Predictors of Lymph Node Metastasis and Prognosis in pT1 Colorectal Cancer Patients with Signet-Ring Cell and Mucinous Adenocarcinomas

Abstract

Background/Aims: The local excision of early colorectal cancer is limited by the presence of lymph node metastasis (LNM). Signet-ring cell carcinomas (SRC) and mucinous adenocarcinomas (MAC) are two relatively infrequent histological subtypes. However, little is known about the predictors of LNM and prognosis to support the feasibility of local excision in early-stage SRC and MAC. Methods: The Surveillance Epidemiology and End Results Database were used to identify all patients with pT1 adenocarcinomas, including conventional adenocarcinoma (AC), MAC, and SRC. The prevalence of LNM was assessed, and the long-term survival rate in the above three types of colorectal cancer was calculated. Results: SRC accounted for 0.3% and MAC accounted for 4.4% of the entire cohort of colorectal adenocarcinomas. Compared to AC, MRC and SRC were more often located in the proximal colon, and exhibited a higher grade. The incidence of LNM in AC, MAC, and SRC was 10.6%, 17.2%, and 33.3% for colon cancers and 14.8%, 25.9%, and 46.2% for rectal cancers, respectively. In patients with lymph nodes resected no less than 12, incidence of LNM in AC, MRC, and SRC was 12%, 21%, and 44% for colon tumors and 17%, 30%, and 14% for rectal tumors, respectively. Although, colon patients MAC showed an entirely worse survival rate than AC, rectum patients MAC showed a similar prognosis to AC. We found that in patients with rectal tumors, SRC had a worse 3 and 5-year prognosis than AC. However, for colon cancers, the prognosis of SRC was similar to that of AC. Histology was not found to be an independent prognostic factor in multivariate survival analysis. Conclusions: MAC and SRC are two distinct subtypes of colorectal cancer that require special attention despite their relatively rare prevalence. pT1 patients with SRC of the rectum and patients with MAC of the colon have higher incidences of LNM, and with these adverse outcomes, local excision is not recommended. AlthoughMAC of the rectum and SRC of colon have a high rate of LNM, the prognosis of these types are similar to that of AC.

Population-based analysis on predictors for lymph node metastasis in T1 colon cancer

“…Mucinous carcinoma is a relatively rare pathological type of colorectal cancer, accounting for approximately 10-15% of all colorectal cancer cases [18]. As a distinct subtype, mucinous carcinoma has been reported to be associated with higher risks of lymph node involvement in stage I and II colorectal cancer [19,20]. Our population-based analysis consistently revealed that patients with mucinous carcinoma of the colon had a higher risk of LNM.…”

Poorly differentiated clusters: prognostic significance in colorectal carcinomas

“…Moreover, the PDCs-G has proven to be a strong parameter for stratifying the risk of LNM in early invasive CRC [7,37]. The prediction of lymph node involvement was more important in the PDCs grading system compared to conventional grading, and this was highlighted in several studies [9,17,18,28,37,38,39]. In a study on 3243 cases of CRC, Ueno et al showed that the incidence of LNM is higher in PDCspositive tumours compared with PDCs-negative tumours [16].…”

Early stage colon cancer: Current treatment standards, evolving paradigms, and future directions

“…Additionally, certain malignant polyps with favorable features, such as well or moderate differentiation, pedunculated morphology, at least 2 mm from the cauterized edge, without lymphovascular invasion and no evidence of distant or nodal metastases, are amenable to endoscopic resection with very low risk of lymph node metastasis and excellent long-term overall survival[ 19 ]. In a study of patients with malignant polyps who were lacking only one listed favorable feature, the risk of lymph node metastasis was 8% and residual carcinoma was 3% following surgery; with the risk of surgical complications at 13%, the balance remained even suggesting that only patients with multiple poor prognostic features would benefit from surgery (Table 2 )[ 20 , 21 ]. Furthermore, some features are high-risk enough on their own to warrant resection even if others are lacking, specifically poorly differentiated tumors or mucinous or signet ring histology or those with deeper submucosal invasion, as these morphologies are associated with rates of lymph node metastases as high as 17%-46%[ 21 , 22 ].…”

“…In a study of patients with malignant polyps who were lacking only one listed favorable feature, the risk of lymph node metastasis was 8% and residual carcinoma was 3% following surgery; with the risk of surgical complications at 13%, the balance remained even suggesting that only patients with multiple poor prognostic features would benefit from surgery (Table 2 )[ 20 , 21 ]. Furthermore, some features are high-risk enough on their own to warrant resection even if others are lacking, specifically poorly differentiated tumors or mucinous or signet ring histology or those with deeper submucosal invasion, as these morphologies are associated with rates of lymph node metastases as high as 17%-46%[ 21 , 22 ]. Thus, for malignant polyps and very small stage I disease, the recommendation for full segmental colonic resection should be an individualized decision based upon the patients’ tumor risk factors and surgical risk factors.…”