Lower lymph node yield following neoadjuvant therapy for rectal cancer has no clinical significance

Short-term outcomes of short- and long-course chemoradiotherapy before total mesorectal excision for locally advanced rectal tumors: A single-center study in Taiwan utilizing propensity score matching

BACKGROUND

Locally advanced rectal tumors are typically treated with neoadjuvant chemoradiotherapy. Short-course chemoradiotherapy (SCRT, 2500 cGy in five fractions) is a convenient alternative to concurrent chemoradiotherapy with long-course radiotherapy (CCRT, 4500 cGy in 25 fractions) without sacrificing efficacy. We aimed to compare the short-term outcomes of SCRT and CCRT in patients with mid- and low- rectal tumors who underwent total mesorectal excision using real-world data.

METHODS

We retrospectively reviewed the data of patients with locally advanced rectal cancer who underwent radical resection after neoadjuvant chemoradiotherapy from 2011 to 2022. We analyzed the clinicopathological findings and prognostic factors for disease-free and overall survival in the SCRT and CCRT groups and compared the outcomes using propensity score matching.

RESULTS

Among the 66 patients in the two groups, no disparities were noted in the demographic features, pathological remission, or downstaging rates. Nonetheless, the SCRT group exhibited superior 3-year disease-free survival (81.8% vs 62.1%, p = 0.011), whereas the overall survival did not differ significantly between the two groups. The initial carcinoembryonic antigen (CEA) levels and neoadjuvant SCRT were associated with the recurrence rates [hazard ratio (HR) = 1.13-4.10; HR = 0.19-0.74], but the harvested lymph node count was not (HR = 0.51-1.97).

CONCLUSION

Among patients with locally advanced rectal cancer, SCRT combined with four cycles of FOLFOX was shown to enhance short-term disease-free survival. Factors impacting recurrence include the initial CEA level and SCRT, but not the harvested lymph node count.

Prognostic significance of lymph node yield on oncologic outcomes according to tumor response after preoperative chemoradiotherapy in rectal cancer patients

PURPOSE

This study aimed to evaluate the predictive value of lymph node yield (LNY) for survival outcomes according to tumor response after preoperative chemoradiotherapy (PCRT) in patients with rectal cancer.

METHODS

This study was a retrospective study conducted in a tertiary center. A total of 1,240 patients with clinical stage II or III rectal cancer who underwent curative resection after PCRT between 2007 and 2016 were included. Patients were categorized into the good response group (tumor regression grade [TRG], 0-1) or poor response group (TRG, 2-3). Propensity score matching was performed for age, sex, and pathologic stage between LNY of ≥12 and LNY of <12 within tumor response group. The primary outcome was 5-year disease-free survival (DFS) and overall survival (OS).

RESULTS

LNY and positive lymph nodes were inversely correlated with TRG. In good responders, 5-year DFS and 5-year OS of patients with LNY of <12 were better than those with LNY of ≥12, but there was no statistical significance. In poor responders, the LNY of <12 group had worse survival outcomes than the LNY of ≥12 group, but there was also no statistical significance. LNY of ≥12 was not associated with DFS and OS in multivariate analysis.

CONCLUSION

LNY of <12 showed contrasting outcomes between the good and poor responders in 5-year DFS and OS. LNY of 12 may not imply adequate oncologic surgery or proper staging in rectal cancer patients treated by PCRT. Furthermore, a decrease in LNY should be comprehended differently according to tumor response.

Optimal examined lymph node number for accurate staging and long-term survival in rectal cancer: a population-based study

BACKGROUND

Although the recommended minimal examined lymph node (ELN) number in rectal cancer (RC) is 12, this standard remains controversial because of insufficient evidence. We aimed to refine this definition by quantifying the relationship between ELN number, stage migration and long-term survival in RC.

METHODS

Data from a Chinese multi-institutional registry (2009-2018) and the Surveillance, Epidemiology, and End Results (SEER) database (2008-2017) on stages I-III resected RC were analysed to determine the relationship between ELN count, stage migration, and overall survival (OS) using multivariable models. The series of odds ratios (ORs) for negative-to-positive node stage migration and hazard ratios (HRs) for survival with more ELNs were fitted using a Locally Weighted Scatterplot Smoothing (LOWESS) smoother, and structural breakpoints were determined using the Chow test. The relationship between ELN and survival was evaluated on a continuous scale using restricted cubic splines (RCS).

RESULTS

The distribution of ELN count between the Chinese registry ( n =7694) and SEER database ( n =21 332) was similar. With increasing ELN count, both cohorts exhibited significant proportional increases from node-negative to node-positive disease (SEER, OR, 1.012, P <0.001; Chinese registry, OR, 1.016, P =0.014) and serial improvements in OS (SEER: HR, 0.982; Chinese registry: HR, 0.975; both P <0.001) after controlling for confounders. Cut-point analysis showed an optimal threshold ELN count of 15, which was validated in the two cohorts, with the ability to properly discriminate probabilities of survival.

CONCLUSIONS

A higher ELN count is associated with more precise nodal staging and better survival. Our results robustly conclude that 15 ELNs are the optimal cut-off point for evaluating the quality of lymph node examination and stratification of prognosis.

Adverse impact of tumor deposits in lymph node negative rectal cancer - a national cohort study

PURPOSE

This study aimed to investigate the prognostic effect of tumor deposits (TDs) in lymph node negative rectal cancer.

METHODS

Patients who had undergone surgery for rectal cancer with curative intention between 2011 and 2014 were extracted from the Swedish Colorectal Cancer Registry. Patients with positive lymph nodes, undisclosed TD status, stage IV disease, non-radical resections, or any outcome (local recurrence (LR), distant metastasis (DM) or mortality) within 90 days after surgery were excluded. TDs status was based on histopathological reports. Cox-regression analyses were used to examine the prognostic impact of TDs on LR, DM, and overall survival (OS) in lymph node-negative rectal cancer.

RESULTS

A total of 5455 patients were assessed for inclusion of which 2667 patients were analyzed, with TDs present in 158 patients. TD-positive patients had a lower 5-year DM-free survival (72.8%, p < 0.0001) and 5-year overall survival (75.9%, p = 0.016), but not 5-year LR-free survival (97.6%) compared to TD-negative patients (90.2%, 83.1% and 95.6%, respectively). In multivariable regression analysis, TDs increased the risk of DM [HR 4.06, 95% CI 2.72-6.06, p < 0.001] and reduced the OS [HR 1.83, 95% CI 1.35-2.48, p < 0.001]. For LR, only univariable regression analysis was performed which showed no increased risk of LR [HR 1.88, 95% CI 0.86-4.11, p = 0.11].

CONCLUSION

TDs are a negative predictor of DM and OS in lymph node-negative rectal cancer and could be taken into consideration when planning adjuvant treatment.

Total Neoadjuvant Therapy in Rectal Cancer: Multi-center Comparison of Induction Chemotherapy and Long-Course Chemoradiation Versus Short-Course Radiation and Consolidative Chemotherapy

BACKGROUND

Total neoadjuvant therapy for locally advanced rectal cancer may include induction chemotherapy and chemoradiation or short-course radiotherapy and consolidative chemotherapy.

METHODS

Patients with clinical stage 2 or 3 rectal cancer who received induction chemotherapy followed by long-course chemoradiation at the University of Colorado (2016-2020) or short-course radiotherapy followed by consolidative chemotherapy at Washington University (2017-2020) were assessed.

RESULTS

Eighty-four patients received induction chemotherapy and chemoradiation and 83 received short-course radiotherapy and consolidative chemotherapy. Among patients with complete re-staging evaluation, clinical complete response rates were similar, 49% (18/37) and 53% (44/83), respectively (p = 0.659). In the induction chemotherapy and chemoradiation group, 80% (n = 67) underwent surgery and 28% (n = 19) achieved a pathologic complete response. In the short-course radiotherapy and consolidative chemotherapy group, 44 (53%) patients underwent surgery and 11% (n = 5) had a pathologic complete response. Overall, a complete response was observed in 43% (n = 36) of patients who received induction chemotherapy and chemoradiation compared to 53% (n = 44) who received short-course radiotherapy and consolidative chemotherapy (p = 0.189). Perioperative outcomes were similar in patients who received induction chemotherapy and chemoradiation compared to short-course radiotherapy and consolidative chemotherapy: intraoperative complications (2% vs 7%), complete mesorectal specimen (85% vs 84%), anastomotic leak (9% vs 7%), organ/space infection (9% vs 5%), readmission (19% vs 21%), and reoperation (8% vs 9%), respectively (all p > 0.05).

CONCLUSIONS

In patients with clinical stage 2 or 3 rectal cancer, total neoadjuvant therapy with either induction chemotherapy and chemoradiation or short-course radiotherapy followed by consolidative chemotherapy were associated with similar perioperative morbidity and complete response rates.

Primary tumour immune response and lymph node yields in colon cancer

Background

The mechanism underlying improved survival in non-metastatic colon cancer with higher lymph node (LN) yield is unknown. This study aimed to identify whether molecular features in the primary tumour were predictive of LN yield.

Methods

Clinical, genomic, transcriptomic, proteomic and methylation data of non-metastatic, colon cancers studied in The Cancer Genome Atlas were interrogated for associations with LN yield. Based on maximal survival effects, patients were segregated into high (>15) and low (≤15) LN yield. Gene set enrichment analysis was performed on transcriptomic changes to identify biological processes associated with LN yield. Correlations were validated in an independent set of Stage II colon cancers.

Results

High LN yield was found predictive of overall and disease-free survival. There was no association of higher LN yield and increasing nodal positivity. High LN yield was strongly linked with gene expression changes associated with the adaptive and dendritic cell immune response. This association was most prominent in node-negative cancers. Analogous findings were reproduced in the validation dataset.

Conclusion

The study shows a strong association of an activated immune response in tumours with a high LN yield. Immunogenic tumours have a better prognosis, likely explaining the survival benefit with higher LN yields.

Optimal Lymph Node Yield for Survival Prediction in Rectal Cancer Patients After Neoadjuvant Therapy

Purpose

A lymph node (LN) yield ≥12 is required to for accurate determination of nodal status for colorectal cancer but cannot always be achieved after neoadjuvant therapy. This study aims to determine the difference in LN yield from rectal cancer patients treated with and without neoadjuvant therapy and the effects of specific LN yields on survival.

Patients and Methods

The study cohort included a total of 4344 rectal cancer patients treated between January 2007 and December 2015, 2260 (52.03%) of whom received neoadjuvant therapy. Data were retrieved from the Taiwan nationwide cancer registry database. The minimum acceptable LN yield below 12 was investigated using the maximum area under the ROC curve.

Results

The median LN yield was 12 (8-17) for patients who received neoadjuvant therapy and 17 (13-24) for those who did not. The recommended LN yield ≥12 was achieved in 82.73% of patients without and 57.96% of those with neoadjuvant therapy (p < 0.0001). Patients with LN yield ≥12 had a higher OS probability than did those with LN <12 (OR, 1.33; 95% CI, 1.06-1.66; p = 0.0124). However, the predictive accuracy for survival was greater for LN yield ≥10 (AUC, 0.7767) than cut-offs of 12, 8, or 6, especially in patients with pathologically-negative nodes (AUC, 0.7660).

Conclusion

Neoadjuvant therapy significantly reduces the LN yield in subsequent surgery. A lower yield (LN ≥ 10) may be adequate for nodal evaluation in rectal cancer patients after neoadjuvant therapy.

Lymph Node Ratio as a Prognostic Marker in Rectal Cancer Survival: A Systematic Review and Meta-Analysis

Introduction 

The lymph node ratio (LNR) is defined as the ratio of the number of positive lymph nodes to the total number of nodes retrieved. LNR has recently emerged as a prognostic factor in rectal cancer. The objective of our study was to pool eligible studies to elucidate the prognostic role of LNR on overall survival (OS) and disease-free survival (DFS) in rectal cancer patients using a meta-analysis.

Methods

A systematic database search was performed in MEDLINE and Embase for relevant studies that reported LNR in rectal cancer. Two authors independently screened the relevant articles for selection and data extraction. As a result, a list of such studies and references, published in English up to December 2019, was obtained, and a total of 4,486 node-positive patients in 18 studies were included in this meta-analysis. RevMan software 5.3 (Cochrane Collaboration, the Nordic Cochrane Centre, Copenhagen) was used for conducting all statistical analyses.

Results

A higher LNR was significantly correlated with worse OS [hazard ratio (HR): 2.60; 95% confidence interval (CI): 2.21-3.06; p≤.00001] and DFS (HR: 2.43; 95% CI: 2.11-2.80; p≤.00001) in node-positive rectal cancer patients. Besides, LNR is an independent predictive and prognostic marker of OS and DFS (HR: 2.52; 95% CI: 2.17-2.94; p≤.00001 with I²=0%; p=.32 and HR: 2.63; 95% CI: 2.17-3.18; p≤.00001 with I²=0%; p=.63 respectively, irrespective of lymph nodal harvest).

Conclusions

Our present study demonstrates that LNR is an independent predictor of survival in rectal cancer. LNR should be considered as a parameter in future oncological staging systems. Further well-designed randomized control trials to prospectively assess LNR as an independent predictor of rectal cancer survival are necessary before its application in daily practice.

A lower cut-off for lymph node harvest predicts for poorer overall survival after rectal surgery post neoadjuvant chemoradiotherapy

Background

A lymph node harvest (LNH) of < 12 is a predictor for poor prognosis in rectal cancer patients. However, neoadjuvant chemoradiotherapy (NACRT) is known to decrease LNH; hence, a cut-off of 12 is inappropriate in such patients. This paper aims to establish a LNH cut-off predictive for disease-free and overall survival in NACRT patients.

Methods

A retrospective review of patients who underwent elective surgery for rectal cancer from 2006 to 2013 was performed. All patients with R1/2 resections and presence of metastases and those operated on for recurrence were excluded. Patient demographics, clinical features, operative details, LNH, 30-day mortality and disease-free and overall survival were recorded. P values of < 0.05 were considered significant.

Results

A total of 257 patients were studied, with 174 (68%) males and a median age of 66 years. Ninety-four (37%) patients received long-course NACRT, and 122 (48%) patients were stage 2 and below. Median LNH was 17, which was reduced in the NACRT group (14 versus 23, P < 0.01). Average length of stay was 9 ± 8 days, with a major post-operative complication rate of 4%. Using hazard ratio plots for the NACRT subgroup, LNH cut-offs of 16.5 and 8.5 were obtained for disease-free survival (DFS) and overall survival (OS) respectively. Survival analysis showed that a LNH cut-off of 8.5 was a significant predictor of OS (P < 0.001).

Conclusion

LNH is reduced in patients receiving NACRT before rectal cancer surgery. A LNH of 9 and above is associated with improved overall survival. We propose that this can be used as a tool for prognosis.