Effect of pathological complete response after neoadjuvant chemoradiotherapy on postoperative complications of rectal cancer: a systematic review and meta-analysis

Multiphase and multiparameter MRI-based radiomics for prediction of tumor response to neoadjuvant therapy in locally advanced rectal cancer

BACKGROUND

To develop and validate radiomics models for prediction of tumor response to neoadjuvant therapy (NAT) in patients with locally advanced rectal cancer (LARC) using both pre-NAT and post-NAT multiparameter magnetic resonance imaging (mpMRI).

METHODS

In this multicenter study, a total of 563 patients were included from two independent centers. 453 patients from center 1 were split into training and testing cohorts, the remaining 110 from center 2 served as an external validation cohort. Pre-NAT and post-NAT mpMRI was collected for feature extraction. The radiomics models were constructed using machine learning from a training cohort. The accuracy of the models was verified in a testing cohort and an independent external validation cohort. Model performance was evaluated using area under the curve (AUC), sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

The model constructed with pre-NAT mpMRI had favorable accuracy for prediction of non-response to NAT in the training cohort (AUC = 0.84), testing cohort (AUC = 0.81), and external validation cohort (AUC = 0.79). The model constructed with both pre-NAT and post-NAT mpMRI had powerful diagnostic value for pathologic complete response in the training cohort (AUC = 0.86), testing cohort (AUC = 0.87), and external validation cohort (AUC = 0.87).

CONCLUSIONS

Models constructed with multiphase and multiparameter MRI were able to predict tumor response to NAT with high accuracy and robustness, which may assist in individualized management of LARC.

Does Pathological Complete Response after Neoadjuvant Therapy Influence Postoperative Morbidity in Rectal Cancer after Transanal Total Mesorectal Excision?

PURPOSE

It is still unclear if pathological complete response (pCR) after neoadjuvant chemoradiotherapy (CRT) in patients treated for rectal cancer causes worse postoperative outcomes, especially after transanal total mesorectal excision (TaTME). Worse postoperative outcomes might be an argument for an organ preserving watch and wait strategy in fragile patients and patients with comorbidities. The aim of this study is to evaluate whether patients treated for rectal cancer who had pCR to neoadjuvant therapy develop worse postoperative outcomes after TaTME than patients without complete response.

METHODS

Comparative retrospective analysis (with nearest neighbor matching algorithm) of postoperative outcomes in two groups of patients, with pCR, n = 15 and without pCR (non-pCR), n = 57. All patients were operated on only by one surgical approach, TaTME, for middle and distal rectal tumors. All procedures were performed by one surgical team between 2014 and 2020 at the University Hospital Brno in Czech Republic.

RESULTS

Overall morbidity was comparable between the groups (pCR group - 53.8% vs. non-pCR - 38.6%, p = 0.381). Anastomotic leak (AL) was observed in 33.3% of patients with pCR and in 17.5% of patients in the non-pCR group without statistical significance (p = 0.281).

CONCLUSION

In conclusion, pathological complete response after neoadjuvant therapy does not appear to affect postoperative morbidity in rectal cancer after TaTME. Therefore, in patients with complete response who are not adherent to W&W surveillance, surgical resection can be perform without increased postoperative complications.

Effect of Glutamine on Short-term Surgical Outcomes in Rectal Cancer Patients Receiving Neoadjuvant Therapy: A Propensity Score Matching Study

The effect of glutamine on postoperative complications and postoperative recovery in rectal cancer (RC) patients receiving neoadjuvant therapy (NT) is unclear. This study aimed to investigate the effects of intravenous glutamine supplementation on short-term postoperative outcomes in these patients. This retrospective study included patients with RC who received NT and underwent radical surgery between January 2013 and July 2022 and were either administered glutamine (glutamine group) or not administered glutamine (non-glutamine group). Propensity score matching method was used to analyze and compare postoperative complications and other outcome indicators. A total of 208 patients were reviewed, and 53 were included in each group post matching. While no significant difference in the time to first solid food intake between the two groups was observed, the glutamine group had a significantly reduced incidence of postoperative complications, shorter length of hospital stay, and shorter time to first defecation, first exhaust, and first fluid diet intake than those of the control group. Moreover, glutamine alleviated the reduction in albumin and prealbumin levels. Perioperative parenteral glutamine supplementation effectively reduces the incidence of postoperative complications, promotes postoperative recovery, and improves albumin levels in patients undergoing RC surgery and receiving NT.

Early and late radiation complications after application of preoperative radiation therapy in complex treatment of cancer recti

Objective. To study and assess the rates and degree of severity of early and late radiation complications in patients after application of preoperative radiation therapy in complex treatment of the patients, suffering cancer recti. Materials and methods. Analysis of the treatment results in 113 patients, suffering locally–advanced (сT3с–4N1–2M0) cancer recti, who have obtained preoperative oncotherapy in 2019–2022 yrs in the Department of Radiation Therapy of Zakarpattya Antitumoral Centre, was performed. Results. Most frequent early radiation affection was rectitis, which have occurred – in 86 (76,1%) patients of 113. Early radiation affections of the reproductive system organs were noted in 5 (4,4%) patients. Late radiation affections were registered in 9 (7,9%) patients, mostly frequent in the gut system – in 5 (4,4%) patients. Conclusion. Аnalysis of the complex treatment results, performed in 113 patients with cancer recti, have shown, that preoperative radiation therapy do not enhance the rate of occurrence of early radiation complications and hematological toxicity. The rate of early radiation affections was 76,1%, and of the late – 7,9%.

Predictors of pathologic complete response in patients with residual flat mucosal lesions after neoadjuvant chemoradiotherapy for locally advanced rectal cancer

OBJECTIVE

The accurate prediction of tumor response to neoadjuvant chemoradiotherapy (nCRT) remains challenging. Few studies have investigated pathologic complete response (ypCR) prediction in patients with residual flat mucosal lesions after treatment. This study aimed to identify variables for predicting ypCR in patients with residual flat mucosal lesions after nCRT for locally advanced rectal cancer (LARC).

METHODS

Data of patients with residual flat mucosal lesions after nCRT who underwent radical resection between 2009 and 2015 were retrospectively collected from the LARC database at Peking University Cancer Hospital. Univariate and multivariate analyses of the association between clinicopathological factors and ypCR were performed, and a nomogram was constructed by incorporating the significant predictors.

RESULTS

Of the 246 patients with residual flat mucosal lesions included in the final analysis, 56 (22.8%) had ypCR. Univariate and multivariate analyses showed that pretreatment cT stage (pre-cT) ≤T2 (P=0.016), magnetic resonance tumor regression grade (MR-TRG) 1-3 (P=0.001) and residual mucosal lesion depth =0 mm (P<0.001) were associated with a higher rate of ypCR. A nomogram was developed with a concordance index (C-index) of 0.759 and the calibration curve showed that the nomogram model had good predictive consistency. The follow-up time ranged from 3.0 to 113.3 months, with a median follow-up time of 63.77 months. The multivariate Cox regression model showed that the four variables in the nomogram model were not risk factors for disease-free survival (DFS) or overall survival (OS).

CONCLUSIONS

Completely flat mucosa, early cT stage and good MR-TRG were predictive factors for ypCR instead of DFS or OS in patients with LARC with residual flat mucosal lesions after nCRT. Endoscopic mucosal re-evaluation before surgery is important, as it may contribute to decision-making and facilitate nonoperative management or organ preservation.