Individualizing surgical treatment based on tumour response following neoadjuvant therapy in T4 primary rectal cancer

MRI navigation surgery for T4b rectal cancer using multiple minimally invasive surgical approaches

BACKGROUND

These days, various surgical techniques such as trans-anal, trans-perineal total mesorectal excision, and transvaginal natural orifice transluminal endoscopic surgery have been utilized with flexibility, which was not possible before the laparoscopic era.

METHODS

From January 2014 to January 2023, 40 cases of c(yc)T4b rectal cancer underwent local curative surgery laparoscopically at Kansai Medical University Hospital. In 25 consecutive cases, we adopted multiple approaches (trans-anal total mesorectal excision, transvaginal natural orifice transluminal endoscopic surgery, trans-perineal total mesorectal excision, or prone position first abdominoperineal excision) to remove the deepest part of the tumor indicated by MRI last as the specimen-oriented surgery. The remaining 15 patients underwent top-to-bottom surgery based on standard surgery. The primary endpoint was the local recurrence rate of the specimen-oriented surgery group compared to that of the standard surgery group.

RESULTS

The specimen-oriented surgery group had a median follow-up of 3.9 (0.4-7.4) years with no local recurrence, while the standard surgery group had a median follow-up of 1.5 (0.7-3.7) years with 5 of 15 patients (33%) experiencing more local recurrence than specimen-oriented surgery group (p = 0.005). Comparison of the local recurrence ( +) and ( -) groups showed significant differences in pCRM positive rate, neoadjuvant therapy, tumor size, and approach (specimen-oriented surgery vs. standard surgery) in univariate analysis (p < 0.05). Still, no significant differences were found in the multivariate analysis.

CONCLUSIONS

In the laparoscopic setting, local cure of c(yc)T4b rectal cancer requires a different strategy than open surgery, and specimen-oriented surgery may be a promising procedure.

Comparison of prognosis for T4b rectal cancer with different pelvic compartment involvement treated using neoadjuvant chemoradiotherapy and implications for refinement of the current T staging system: A retrospective cohort study

PURPOSE

Although classified as one stage, T4b rectal cancer actually represents a group of heterogeneous diseases. Our study aimed to assess the prognosis difference of T4b rectal cancer involving inferior pelvic and other pelvic compartments. This information may be helpful in refinement of the current T staging system.

METHODS

We retrospectively analysed data from 195 patients with magnetic resonance imaging-identified locally advanced T4b rectal cancer who received neoadjuvant chemoradiotherapy between January 2010 and December 2019. 104 patients had only inferior pelvic compartment involvement (group A) while 91 patients had anterior, posterior or lateral pelvic compartment involvement (group B). Short-term and long-term outcomes were compared between the two groups.

RESULTS

After neoadjuvant therapy, 80.8 % patients (84/104) in group A and 92.3 % patients (84/91) in group B underwent surgery. The R0 resection rates were 97.6 % and 89.3 %, respectively. 8.7 % patients (9/104) in group A achieved clinical complete response and adopted watch-and-wait strategy. Patients in group A had significantly superior 5-year progression-free survival (PFS) (67.8 % vs. 55.5 %, P = 0.032) and overall survival (OS) (89.6 % vs. 71.8 %, P = 0.001) than group B. Multivariable Cox regression analysis also identified pelvic compartment involvement classification as an independent predictor of PFS (hazard ratio 1.776, P = 0.046) and OS (hazard ratio 3.477, P = 0.004).

CONCLUSION

T4b rectal cancers with involvement limited to the inferior pelvic compartment had superior prognosis compared to those involving other pelvic compartments. These differences should be investigated further and taken into consideration in refinement of the current T staging system.

Laparoscopic Versus Robotic Lateral Pelvic Lymph Node Dissection in Locally-Advanced Rectal Cancer: A Cohort Study Comparing Perioperative Morbidity and Short-Term Oncological Outcomes

BACKGROUND

Robotic surgery has been associated with superior short-term outcomes in patients undergoing total mesorectal excision (TME) for organ-confined rectal cancer. However, whether this approach offers an additional benefit over laparoscopy when performing lateral pelvic lymph node dissection (LPLND) with TME or extended TME (e-TME) in locally advanced rectal cancer (LARC) is not known.

AIMS

This study was conducted to evaluate the outcomes of robotic and laparoscopic LPLND in patients with lateral pelvic node-positive LARC with reference to intraoperative safety, postoperative morbidity, pathological indices including nodal yield and node positivity rates, lateral pelvic recurrence rates, and short term event-free and overall survival.

METHODS AND RESULTS

In this retrospective single-center study, consecutive patients with non-metastatic histologically proven LARC and clinically significant lateral pelvic lymphadenopathy who had undergone laparoscopic or robotic LPLND with TME or e-TME between 2014 and 2023 were included, all procedures having been performed by minimal-access colorectal surgeons who were beyond the learning curve for either surgical approach. Of the 115 patients evaluated, 98.3% received neoadjuvant chemoradiotherapy, following which 27 (23.5%) underwent robotic and 88 (76.5%) laparoscopic LPLND with TME or e-TME. The baseline clinicodemographic features, treatment-related characteristics, and proportion of patients undergoing extended resections for persistent circumferential resection margin-positive rectal cancer (22.7% vs. 18.5%, respectively) were statistically similar in both groups. When comparing robotic with laparoscopic resections, no significant difference was observed in intraoperative parameters including procedure-associated blood loss (median 250 mL vs. 400 mL) and on-table adverse events or conversion rates (none in either group), postoperative outcomes comprising clinically significant early (14.8% vs. 9.1%), intermediate (5.3% vs. 1.9%) and late (5.3% vs. 2.0%) surgical morbidity, re-exploration rates (7.4% vs. 3.4%) and duration of hospital stay (median 6 days in both groups), or the pathological quality indices of margin involvement (7.4% vs. 2.3%), nodal yield (median 4 vs. 7 nodes) and lateral node positivity (22.2% vs. 26.1%), respectively. At a median 11 months follow-up, oncological outcomes in terms of lateral pelvic recurrence rates (3.7% vs. 4.5%), 2-year event-free survival (78.7% vs. 79.3%) and 2-year overall survival (83.1% vs. 93.8%) were also comparable.

CONCLUSION

Surgical competence in laparoscopy may offset the potential benefits extended by robotic platforms. In a high-volume setup with experienced minimal-access surgeons, the clinical, pathological, and short-term oncological outcomes associated with both approaches may be considered equivalent.

Abdominoperineal Resection for T4 Low Rectal Cancer After Neoadjuvant Therapy-Are the Outcomes Acceptable?

Introduction

There is no clear consensus on using the response MRI as opposed to the pretreatment MRI for surgical planning in cT4 low rectal cancer. The objective of this study is to determine the safety of using response MRI in surgical planning for T4 rectal cancer.

Methods

This study is a retrospective review of a prospectively maintained database of abdominoperineal resections conducted at a single tertiary cancer center. Patients undergoing an abdominoperineal resection were divided into 2 groups: group A (clinical T3, mesorectal fascia positive) and group B (clinical T4), and propensity matching was used to account for uneven distribution of baseline characteristics. Primary outcome was the rate of pathological circumferential resection margin positivity. Secondary outcomes were survival outcomes and recurrence patterns.

Results

There were 237 patients in group A and 127 in group B, in the unmatched cohort, with a significantly higher number of females (43.3% vs. 28.7%, p = 0.005) and anterior circumferential resection margin positivity (68.5% vs. 49%, p < 0.001), with a lower number of patients receiving neoadjuvant chemotherapy in group B (38.6% vs. 49.8%, p = 0.041). After propensity matching baseline characters were comparable. There was a higher percentage of extended-total mesorectal excisions in group B (58.5% vs. 40.5%, p = 0.004). The rate of pathological circumferential positivity was comparable in both groups (20/168 in group A {11.9%} vs. 13/107 in group B {12.1%}, p = 0.951) with no impact of group on circumferential resection margin positivity on univariate (OR 1.023, p = 0.951) or multivariate regression (OR 0.993, p = 0.987). Both the DFS (median DFS 39 months vs. 54 months, p = 0.970) and OS (3-year OS 72% vs. 67%, p = 0.798) were comparable between both groups.

Conclusion

For T4 low rectal cancers, post-treatment MRI can be used for surgical planning without any detriment in pathological or long-term oncological outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13193-024-02028-3.

Outcomes and failure patterns after chemoradiotherapy for locally advanced rectal cancer with positive lateral pelvic lymph nodes: a propensity score-matched analysis

PURPOSE

This study aimed to use propensity score matching (PSM) to explore the long-term outcomes and failure patterns in locally advanced rectal cancer (LARC) patients with positive versus negative lateral pelvic lymph node (LPLN).

MATERIALS AND METHODS

Patients with LARC were retrospectively divided into LPLN-positive and LPLN-negative groups. Clinical characteristics were compared between the groups using the chi-square test. PSM was applied to balance these differences. Progression-free survival (PFS) and overall survival (OS), and local-regional recurrence (LRR) and distant metastasis (DM) rates were compared between the groups using the Kaplan-Meier method and log-rank tests.

RESULTS

A total of 651 LARC patients were included, 160 (24.6%) of whom had positive LPLN and 491 (75.4%) had negative LPLN. Before PSM, the LPLN-positive group had higher rates of lower location (53.1% vs. 43.0%, P = 0.025), T4 stage (37.5% vs. 23.2%, P = 0.002), mesorectal fascia (MRF)-positive (53.9% vs. 35.4%, P < 0.001) and extramural venous invasion (EMVI)-positive (51.2% vs. 27.2%, P < 0.001) disease than the LPLN-negative group. After PSM, there were 114 patients for each group along with the balanced clinical factors, and both groups had comparable surgery, pathologic complete response (pCR), and ypN stage rates. The median follow-up was 45.9 months, 3-year OS (88.3% vs. 92.1%, P = 0.276) and LRR (5.7% vs. 2.8%, P = 0.172) rates were comparable between LPLN-positive and LPLN-negative groups. Meanwhile, despite no statistical difference, 3-year PFS (78.8% vs. 85.9%, P = 0.065) and DM (20.4% vs. 13.3%, P = 0.061) rates slightly differed between the groups. 45 patients were diagnosed with DM, 11 (39.3%) LPLN-positive and 3 (17.6%) LPLN-negative patients were diagnosed with oligometastases (P = 0.109).

CONCLUSIONS

Our study indicates that for LPLN-positive patients, there is a tendency of worse PFS and DM than LPLN-negative patients, and for this group patients, large samples are needed to further confirm our conclusion.

Predicting the response to neoadjuvant chemoradiation for rectal cancer using nomograms based on MRI tumour regression grade

PURPOSE

This study aimed to develop nomograms that combine clinical factors and MRI tumour regression grade to predict the pathological response of mid-low locally advanced rectal cancer to neoadjuvant chemoradiotherapy.

METHODS

The retrospective study included 204 patients who underwent neoadjuvant chemoradiotherapy and surgery between January 2013 and December 2021. Based on pathological tumour regression grade, patients were categorized into four groups: complete pathological response (pCR, n=45), non-complete pathological response (non-pCR; n=159), good pathological response (pGR, n=119), and non-good pathological response (non-pGR, n=85). The patients were divided into a training set and a validation set in a 7:3 ratio. Based on the results of univariate and multivariate analyses in the training set, two nomograms were respectively constructed to predict complete and good pathological responses. Subsequently, these predictive models underwent validation in the independent validation set. The prognostic performances of the models were evaluated using the area under the curve (AUC).

RESULTS

The nomogram predicting complete pathological response incorporates tumour length, post-treatment mesorectal fascia involvement, white blood cell count, and MRI tumour regression grade. It yielded an AUC of 0.787 in the training set and 0.716 in the validation set, surpassing the performance of the model relying solely on MRI tumour regression grade (AUCs of 0.649 and 0.530, respectively). Similarly, the nomogram predicting good pathological response includes the distance of the tumour's lower border from the anal verge, post-treatment mesorectal fascia involvement, platelet/lymphocyte ratio, and MRI tumour regression grade. It achieved an AUC of 0.754 in the training set and 0.719 in the validation set, outperforming the model using MRI tumour regression grade alone (AUCs of 0.629 and 0.638, respectively).

CONCLUSIONS

Nomograms combining MRI tumour regression grade with clinical factors may be useful for predicting pathological response of mid-low locally advanced rectal cancer to neoadjuvant chemoradiotherapy. The proposed models could be applied in clinical practice after validation in large samples.

Feasibility of a tailored operative strategy from organ preservation to pelvic exenteration for cT4 rectal cancer depending on neoadjuvant response

PURPOSE

Improvements in neoadjuvant therapy for locally advanced cT4 rectal cancer have led to improved tumour response and thus a variety of suitable management strategies. The aim of this study was to report management and outcomes of patients with cT4 rectal cancer undergoing a spectrum of treatment strategies from organ preservation (OP) to pelvic exenteration (PE).

METHODS

Patients who underwent elective treatment for cT4 rectal cancer between 2016 and 2021 were included. All patients were treated with curative intent. Surgical management was adapted to tumour response. Kaplan-Meier curves were generated to compare 3-year overall survival (3y-OS), local recurrence (3y-LR) and distant metastases (3y-DM) between different strategies.

RESULTS

Among 152 patients included, 13 (8%) underwent OP, 71 (47%) TME and 68 (45%) APR/PE. The median follow-up was 31.3 months. Patients undergoing OP had a lower tumour pretreatment (p < 0.001). Compared to patients with TME, those with APR/PE had a higher rate of ypT4 (p = 0.001) with a lower R0 rate (p = 0.044). The 3y-OS and 3y-DM were 78% and 15.1%, respectively, without significant differences. The 3y-LR was 6.6%, and patients with OP had a significantly worse 3y-local regrowth compared to 3y-LR in patients with TME and APR/PE (30.2% vs. 5.4% vs. 2%, p = 0.008).

CONCLUSION

cT4 tumours may be suitable for the full spectrum of rectal cancer management from organ preservation to pelvic exenteration depending on tumour response to neoadjuvant therapy. However, careful attention is required in OP as local regrowth in up to 30% of cases reinforces the need for sustained active surveillance in Watch&Wait programmes.

A novel classification of posterior pelvic exenteration to assess prognosis in female patients with locally advanced primary rectal cancer: a retrospective cohort study from China PelvEx collaborative

PURPOSE

Surgical techniques and the prognosis of posterior pelvic exenteration for locally advanced primary rectal cancer in female patients pose challenges that need to be addressed. Therefore, we investigated the short-term and survival outcomes of posterior pelvic exenteration in female patients using a novel Peking classification.

METHODS

We retrospectively analysed a prospective database from China PelvEx Collaborative across three tertiary referral centres. A total of 172 patients who underwent combined resection for locally advanced primary rectal cancer were classified based on four subtypes (PPE-I [64/172], PPE-II [68/172], PPE-III [21/172], and PPE-IV [19/172]) according to the Peking classification; perioperative characteristics and short-term and oncological outcomes were analysed.

RESULTS

Differences were significant among the four groups regarding colorectal reconstruction (p < 0.001), perineal reconstruction (p < 0.001), in-hospital complications (p < 0.05), and urinary retention (p < 0.05). The R0 resection rates for PPE-I, PPE-II, PPE-III, and PPE-IV were 90.6%, 89.7%, 90.5%, and 89.5%, respectively. The 5-year overall survival rates of the PPE-I, PPE-II, PPE-III, and PPE-IV groups were 73.4%, 68.8%, 54.7%, and 37.3%, respectively. Correspondingly, their 5-year disease-free survival rates were 76.0%, 62.5%, 57.7%, and 43.1%, respectively. Notably, the PPE-IV group demonstrated the lowest 5-year overall survival rate (p < 0.001) and 5-year disease-free survival rate (p < 0.001).

CONCLUSION

The Peking classification can aid in determining suitable surgical techniques and conducting prognostic assessments in female patients with locally advanced primary rectal cancer.

Radiomics from Mesorectal Blood Vessels and Lymph Nodes: A Novel Prognostic Predictor for Rectal Cancer with Neoadjuvant Therapy

The objective of our study is to investigate the predictive value of various combinations of radiomic features from intratumoral and different peritumoral regions of interest (ROIs) for achieving a good pathological response (pGR) following neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC). This retrospective study was conducted using data from LARC patients who underwent nCRT between 2013 and 2021. Patients were divided into training and validation cohorts at a ratio of 4:1. Intratumoral ROIs (ROI_ITU) were segmented on T2-weighted imaging, while peritumoral ROIs were segmented using two methods: ROI_{PTU_2mm}, ROI_{PTU_4mm}, and ROI_{PTU_6mm}, obtained by dilating the boundary of ROI_ITU by 2 mm, 4 mm, and 6 mm, respectively; and ROI_{MR_F} and ROI_{MR_BVLN}, obtained by separating the fat and blood vessels + lymph nodes in the mesorectum. After feature extraction and selection, 12 logistic regression models were established using radiomics features derived from different ROIs or ROI combinations, and five-fold cross-validation was performed. The average area under the receiver operating characteristic curve (AUC) was used to evaluate the performance of the models. The study included 209 patients, consisting of 118 pGR and 91 non-pGR patients. The model that integrated ROI_ITU and ROI_{MR_BVLN} features demonstrated the highest predictive ability, with an AUC (95% confidence interval) of 0.936 (0.904-0.972) in the training cohort and 0.859 (0.745-0.974) in the validation cohort. This model outperformed models that utilized ROI_ITU alone (AUC = 0.779), ROI_{MR_BVLN} alone (AUC = 0.758), and other models. The radscore derived from the optimal model can predict the treatment response and prognosis after nCRT. Our findings validated that the integration of intratumoral and peritumoral radiomic features, especially those associated with mesorectal blood vessels and lymph nodes, serves as a potent predictor of pGR to nCRT in patients with LARC. Pending further corroboration in future research, these insights could provide novel imaging markers for refining therapeutic strategies.

Outcomes of extended total mesorectal excision in patients with locally advanced rectal cancer

AIM

Extended total mesorectal excision (eTME) is a complex procedure involving en bloc resection of the structures surrounding the various quadrants of the rectum. This study, presenting the largest series so far of patients undergoing eTME, aimed to assess the surgical and survival outcomes of patients following treatment with eTME and to compare these outcomes with historical data on pelvic exenteration.

METHOD

The study is a retrospective review of all patients with locally advanced rectal cancer requiring an eTME (2014-2020). The database includes the demographic profile, operative details, histopathological features and follow-up.

RESULTS

One hundred and sixty three patients who underwent eTME were analysed. The overall Clavien-Dindo complication rate of > IIIa was 21.1%. The anterior quadrant was the most common anatomical site resected (68.5%). The R1 resection rate was 10.4%. After a median follow-up of 28 months, there were 51 recurrences in the study and twenty two deaths were recorded. The local recurrence rate was 7.3% among the study population. The disease-free survival (DFS) and overall survival were 66.7% and 80.4%, respectively, at 3 years. The majority of the recurrences were distant metastasis (84.3%). In univariate analysis, the quadrant involved did not affect survival. In multivariate analysis, signet ring histology, metastatic presentation, inadequate tumour response and R1 resection affected DFS.

CONCLUSION

The recurrence pattern, R1 resection rate and survival outcomes of patients in the present study were comparable with those for patients undergoing an exenteration. Therefore, eTME is probably a safe alternative to pelvic exenterations when R0 resection is achievable and when the procedure is performed in high-volume specialist tertiary care centres.

Dentate line invasion as a predictive factor of poor distant relapse-free survival in locally advanced lower rectal cancer with anal sphincter involvement

Background

While an important surgical landmark of the dentate line has been established for locally advanced lower rectal cancer (LALRC), the prognostic significance of dentate line invasion (DLI) has not been well defined. This study aimed to explore the impact of DLI on prognosis in LALRC patients with anal sphincter involvement after neoadjuvant chemoradiotherapy followed by surgery.

Methods

We analyzed 210 LALRC patients and classified them into DLI group (n = 45) or non-DLI group (n = 165). The exact role of DLI in survival and failure patterns was assessed before and after propensity-score matching(PSM). Finally, 50 patients were matched.

Results

Before matching, patients in the DLI group had poorer 5-year distant relapse-free survival (DRFS) (P < 0.001), disease-free survival (DFS) (P < 0.001), and overall survival (OS) (P = 0.022) than those in the non-DLI group, with the exception of local recurrence-free survival (LRFS) (P = 0.114). After PSM, the 5-year DRFS, DFS, OS, and LRFS were 51.7% vs. 79.8%(P = 0.026), 51.7% vs. 79.8%(P = 0.029), 71.6% vs. 85.4%(P = 0.126), and 85.7% vs. 92.0%(P = 0.253), respectively, between the two groups. DLI was also an independent prognostic factor for poor DRFS with (Hazard ratio [HR] 3.843, P = 0.020) or without matching (HR 2.567, P = 0.001). The DLI group exhibited a higher rate of distant metastasis before (44.4% vs. 19.4%, P < 0.001) and after matching (48.0% vs. 20.0%, P = 0.037) and similar rates of locoregional recurrence before (13.3% vs.7.9%, P = 0.729) and after matching (16.0% vs.12.0%, P = 1.000).

Conclusions

DLI may portend worse DRFS and distant metastasis in LALRC patients with anal sphincter involvement, and this may be an important variable to guide clinicians.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10299-8.

Machine learning-based multiparametric MRI radiomics for predicting poor responders after neoadjuvant chemoradiotherapy in rectal Cancer patients

BACKGROUND

The purpose of this study was to investigate and validate multiparametric magnetic resonance imaging (MRI)-based machine learning classifiers for early identification of poor responders after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC).

METHODS

Patients with LARC who underwent nCRT were included in this retrospective study (207 patients). After preprocessing of multiparametric MRI, radiomics features were extracted and four feature selection methods were used to select robust features. The selected features were used to build five machine learning classifiers, and 20 (four feature selection methods × five machine learning classifiers) predictive models for the screening of poor responders were constructed. The predictive models were evaluated according to the area under the curve (AUC), F1 score, accuracy, sensitivity, and specificity.

RESULTS

Eighty percent of all predictive models constructed achieved an AUC of more than 0.70. A predictive model using a support vector machine classifier with the minimum redundancy maximum relevance (mRMR) selection method followed by the least absolute shrinkage and selection operator (LASSO) selection method showed superior prediction performance, with an AUC of 0.923, an F1 score of 88.14%, and accuracy of 91.03%. The predictive performance of the constructed models was not improved by ComBat compensation.

CONCLUSIONS

In rectal cancer patients who underwent neoadjuvant chemoradiotherapy, machine learning classifiers with radiomics features extracted from multiparametric MRI were able to accurately discriminate poor responders from good responders. The techniques should provide additional information to guide patient-tailored treatment.

Postoperative MRI Findings Following Conventional and Extralevator Abdominoperineal Excision in Low Rectal Cancer

Aim: The disparity in outcomes for low rectal cancer may reflect differences in operative approach and quality. The extralevator abdominoperineal excision (ELAPE) was developed to reduce margin involvement in low rectal cancers by widening the excision of the conventional abdominoperineal excision (c-APE) to include the posterior pelvic diaphragm. This study aimed to determine the prevalence and localization of inadvertent residual pelvic diaphragm on postoperative MRI after intended ELAPE and c-APE. Methods: A total of 147 patients treated with c-APE or ELAPE for rectal cancer were included. Postoperative MRI was performed on 51% of the cohort (n = 75) and evaluated with regard to the residual pelvic diaphragm by a radiologist trained in pelvic MRI. Patient records, histopathological reports, and standardized photographs were assessed. Pathology and MRI findings were evaluated independently in a blinded fashion. Additionally, preoperative MRIs were evaluated for possible risk factors for margin involvement. Results: Magnetic resonance imaging-detected residual pelvic diaphragm was identified in 45 (75.4%) of 61 patients who underwent ELAPE and in 14 (100%) of 14 patients who underwent c-APE. An increased risk of margin involvement was observed in anteriorly oriented tumors with 16 (22%) of 73 anteriorly oriented tumors presenting with margin involvement vs. 7 (9%) of 74 non-anteriorly oriented tumors (p = 0.038). Conclusion: Residual pelvic diaphragm following abdominoperineal excision can be depicted by postoperative MRI. Inadvertent residual pelvic diaphragm (RPD) was commonly found in the series of patients treated with the ELAPE technique. Anterior tumor orientation was a risk factor for circumferential resection margin (CRM) involvement regardless of surgical approach.

Brazilian society of surgical oncology: Guidelines for the surgical treatment of mid-low rectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer in North America, Western Europe, and Brazil, and represents an important public health problem. It is estimated that approximately 30% of all the CRC cases correspond to tumors located in the rectum, requiring complex multidisciplinary treatment. In an effort to provide surgeons who treat rectal cancer with the most current information based on the best evidence in the literature, the Brazilian Society of Surgical Oncology (SBCO) has produced the present guidelines for rectal cancer treatment that is focused on the main topics related to daily clinical practice.

OBJECTIVES

The SBCO developed the present guidelines to provide recommendations on the main topics related to the treatment of mid-low rectal cancer based on current scientific evidence.

METHODS

Between May and June 2021, 11 experts in CRC surgery met to develop the guidelines for the treatment of mid-low rectal cancer. A total of 22 relevant topics were disseminated among the participants. The methodological quality of a final list with 221 sources was evaluated, all the evidence was examined and revised, and the treatment guideline was formulated by the 11-expert committee. To reach a final consensus, all the topics were reviewed via a videoconference meeting that was attended by all 11 of the experts.

RESULTS

The prepared guidelines contained 22 topics considered to be highly relevant in the treatment of mid-low rectal cancer, covering subjects related to the tests required for staging, surgical technique-related aspects, recommended measures to reduce surgical complications, neoadjuvant strategies, and nonoperative treatments. In addition, a checklist was proposed to summarize the important information and offer an updated tool to assist surgeons who treat rectal cancer provide the best care to their patients.

CONCLUSION

These guidelines summarize concisely the recommendations based on the most current scientific evidence on the most relevant aspects of the treatment of mid-low rectal cancer and are a practical guide that can help surgeons who treat rectal cancer make the best therapeutic decision.

A phase III randomized trial evaluating chemotherapy followed by pelvic reirradiation versus chemotherapy alone as preoperative treatment for locally recurrent rectal cancer - GRECCAR 15 trial protocol

AIM

Treatment strategies in locally recurrent rectal cancer (LRRC) are complex and need to be balanced against previous treatments received for the primary rectal cancer. Radiotherapy is an important component of treatment in LRRC. However, there is little high-quality evidence on the role of reirradiation in this cohort. Therefore, the aim of this trial is to assess the efficacy of neoadjuvant chemotherapy followed by pelvic reirradiation versus neoadjuvant chemotherapy alone on the rate of curative surgery (R0) in previously irradiated patients with LRRC.

METHOD

GRECCAR 15 is a prospective, multicentre, open-label, outcome assessor-blinded, superiority randomized controlled phase III clinical trial comparing neoadjuvant chemotherapy followed by pelvic reirradiation versus neoadjuvant chemotherapy alone in patients with LRRC previously irradiated for the primary cancer. Adult patients (>18 years old) with a histologically proven resectable LRRC, who have previously received pelvic radiotherapy for their primary rectal cancer at a dose of 25-50.4 Gy, and an Eastern Cooperative Oncology Group performance status of <2 will be eligible to participate. The pelvic reirradiation will consist of conformational intensity-modulated external irradiation, delivering a dose of 30.6 Gy with concomitant chemotherapy using capecitabine. The primary outcome of this trial is the R0 resection rate. Overall, GRECCAR 15 aims to recruit 186 patients to detect an absolute difference of 20% in the R0 resection rate with 80% power and 5% two-sided significance level.

CONCLUSION

The GRECCAR 15 trial is the first, definitive, phase III trial to investigate reirradiation in LRRC. The results of this trial will inform definitively the neoadjuvant treatment strategy in previously irradiated patients and assess whether there is any associated benefit of reirradiation in combination with induction chemotherapy in improving R0 resection rates.

Patterns of failure and implications for clinical target volume definition of locally advanced T4b rectal cancer identified with magnetic resonance imaging and treated using neoadjuvant chemoradiotherapy and surgery

BACKGROUND AND PURPOSE

Elective irradiation of the external iliac lymph nodes (EIN) has always been advocated for T4b rectal cancer with anterior organ invasion without convincing evidence. This study aimed to explore the patterns of treatment failure for locally advanced T4b rectal cancer treated using neoadjuvant chemoradiotherapy (NCRT) and surgery. This information may help to clarify whether the current definition of the clinical target volume (CTV) is still appropriate.

MATERIALS AND METHODS

We retrospectively analyzed data from 126 patients with locally advanced T4b rectal cancer who received NCRT, without elective EIN irradiation, followed by surgery between January 2010 and October 2018. Pretreatment magnetic resonance imaging was used to identify the T4b disease in all cases. The locoregional recurrence (LRR) rate and EIN failure rate were evaluated, and the LRR locations were identified using a three-dimensional model.

RESULTS

After a median follow-up of 53.9 months, LRR occurred in 11.1% of patients (14/126). All LRRs were located in the previously irradiated fields and below the S2-S3 junction. The EIN failure rate was 0.8% (1/126) among all patients and 1.8% (1/56) in the group with anterior genitourinary organ invasion. The estimated 4-year distant relapse-free survival, disease-free survival and overall survival were 79.3%, 73.2% and 86.9%, respectively.

CONCLUSIONS

It may be feasible to exclude the external iliac region from the CTV during NCRT for locally advanced T4b rectal cancer. However, further studies are needed to clarify whether the cranial border of the CTV can be lowered.

Intraoperative complications during laparoscopic total mesorectal excision

Intraoperative complication during laparoscopic mesorectal excision for rectal cancer is a common complication occurring in 11% to 15% of the cases. They are probably underestimated because not systematically reported. The most frequent intraoperative complications are haemorrhage (3-7%), tumour perforation (1-4%), bowel injury (1-3%), ureter injury (1%), urogenital injury (2%), other organ injury (<1%), and anastomotic complications (1%). The mechanisms, management and prevention of vascular port injury, inferior mesenteric artery bleeding, small bowel and colon perforation, ureteral and urethral injury, pelvic nerve damage, tumour perforation and anastomotic failure are described. This review underlines the necessity to prevent intraoperative complication to avoid operative death and severe side-effects.

Outcomes of exenteration in cT4 and fixed cT3 stage primary rectal adenocarcinoma: a subgroup analysis of consolidation chemotherapy following neoadjuvant concurrent chemoradiotherapy

PURPOSE

The aim was to evaluate the oncological outcomes and the prognostic factors following pelvic exenteration (PE) in cT4 and fixed cT3 stage primary rectal adenocarcinoma and to study the impact of consolidation chemotherapy following neoadjuvant concurrent chemoradiotherapy (NACRT).

METHODS

A retrospective analysis of a prospectively maintained database of PE from 2013 to 2018.

RESULTS

Out of 2900 colorectal resections, there were 131 pelvic exenterations that were performed, and 100 of these patients had undergone exenteration for primary rectal adenocarcinoma. Of these 100 patients, there were 81 patients who had received NACRT followed by surgery, 50 of whom who had received consolidation chemotherapy and 31 who had undergone surgery without consolidation chemotherapy. R0 resection was achieved in 90% cases. At a median follow-up of 32 months, 2-year disease free survival was 61.8% and estimated 5-year overall survival was 62%. The incidence of distant metastases was 44% vs. 19% (p = 0.023), and the 2-year distant recurrence-free survival was 58% vs. 89% (p = 0.025), respectively, in the 'consolidation chemotherapy group' and the 'no chemotherapy group'. The poorly differentiated grade of tumours, presence of lympho-vascular-invasion, consolidation chemotherapy, and disease recurrence were all found to affect the survival.

CONCLUSION

PE with R0 resection achieves excellent survival rates in cT4 and fixed cT3 stage primary rectal adenocarcinoma. The distant recurrence rate may not be altered by consolidation chemotherapy in the subset of high-risk patients. However, further research on consolidation chemotherapy following NACRT in cT4 and fixed cT3 stage primary rectal adenocarcinoma will give a definite answer in the future.

Feasibility of laparoscopic-assisted transanal pelvic exenteration in locally advanced rectal cancer with anterior invasion

BACKGROUND

Transanal (Ta) pelvic exenteration is a promising, minimally invasive method for treating locally advanced colorectal cancer. However, since it is technically difficult to perform, Ta pelvic exenteration is rarely reported in locally advanced T4 rectal cancer cases. The aim of this study was to evaluate the feasibility of transabdominal laparoscopy-assisted Ta pelvic exenteration.

METHODS

Six patients (4 males and 2 females) had laparoscopy-assisted Ta total or posterior pelvic exenteration for locally advanced or recurrent colorectal cancer cases at the Nagasaki University Hospital between September 2018 and August 2019. Clinical and pathological outcomes were measured and analyzed.

RESULTS

The median operation time and intraoperative blood loss were 481 (range 456-709) minutes and 352.5 (range 257-1660) ml, respectively. R0 resection was achieved in all cases, and no patient required open surgery. Two patients had grade 3 complications (Clavien-Dindo) or higher. There was no mortality, and no reoperation was required.

CONCLUSIONS

The results suggest that laparoscopic-assisted Ta pelvic exenteration is an acceptable procedure, may help overcome the current technical difficulties, and may improve outcomes in patients with locally advanced rectal cancer.

Predicting poor response to neoadjuvant chemoradiotherapy for locally advanced rectal cancer: Model constructed using pre-treatment MRI features of structured report template

PURPOSE

To develop a predictive model with pre-treatment magnetic resonance imaging (MRI) findings of the structured report template and clinical parameters for poor responses prediction after neoadjuvant chemoradiotherapy (neoCRT) in locally advanced rectal cancers (LARC) patients.

METHOD

Patients with clinicopathologically confirmed LARC (training and validation datasets, n = 100 and 71, respectively) were enrolled. Patients' clinical data were retrospectively collected. MRI findings of the structured report template were analysed. The tumour regression grade (TRG) system as proposed by Mandard et al was used. Poor response was defined as TRG 3-5. Univariate logistic regression analysis and a lasso regression model were performed to select the significant predictive features from the training set. A nomogram was constructed based on a multivariable logistic regression analysis. Calibration, discrimination, and clinical usefulness of the nomogram were assessed. The calibrative and discriminative ability of our model were compared with those of models including the tumour-node-metastasis (TNM) stage and clinical factors.

RESULTS

The MRI-reported T4b stage, MRI-reported extramural venous invasion (EMVI) positivity, MRI-detected number of positive mesorectal lymph nodes (LNs) > 0, and preoperative oxaliplatin and capecitabine (CAPOX) chemotherapy regimen were incorporated into our nomogram. The nomogram showed good discrimination, with areas under the receiver operating characteristic (ROC) curves of 0·823 and 0·820 in the training and test sets, respectively, and good calibration in both datasets. The decision curve analysis confirmed that the nomogram was clinically useful. The calibrative and discriminative ability of our model were better than those models including the TNM stage and clinical factors.

CONCLUSION

A nomogram based on pre-treatment MRI features of the structured report template and clinical risk factors has potential for use as a non-invasive tool to preoperatively predict poor responses in LARC patients after neoCRT.

Persistent involvement of anterior mesorectal fascia in carcinoma rectum - extended resection of rectum vs total pelvic exenteration: results from a single-centre retrospective study

AIM

Involvement of the anterior mesorectal fascia (iAMRF) after neoadjuvant treatment leads to either resection of the involved organ alone [extended resection of the rectum (ERR)] or total pelvic exenteration (TPE). The purpose of this study was to compare the rate of recurrence and survival of patients undergoing ERR or TPE for iAMRF after neoadjuvant treatment. The outcome of patients who underwent total mesorectal excision after downstaging was also compared.

METHOD

This was a retrospective study of primary rectal cancer patients.

RESULTS

Of 237 patients, 61 (21.5%) patients with nonmetastatic carcinoma rectum had iAMRF at baseline. Ten patients defaulted before completion of neoadjuvant chemoradiotherapy. After neoadjuvant chemoradiotherapy, 22 patients (43.1%) developed systemic metastases, seven patients (13.8%) were downstaged to free anterior mesorectal fascia and underwent total mesorectal excision (anterior resection/abdominoperineal resection) and the remaining 22 patients (43.1%) had persistent iAMRF. Thirteen patients with persistent iAMRF underwent ERR, whereas nine patients underwent TPE. The median duration of hospital stay in the TPE group was 13 days (10-26), whereas it was 7 days (5-21) in the ERR group. A clear circumferential resection margin, R0 resection, was achieved in all patients with TPE and ERR. After a median follow-up of 31.6 months, five patients with TPE (55.6%), four patients with ERR (30.7%) and three patients in the downstaged group (42.9%) developed systemic recurrence. None of the patients with TPE and the downstaged group developed local recurrence, whereas three patients with ERR (23.1%) developed local recurrence. Median disease-free survival was 12.3 months in the TPE group, 18.9 months in the ERR group and 10.6 months in the downstaged group, whereas mean overall survival was 36.2, 32.8 and 27.9 months, respectively.

CONCLUSION

Although there is no significant difference in the overall survival and disease-free survival, ERR is associated with a high risk of local recurrence compared to TPE and the downstaged group.

Locally Advanced Disease and Pelvic Exenterations

Advanced primary and recurrent colorectal cancer can be successfully treated by experienced, dedicated centers delivering good outcomes with low mortality and morbidity. Development and implementation of a comprehensive referral pathway is to be encouraged. Multidisciplinary team management is essential in the management of this complex group of patients and is associated with significantly more complete preoperative evaluation and more accurate provision of patient information, as well as improved access to the most appropriate individualized management plan. A structured selection process can improve outcomes through standardized approaches to service delivery to provide the highest quality of care.

Preliminary results of a cohort study of induction chemotherapy-based treatment for locally recurrent rectal cancer

BACKGROUND

A significant number of patients treated for locally recurrent rectal cancer have local or systemic failure, especially after incomplete surgical resection. Neoadjuvant treatment regimens in patients who have already undergone preoperative (chemo)radiotherapy for the primary tumour are limited. The objective of the present study was to evaluate the influence of a neoadjuvant regimen incorporating induction chemotherapy (ICT) in patients with locally recurrent rectal cancer who had preoperative (chemo)radiotherapy for the primary cancer or an earlier local recurrence.

METHODS

Patients were treated with a sequential neoadjuvant regimen including three or four cycles of 5-fluorouracil and oxaliplatin-containing chemotherapy. When no progressive disease was found at evaluation, neoadjuvant treatment was continued with chemoradiation therapy (CRRT) using 30 Gy with concomitant capecitabine. If there was a response to ICT, the patient was advised to continue with systemic chemotherapy after CRRT as consolidation chemotherapy while waiting for resection. These patients were compared with patients who received CRRT alone in the same time interval.

RESULTS

Of 58 patients who had ICT, 32 (55 per cent) had surgery with clear resection margins, of whom ten (17 per cent) exhibited a pathological complete response (pCR). The remaining 26 patients had 23 R1 and three R2 resections. In 71 patients who received CRRT, a similar rate of R0 (35 patients) and R1 (36) resection was found (P = 0·506), but only three patients (4 per cent) had a pCR (P = 0·015).

CONCLUSION

The incorporation of ICT in neoadjuvant regimens for locally recurrent rectal cancer is a promising strategy.