Extracapsular involvement in nodal metastasis as a prognostic factor in colorectal cancer.

BACKGROUND: Extracapsular extension of nodal metastasis has recently emerged as an important prognostic factor in different malignancies. In colorectal cancer (CRC), only a limited number of studies have been published and its prognostic value has not yet been completely established.

AIMS: To assess the incidence of extracapsular invasion (ECI) in lymph node (LN) metastasis in colorectal adenocarcinoma and to investigate the correlation between this parameter and other clinico-pathological factors.  Furthermore, its effect on overall and disease free survival were evaluated.

METHODS: Seventy-five patients who underwent colorectal resection for adenocarcinoma with node metastasis were included in this study. Extracapsular invasion was evaluated by two pathologists. Associations between clinicopathologic factors, survival, and the nodal findings were evaluated. The 2009 pTNM staging of CRC was used.

RESULTS: Extracapsular invasion was identified in 45 patients (60 %). Average follow-up time was 25 months. Extracapsular invasion was correlated with pT stage> pT2 (p=0,015), pN stage > pN1 (p= 0,014), distant metastasis at diagnosis (p=0,005) and later (p=0,01) and with local recurrences (p=0,0001). Univariate analysis indicated that ECI tends to decrease overall survival but not significantly.  Multivariate analysis showed that age and synchronic metastasis were independent prognostic factors (HR = 2,03 and 2,24; p= 0,039 and 0,012 respectively). Patients with ECI had a significantly worse five-year disease-free survival than ECI-negative groups.

CONCLUSION: In patients with CRC, ECI in regional LNs would reflect an aggressive behavior. It would therefore be useful to include this parameter in standardized pathologic reports and future staging systems.