Risk factors for lymph node metastasis in T2 colorectal cancer: a systematic review and meta-analysis

BACKGROUND

Lymph node metastasis (LNM) occurs in 20-25% of patients with T2 colorectal cancer (CRC). Identification of risk factors for LNM in T2 CRC may help identify patients who are at low risk and thereby potential candidates for endoscopic full-thickness resection. We examined risk factors for LNM in T2 CRC with the goal of establishing further criteria of the indications for endoscopic resection.

METHODS

MEDLINE, CENTRAL, and EMBASE were systematically searched from inception to November 2023. Studies that investigated the association between the presence of LNM and the clinical and pathological factors of T2 CRC were included. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Certainty of evidence (CoE) was assessed using the GRADE approach.

RESULTS

Fourteen studies (8349 patients) were included. Overall, the proportion of LNM was 22%. The meta-analysis revealed that the presence of lymphovascular invasion (OR, 5.5; 95% CI 3.7-8.3; high CoE), high-grade tumor budding (OR, 2.4; 95% CI 1.5-3.7; moderate CoE), poor differentiation (OR, 2.2; 95% CI 1.8-2.7; moderate CoE), and female sex (OR, 1.3; 95% CI 1.1-1.7; high CoE) were associated with LNM in T2 CRC. Lymphatic invasion (OR, 5.0; 95% CI 3.3-7.6) was a stronger predictor of LNM than vascular invasion (OR, 2.4; 95% CI 2.1-2.8).

CONCLUSIONS

Lymphovascular invasion, high-grade tumor budding, poor differentiation, and female sex were risk factors for LNM in T2 CRC. Endoscopic resection of T2 CRC in patients with very low risk for LNM may become an alternative to conventional surgical resection.

TRIAL REGISTRATION

PROSPERO, CRD42022316545.

Prognostic Factors Among Colonic Adenocarcinomas Invading Into the Muscularis Propria

Depth of invasion through the intestinal wall, categorized as primary tumor stage (pT), is an important prognostic factor in colorectal cancer. However, additional variables that may affect clinical behavior among tumors involving the muscularis propria (pT2) have not been examined at length. We evaluated 109 patients with pT2 colonic adenocarcinomas (median age: 71 y, interquartile range: 59 to 79 y) along various clinicopathologic parameters, including invasion depth, regional lymph node involvement, and disease progression after resection. Tumors extending to the outer muscularis propria (termed pT2b) were associated in multivariate analysis with older patient age (P=0.04), larger tumor size (P<0.001), higher likelihood of lymphovascular invasion (LVI; P=0.03) and higher lymph node stage (pN; P=0.04), compared with tumors limited to the inner muscle layer (pT2a), and LVI was the single most important variable predicting regional lymph node metastasis at resection in these tumors (P=0.001). The Kaplan-Meier analysis during a median clinical follow-up of 59.7 months (interquartile range: 31.5 to 91.2) revealed that disease progression was more likely in pT2 tumors that exhibited, at the time of staging: size >2.5 cm (P=0.039), perineural invasion (PNI; P=0.047), high-grade tumor budding (P=0.036), higher pN stage (P=0.002), and distant metastasis (P<0.001). Proportional hazards (Cox) regression identified high-grade tumor budding (P=0.02) as independently predicting shorter progression-free survival in pT2 tumors. Finally, among cases that would not ordinarily be candidates for adjuvant treatment (ie, pT2N0M0), the presence of high-grade tumor budding was significantly associated with disease progression (P=0.04). These data suggest that, during the diagnosis of pT2 tumors, pathologists may wish to pay particular attention and ensure adequate reporting of certain variables such as tumor size, depth of invasion within the muscularis propria (ie, pT2a vs. pT2b), LVI, PNI, and, especially, tumor budding, as these may affect clinical treatment decisions and proper patient prognostication.

D3 lymph node dissection improves the survival outcome in patients with pT2 colorectal cancer

BACKGROUND

The extent of lymphadenectomy in patients with pT2 colorectal cancer (CRC) remains controversial. This study aimed to elucidate the effects of D3 and D2 lymph node dissection (LND) on survival in patients diagnosed with pT2 CRC.

METHODS

This was a retrospective cohort study from a high-volume cancer center in Japan. From April 2007 to December 2020, 6273 patients with primary CRC were included in the study; among these, 616 patients diagnosed with pT2 CRC underwent radical colorectal resection. Propensity score matching (PSM) was applied to balance potential confounding factors, and a total of 104 matched pairs were extracted from the entire cohort. Independent risk factors associated with prognosis were determined by Cox regression analysis. The main outcome measures were overall survival (OS) and cancer-specific survival (CSS).

RESULTS

Before PSM, there was a statistically significant difference across the cohort in OS and CSS (p = 0.000 and 0.013) between D3 and D2 LND groups; the estimated hazard ratio (HR) was 2.2 (95% confidence interval (CI), 1.1-4.4, p = 0.031) for OS in the D3 LND and 4.4 (95% CI, 1.7 to 11, p = 0.0027) for CSS (p = 0.013). There was also a significant difference (p = 0.024) in OS between the D3 and D2 LND groups in the matched cohort, with an estimated HR for OS of 3.3 (95% CI, 1.2 to 9.1, p = 0.024) and an estimated HR for CSS of 7.2 (95% CI, 1.6 to 33, p = 0.011).

CONCLUSIONS

D3 LND had a significant survival advantage in the treatment of pT2 CRC. The results of this study provide a theoretical basis for the application of D3 LND in radical surgery for preoperative T2 CRC.

Evaluation of risk factors for lymph node metastasis in T2 lower rectal cancer to perform chemoradiotherapy after local resection

The oncological outcome of chemoradiotherapy (CRT) after local excision (LE) for T2 lower rectal cancer has demonstrated a high local recurrence (LR) rate. The aim of the present study was to determine the risk factors for lymph node metastasis (LNM) in order to reduce LR in T2 lower rectal cancer after LE and CRT. Specimens were collected from 95 consecutive patients with T2 lower rectal adenocarcinoma who underwent R0 resection by total mesenteric excision or tumor-specific mesenteric excision between January 2008 and December 2018 at Osaka International Cancer Institute. All specimens were checked and evaluated to determine the risk factors for LNM. LNM was observed in 26 patients (27%), including 2 patients (2%) with lateral pelvic lymph node metastasis. Univariate analysis indicated lymphovascular invasion (LVI; P=0.008), tumor budding (P=0.012) and histology other than well-differentiated adenocarcinoma (P=0.08) were associated with LNM; multivariate analysis revealed that LVI (P=0.03) was the only independent risk factor for LNM. LNM was confirmed in 0% (0/8) of patients without LVI, tumor budding and histological type. LVI, tumor budding and histological type can be risk factors for LNM in lower rectal cancer. The present study may be helpful to select patients for performing LE and CRT with good oncological outcome.

Current concepts of colorectal cancer resection pathology

The discussion of pathology results is one of the important items in the multidisciplinary meeting. These results describe not only the adequacy of earlier treatments (neoadjuvant therapy, surgery), but guide subsequent treatment decisions by providing staging information and additional prognostic and predictive factors. In the era of next-generation sequencing, every so often the emphasis is put on the molecular background of tumours, but the information that can be retrieved from the resection specimen remains essential for optimal patient care. In the current review the different surgical approaches will be described, together with the relevant macroscopic evaluations. Microscopic features will be addressed, giving an overview that is aimed at optimal information exchange in the multidisciplinary meeting. Finally, special requirements for reporting local excisions and specimen after neoadjuvant therapy will be discussed.

The integration of macroscopic tumor invasion of adjacent organs into TNM staging system for colorectal cancer

Objective

In addition to pathological TNM (pTNM) staging, the macroscopic staging (surgical TNM, sTNM) is another method used to stage and assess tumors, and it also potentially influences patient treatment guidelines. However, for the same patient, surgeons and pathologists might assess tumor depth differently. We aimed to evaluate the prognosis of patients who exhibit unconformity of intraoperative and postoperative results and propose a revised pT category (r-pT category) to predict survival in colorectal cancer.

Methods and Results

In our study, 948 colorectal cancer patients were reviewed. We proposed a novel r-pT category in which surgical macroscopic T4b (sT4b) is incorporated into the pT category, namely, patients in the pT3 category with sT4b cancers are reclassified as being in the r-pT4a category; patients in the pT4a category with sT4b cancers are reclassified as being in the r-pT4b category. Cancer-specific survival according to the r-pT category was analyzed using Kaplan-Meier survival curves. A two-step multivariate analysis was used to determine correlations between the r-pT category and the prognosis. Harrell’s C statistic was utilized to test the predictive capacity. There were significant prognostic differences among the r-pT subcategories. We substituted the r-pT category for the pT category in current TNM staging in a 2-step multivariate analysis. The Harrell’s C statistical analysis results demonstrated that the r-pT category had superior predictive capacity compared to the pT category (Harrell’ C: 0.668 vs. 0.636; P = 0.002).

Conclusions

Patients in the pT3 category with sT4b cancers, and patients in the pT4a category with sT4b cancers, are potentially under-staged, reclassification into higher categories could potentially benefit these patients. The results indicate that the r-pT category we proposed is potentially superior to the pT category in the assessment of prognosis for colorectal cancer.

Risk factors for lymph node metastasis in pT1 and pT2 rectal cancer: a single-institute experience in 943 patients and literature review

BACKGROUND

Local excision has become an alternative for radical resection in rectal cancer for selected patients. The purpose of this study was to assess the clinicopathologic factors determining lymph node metastasis (LNM) in patients with T1-2 rectal cancer.

METHODS

Between January 1995 and December 2009, a total of 943 patients with pT1 or pT2 rectal adenocarcinoma received radical resection at a single institution. Clinicopathologic factors were evaluated by univariate and multivariate analyses to identify risk factors for LNM.

RESULTS

A total of 943 patients (544 men and 399 women) treated for T1-2 rectal cancer were included in this study. LNM was found in 188 patients (19.9%). In multivariate analysis, lymphovascular invasion (LVI; P < 0.001, hazard ratio 11.472), poor differentiation (PD; P = 0.007, hazard ratio 3.218), and depth of invasion (presence of pT2; P = 0.032, hazard ratio 1.694) were significantly related to nodal involvement. The incidence for LNM lesions in the presence of LVI, PD, and pT2 was 68.8, 50.0, and 23.1%, respectively, while that for pT1 carcinomas with no LVI or PD was 7.5%.

CONCLUSIONS

LVI, PD, and pT2 are independent risk factors predicting LNM in pT1-2 rectal carcinoma.