Clinicopathological characteristics predict lymph node metastases in ypT0-2 rectal cancer after chemoradiotherapy

Clinicopathological factors predict residual lymph node metastasis in locally advanced rectal cancer with ypT0-2 after neoadjuvant chemoradiotherapy

PURPOSE

Residual lymph node metastases (RLNM) remained a great concern in the implementation of organ-preserving strategies and led to poor prognosis in locally advanced rectal cancer (LARC). In this study, we aimed to identify the clinicopathological factors correlated with RLNM in LARC patients with ypT0-2 after neoadjuvant chemoradiotherapy (NCRT).

METHODS

We retrospectively analyzed 417 patients histologically diagnosed middle-low LARC after NCRT and total mesorectal excision (TME), whose pathological staging was ypT0-2. All patients received pelvic magnetic resonance imaging (MRI) before NCRT. The radiation doses were 50-50.6 Gy for the planning gross tumor volume and 41.8-45 Gy for the planning target volume, respectively. A nomogram for predicting RLNM was constructed using a binary logistic regression. Nomogram performance was assessed by receiver operating characteristic (ROC) curve, calibration curve, decision curve analysis (DCA) and clinical impact curve (CIC).

RESULTS

After surgery, 191 patients (45.8%) were ypT0, 43 patients (10.3%) were ypT1 and 183 patients (43.9%) were ypT2, and a total of 49 patients (11.8%) were found the presence of RLNM. Multivariable analyses identified MRI-defined mesorectal fascia (MRF)-positive, high-grade histopathology at biopsy, advanced ypT-category, and the presence of perineural invasion (PNI) as the predictive factors. The nomogram, incorporating all these predictors, showed good discrimination and calibration efficacy, with the areas under the ROC curve of 0.690 (95% CI: 0.610-0.771). Both DCA and CIC demonstrated that this nomogram has good clinical usefulness.

CONCLUSION

The nomogram model can predict RLNM in patients with ypT0-2 tumors. It can help select suitable patients for performing organ-preserving strategies after NCRT.

A nomogram prediction model for lymph node metastasis risk after neoadjuvant chemoradiotherapy in rectal cancer patients based on SEER database

Background

Rectal cancer patients who received neoadjuvant chemoradiotherapy (CRT) may have a lower cancer stage and a better prognosis. Some patients may be able to avoid invasive surgery. It is critical to accurately assess lymph node metastases (LNM) after neoadjuvant chemoradiotherapy. The goal of this study is to identify clinical variables associated with LNM and to develop a nomogram for LNM prediction in rectal cancer patients following nCRT.

Methods

From 2010 to 2015, patients were drawn from the Surveillance, Epidemiology, and End Results (SEER) database. To identify clinical factors associated with LNM, the least absolute shrinkage and selection operator (LASSO) aggression and multivariate logistic regression analyses were used. To predict the likelihood of LNM, a nomogram based on multivariate logistic regression was created using decision curve analyses.

Reslut

The total number of patients included in this study was 6,388. The proportion of patients with pCR was 17.50% (n=1118), and the proportion of patients with primary tumor pCR was 20.84% (n = 1,331). The primary tumor was pCR in 16.00% (n=213) of the patients. Age, clinical T stage, clinical N stage, and histology were found to be significant independent clinical predictors of LNM using LASSO and multivariate logistic regression analysis. The nomogram was developed based on four clinical factors. The 5-year overall survival rate was 78.9 percent for those with ypN- and 66.3 percent for those with ypN+, respectively (P<0.001).

Conclusion

Patients over 60 years old, with clinical T1-2, clinical N0, and adenocarcinoma may be more likely to achieve ypN0. The watch-and-wait (WW) strategy may be considered. Patients who had ypN0 or pCR had a better prognosis.

Correlation between T stage and lymph node metastasis in rectal cancer treated with preoperative chemoradiotherapy

Background:

Depth of tumor is a risk factor for lymph node metastasis in rectal cancer, but impact of yield pathologic T (ypT) stage on lymph node involvement in rectal cancer remains unclear. The aim of this study was to evaluate the correlation between ypT stage and lymph node metastasis.

Methods:

From January 2010 to December 2015, 602 patients who were diagnosed with rectal cancer and treated with neoadjuvant chemoradiotherapy (CRT) followed by radical operation were reviewed retrospectively. The correlations between ypT stage and lymph node status and survival were evaluated.

Results:

On pathology, 179 (29.7%) patients exhibited regional lymph node metastasis. Lymph node metastasis was seen in 8.5% of ypT0 patients, 20% of ypT1, 18.4% of ypT2, 47.5% of ypT3, and 27.3% of ypT4. Positive lymph node metastasis was correlated with ypT stage. In addition, the difference of lymph node metastasis in ypT stage subgroups was statistically significant (p < 0.001). Five-year disease-free survival was significantly different in the ypT stage subgroups (88.7% versus 86.7% versus 82.6% versus 64.7% versus 72.7%, p < 0.001), as was 5-year overall survival (96.2% versus 90.0% versus 95.8% versus 80.0% versus 90.9%, p < 0.001).

Conclusion:

YpT stage is associated with lymph node metastasis in rectal cancer treated with neoadjuvant CRT and radical operation, and ypT0 patients exhibited an 8.5% lymph node metastasis rate. Therefore, the decision for local excision or the watch-and-wait strategy for rectal cancer treated with neoadjuvant CRT and predicted to show a pathologic complete response should be considered with caution.

Prevalence of nodal involvement in rectal cancer after chemoradiotherapy

BACKGROUND

The purpose of this study was to investigate the prevalence of ypN+ status according to ypT category in patients with locally advanced rectal cancer treated with chemoradiotherapy and total mesorectal excision, and to assess the impact of ypN+ on disease recurrence and survival by pooled analysis of individual-patient data.

METHODS

Individual-patient data from 10 studies of chemoradiotherapy for rectal cancer were included. Pooled rates of ypN+ disease were calculated with 95 per cent confidence interval for each ypT category. Kaplan-Meier and Cox regression analyses were undertaken to assess influence of ypN status on 5-year disease-free survival (DFS) and overall survival (OS).

RESULTS

Data on 1898 patients were included in the study. Median follow-up was 50 (range 0-219) months. The pooled rate of ypN+ disease was 7 per cent for ypT0, 12 per cent for ypT1, 17 per cent for ypT2, 40 per cent for ypT3, and 46 per cent for ypT4 tumours. Patients with ypN+ disease had lower 5-year DFS and OS (46.2 and 63.4 per cent respectively) than patients with ypN0 tumours (74.5 and 83.2 per cent) (P < 0.001). Cox regression analyses showed ypN+ status to be an independent predictor of recurrence and death.

CONCLUSION

Risk of nodal metastases (ypN+) after chemoradiotherapy increases with advancing ypT category and needs to be considered if an organ-preserving strategy is contemplated.

How to measure tumour response in rectal cancer? An explanation of discrepancies and suggestions for improvement

Various methods categorize tumour response after neoadjuvant therapy, including down-staging and tumour regression grading. Response categories allow comparison of different treatments within clinical trials and predict outcome. A reproducible response categorization could identify subgroups with high or low risk for the most appropriate subsequent treatments, like watch and wait. Lack of standardization and interpretation difficulties currently limit the usability of these approaches. In this review we describe these difficulties for the evaluation of chemoradiation in rectal cancer. An alternative approach of tumour response is based on patterns of residual disease, including fragmentation. We summarise the evidence behind this alternative method of response categorisation, which explains a number of very relevant clinical discrepancies. These issues include differences between downstaging and tumour regression, high local regrowth in advanced tumours during watchful waiting procedures, the importance of resection margins, the limited value of post-treatment biopsies and the relatively poor outcome of patients with a near complete pathological response. Recognition of these patterns of response can allow meaningful development of novel biomarkers in the future.

Global variation in the long-term outcomes of ypT0 rectal cancers

BACKGROUND

Colorectal cancer mortality presents world-wide variation. In rectal cancers presenting a complete/nearly-complete tumor response (ypT0/ypTis) following neoadjuvant treatment, the features correlated to nodal metastases and relapses still need to be defined.

METHODS

An international cohort study enrolling ypT0/ypTis rectal cancers surgically treated from 2012 to 2017 was conducted. A propensity matching was used to balance nodal-positive and nodal-negative patients and statistical analyses were performed to investigate survivals, using a bootstrap model for internal validation. The features correlated with nodal metastasis were studied. Countries with participating centers were ranked using the World Bank (WBI), Human Development (HDI) and Global Gender Gap (GGG) indexes to compare survivals.

RESULTS

680 ypT0/ypTis from 52 European, Australian, Indian and American Institutions were analyzed. Mean follow-up was of 30.4 months. 96.5% were treated with total mesorectal excision, 7.2% were nodal-positive and 8.8% relapsed. Distal cancers (HR 0.71 95%CI: 0.56-0.91) and nodal metastasis and nodal metastasis (HR 3.85 95%CI:1.12-13.19) correlated with worse DFS, whereas a younger age was of borderline significance (HR 0.95 95%CI:0.91-0.99). The bootstrap analysis validated the model on 5000 repetitions. A short-course radiotherapy (OR 0.18 95%CI:0.09-0.37) correlated with the occurrence of nodal metastasis. Those countries classified in the low/medium-WBI, medium-HDI and lower-GGG ranks documented worse DFS curves (respectively p < 0.0001, p < 0.0001 and p 0.0002). However, the clinical stages were similar and patients from medium-HDI countries received more adjuvant chemotherapy than the others (p < 0.0001).

CONCLUSION

Sub-groups at risk for relapses and nodal metastasis were identified. A global variation exists also when benchmarking a rectal cancer complete regression.

Can clinicopathological parameters predict for lymph node metastases in ypT0-2 rectal carcinoma? Results of the CAO/ARO/AIO-94 and CAO/ARO/AIO-04 phase 3 trials

BACKGROUND

The advent of less radical surgical approaches has generated concern about leaving locoregional lymph node metastases (LNM) unresected that could lead to adverse outcome. We examined the prognostic role of clinicopathological factors for ypN-positivity in patients with ypT0-2 rectal carcinoma treated within the CAO/ARO/AIO-94 and CAO/ARO/AIO-04 randomized phase 3 trials.

METHODS

The correlation of clinicopathological factors with ypN-status (ypN0 vs ypN1/2) was examined in n = 776 patients with ypT0-2 rectal carcinoma after preoperative CRT and total mesorectal excision surgery using Pearson's Chi-squared test for categorical variables and Kruskal-Wallis' test for continuous variables. Multivariable analysis was performed using binary logistic regression to identify independent prognosticators for ypN-positivity.

RESULTS

Residual LNM (ypN+) were found in 6%, 20.8% and 21.4% of patients with ypT0, ypT1 and ypT2 carcinomas, respectively. Independent prognosticators for LNM were advanced ypT category (p = 0.002) and lymphatic invasion (p = 0.020). In a separate multivariable analysis performed upon exclusion of ypT-category due to multicollinearity with residual tumor diameter (RTD), lymphatic invasion (p = 0.015) and RTD ≥10 mm (p = 0.005) demonstrated strong correlation with LNM.

CONCLUSION

Advanced ypT-stage, lymphatic invasion and RTD ≥10 mm were prognostic factors for LNM in patients ypT0-2 rectal carcinoma treated with CRT and surgery within both phase 3 trials. The high incidence of LNM in the ypT1-2 group needs to be taken into consideration in the context of oncological safety and indicate that LE should be advocated with great caution in this patient subgroup. The prognostic pathological factor identified here could help guide decision of LE vs TME after standard CRT.

The influence of endorectal filling on rectal cancer staging with MRI

OBJECTIVE

To assess the influence of endorectal filling (EF) on rectal cancer staging.

METHODS

47 patients who underwent a staging MRI of rectal cancer in the period from 2011 to 2014 were included. The MRI protocol included T₂ weighted fast spin echo sequences without and with EF at 3 T (EF-MRI). Images were scored by two readers for T-stage, distance of the lower pole of the tumour to the anorectal junction, distance to the mesorectal fascia (MRF), and number of (suspicious) lymph nodes. Agreement in T-staging was calculated using the Cohen's κ value. Comparison of continuous variables was performed using Wilcoxon matched pairs signed-rank test.

RESULTS

The interobserver agreement for T-staging with and without EF-MRI showed a poor agreement between both readers (weighted κ = 0.156, weighted κ = 0.037, respectively). Tumours tended to be overstaged more prominently with EF-MRI. The accuracy of predicting the pathological T-stage slightly improved from 55% with EF to 64% without EF for Reader 1 and from 59 to 68% for Reader 2, respectively. The distance of the tumour to the anorectal junction increased from 33.9 to 49.3 mm (p < 0.001) after EF for Reader 2. EF-MRI did not significantly influence the number of (suspicious) lymph nodes and distance to the mesorectal fascia.

CONCLUSION

EF-MRI did not lead to an improved tumour staging and it has the potential to influence the distance to a key anatomical landmark. EF-MRI is therefore not recommended in primary staging rectal cancer. Advances in knowledge: EF-MRI may not be used as an additional tool to stage rectal cancer patients, as it does not seem to facilitate in locoregionally staging the disease.

Long-term outcomes in ypT0 rectal cancers: An international multi-centric investigation on behalf of Italian Society of Surgical Oncology Young Board (YSICO)

AIM

To investigate the outcome and pattern of survivals of rectal cancer patients presenting a complete or nearly complete tumor response after neo-adjuvant treatment.

METHODS

Young surgeons <40 years old affiliated to the Italian Society of Surgical Oncology (YSICO) from 13 referral centers for colorectal cancer treatment, were invited to participate a retrospective study. Records from patients treated from 2005 to 2015 with a pathological diagnosis of ypT0/ypTis were retrieved and pooled in a common data-base for statistical purposes. All clinical and pathological variables were reviewed. Univariate and multivariate analyses were conducted with the end-point of survivals.

RESULTS

Two hundreds and sixty-one patients were analyzed including 237 ypT0 and 24 ypTis. Nodal positive patients were 8.7%. More than sixty-six percent of the patients did not perform adjuvant chemotherapy, with a statistical difference comparing N0 versus N+ patients (66.8% vs 40.9%, p 0.02). Mean follow-up was of 47.6 months. Twenty-two relapses were observed, 91.6% at a distant site. The mean time to recurrence was of 35.3 months. On univariate analysis, the use of adjuvant chemotherapy correlated with better OS exclusively in ypT0N + patients and not in ypT0N0. Univariate and multivariate analyses documented nodal positivity as the only prognostic factor correlated with a worse OS.

CONCLUSION

Recurrences were mostly diagnosed at a distant site and within the third year of follow-up. Nodal positivity was the only variable independently correlated with a worse OS. Univariate analysis documented a benefit for the use of adjuvant chemotherapy treatment exclusively in ypT0N + rectal cancers.