A single-centre experience of chemoradiotherapy for rectal cancer: is there potential for nonoperative management?

Randomized Phase II Trial of Immunotherapy-Based Total Neoadjuvant Therapy for Proficient Mismatch Repair or Microsatellite Stable Locally Advanced Rectal Cancer (TORCH)

PURPOSETo assess whether the integration of PD-1 inhibitor with total neoadjuvant therapy (iTNT) can lead to an improvement in complete responses (CRs) and favors a watch-and-wait (WW) strategy in patients with proficient mismatch repair or microsatellite stable (pMMR/MSS) locally advanced rectal cancer (LARC).PATIENTS AND METHODSWe conducted a prospective, multicenter, randomized, open-label, phase II trial using a pick-the-winner design. Eligible patients with clinical T3-4 and/or N+ rectal adenocarcinoma were randomly assigned to group A for short-course radiotherapy (SCRT) followed by six cycles of consolidation immunochemotherapy with capecitabine and oxaliplatin and toripalimab or to group B for two cycles of induction immunochemotherapy followed by SCRT and the rest four doses. Either total mesorectal excision or WW was applied on the basis of tumor response. The primary end point was CR which included pathological CR (pCR) after surgery and clinical CR (cCR) if WW was applicable, with hypothesis of an increased CR of 40% after iTNT compared with historical data of 25% after conventional TNT.RESULTSOf the 130 patients enrolled, 121 pMMR/MSS patients were evaluable (62 in group A and 59 in group B). At a median follow-up of 19 months, CR was achieved at 56.5% in group A and 54.2% in group B. Both groups fulfilled the predefined statistical hypothesis (P < .001). Both groups reported a pCR rate of 50%. Respectively, 15 patients in each group underwent WW and remained disease free. The most frequent grade 3 to 4 toxicities were thrombocytopenia and neutropenia. Patients in group A had higher rate of cCR (43.5% v 35.6%) at restaging and lower rate of grade 3 to 4 thrombocytopenia (24.2% v 33.9%) during neoadjuvant treatment.CONCLUSIONThe iTNT regimens remarkably improved CR rates in pMMR/MSS LARC compared with historical benchmark with acceptable toxicity. Up-front SCRT followed by immunochemotherapy was selected for future definitive study.

Comparative analysis of organ preservation attempt and radical surgery in clinical T2N0 mid to low rectal cancer

PURPOSE

Debate persists regarding the feasibility of adopting an organ-preserving strategy as the treatment modality for clinical T2N0 rectal cancer. This study aimed to compare the outcomes of attempting organ-preserving strategies versus radical surgery in patients with clinical T2N0 mid to low rectal cancer.

METHODS

Patients diagnosed with clinical T2N0 rectal cancer, with lesions located within 8 cm from the anal verge as determined by pre-treatment magnetic resonance imaging between January 2010 and December 2020 were included.

RESULTS

Of 119 patients, 91 and 28 were categorized into the organ-preserving attempt group and the radical surgery group, respectively. The median follow-up duration was 48.8 months (range, 0-134 months). The organ-preserving attempt group exhibited a reduced incidence of stoma formation (44.0% vs. 75.0%; p = 0.004) and a lower occurrence of grade 3 or higher surgical complications (5.8% vs. 21.4%; p = 0.025). Univariate analyses revealed no significant association between treatment strategy and 3-year local recurrence-free survival (organ-preserving attempt 87.9% vs. radical surgery 96.2%; p = 0.129), or 3-year disease-free survival (79.6% vs. 84.9%; p = 0.429). Multivariate analysis did not identify any independent prognostic factors associated with oncologic outcomes.

CONCLUSION

Compared with radical surgery, attempted organ preservation resulted in lower incidences of stoma formation and severe surgical complications, whereas oncological outcomes were comparable. Attempting organ preservation may be a safe alternative to radical surgery for clinical T2N0 mid to low rectal cancer.

Whether the watch-and-wait strategy has application value for rectal cancer with clinical complete response after neoadjuvant chemoradiotherapy? A network meta-analysis

The aim was to evaluate the efficacy and safety between the watch-and-wait strategy (WW), radical surgery (RS), and local excision (LE) for rectal cancer with clinical complete response (cCR) after neoadjuvant radiotherapy (nCRT). We searched MEDLINE, EMBASE, the Cochrane Library, and clinical trials to compare WW with RS and LE for patients with cCR until March 2023 and collected the following data: local recurrence (LR), distant metastasis (DM), cancer-related death (CRD), overall survival (OS), and disease-free survival (DFS). In total, 2240 patients from 21 studies were included. Pairwise meta-analysis revealed no statistically significant differences between the three groups in terms of CRD and 2-, 3-, and 5-year OS (P < 0.05). The RS group was significantly better than the WW group in terms of the LR rate (odds ratio [OR] = 0.12, 95 % confidence interval [CI]: 0.06-0.21, P < 0.001, I2 = 0 %], 3-year DFS (OR = 1.56, 95 % CI: 1.10-2.21, P = 0.01, I2 = 38 %), and 5-year DFS (OR = 2.30, 95 % CI: 1.53-3.46, P < 0.001, I2 = 34 %). The results of network meta-analysis were also similar. After sensitivity analysis, the 5-year OS of the RS group was significantly better than that of the WW group (OR = 2.77, 95 % CI: 1.28-6.00, P = 0.009, I2 = 33 %). Nevertheless, neither regression analysis nor subgroup analysis provided meaningful results. However, the cumulative meta-analysis of LR, DM, and 3- and 5-year DFS revealed significant turning points (P < 0.05). Our meta-analysis recommends using the WW strategy for patients with cCR having poor underlying conditions and high surgical risk; however, there is a risk of higher LR and worse survival after 3 years.

Survival outcomes of salvage surgery in the watch-and-wait approach for rectal cancer with clinical complete response after neoadjuvant chemoradiotherapy: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis compared the outcomes of the watch-and-wait (WW) approach versus radical surgery (RS) in rectal cancers with clinical complete response (cCR) after neoadjuvant chemoradiotherapy.

METHODS

This study followed the PRISMA guidelines. Major databases were searched to identify relevant articles. WW and RS were compared through meta-analyses of pooled proportions. Primary outcomes included overall survival (OS), disease-free survival (DFS), local recurrence, and distant metastasis rates. Pooled salvage surgery rates and outcomes were also collected. The Newcastle-Ottawa scale was employed to assess the risk of bias.

RESULTS

Eleven studies including 1,112 rectal cancer patients showing cCR after neoadjuvant chemoradiation were included. Of these patients, 378 were treated nonoperatively with WW, 663 underwent RS, and 71 underwent local excision. The 2-year OS (risk ratio [RR], 0.95; P = 0.94), 5-year OS (RR, 2.59; P = 0.25), and distant metastasis rates (RR, 1.05; P = 0.80) showed no significant differences between WW and RS. Local recurrence was more frequent in the WW group (RR, 6.93; P < 0.001), and 78.4% of patients later underwent salvage surgery (R0 resection rate, 97.5%). The 2-year DFS (RR, 1.58; P = 0.05) and 5-year DFS (RR, 2.07; P = 0.02) were higher among RS cases. However, after adjustment for R0 salvage surgery, DFS showed no significant between-group difference (RR, 0.82; P = 0.41).

CONCLUSION

Local recurrence rates are higher for WW than RS, but complete salvage surgery is often possible with similar long-term outcomes. WW is a viable strategy for rectal cancer with cCR after neoadjuvant chemoradiation, but further research is required to improve patient selection.

The ultimate local failure rate after the watch-and-wait strategy for rectal cancer: a systematic review of literature and meta-analysis

BACKGROUND

We hypothesise that a high rate of tumour regrowth after the watch-and-wait (w&w) strategy may lead, despite salvage surgery, to a significant impairment of ultimate local control compared with immediate surgery.

MATERIALS AND METHODS

To test this hypothesis, we conducted meta-analyses of studies on the w&w strategy (both opportunistic and planned) with an ultimate local failure rate as an endpoint in three patient groups: (1) in all starting radio(chemo)therapy as potential w&w candidates, (2) in a subgroup starting w&w, and (3) in a subgroup with regrowth.

RESULTS

We identified eight studies for evaluation of local failure in group 1 (N = 837) and 36 studies in group 2 (N = 1914) and in group 3 (N = 439). The meta-analysis revealed an ultimate local failure rate of 8.0% (95% CI 4.8%-12.1%) in group 1 and 5.4% (95% CI 3.9%-7.1) in group 2. These rates are similar to those reported in the literature following preoperative chemoradiation and surgery. However, in the most unfavourable group 3 (with regrowth), the rate of ultimate local failure was 24.1% (95% CI 17.9%-30.9%), with the most common causes being patients' refusal of salvage total mesorectal excision (TME) (9.1%), recurrence after salvage TME (7.8%), distant metastases (4.1%), frailty (2.4%), and pelvic tumour unresectability (1.7%).

CONCLUSION

Nearly 25% of patients with regrowth (unfavourable subgroup) experienced ultimate local failure, primarily due to refusing salvage TME. The risk of ultimate local failure in patients initiating radio(chemo)therapy as potential w&w candidates, or in patients starting w&w, appears comparable to that reported after preoperative chemoradiation and surgery. However, this comparison may be biased, because w&w studies included more early tumours compared with surgical studies.

Predictors of Nodal Disease in Rectal Cancer Patients with Complete Mucosal Response to Neoadjuvant Therapy

BACKGROUND

Some patients with locally advanced rectal cancer (LARC) achieve complete mucosal response following neoadjuvant therapy (NAT) and may be candidates for watch and wait strategy. This study aimed to identify predictors of nodal disease in patients with LARC who had a complete mucosal response to NAT.

METHODS

This case-control study included patients with LARC who were treated with NAT in the National Cancer Database between 2004 and 2019. Patients with complete mucosal response, defined as pathologic T0, were identified and classified according to the status of the pathologic N stage into complete response (pT0, pN0) and complete mucosal response with positive nodal disease (pT0, pN +). The two groups were compared regarding baseline demographics and tumor characteristics to determine the predictors of nodal disease after NAT.

RESULTS

A total of 5529 patients (59.7% male) with a mean age of 59.6 ± 12.2 years had a complete mucosal response following NAT. Nodal disease was detected in 443 (8%) patients with a complete mucosal response. Independent predictors of nodal disease were clinical N + stage (OR: 1.87, p < 0.001), mucinous histology (OR: 3.8, p = 0.003), and lymphovascular invasion (OR = 4.01, p < 0.001). The clinical T stage was inversely related to the risk of nodal disease.

CONCLUSIONS

Despite having a complete mucosal response following NAT, 8% of patients had nodal disease. Clinical evidence of nodal involvement on preoperative assessment, mucinous tumor histology, and lymphovascular invasion predicted nodal disease after NAT. These findings should be considered when making a decision on watch and wait strategy in patients with clinical complete response.

Limits of Clinical Restaging in Detecting Responders After Neoadjuvant Therapies for Rectal Cancer

BACKGROUND

Accurate clinical restaging is required to select patients who respond to neoadjuvant chemoradiotherapy for locally advanced rectal cancer and who may benefit from an organ preservation strategy.

OBJECTIVE

The purpose of this study was to review our experience with the clinical restaging of rectal cancer after neoadjuvant therapy to assess its accuracy in detecting major and pathological complete response to treatment.

DESIGN

This was a retrospective cohort study.

SETTING

This study was conducted at 2 high-volume Italian centers for Colorectal Surgery.

PATIENTS

Data were included from all consecutive patients who underwent neoadjuvant therapy and surgery for locally advanced rectal cancer from January 2012 to July 2020. Criteria to define clinical response were no palpable mass, a superficial ulcer <2 cm (major response), or no mucosal abnormality (complete response) at endoscopy and no metastatic nodes at MRI.

MAIN OUTCOME MEASURES

The main outcome measures were sensitivity, specificity, positive predictive values, and negative predictive values of clinical restaging in detecting pathological complete response (ypT0) or major pathological response (ypT0-1) after neoadjuvant therapy.

RESULTS

A total of 333 patients were included; 81 (24.3%) had a complete response whereas 115 (34.5%) had a pathological major response. Accuracy for clinical complete response was 80.8% and for major clinical response was 72.9%. Sensitivity was low for both clinical complete response (37.5%) in detecting ypT0 and clinical major response (59.3%) in detecting ypT0-1. Positive predictive value was 68.2% for ypT0 and 60.4% for ypT0-1.

LIMITATIONS

The main limitation of the study its retrospective nature.

CONCLUSION

Accuracy of actual clinical criteria to define pathological complete response or pathological major response is poor. Failure to achieve good sensitivity and precision is a major limiting factor in the clinical setting. Current clinical assessments need to be revised to account for indications for rectal preservation after neoadjuvant chemoradiotherapy. See Video Abstract at http://links.lww.com/DCR/C63 .

LMITES DE LA REESTADIFICACIN CLNICA EN LA DETECCIN DE RESPONDEDORES DESPUS DE TERAPIAS NEOADYUVANTES PARA EL CNCER DE RECTO

ANTECEDENTES:Se requiere una nueva reestadificación clínica precisa para seleccionar pacientes que respondan a la quimiorradioterapia neoadyuvante para el cáncer de recto localmente avanzado y que puedan beneficiarse de una estrategia de preservación de órganos.OBJETIVO:El propósito de este estudio fue revisar nuestra experiencia con la reestadificación clínica del cáncer de recto después de la terapia neoadyuvante para evaluar su precisión en la detección de una respuesta patológica importante y completa al tratamiento.DISEÑO:Estudio de cohorte retrospectivo.AJUSTE:Este estudio se realizó en dos centros italianos de alto volumen para cirugía colorrectal.PACIENTES:Incluimos datos de todos los pacientes consecutivos que se sometieron a terapia neoadyuvante y cirugía por cáncer de recto localmente avanzado desde enero de 2012 hasta julio de 2020. Los criterios para definir la respuesta clínica fueron ausencia de masa palpable, úlcera superficial <2 cm (respuesta mayor) o ausencia de anomalías en la mucosa. (respuesta completa) en la endoscopia, y sin ganglios metastásicos en la resonancia magnética.PRINCIPALES MEDIDAS DE RESULTADO:Exploramos la sensibilidad, la especificidad, los valores predictivos positivos y negativos de la reestadificación clínica para detectar una respuesta patológica completa (ypT0) o mayor (ypT0-1) después de la terapia neoadyuvante.RESULTADOS:Se incluyeron 333 pacientes; 81 (24,3%) tuvieron una respuesta completa mientras que 115 (34,5%) tuvieron una respuesta patológica mayor. La precisión de la respuesta clínica completa y la respuesta clínica importante fue del 80,8 % y el 72,9 %, respectivamente. La sensibilidad fue baja tanto para la respuesta clínica completa (37,5 %) en la detección de ypT0 como para la respuesta clínica mayor (59,3 %) en la detección de ypT0-1. El valor predictivo positivo fue del 68,2 % para ypT0 y del 60,4 % para ypT0-1.LIMITACIONES:Nuestro estudio tiene como principal limitación su carácter retrospectivo.CONCLUSIÓNES:La precisión de los criterios clínicos reales para definir una respuesta patológica completa o mayor es pobre. El hecho de no lograr una buena sensibilidad y precisión es un factor limitante importante en el entorno clínico. La indicación para la preservación rectal después de la quimiorradioterapia neoadyuvante necesita una mejora de la evaluación clínica actual. Consulte Video Resumen en http://links.lww.com/DCR/C63 . (Traducción-Dr. Mauricio Santamaria ).

Radiomic features derived from pretherapeutic MRI predict chemoradiation response in locally advanced rectal cancer

BACKGROUND

The standard treatment for locally advanced rectal cancer (LARC) is neoadjuvant concurrent chemoradiotherapy (CRT) followed by surgical excision. Current evidence suggests a favorable prognosis for those with pathological complete response (pCR), and surgery may be spared for them. We trained and validated regression models for CRT response prediction with selected radiomic features extracted from pretreatment magnetic resonance (MR) images to recruit potential candidates for this watch-and-wait strategy.

METHODS

We retrospectively enrolled patients with LARC who underwent pre-CRT MR imaging between 2010 and 2019. Pathological complete response in surgical specimens after CRT was defined as the ground truth. Quantitative features derived from both unfiltered and filtered images were extracted from manually segmented region of interests on T2-weighted images and selected using variance threshold, univariate statistical tests, and cross-validation least absolute shrinkage and selection operator (Lasso) regression. Finally, a regression model using selected features with high coefficients was optimized and evaluated. Model performance was measured by classification accuracies and area under the receiver operating characteristic (AUROC).

RESULTS

We extracted 1223 radiomic features from each MRI study of 133 enrolled patients. After tumor excision, 34 (26 %) of 133 patients had pCR in resected specimens. When 25 image-derived features were selected from univariate analysis, classification AUROC was 0.86 and 0.79 with the addition of six clinical features on the hold-out internal validation dataset. When 11 image-derived features were used, the optimized linear regression model had an AUROC value of 0.79 and 0.65 with the addition of six clinical features on the hold-out dataset. Among the radiomic features, texture features including gray level variance, strength, and cluster prominence had the highest coefficient by Lasso regression.

CONCLUSION

Radiomic features derived from pretreatment MR images demonstrated promising efficacy in predicting pCR after CRT. However, radiomic features combined with clinical features did not result in remarkable improvement in model performance.

Usefulness of close surveillance for rectal cancer patients after neoadjuvant chemoradiotherapy

It is controversial whether patients who achieve clinical complete remission (cCR) of rectal cancer should be treated with the “watch and wait” (W&W) or radical resection (RR) strategy. Our study aimed to compare the survival outcomes and ostomy rate of the W&W and RR strategies. Between January 2008 and December 2015, we investigated 26 patients who achieved pathologic complete remission after undergoing RR and 36 patients who adopted the W&W strategy because of cCR. The tumor regrowth, salvage surgery, recurrence, disease-free, and overall survival (OS) rates were assessed. In our study, recurrences occurred in nine and two patients from the W&W and RR groups, respectively. Each patient in the RR group had a temporary or permanent ostomy, but only three (8.3%) had an ostomy in the W&W group. The 5-year recurrence rate was 25.0% in the W&W group and 7.7% in the RR group. Six patients (16.7%) had tumor regrowth in the W&W group, and all were resectable when regrowth. The 5-year OS rates between the two groups were nonsignificant. There is no specific risk factor for recurrence and OS. Under close surveillance, the W&W group achieved similar OS to the RR group and benefited from a lower ostomy rate.

A Pilot, Prospective, Observational Study to Investigate the Value of NGS in Liquid Biopsies to Predict Tumor Response After Neoadjuvant Chemo-Radiotherapy in Patients With Locally Advanced Rectal Cancer: The LiBReCa Study

Introduction

Circulating tumor DNA (ctDNA) correlates with the response to therapy in different types of cancer. However, in patients with locally advanced rectal cancer (LARC), little is known about how ctDNA levels change with neoadjuvant chemoradiation (Na-ChRT) and how they correlate with treatment response. This work aimed to explore the value of serial liquid biopsies in monitoring response after Na-ChRT with the hypothesis that this could become a reliable biomarker to identify patients with a complete response, candidates for non-operative management.

Materials and Methods

Twenty-five consecutive LARC patients undergoing long-term Na-ChRT therapy were included. Applying next-generation sequencing (NGS), we characterized DNA extracted from formalin-fixed paraffin embedded diagnostic biopsy and resection tissue and plasma ctDNA collected at the following time points: the first and last days of radiotherapy (T0, Tend), at 4 (T4), 7 (T7) weeks after radiotherapy, on the day of surgery (Top), and 3–7 days after surgery (Tpost-op). On the day of surgery, a mesenteric vein sample was also collected (TIMV). The relationship between the ctDNA at those time-points and the tumor regression grade (TRG) of the surgical specimen was statistically explored.

Results

We found no association between the disappearance of ctDNA mutations in plasma samples and pathological complete response (TRG1) as ctDNA was undetectable in the majority of patients from Tend on. However, we observed that the poor (TRG 4) response to Na-ChRT was significantly associated with a positive liquid biopsy at the Top.

Conclusions

ctDNA evaluation by NGS technology may identify LARC patients with poor response to Na-ChRT. In contrast, this technique does not seem useful for identifying patients prone to developing a complete response.

A longitudinal cohort study of watch and wait in complete clinical responders after chemo-radiotherapy for localised rectal cancer: study protocol

Background

Rectal Cancer is a common malignancy. The current treatment approach for patients with locally advanced rectal cancer involves neoadjuvant chemoradiotherapy followed by surgical resection of the rectum. The resection can lead to complications and long-term consequences.

A clinical complete response is observed in some patients after chemoradiotherapy. A number of recent studies have shown that patients can be observed safely after completing chemoradiotherapy (without surgery), provided clinical complete response has been achieved. In this approach, resection is reserved for cases of regrowth. This is called the watch and wait approach. This approach potentially avoids unnecessary surgical resection of the rectum and the resulting complications. In this study, we will prospectively investigate this approach.

Methods

Adult patients with a diagnosis of rectal cancer planned to receive neoadjuvant long course chemoradiotherapy (± subsequent combination chemotherapy) will be consented into the study prior to commencing treatment. After completing the chemoradiotherapy (± subsequent combination chemotherapy), based on the clinical response, subjects will be allocated to one of the following arms: subjects who achieved a clinical complete response will be allocated to the watch and wait arm and others to the standard management arm (which includes resection). The aim of the study is to determine the rate of local failure and other safety and efficacy outcomes in the watch and wait arm. Patient reported outcome measures and the use of biomarkers as part of the clinical monitoring will be studied in both arms of the study.

Discussion

This study will prospectively investigate the safety of the watch and wait approach. We will investigate predictive biomarkers (molecular biomarkers and imaging biomarkers) and patient reported outcome measures in the study population and the cost effectiveness of the watch and wait approach. This study will also help evaluate a defined monitoring schedule for patients managed with the watch and wait approach. This protocol covers the first two years of follow up, we are planning a subsequent study which covers year 3–5 follow up for the study population.

Trial registration.

Name of the registry: Australia and New Zealand Clinical Trials Registry (ANZCTR). Trial registration number: Trial ID: ACTRN12619000207112 Registered 13 February 2019,https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=376810

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09304-x.

Efficacy and safety of the "watch-and-wait" approach for rectal cancer with clinical complete response after neoadjuvant chemoradiotherapy: a meta-analysis

BACKGROUND

Watch-and-Wait (WW) approach is positioned at the cutting edge of non-invasive approach for rectal cancer patients who achieve clinical complete response (cCR) after neoadjuvant chemoradiotherapy (nCRT). This meta-analysis aimed to compare the clinical, oncologic, and survival outcomes of WW versus radical surgery (RS) and to evaluate the efficacy, safety, and possible superiority of WW.

METHODS

A systematic search for studies comparing WW with RS was conducted on MEDLINE, Ovid, Embase, Cochrane Library, and Web of Science databases. After screening for inclusion, data extraction, and quality assessment, statistical analysis was performed using Stata/SE14.0 software. Permanent colostomy (PC), local recurrence (LR), distant metastasis (DM), cancer-related death (CRD), 2-, 3-, and 5-year disease-free survival (DFS), and overall survival (OS) were analyzed using fixed effects or random-effects models depending on the heterogeneity.

RESULTS

Fourteen studies with moderate-high quality involving 1254 patients were included. Of these, 513 patients were managed with WW and 741 patients were subjected to RS. Compared to RS group, WW group had higher rate of LR (odds ratio OR = 11.09, 95% confidence interval CI = 5.30-23.20, P = 0.000), 2-year OS, and 3-year OS and had lower rate of PC (OR = 0.12, 95% CI = 0.05-0.29, P = 0.000). There were no significant between-group differences with respect to DM, CRD, 2-, 3-, and 5-year DFS (OR = 0.92, 95% CI = 0.81-1.03, P = 0.153), or 5-year OS (OR = 1.01, 95% CI = 0.28-3.63, P = 0.988).

CONCLUSION

The WW is a promising treatment approach and is a relatively safe alternative to RS for managing patients with rectal cancer who achieve cCR after nCRT. However, this modality requires rigorous screening criteria and standardized follow-up. Large-scale, multicenter prospective randomized controlled trials are warranted to further verify the outcomes of WW approach.

Short- and long-term outcomes of local excision with adjuvant radiotherapy in high-risk T1 rectal cancer patients

Purpose

Methods

Results

Conclusion

A meta-analysis of the watch-and-wait strategy versus total mesorectal excision for rectal cancer exhibiting complete clinical response after neoadjuvant chemoradiotherapy

Background

Some clinical researchers have reported that patients with cCR (clinical complete response) status after neoadjuvant chemoradiotherapy (nCRT) could adopt the watch-and-wait (W&W) strategy. Compared with total mesorectal excision (TME) surgery, the W&W strategy could achieve a similar overall survival. Could the W&W strategy replace TME surgery as the main treatment option for the cCR patients? By using the meta-analysis method, we evaluated the safety and efficacy of the W&W strategy and TME surgery for rectal cancer exhibiting cCR after nCRT.

Methods

We evaluated two treatment strategies for rectal cancer with cCR after nCRT up to July 2021 by searching the Cochrane Library, PubMed, Wanfang, and China National Knowledge Infrastructure (CNKI) databases. Clinical data for primary outcomes (local recurrence, cancer-related death and distant metastasis), and secondary outcomes (disease-free survival (DFS) and overall survival (OS)) were collected to evaluate the efficacy and safety in the two groups.

Results

We included nine studies with 818 patients in the meta-analysis, and there were five moderate-quality studies and four high-quality studies. A total of 339 patients were in the W&W group and 479 patients were in the TME group. The local recurrence rate in the W&W group was greater than that in the TME group in the fixed-effects model (OR 8.54, 95% CI 3.52 to 20.71, P < 0.001). The results of other outcomes were similar in the two groups.

Conclusion

The local recurrence rate of the W&W group was greater than that in the TME group, but other results were similar in the two groups. With the help of physical examination and salvage therapy, the W&W strategy could achieve similar treatment effects with the TME approach.

Trial registration

Protocol registration number: CRD42021244032.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02415-y.

The efficacy and safety of different radiotherapy doses in neoadjuvant chemoradiotherapy for locally advanced rectal cancer

Background

This study aimed to evaluate efficacy and adverse effects of different radiotherapy (RT) doses in neoadjuvant chemoradiotherapy for locally advanced rectal cancer.

Methods

Fifty-nine patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy in hospital between January 2015 and May 2017 were enrolled in retrospective analysis. The patients were divided into the 56-Gy group and the 50-Gy group. The concurrent chemotherapy regimen was based on capecitabine. All patients received one cycle of oxaliplatin combined with capecitabine induction chemotherapy. All patients completed neoadjuvant chemoradiotherapy and received radical surgery.

Results

Of the patients in this study, 29 patients and 30 patients received a radiation dose of 56- and 50-Gy, respectively. All clinical characteristics were matched between the two groups. All patients received surgery 6 to 8 weeks after completing RT. The therapeutical effective rate in the 56-Gy group was 93.10% (27/29), compared with 66.67% in the 50-Gy group (20/30); the difference between the two groups was statistically significant (χ²=6.36, P=0.01). The pathological complete remission (pCR) rate in the 56-Gy group (37.93%, 11/29) was statistically significantly higher than that in the 50-Gy group (13.33%, 4/30) (χ²=4.71, P=0.030). The anal preservation rate in the 56-Gy group (65.5%, 19/29) was statistically significantly higher than that in the 50-Gy group (33.33%, 10/30) (χ²=6.11, P=0.01). The 56-Gy group had a local recurrence rate of 0% (0/29) and a distant metastasis rate of 10.34% (3/29), while the 50-Gy group had a local recurrence rate of 6.67% (2/30) and a distant metastasis rate of 16.67% (5/30); no significant difference existed between the two groups (χ²=2.00, 0.50, P=0.16, 0.48). The incidence of adverse reactions (gastrointestinal reactions, bone marrow suppression, and perianal skin reactions) in the 56-Gy group was not significantly different from that in the 50-Gy group (P>0.05).

Conclusions

Increasing the radiation dose can significantly improve the anal preservation and pCR rates of patients with locally advanced rectal cancer, thus improving their life quality. Moreover, it does not increase the rates of recurrence or adverse reactions. Our findings have certain clinical significance, but further prospective study is needed.

Could the conservative approach be considered safe in the treatment of locally advanced rectal cancer in case of a clinical near-complete or complete response? A retrospective analysis

BACKGROUND

Conservative approach has emerged as an option for the management of rectal cancer (RC) patients with a near or complete clinical response after neoadjuvant chemoradiotherapy (nCRT). The aim of this study is to assess the impact of the conservative approach by comparing patients' survival outcomes and quality of life with those who had surgical resection.

METHODS

A single-institution and retrospective study including RC patients who reached a near complete or complete clinical response after nCRT from January 2010 to September 2019. Conservative approaches included local excision or watch and wait strategy; surgery approaches included anterior resection or abdominal-perineal resection.Local regrowth (LR), overall survival, disease free survival, metastasis free survival and colostomy free survival were evaluated through Kaplan-Meier curves and compared trough log-rank tests. Quality of life was measured by the following validated questionnaires: EORTC QLC30, EORTC QLQ - CR29 and Fecal Incontinence Quality of Life scale.

RESULTS

Overall 157 patients were analyzed: 105 (66,9%) underwent radical surgery and 52 (33,1%) had a conservative approach. With a median follow-up of 51 months, 2 patients in the surgical group had a local recurrence and 8 in the conservative group had a LR, respectively. Distance metastasis occurred in 7 and 1 patients of surgical and conservative group, respectively. No differences were detected in terms of survival outcomes except for colostomy free survival (p: 0,01). The conservative group showed better intestinal (p < 0.01) and sexual (p: 0,04) function and emotional status (p: 0,02).

CONCLUSIONS

Conservative approach seems to be safe in terms of survival outcomes with a significant advantage on quality of life in RC patients who achieved clinical complete response after nCRT.

Functional outcome and quality of life following treatment for rectal cancer

Introduction Over the last decades, treatment for rectal cancer has substantially improved with development of new surgical options and treatment modalities. With the improvement of survival, functional outcome and quality of life are getting more attention.

Study objective To provide an overview of current modalities in rectal cancer treatment, with particular emphasis on functional outcomes and quality of life.

Results Functional outcomes after rectal cancer treatment are influenced by patient and tumor characteristics, surgical technique, the use of preoperative radiotherapy and the method and level of anastomosis. Sphincter preserving surgery for low rectal cancer often results in poor functional outcomes that impair quality of life, referred to as low anterior resection syndrome. Abdominoperineal resection imposes the need for a permanent stoma but avoids the risk of this syndrome. Contrary to general belief, long-term quality of life in patients with a permanent stoma is similar to those after sphincter preserving surgery for low rectal cancer.

Conclusion All patients should be informed about the risks of treatment modalities. Decision on rectal cancer treatment should be individualized since not all patients may benefit from a sphincter preserving surgery “at any price”. Non-resection treatment should be the future focus to avoid the need of a permanent stoma and bowel dysfunction.

MRI Assessment of Complete Response to Preoperative Chemoradiation Therapy for Rectal Cancer: 2020 Guide for Practice from the Korean Society of Abdominal Radiology

Objective

To provide an evidence-based guide for the MRI interpretation of complete tumor response after neoadjuvant chemoradiation therapy (CRT) for rectal cancer using visual assessment on T2-weighted imaging (T2) and diffusion-weighted imaging (DWI).

Materials and Methods

PubMed MEDLINE, EMBASE, and Cochrane Library were searched on November 28, 2019 to identify articles on the following issues: 1) sensitivity and specificity of T2 or DWI for diagnosing pathologic complete response (pCR) and the criteria for MRI diagnosis; 2) MRI alone vs. MRI combined with other test(s) in sensitivity and specificity for pCR; and 3) tests to select patients for the watch-and-wait management. Eligible articles were selected according to meticulous criteria and were synthesized.

Results

Of 1615 article candidates, 55 eligible articles (for all three issues combined) were identified. Combined T2 and DWI performed better than T2 alone, with a meta-analytic summary sensitivity of 0.62 (95% confidence interval [CI], 0.43–0.77; I² = 80.60) and summary specificity of 0.89 (95% CI, 0.80–0.94; I² = 92.61) for diagnosing pCR. The criteria for the complete response on T2 in most studies had the commonality of remarkable tumor decrease to the absence of mass-like or nodular intermediate signal, although somewhat varied, as follows: (near) normalization of the wall; regular, thin, hypointense scar in the luminal side with (near) normal-appearance or homogeneous intermediate signal in the underlying wall; and hypointense thickening of the wall. The criteria on DWI were the absence of a hyperintense signal at high b-value (≥ 800 sec/mm²) in most studies. The specific algorithm to combine T2 and DWI was obscure in half of the studies. MRI combined with endoscopy was the most utilized means to select patients for the watch-and-wait management despite a lack of strong evidence to guide and support a multi-test approach.

Conclusion

This systematic review and meta-analysis provide an evidence-based practical guide for MRI assessment of complete tumor response after CRT for rectal cancer.

Non-Operative Management Versus Total Mesorectal Excision for Locally Advanced Rectal Cancer with Clinical Complete Response After Neoadjuvant Chemoradiotherapy: a GRADE Approach by the Rectal Cancer Guidelines Writing Group of the Italian Association of Medical Oncology (AIOM)

BACKGROUND

The standard approach for locally advanced rectal cancer (LARC) is neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision (TME). After nCRT 20% of patients achieve a clinical complete response (pCR) and could be treated with a non-operative management (NOM).

METHODS

The panel of the Italian Association of Medical Oncology (AIOM) Guidelines on rectal cancer applied the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach addressing the following question: Should NOM vs. TME be used for patients with rectal cancer with clinical complete response after nCRT? Five outcomes were identified: disease-free survival (DFS), mortality, local recurrence, colostomy rate, and functional outcomes.

RESULTS

Nine studies were included in the analysis. A higher risk of disease recurrence was observed in the NOM group compared to the TME group (RR = 1.69, 95% CI 1.08, 2.64) on the other hand, we observed a slightly positive but not significant effect on mortality of NOM (RR = 0.82, 95% CI 0.46, 1.45). Patients in the NOM group were more likely to experience local recurrence (RR = 5.37, 95% CI 2.56, 11.27) and patients in the TME group were more likely to have a permanent colostomy (RR = 0.15, 95% CI 0.08, 0.29). Only one study evaluated functional outcomes. The overall certainty of evidence was rated as very low.

CONCLUSIONS

NOM was found to correlate with a higher risk of local recurrence which did not translate in worse OS and a lower colostomy rate. Due to the paucity of evidences, no recommendations are possible. NOM remains an experimental treatment; thus, patients managed with NOM should be enrolled in clinical trials with a dedicated follow-up schedule.

Efficacy and safety of wait and see strategy versus radical surgery and local excision for rectal cancer with cCR response after neoadjuvant chemoradiotherapy: a meta-analysis

Background

Neoadjuvant therapy can shrink tumors, increase anus preservation rate, and protect anal function. Radical surgery need cut off the diseased bowel, clean up the lymph nodes, and then restore bowel function. It could bring traumatic effect and poor postoperative quality of life to the patient. Local resection requires removal of the diseased bowel with circular negative margin. The surgical trauma is small, and the postoperative quality of life is good. In this meta-analysis, we aimed to evaluate the efficacy and safety between wait and see strategy (WS), radical surgery (RS), and local excision (LE) of rectal cancer patients with clinical complete response (cCR) response after neoadjuvant chemoradiotherapy.

Methods

We searched PubMed, Cochrane Library, CNKI (China National Knowledge Infrastructure), and Wanfang databases to compare wait and see strategy with radical surgery and local excision for rectal cancer with cCR response after neoadjuvant chemoradiotherapy up to March 2020. We collected the data of local recurrence, distant metastasis, cancer-related death, overall survival, and disease-free survival and used RevMan 5.0 to carry out the meta-analysis. Continuous data were evaluated by the standardized mean differences (SMD) with 95% confidence intervals (95% CIs), and dichotomous data were evaluated by relative risks (ORs or RRs) with 95% CIs. We aimed to compare the advantages and disadvantages of the three groups.

Results

Eleven English studies with 1131 patients were included. There were 412 patients in WS group, 678 patients in RS group, and 41 patients in LE group. WS group had a higher local recurrence rate than RS group (OR 7.32, 95% CI 3.58 to 14.95, P < 0.001). There was no significant difference in the other data between the three groups.

Conclusion

Compared with the RS group, the WS group had an increased risk of local recurrence. However, the WS group had a similar DFS and OS compared with the RS group and the local excision group. Hence, we speculated that the WS group would have similar results as the surgery group for patients with cCR status.

Watch and wait approach in rectal cancer: Current controversies and future directions

According to the main international clinical guidelines, the recommended treatment for locally-advanced rectal cancer is neoadjuvant chemoradiotherapy followed by surgery. However, doubts have been raised about the appropriate definition of clinical complete response (cCR) after neoadjuvant therapy and the role of surgery in patients who achieve a cCR. Surgical resection is associated with significant morbidity and decreased quality of life (QoL), which is especially relevant given the favourable prognosis in this patient subset. Accordingly, there has been a growing interest in alternative approaches with less morbidity, including the organ-preserving watch and wait strategy, in which surgery is omitted in patients who have achieved a cCR. These patients are managed with a specific follow-up protocol to ensure adequate cancer control, including the early identification of recurrent disease. However, there are several open questions about this strategy, including patient selection, the clinical and radiological criteria to accurately determine cCR, the duration of neoadjuvant treatment, the role of dose intensification (chemotherapy and/or radiotherapy), optimal follow-up protocols, and the future perspectives of this approach. In the present review, we summarize the available evidence on the watch and wait strategy in this clinical scenario, including ongoing clinical trials, QoL in these patients, and the controversies surrounding this treatment approach.

Nonsurgical Management of Rectal Cancer

Neoadjuvant chemoradiotherapy followed by surgical resection is the standard of care for locally advanced rectal adenocarcinoma. Up to one third of patients achieve pathologic complete response (CR) with neoadjuvant therapy. Promising disease-free and overall survival outcomes have been reported in patients who achieve clinical CR after neoadjuvant therapy without surgical resection. Furthermore, patients who have local recurrence have acceptable disease control outcomes with salvage resection. With consideration of morbidities associated with surgical resection and similar clinical outcomes, interest in nonsurgical management of low rectal cancers has emerged. Randomized clinical trials are being conducted to evaluate a nonsurgical approach in rectal cancer. Lack of consensus on the definition of clinical CR, molecular biomarkers, and standardized nonsurgical management protocols is a significant barrier for routine clinical implementation of a nonsurgical management approach. This article aims to provide a concise review of the clinical experience and practical approach to the nonsurgical management of locoregional rectal adenocarcinoma.

Low rectal cancer treatment strategies: a cohort study assessing watch and wait

PURPOSE

Treatment strategies for low rectal cancer have been evolving toward achieving less treatment morbidity with the same oncological success-we aimed to assess the results of the new watch and wait (W&W) strategy in our cohort.

METHODS

A tertiary care cohort study was conducted. New patients with rectal adenocarcinoma up to 6 cm from the anal margin, cM0, locally staged higher than cT1N0, evaluated between November 2014 and October 2018, were included. All 93 patients received neoadjuvant radiotherapy ± chemotherapy. Re-evaluation was planned 8-12 weeks after the end of treatment. Patients showing clinical complete response (cCR) were given the choice of either to proceed to surgery or to enter W&W.

RESULTS

Of the 93 patients, 82.8% were re-evaluated and 20.8% had cCR. Patients in clinical stages II/III were significantly less likely to achieve cCR than those in stage I (p = 0.017). After a mean follow-up of 17.44 months, there were 4 regrowths in the 16 patients under W&W, all submitted to R0 surgery, ypN0; there were no deaths or local recurrences; one patient with regrowth had distant recurrence. Sixty patients underwent direct surgery after a mean follow-up of 16.23 months; 3 patients had local and distant recurrences; 7 others had only distant recurrences; there were 8 deaths. There were no statistically significant differences between patients under W&W and patients who underwent direct surgery regarding local or distant recurrences, or death (p > 0.9; p =  0.44; p =  0.19, respectively).

CONCLUSION

The W&W strategy for low rectal cancer achieved the same oncological outcomes as the traditional strategy while sparing some patients from surgery.

[Preoperative intensity-modulated radiotherapy of rectal cancers: Relevance and modalities]

Preoperative radiotherapy boosted by chemotherapy is a recommended treatment in locally advanced rectal cancers. This treatment is delivered by three dimensional conformal irradiation, which is usually well tolerated but can induce potential toxicity such as rectitis, cystitis and hematologic adverse effects. Intensity-modulated radiotherapy, widely available nowadays, allows optimization of volume covering and sparing of organs at risk such as bladder and bone marrow. This review presents relevant clinical situations and requirements for a beneficial and safe preoperative irradiation of rectal cancers by intensity-modulated technique. This technique is compared to three-dimensional conformal radiotherapy.

RHBDD2 overexpression promotes a chemoresistant and invasive phenotype to rectal cancer tumors via modulating UPR and focal adhesion genes

The current standard of care for locally advanced rectal cancer (RC) is neoadjuvant radio-chemotherapy (NRC) with 5-fluorouracil (5Fu) as the main drug, followed by surgery and adjuvant chemotherapy. While a group of patients will achieve a pathological complete response, a significant percentage will not respond to the treatment. The Unfolding Protein Response (UPR) pathway is generally activated in tumors and results in resistance to radio-chemotherapy. We previously showed that RHBDD2 gene is overexpressed in the advanced stages of colorectal cancer (CRC) and that it could modulate the UPR pathway. Moreover, RHBDD2 expression is induced by 5Fu. In this study, we demonstrate that the overexpression of RHBDD2 in CACO2 cell line confers resistance to 5Fu, favors cell migration, adhesion and proliferation and has a profound impact on the expression of both, the UPR genes BiP, PERK and CHOP, and on the cell adhesion genes FAK and PXN. We also determined that RHBDD2 binds to BiP protein, the master UPR regulator. Finally, we confirmed that a high expression of RHBDD2 in RC tumors after NRC treatment is associated with the development of local or distant metastases. The collected evidence positions RHBDD2 as a promising prognostic biomarker to predict the response to neoadjuvant therapy in patients with RC.

Controversies in Rectal Cancer Treatment and Management

Incorporation of new treatment modalities has significantly increased the complexity of the treatment and management of rectal cancer, including perioperative therapy for local advanced disease and organ preservation for those with response to the preoperative treatment. This review may help practitioners better understand the rationale and selection.

Predicting pathological complete response in rectal cancer after chemoradiotherapy with a random forest using 18F-fluorodeoxyglucose positron emission tomography and computed tomography radiomics

Background

Neoadjuvant chemoradiotherapy (NCRT) followed by surgery is the standard treatment for patients with locally advanced rectal cancer. This study developed a random forest (RF) model to predict pathological complete response (pCR) based on radiomics derived from baseline ¹⁸F-fluorodeoxyglucose ([¹⁸F]FDG)-positron emission tomography (PET)/computed tomography (CT).

Methods

This study included 169 patients with newly diagnosed rectal cancer. All patients received ¹⁸F[FDG]-PET/CT, NCRT, and surgery. In total, 68 radiomic features were extracted from the metabolic tumor volume. The numbers of splits in a decision tree and trees in an RF were determined based on their effects on predictive performance. Receiver operating characteristic curve analysis was performed to evaluate predictive performance and ascertain the optimal threshold for maximizing prediction accuracy.

Results

After NCRT, 22 patients (13%) achieved pCR, and 42 features that could differentiate tumors with pCR were used to construct the RF model. Six decision trees and seven splits were suitable. Accordingly, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 81.8%, 97.3%, 81.8%, 97.3%, and 95.3%, respectively.

Conclusions

By using an RF, we determined that radiomics derived from baseline ¹⁸F[FDG]-PET/CT could accurately predict pCR in patients with rectal cancer. Highly accurate and predictive values can be achieved but should be externally validated.

Organ-saving surgery for rectal cancer after neoadjuvant chemoradiation: Analysis of failures and long-term results

BACKGROUND

To analyze long-term results and risk of relapse in the clinical TNM stages II and III, mid-low rectal cancer patients (RC pts), treated with transanal local excision (LE) after major response to neoadjuvant chemoradiation (n-CRT).

METHODS

Thirty-two out of 345 extraperitoneal cT3-4 or N+ RC pts (9.3%) underwent LE.

INCLUSION CRITERIA

extraperitoneal RC, adenocarcinoma, ECOG Performance Status ≤2. Pts with distant metastases were excluded.

RESULTS

All pts showed histologically clear margins of resection and 81.2% were restaged ypT0/mic/1. Nine out of 32 (28.1%) pts relapsed: 7 (21.8%) showed a local recurrence, of which 5 (15.6%) at the endorectal suture, 1 (3.1%) pelvic and 1 (3.1%) mesorectal. Two pts (6.2%) relapsed distantly. Among the pT0/1, 11.5% relapsed vs 100% of the pT2 and pT4 ones. The six pts relapsing locally or in the mesorectal fat underwent a salvage total mesorectal excision surgery. The old patient with pelvic recurrence relapsed after 108 months and underwent a re-irradiation; the two pts with distant metastases were treated with chemotherapy followed by radical surgery.

CONCLUSIONS

Presently combined approach seems a valid option in major responders, confirming its potential curative impact in the ypT0/mic/1 pts. A strict selection of pts is basic to obtain favourable results.

Magnetic Resonance Guided Radiotherapy for Rectal Cancer: Expanding Opportunities for Non-Operative Management

Colorectal cancer is the third most common cancer in men and the second most common in women worldwide, and the incidence is increasing among younger patients. 30% of these malignancies arise in the rectum. Patients with rectal cancer have historically been managed with preoperative radiation, followed by radical surgery, and adjuvant chemotherapy, with permanent colostomies in up to 20% of patients. Beginning in the early 2000s, non-operative management (NOM) of rectal cancer emerged as a viable alternative to radical surgery in select patients. Efforts have been ongoing to optimize neoadjuvant therapy for rectal cancer, thereby increasing the number of patients potentially eligible to forgo radical surgery. Magnetic resonance guided radiotherapy (MRgRT) has recently emerged as a treatment modality capable of intensifying preoperative radiation therapy for rectal cancer patients. This technology may also predict which patients will achieve a complete response to preoperative therapy, thereby allowing for more appropriate selection of patients for NOM. The present work seeks to illustrate the potential role MRgRT could play in personalizing rectal cancer treatment thus expanding the role of NOM in rectal cancer.

Radiomics features on radiotherapy treatment planning CT can predict patient survival in locally advanced rectal cancer patients

This retrospective study was to investigate whether radiomics feature come from radiotherapy treatment planning CT can predict prognosis in locally advanced rectal cancer patients treated with neoadjuvant chemoradiation followed by surgery. Four-hundred-eleven locally advanced rectal cancer patients which were treated with neoadjuvant chemoradiation enrolled in this study. All patients’ radiotherapy treatment planning CTs were collected. Tumor was delineated on these CTs by physicians. An in-house radiomics software was used to calculate 271 radiomics features. The results of test-retest and contour-recontour studies were used to filter stable radiomics (Spearman correlation coefficient > 0.7). Twenty-one radiomics features were final enrolled. The performance of prediction model with the radiomics or clinical features were calculated. The clinical outcomes include local control, distant control, disease-free survival (DFS) and overall survival (OS). Model performance C-index was evaluated by C-index. Patients are divided into two groups by cluster results. The results of chi-square test revealed that the radiomics feature cluster is independent of clinical features. Patients have significant differences in OS (p = 0.032, log rank test) for these two groups. By supervised modeling, radiomics features can improve the prediction power of OS from 0.672 [0.617 0.728] with clinical features only to 0.730 [0.658 0.801]. In conclusion, the radiomics features from radiotherapy CT can potentially predict OS for locally advanced rectal cancer patients with neoadjuvant chemoradiation treatment.

Emerging trends in the treatment of rectal cancer

The conventional treatment for cT3-T4 or node-positive clinically resectable rectal cancer is long course preoperative chemoradiation followed by surgery and postoperative adjuvant chemotherapy. Disadvantages of this approach include possible overtreatment of patients, 6 weeks of daily radiation treatment, and undetected metastatic disease. There are a number of emerging trends which are changing this approach to treatment. Selected topics included in this manuscript include the selective use of pelvic radiation, the role of radiation for a positive radial margin, the interval between radiation and surgery, non-operative management, new chemoradiation regimens, short vs. long course radiation, and the role of postoperative adjuvant chemotherapy.

Systematic review and meta-analysis on outcomes of salvage therapy in patients with tumour recurrence during 'watch and wait' in rectal cancer

INTRODUCTION

The 'watch and wait' approach has recently emerged as an alternative approach for managing patients with complete clinical response in rectal cancer. However, less is understood whether the intervention is associated with a favourable outcome among patients who require salvage therapy following local recurrence.

MATERIALS AND METHODS

A comprehensive systematic search was performed using EMBASE, PubMed, MEDLINE, Journals@Ovid as well as hand searches; published between 2004 and 2018, to identify studies where outcomes of patients undergoing watch and wait were compared with conventional surgery. Study quality was assessed using the Newcastle-Ottawa assessment scale. The main outcome was relative risks for overall and disease specific mortality in salvage therapy.

RESULTS

Nine eligible studies were included in the meta-analysis. Of 248 patients who followed the watch and wait strategy, 10.5% had salvage therapy for recurrent disease. No statistical heterogeneity was found in the results. The relative risk of overall mortality in the salvage therapy group was 2.42 (95% confidence interval 0.96-6.13) compared with the group who had conventional surgery, but this was not statistically significant (P > 0.05). The relative risk of disease specific mortality in salvage therapy was 2.63 (95% confidence interval 0.81-8.53).

CONCLUSION

Our findings demonstrated that there was no significant difference in overall and disease specific mortality in patients who had salvage treatment following recurrence of disease in the watch and wait group compared with the standard treatment group. However, future research into the oncological safety of salvage treatment is needed.

Initial Experience With Staging Rectal Adenocarcinoma Using 7T Magnetic Resonance Imaging

BACKGROUND

Magnetic resonance imaging (MRI) has become the preferred method for local staging of rectal cancer. Current MRI technology, operating at 1.5-3 T, results in incorrectly reported tumor depth and therefore inaccurate staging in one-third of individuals. Inaccurate staging can result in suboptimal treatment in patients with rectal cancer and can submit them to unnecessary treatments. The Medical College of Wisconsin Center for Imaging Research houses one of approximately twenty experimental 7 T MRIs worldwide capable of imaging the human pelvis. We present our initial experience with this novel imaging technique for the human rectum.

METHODS

This was a prospective observational trial conducted at a single institution. Patients diagnosed with rectal cancer and who underwent low anterior resection or abdominoperineal resection between July 2015 and July 2017 were included. Excised rectal specimens were suspended in a saline-filled container and imaged by MRI at 7T. Tumor depth and lymph node status were determined by a single radiologist who was blinded to the pathologic results. These MRI interpretations were then compared with the pathologic stage.

RESULTS

Seven of the 10 patients received neoadjuvant chemoradiation. When using the T1-weighted volumetric interpolated breath-hold examination-flex fat-suppressed sequences, radiologic and pathologic interpretation was identical regarding tumor depth in 7 of 10 patients (70%). Nodal status was correctly interpreted by 7T MRI in 8 of 10 patients (80%). Lymph nodes as small as 2 mm were able to be correctly characterized as harboring malignancy.

CONCLUSIONS

We have demonstrated that 7T MRI of the rectum ex vivo has a strong correlation with histologic results. With its superior signal-to-noise ratio and spatial resolution, 7T MRI holds promise in more accurately staging rectal cancer and may be useful in correctly categorizing response to neoadjuvant therapy.

The impact of total neo-adjuvant treatment on nonoperative management in patients with locally advanced rectal cancer: The evaluation of 66 cases

BACKGROUND

The study aimed to assess if adherence to a total-neoadjuvant-treatment (TNT) protocol followed by observation(watch-and-wait) led to the successful nonoperative-management of low-rectal-cancer.

METHODS

In this study, patients with primary, resectable-T3-T4, N0-N1 distal-rectal-adenocarcinoma underwent-chemoradiotherapy + consolidation-chemotherapy (TNT). During the-TNT-period, endoscopy, MRI, and FDG-PET/CT were performed. We allocated patients with complete-clinical-tumor-regression, who underwent endoscopy every two months, MRI every-four-months, and PET/CT every-six-months-after-treatment, to the observation-group(OG). All other patients were referred for surgery. The OG was followed-up. The primary endpoint was local tumor-ecurrence after allocation to the OG.

RESULTS

Between 2015 and 2018, we enrolled 66-patients. Of 60-patients who were eligible to participate, 39 had complete-clinical-response(cCR) and were allocated to the OG, six underwent local-excision (LE), and 15 underwent total-mesorectal-excision (TME). The median follow-up duration was 22 (9-42) months. The local-recurrence-rate in the OG was 15.3%, and the LE and TME rates were 16.6% and 0%, respectively. All recurrence cases were salvaged through either LE or TME. The-distant-metastasis rate was 5.1%, 16.6%, and 12.5% in the OG, LE, and TME groups, respectively. The endoscopic negative-predictive-value(NPV) was 50%, and the positive-predictive-value(PPV) was 76.9% in the surgery group (LE + TME). MRI; NPV-50%, PPV-76.9%. PET/CT; NPV-100%, PPV-93.3%. Six patients(28.57%) from surgery group achieved complete pathological response (cPR).

CONCLUSION

Our results indicated a high proportion of selected-rectal-cancers with-cCR after neo-adjuvant-therapy could potentially be managed non-operatively, and major surgery may be avoided.

Tumor-Infiltrating Lymphocyte Function Predicts Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

Purpose

The presence of tumor-infiltrating lymphocytes (TILs) in tumors is superior to conventional pathologic staging in predicting patient outcome. However, their presence does not define TIL functionality. Here we developed an assay that tests TIL cytotoxicity in patients with locally advanced rectal cancer before definitive treatment, identifying those who will obtain a pathologic complete response (pCR). We also used the assay to demonstrate the rescue of TIL function after checkpoint inhibition blockade (CIB).

Patients and Methods

Thirty-four consecutive patients were identified initially, with successful completion of the assay before surgery in those 17 patients who underwent full treatment. An in vitro cytotoxic assay of rectal cancer tumoroids cocultured with patient-matched TILs was established and validated. Newly diagnosed patients were recruited with pretreatment biopsy specimens processed within 1 month. Evaluation of TIL-mediated tumoroid lysis was performed by measuring the mean fluorescence intensity of cell death marker, propidium iodide. CIB (anti–programmed cell death protein 1 [anti–PD-1] antibody) response was also assessed in a subset of patient specimens.

Results

Six of the 17 patients achieved an objective pCR on final evaluation of the resected specimen after neoadjuvant chemoradiotherapy. Cytotoxic killing identified the pCR group with a higher mean fluorescence intensity (27,982 [95% CI, 25,340 to 30,625]) compared with the non-pCR cohort (12,428 [95% CI, 9,434 to 15,423]; p < .001). Assessment of the effectiveness of CIB revealed partial restoration of cytotoxicity in TILs with increased PD-1 expression with anti–PD-1 antibody exposure.

Conclusion

Evaluating TIL function can be undertaken within weeks of the diagnostic biopsy, affording the potential to alter patient management decisions and refine selection for a watch-and-wait protocol. This cytotoxic assay also has the potential to serve as a platform to assist in the additional development of CIB.

Factors affecting local regrowth after watch and wait for patients with a clinical complete response following chemoradiotherapy in rectal cancer (InterCoRe consortium): an individual participant data meta-analysis

BACKGROUND

In patients with rectal cancer who achieve clinical complete response after neoadjuvant chemoradiotherapy, watch and wait is a novel management strategy with potential to avoid major surgery. Study-level meta-analyses have reported wide variation in the proportion of patients with local regrowth. We did an individual participant data meta-analysis to investigate factors affecting occurrence of local regrowth.

METHODS

We updated search results of a recent systematic review by searching MEDLINE and Embase from Jan 1, 2016, to May 5, 2017, and used expert knowledge to identify published studies reporting on local regrowth in patients with rectal cancer managed by watch and wait after clinical complete response to neoadjuvant chemoradiotherapy. We restricted studies to those that defined clinical complete response using criteria equivalent to São Paulo benchmarks (ie, absence of residual ulceration, stenosis, or mass within the rectum on clinical and endoscopic examination). The primary outcome was 2-year cumulative incidence of local regrowth, estimated with a two-stage random-effects individual participant data meta-analysis. We assessed the effects of clinical and treatment factors using Cox frailty models, expressed as hazard ratios (HRs). From these models, we derived percentage differences in mean θ as an approximation of the effect of measured covariates on between-centre heterogeneity. This study is registered with PROSPERO, number CRD42017070934.

FINDINGS

We obtained individual participant data from 11 studies, including 602 patients enrolled between March 11, 1990, and Feb 13, 2017, with a median follow-up of 37·6 months (IQR 25·0-58·7). Ten of the 11 datasets were judged to be at low risk of bias. 2-year cumulative incidence of local regrowth was 21·4% (random-effects 95% CI 15·3-27·6), with high levels of between-study heterogeneity (I²=61%). We noted wide between-centre variation in patient, tumour, and treatment characteristics. We found some evidence that increasing cT stage was associated with increased risk of local regrowth (random-effects HR per cT stage 1·40, 95% CI 1·00-1·94; p_trend=0·048). In a subgroup of 459 patients managed after 2008 (when pretreatment staging by MRI became standard), 2-year cumulative incidence of local regrowth was 19% (95% CI 13-28) for stage cT1 and cT2 tumours, 31% (26-37) for cT3, and 37% (21-60) for cT4 (random-effects HR per cT stage 1·50, random-effects 95% CI 1·03-2·17; p_trend=0·0330). We estimated that measured factors contributed 4·8-45·3% of observed between-centre heterogeneity.

INTERPRETATION

In patients with rectal cancer and clinical complete response after chemoradiotherapy managed by watch and wait, we found some evidence that increasing cT stage predicts for local regrowth. These data will inform clinician-patient decision making in this setting. Research is needed to determine other predictors of a sustained clinical complete response.

FUNDING

None.

MRI-Based Apparent Diffusion Coefficient for Predicting Pathologic Response of Rectal Cancer After Neoadjuvant Therapy: Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study was to assess the use of apparent diffusion coefficient (ADC) during DWI for predicting complete pathologic response of rectal cancer after neoadjuvant therapy.

MATERIALS AND METHODS

A systematic review of available literature was conducted to retrieve studies focused on the identification of complete pathologic response of locally advanced rectal cancer after neoadjuvant chemoradiation, through the assessment of ADC evaluated before, after, or both before and after treatment, as well as in terms of the difference between pretreatment and posttreatment ADC. Pooled mean pretreatment ADC, posttreatment ADC, and Δ-ADC (calculated as posttreatment ADC minus pretreatment ADC divided by pretreatment ADC and multiplied by 100) in complete responders versus incomplete responders were calculated. For each parameter, we also pooled sensitivity and specificity and calculated the area under the summary ROC curve.

RESULTS

We found 10 prospective and eight retrospective studies. Overall, pathologic complete response was observed in 22.2% of patients. Pooled mean pretreatment ADC in complete responders was 0.84 × 10^-3 mm²/s versus 0.89 × 10^-3 mm²/s in incomplete responders (p = 0.33). Posttreatment ADC values were 1.51 × 10^-3 mm²/s and 1.29 × 10^-3 mm²/s, in complete and incomplete responders, respectively (p = 0.00001). The Δ-ADC percentages were also significantly higher in complete responders than in incomplete responders (59.7% vs 29.7%, respectively, p = 0.016). Pooled sensitivity, specificity, and AUC were 0.743, 0.755, and 0.841 for pretreatment ADC; 0.800, 0.737, and 0.782 for posttreatment ADC; and 0.832, 0.806, and 0.895 for Δ-ADC.

CONCLUSION

Use of ADC during DWI is a promising technique for assessment of results of neoadjuvant treatment of rectal cancer.

Clinical and molecular diagnosis of pathologic complete response in rectal cancer: an update

INTRODUCTION

The standard of care for locally advanced rectal cancer includes neoadjuvant chemoradiation with subsequent total mesorectal excision. This approach has shown various degrees of response to neoadjuvant chemoradiation (ranging from complete response to further tumor growth), which have substantial prognostic and therapeutic implications. A total regression of the tumor is a predictor of superior oncologic outcomes compared with partial responders and non-responders. Further, this concept has opened the possibility of nonoperative strategies for complete responders and explains the widespread research interest in finding clinical, radiographic, pathologic, and biochemical parameters that allow for identification of these patients. Areas covered: The present review evaluates the most recent efforts in the literature to identify predictors of patients likely to achieve a complete response following neoadjuvant treatment for the management of rectal cancer. This includes clinical predictors of pathologic complete response such as tumor location, size, and stage, molecular predictors such as tumor biology and microRNA, serum biomarkers such as carcinoembryogenic antigen and nomograms. Expert commentary: There has been significant progress in our ability to predict pathological complete response. However, more high-quality research is still needed to use this concept to confidently dictate clinical management.

'Watch and wait' in rectal cancer: summary of the current evidence

BACKGROUND

The management of rectal cancer has evolved considerably over the last few decades with increasing use of neoadjuvant chemoradiotherapy (nCRT). Complete clinical response (cCR) and even complete pathological response (pCR) have been noted in a proportion of patients who had surgery after nCRT. This raises the concern that we may have been 'over-treating' some of these patients and lead to an increasing interest in 'watch and wait' (W&W) approach for patients who had cCR to avoid the morbidity associated with rectal surgery.

METHODS

A review of the literature in English pertaining to rectal cancer in the context of W&W, organ preservation and active surveillance.

RESULTS

Evidence available to support W&W approach comes from non-randomised controlled trials (RCTs) with no current consensus on patients' selection criteria, lack of viable predictors of both cCR and pCR and lack of universal definitions of cCR and pCR. Also, there is no agreed protocol for disease surveillance.

CONCLUSION

Even though there has been increasing reports on the outcomes of W&W in rectal cancer, the current evidence cannot support its routine use in clinical practice. This approach should be used in clinical trials settings or after thorough counselling with the patient on the outcomes of various treatment options.

'Watch and wait' after chemoradiotherapy for rectal cancer

Surgery remains the cornerstone of rectal cancer treatment. However, there is significant morbidity and mortality associated with pelvic surgery, and the past decade has illustrated that a cohort of rectal cancer patients sustain a remission of local disease with chemoradiation alone. Thus, questions remain regarding the optimal management for rectal cancer; namely, accurately identifying patients who have a complete pathologic response and determining the oncologic safety of the observational approach for this patient group. This review aims to summarize the current evidence to provide an overview to the 'watch and wait' approach in rectal cancer patients with a complete response to neoadjuvant chemoradiation therapy.

Observation of "complete clinical response" in rectal cancer after neoadjuvant chemoradiation: The Flinders experience

AIM

Observation with close follow-up ("watch and wait") is a recognized treatment option in patients who achieve a complete clinical response to long course chemoradiotherapy. This review of a prospective database aims to evaluate the clinical outcomes among patients with a complete clinical response managed with observation.

METHODS

A prospective study of 32 patients who achieved a complete clinical response was undertaken. The primary outcomes measured were overall and recurrence-free survival, and rate of organ preservation in patients who deferred immediate surgery.

RESULTS

Seven patients developed local regrowth over a median follow-up period of 38 months (range, 9-91 months). Median time to detection was 12 months. All seven underwent salvage surgery with complete surgical clearance. One patient developed combined local and systemic recurrence following a low anterior resection. Organ preservation was possible in 25 (78%) patients who sustained a complete clinical response with no evidence of local regrowth or disease recurrence. Among the patients who sustained a complete response, two developed isolated systemic disease. Overall and recurrence-free survival was 95.7% and 87.0%, respectively.

CONCLUSION

The majority of patients with rectal cancer who achieved a complete clinical response after chemoradiotherapy and managed with a "watch and wait" approach preserved their rectum and did not develop cancer relapse. Salvage surgery was achieved in all patients who developed local regrowth. The study supports a period of observation in rectal cancer patients who achieve a complete clinical response.

Decision-Making Strategy for Rectal Cancer Management Using Radiation Therapy for Elderly or Comorbid Patients

Rectal cancer predominantly affects patients older than 70 years, with peak incidence at age 80 to 85 years. However, the standard treatment paradigm for rectal cancer oftentimes cannot be feasibly applied to these patients owing to frailty or comorbid conditions. There are currently little information and no treatment guidelines to help direct therapy for patients who are elderly and/or have significant comorbidities, because most are not included or specifically studied in clinical trials. More recently various alternative treatment options have been brought to light that may potentially be utilized in this group of patients. This critical review examines the available literature on alternative therapies for rectal cancer and proposes a treatment algorithm to help guide clinicians in treatment decision making for elderly and comorbid patients.

Watch-and-Wait as a Therapeutic Strategy in Rectal Cancer

Purpose of Review

Pathological complete response is seen in approximately one fifth of rectal cancer patients following neoadjuvant chemoradiation. Since these patients have excellent oncological outcomes, there has been a rapidly growing interest in organ preservation for those who develop a clinical complete response. We review the watch-and-wait strategy and focus on all aspects of this hot topic, including who should be considered for this approach, how should we identify treatment response and what are the expected outcomes.

Recent Findings

The major challenges in interpreting the data on watch-and-wait are the significant heterogeneity of patients selected for this approach and of methods employed to identify them. The evidence available comes mostly from retrospective cohort studies, but has shown good oncological outcomes, including the rate of successful salvage surgery, locoregional control and overall survival.

Summary

There is currently not enough and not robust enough evidence to support watch-and-wait as a standard approach, outside a clinical trial, for patients achieving clinical complete response following neoadjuvant chemoradiation. Furthermore, there is a lack of data on long-term outcomes. However, the results we have so far are promising, and there is therefore an urgent need for randomised control studies such as the TRIGGER trial to confirm the safety of this strategy.

Total Mesorectal Excision Versus Local Excision After Preoperative Chemoradiotherapy in Rectal Cancer With Lymph Node Metastasis: A Propensity Score-Matched Analysis

PURPOSE

To determine whether local excision (LE) outcomes were comparable to total mesorectal excision (TME) outcomes in node-positive (cN+) rectal cancer patients who were good responders.

METHODS AND MATERIALS

This retrospective study included clinical T2-3 and cN+ low rectal cancer patient who received preoperative chemoradiotherapy (PCRT) followed by TME or LE. Clinical stage T1 or T4 tumors, upper-to-middle rectal tumors (>7 cm from anal verge), and synchronous distant metastases were excluded. Lymph nodes ≥5 mm in size were defined as tumor-positive, and patients with metastatic lymph nodes >20 mm in size were excluded. Preoperative chemoradiotherapy comprised radiation (50-50.4 Gy/25-28 fractions over 5 weeks) with 2 cycles of 5-fluorouracil or oral capecitabine. Propensity scores were computed from tumor and patient variables and used for 1-to-1 matched analysis. Local recurrence-free survival, disease-free survival, and overall survival were compared between the 2 matched groups.

RESULTS

Between January 2007 and December 2013, 563 and 55 patients underwent TME and LE, respectively. The median follow-up period was 54 months. In propensity score-matched analysis, 48 patients were included in each group. No statistical differences were observed in 3-year local recurrence-free survival (97.9% vs 97.9%, P = .994), 3-year disease-free survival (91.5% vs 91.4%, P = .968), or 3-year OS (93.7% vs 97.9%, P = .809) between the TME and LE groups.

CONCLUSIONS

In clinical N+ rectal cancer patients, oncologic outcomes of PCRT followed by LE were comparable to those of TME; this finding might be applicable only to those patients with good response in the primary tumor and small lymph node metastases.

Wait-and-see treatment strategies for rectal cancer patients with clinical complete response after neoadjuvant chemoradiotherapy: a systematic review and meta-analysis

Wait-and-see treatment strategies may benefit rectal cancer patients who achieve a clinical complete response (cCR) after neoadjuvant chemoradiotherapy (NCRT). In this study, we analyzed data from 9 eligible trials to compare the oncologic outcomes of 251 rectal cancer patients achieving a cCR through nonsurgical management approaches with the outcomes of 344 patients achieving a pathologic complete response (pCR) through radical surgery. The two patient groups did not differ in distant metastasis rates or disease-free and overall survival, but the nonsurgical group had a higher risk of 1, 2, 3, and 5-year local recurrence. Hence, we concluded that for rectal cancer patients achieving a cCR after NCRT, a wait-and-see strategy with strict selection criteria, an appropriate follow-up schedule, and salvage treatments achieved outcomes at least as good as radical surgery. Long-term randomized and controlled trials with more uniform inclusion criteria and standardized follow-up schedules will help clarify the risks and benefits of wait-and-see treatment strategies for these patients.

Management of the Complete Clinical Response

Organ preservation is considered in the management of selected patients with rectal cancer. Complete clinical response observed after neoadjuvant chemoradiation for rectal cancer is one of these cases. Patients who present complete clinical response are candidates to the watch-and-wait approach, when radical surgery is not immediately performed and is offered only to patients in the event of a local relapse. These patients are included in a strict follow-up, and up of 70% of them will never be operated during the follow-up. This strategy is associated with similar oncological outcomes as patients operated on, and the advantage of avoiding the morbidity associated to the radical operation. In this article we will discuss in detail the best candidates for this approach, the protocol itself, and the long-term outcomes.

Predicting response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer with serum biomarkers

Introduction The aim of this study was to identify patient factors including serum biomarkers that may predict response to neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer staged on magnetic resonance imaging. Prediction of response may be helpful when selecting patients for a non-operative programme. Methods A retrospective review was carried out of patients undergoing neoadjuvant CRT for rectal cancer, conducted at the Royal Devon and Exeter Hospital. All patients were managed through the multidisciplinary team. Receiver operating characteristic (ROC) curve analysis was undertaken to assess the ability of biomarkers to predict response to neoadjuvant CRT. The biomarkers assessed included neutrophils, lymphocytes, monocytes, haemoglobin, platelets, C-reactive protein and carcinoembryonic antigen. Results Seventy-three patients underwent neoadjuvant CRT between January 2006 and December 2011. Nine (12.3%) of these experienced a clinical complete response and were managed with a 'watch and wait' approach. An additional ten patients (13.7%) had a pathological complete response following surgery. Using ROC curve analysis, the biomarkers with the largest area under the curve (AUC) were pre-CRT haemoglobin and post-CRT lymphocyte concentrations, producing AUC values of 0.673 and 0.618 respectively for clinical complete response. Pre-CRT haemoglobin and neutrophil concentrations produced the highest AUC values for pathological complete response at 0.591 and 0.614 respectively. Conclusions None of the assessed biomarkers offer the ability to predict response to neoadjuvant CRT in patients with rectal cancer. They cannot therefore assist in identifying complete clinical or pathological responders who could be considered for a non-operative, observational approach.