients with metastatic colorectal cancer (mCRC)

Date 29 September 2014
Event ESMO 2014
Session Poster Display session
Topics Colon Cancer
Rectal Cancer
Pathology/Molecular Biology
Presenter Shiva Kumar Mukkamalla
Citation Annals of Oncology (2014) 25 (suppl_4): iv167-iv209. 10.1093/annonc/mdu333
Authors S.K.R. Mukkamalla1, R. Chakraborty1, K. Singam2, N. Calderon1
  • 1Internal Medicine, Icahn School of Medicine at Mount Sinai/Queens Hospital Center, 11432 - New York/US
  • 2Internal Medicine, Queens Hospital Center, 11432 - New York/US

Abstract

Aim

T and N status, though commonly reported, do not affect the final staging or choice of therapy in patients with mCRC. The impact of T and N status on outcomes in patients with mCRC is unknown. Through our study we try to address this question using Surveillance, Epidemiology, and End Results (SEER) registry.

Methods

The SEER registry was searched for patients with mCRC, with known T and N status, diagnosed between 2004 and 2008. Patients with T0 and Tis were excluded. Additionally, survival characteristics were analyzed by age, gender and ethnicities. Five-year Overall survival (OS) was estimated by Kaplan-Meier method, and hazard ratios (HR) were calculated using Cox proportional hazard models.

Results

A total of 20,132 patients were included in our analysis. T1, T2, T3, and T4 disease were observed in 7.22%, 2.84%, 54.49% and 35.45%, and N0, N1, and N2 disease in 26.54%, 33.38% and 40.08% of the cases respectively. Mean age of study population was 64 ± 14 years. OS worsened with advancing T and N stage (table 1), with the exception of T1 disease - which was associated with a worse survival compared to T4 disease (HR 1.321; p < 0.0001). Both T and N were identified as independent predictors for OS through multivariate analysis adjusted for age, gender and race. It was also noted that mortality was significantly higher in Blacks as compared to whites (HR 1.177; p <0.0001).

Prognostic impact of T and N on survival in mCRC

Stage 3-yr OS (%) 5-yr OS (%) 3-yr HR (95% CI); p-value 5-yr HR (95% CI); p-value
T4 14.7 3.36 1 1
T3 22.86 5.6 0.705(0.683-0.729); <0.0001 0.734(0.712-0.757); <0.0001
T2 30.34 8.57 0.594(0.537-0.658); <0.0001 0.633(0.579-0.693); <0.0001
T1 9.83 2.48 1.336(1.255-1.422); <0.0001 1.321(1.245-1.402); <0.0001
N2 16.11 3.41 1 1
N1 21.52 4.93 0.825(0.796-0.855); <0.0001 0.844(0.816-0.872); <0.0001
N0 21.07 6.23 0.774(0.743-0.807); <0.0001 0.768(0.739-0.797); <0.0001

Conclusions

Both T and N status are independent predictors for OS in patients with mCRC. These findings suggest a potential role for stratifying patients with mCRC based on T and N status. Such stratification would be especially important in the setting of clinical trials, to enable a better interpretation of outcomes. It is possible that an overrepresentation of tumors, with a distinct biological subtype characterized by a tendency for early dissemination, in T1M1 disease explains the poor outcomes observed in this patient cohort. Nevertheless, additional well-designed studies are required to validate these findings.

Disclosure

All authors have declared no conflicts of interest.