Complete Response after Chemoradiotherapy in Rectal Cancer (Watch-and-Wait): Have we Cracked the Code?

Endoscopic ultrasound-guided injection of carbon nanoparticles suspension to label rectal cancer before neoadjuvant chemoradiotherapy: a retrospective cohort study

Background

Localization of the primary tumor and ensuring safe distal surgical margins (DSMs) following neoadjuvant chemoradiotherapy (nCRT) are challenging in locally advanced rectal cancers (LARCs). This study investigated the effectiveness of carbon nanoparticles suspension (CNS) for labeling the primary tumor and allowing precise tumor resection after nCRT.

Methods

Clinicopathological data of LARC patients who underwent nCRT followed by laparoscopic radical anal preservation surgery at our center between January 2018 and February 2023 were prospectively collected. The patients were divided into the CNS tattooed (CNS) and non-tattooed (control) groups. In the CNS group, CNS was injected in four quadrants on the anal side 1 cm away from the lower tumor margin. DSMs were determined through intraoperative distal rectal examination in the control group and observation of CNS tattoos in the CNS group. DSM lengths and positive DSM rates were compared between the two groups to analyse the feasibility and effectiveness of CNS for labeling LARCs before nCRT.

Results

There was no statistically significant difference in the basic demographic data, effectiveness of nCRT, or post-operative recovery rates between the two groups (all P > 0.05). In the CNS group, CNS tattoos were observed on the outside of the rectal wall, with an overall efficiency of 87.1% (27/31). The CNS group had fewer positive DSMs and safer DSM lengths (2.73 ± 0.88 vs 2.12 ± 1.15 cm, P = 0.012) than the control group (P < 0.05).

Conclusions

Endoscopic ultrasound-guided injection of CNS tattoos before nCRT could effectively label the LARCs, ensuring safe DSMs during anus-preserving surgeries (Chictr.org.cn No.: ChiCTR2300068991).

First-In-Human Pilot PET Immunoimaging Study of 64Cu-Anti-Carcinoembryonic Antigen Monoclonal Antibody (hT84.66-M5A) in Patients with Carcinoembryonic Antigen-Producing Cancers

Background: PET imaging using radiolabeled immunoconstructs shows promise in cancer detection and in assessing tumor response to therapies. The authors report the first-in-human pilot study evaluating M5A, a humanized anti-carcinoembryonic antigen (CEA) monoclonal antibody (mAb), radiolabeled with ⁶⁴Cu in patients with CEA-expressing malignancies. The purpose of this pilot study was to identify the preferred patient population for further evaluation of this agent in an expanded trial. Methods: Patients with CEA-expressing primary or metastatic cancer received ⁶⁴Cu-DOTA-hT84.66-M5A with imaging performed at 1 and 2 days postinfusion. ⁶⁴Cu-DOTA-hT84.66-M5A PET scan findings were correlated with CT, MRI, and/or FDG PET scans and with histopathologic findings from planned surgery or biopsy performed postscan. Results: Twenty patients received ⁶⁴Cu-DOTA-hT84.66-M5A. Twelve patients demonstrated positive images, which were confirmed in 10 patients as tumor by standard-of-care (SOC) imaging, biopsy, or surgical findings. Four of the 8 patients with negative imaging were confirmed as true negative, with the remaining 4 patients having disease demonstrated by SOC imaging or surgery. All 5 patients with locally advanced rectal cancer underwent planned biopsy or surgery after ⁶⁴Cu-DOTA-hT84.66-M5A imaging (4 patients imaged 6-8 weeks after completing neoadjuvant chemotherapy and radiation therapy) and demonstrated a high concordance between biopsy findings and ⁶⁴Cu-DOTA-hT84.66-M5A PET scan results. Three patients demonstrated positive uptake at the primary site later confirmed by biopsy and at surgery as residual disease. Two patients with negative scans each demonstrated complete pathologic response. In 5 patients with medullary thyroid cancer, ⁶⁴Cu-DOTA-hT84.66-M5A identified disease not seen on initial CT scans in 3 patients, later confirmed to be disease by subsequent surgery or MRI. Conclusions: ⁶⁴Cu-DOTA-hT84.66-M5A demonstrates promise in tumor detection, particularly in patients with locally advanced rectal cancer and medullary thyroid cancer. A successor trial in locally advanced rectal cancer has been initiated to further evaluate this agent's ability to define tumor extent before and assess disease response after neoadjuvant chemotherapy and radiotherapy. clinical trial.gov (NCT02293954).

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.

Quantitative analysis of diffusion weighted imaging in rectal cancer during radiotherapy using a magnetic resonance imaging integrated linear accelerator

Background and purpose

Magnetic resonance imaging integrated linear accelerator (MR-Linac) platforms enable acquisition of diffusion weighted imaging (DWI) during treatment providing potential information about treatment response. Obtaining DWI on these platforms is technically different from diagnostic magnetic resonance imaging (MRI) scanners. The aim of this project was to determine feasibility of obtaining DWI and calculating apparent diffusion coefficient (ADC) parameters longitudinally in rectal cancer patients on the MR-Linac.

Materials and methods

Nine patients undergoing treatment on MR-Linac had DWI acquired using b-values 0, 30, 150, 500 s/mm2. Gross tumour volume (GTV) and normal tissue was delineated on DWI throughout treatment and median ADC was calculated using an in-house tool (pyOsirix ®).

Results

Seven out of nine patients were included in the analysis; all demonstrated downstaging at follow-up. A total of 63 out of 70 DWI were analysed (7 excluded due to poor image quality). An increasing trend of ADC median for GTV (1.15 × 10-3 mm2/s interquartile range (IQ): 1.05-1.17 vs 1.59 × 10-3 mm2/s IQ: 1.37 - 1.64; p = 0.0156), correlating to treatment response. In comparison ADC median for normal tissue remained the same between first and last fraction (1.61 × 10-3 mm2/s IQ: 1.56-1.71 vs 1.67 × 10-3 mm2/s IQ: 1.37-2.00; p = 0.9375).

Conclusions

DWI assessment in rectal cancer patients on MR-Linac is feasible. Initial results provide foundations for further studies to determine DWI use for treatment adaptation in rectal cancer.

IMMUNOEXPRESSION OF DEK AND PHOSPHO-P38 PROTEINS IN RECTAL CANCER BEFORE CHEMORADIATION THERAPY

BACKGROUND

Colorectal cancer is the third cause of cancer worldwide and a quarter of them are in the rectum. DEK oncogene is involved in several nuclear processes and can accelerate tumorigenesis.

OBJECTIVE

This study aims to evaluate the immunoexpression of DEK and Phospho-P38 proteins before neoadjuvant therapy in patients with rectum adenocarcinoma and correlate it with a clinical response and survival.

METHODS

Patients with adenocarcinoma of the middle and low rectum who underwent chemotherapy and radiotherapy followed by surgical tumor resection were included. The expression and quantification were studied by immunohistochemistry in the tumor biopsy tissues using a HScore system. Score ≥4 were considered positive and those with <4 negative.

RESULTS

22 patients were included with a mean age of 63.55 years (SD: ±13.49). The clinical-stage before treatment was T3 on 72.7%, T4 on 18.2%, 31.8% were N1, 50% N0 and all M0. After chemo and radiotherapy, 54.6% were T3; 22.7% were classified as T2; 9.1% as T1, and 13.6% were T0. Among the tumors, 22.7% were positive for DEK and 63.6% positive for Phospho-P38. There was a positive correlation between DEK protein before treatment and pTNM stage (P=0.011). Phospho-P38 protein showed no correlation with these parameters. Patients with a negative HScore had a mean survival of 141.33 months (95%CI: 112.41-170.25) and those with a positive HSscore had a mean survival of 25.10 months (95%CI: 17.36-32.84; P<0.001).

CONCLUSION

A higher expression of DEK was observed in advanced stages. Patients who presented DEK expression <4 had a higher survival, being a factor of worst prognosis.

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.

Evaluation and Predictive Factors of Complete Response in Rectal Cancer after Neoadjuvant Chemoradiation Therapy

The response to neoadjuvant chemoradiation therapy is an important prognostic factor for locally advanced rectal cancer. Although the majority of the patients after neoadjuvant therapy are referred to following surgery, the clinical data show that complete clinical or pathological response is found in a significant proportion of the patients. Diagnostic accuracy of confirming the complete response has a crucial role in further management of a rectal cancer patient. As the rate of clinical complete response, unfortunately, is not always consistent with pathological complete response, accurate diagnostic parameters and predictive markers of tumor response may help to guide more personalized treatment strategies and identify potential candidates for nonoperative management more safely. The management of complete response demands interdisciplinary collaboration including oncologists, radiotherapists, radiologists, pathologists, endoscopists and surgeons, because the absence of a multidisciplinary approach may compromise the oncological outcome. Prediction and improvement of rectal cancer response to neoadjuvant therapy is still an active and challenging field of further research. This literature review is summarizing the main, currently known clinical information about the complete response that could be useful in case if encountering such condition in rectal cancer patients after neoadjuvant chemoradiation therapy, using as a source PubMed publications from 2010–2021 matching the search terms “rectal cancer”, “neoadjuvant therapy” and “response”.

[Effects of neoadjuvant chemoradiotherapy on infiltrating immune cells in the tumor microenvironment of rectal cancer]

OBJECTIVE

To detect the changes in the number and phenotype of tumor infiltrating immune cells in rectal cancer tissues before and after neoadjuvant concurrent chemoradiotherapy (CRT) and analyze their correlation with the clinicopathological parameters of the patients.

METHODS

The protein expressions of CD3, CD4, CD8, CD56 and Foxp3 in biopsy specimens and postoperative pathological specimens collected from 20 rectal cancer patients before and after neoadjuvant CRT were detected using Elivision^TM Plus immunohistochemistry, and the results were statistically analyzed.

RESULTS

Compared with the measurements before the therapy, neoadjuvant CRT resulted in significant increments in CD3 (21.8% vs 48.8%, P < 0.001), CD4(16.5% vs 42.2%, P < 0.001), CD8(8.3% vs 33.4%, P < 0.001)and CD56(0 vs 7.6%, P=0.012), obvious reduction in Foxp3 expression(26.0% vs 15.3%, P=0.005), but no significant changes in CD4/CD8 ratio of(2.7 vs 5.1).Multivariate analysis showed that the increase of CD3-positive cells(HR=0.16, P=0.028)and CD8-positive cells(HR=0.03, P=0.001)was positively correlated with the disease-free survival of the patients after the operation.

CONCLUSION

Neoadjuvant CRT can significantly increase the proportions of infiltrating immune cells positive for CD3, CD4, CD8 and CD56 and decrease the proportion of Treg lymphocytes in the tumor tissues in patients with rectal cancer.The patients with increased CD3-and CD8-positive T lymphocytes may have longer disease-free survival after the surgery.

Long-term outcomes of transanal endoscopic microsurgery for clinical complete response after neoadjuvant treatment in T2-3 rectal cancer

BACKGROUND

Organ sparing by the transanal endoscopic microsurgery (TEM) procedure is a treatment for patients with locally advanced rectal cancer after chemoradiotherapy (CRT) and complete clinical response (cCR).

AIMS

To assess the surgical and long-term oncological outcomes of TEM for the treatment in T2-3 rectal cancer after CRT and cCR.

METHODS

This study was a retrospective review of a prospective database of patients with rectal cancer who underwent TEM after CRT and cCR from April 2011 to March 2020.

RESULTS

52 patients underwent TEM during a period of 9 years. This group of patients included 27 females and 25 males. The median age was 62 (32-86) years, lesion size was 2.5 (1-4) cm, and lesion distance from the anal verge 7.3 (4-10) cm. Median operative time was 79.5 (25-120) min and hospital stay was 1 day (14 h-4 days). Morbidity rate was 13.5% and reoperation rate due to major complications was 3.8%. Final histological findings confirmed 34 (65.4%) patients with ypT0, 7 (13.5%), 6 (11.5%), and 5 (9.6%) patients with carcinoma ypT1, ypT2, and ypT3, respectively. After a median follow-up period of 86 (5-107) months, 1 (2.4%) patient had local recurrences and 3 (7.3%) distant metastases. The 5-year disease-free survival was 91.7% and 5-year overall survival 89.5%.

CONCLUSION

Our experience has shown significant rates of ypT0 and ypT1 associated with excellent long-term results. Performing TEM to treat T2-3N0 rectal cancer after CRT and cCR appears to be an oncologically safe and effective procedure.

Unintended consequences of treating early rectal cancers for complete clinical response with chemoradiotherapy

The aim was to examine the current trend in rectal cancer, which is to extend ’watch-and-wait’ to earlier-stage tumors, not normally treated with chemoradiotherapy, to define the up-side and down-side regarding quality of life (QOL) and anorectal/sexual/urinary function from this approach. We reviewed the literature regarding a ‘watch-and-wait’ strategy after neoadjuvant chemoradiotherapy. The primary outcome measure was complete clinical response. Secondary measures included colostomy rate, functional outcomes and QOL. There is a trend to use chemoradiotherapy in earlier tumors using dose-escalation of radiation and/or additional chemotherapy, resulting in high rates of complete clinical response, which may impact adversely on QOL if radical surgery is subsequently required. Focusing on organ-preservation as the primary goal of treatment rather than overall functional outcomes and QOL for the whole population, may not provide patients with sufficient information for optimal decision-making.

Organ preservation with chemoradiotherapy plus local excision for rectal cancer: 5-year results of the GRECCAR 2 randomised trial

BACKGROUND

GRECCAR 2 was the first multicentre, randomised trial to compare local excision with total mesorectal excision in downstaged low rectal cancer. Encouraging oncological results were noted at 3 years' follow-up but needed to be corroborated with longer follow-up. In this study, we aimed to report the 5-year oncological outcomes, including local recurrence, metastatic disease, and survival.

METHODS

Patients age 18 years and older with T2T3 low rectal cancer, of maximum size 4 cm, who were clinically good responders after chemoradiotherapy (residual tumour ≤2 cm) were randomly assigned before surgery to either local excision or total mesorectal excision. Randomisation was centralised and not stratified and used permuted blocks of size eight. In the local excision group, a completion total mesorectal excision was performed if pathological tumour stage was ypT2-3. The primary objective of this study was to assess the 5-year oncological outcomes of local recurrence, metastatic disease, disease-free survival, overall survival, and cancer-specific mortality, which were the secondary endpoints of GRECCAR 2. We used Kaplan-Meier estimates and Cox modelling to estimate and compare recurrence and survival in modified intention-to-treat and as-treated populations. This trial was registered with ClinicalTrials.gov, number NCT00427375.

FINDINGS

Between March 1, 2007, and Sept 24, 2012, 148 patients who were good clinical responders were randomly assigned to treatment, three patients were excluded after randomisation (because they had metastatic disease, tumour >8 cm from anal verge, or withdrew consent), leaving 145 for analysis: 74 in the local excision group and 71 in the total mesorectal excision group. Median follow-up was 60 months (IQR 58-60) in the local excision group and 60 months (57-60) in the total mesorectal excision group. 23 patients died and five were lost to follow-up. In the local excision group, 26 had a completion total mesorectal excision for ypT2-3 tumour. In the modified intention-to-treat analysis, there was no difference between the local excision and total mesorectal excision groups in 5-year local recurrence (7% [95% CI 3-16] vs 7% [3-16]; adjusted hazard ratio [HR] 0·71 [95% CI 0·19-2·58]; p=0·60), metastatic disease (18% [CI 11-30] vs 19% [11-31]; 0·86 [0·36-2·06]; p=0·73), overall survival (84% [73-91] vs 82% [71-90]; 0·92 [0·38-2·22]; p=0·85), disease-free survival (70% [58-79] vs 72% [60-82]; 0·87 [0·44-1·72]; p=0·68), or cancer-specific mortality (7% [3-17] vs 10% [5-20]; 0·65 [0·17-2·49]; p=0·53).

INTERPRETATION

The 5-year results of this multicentre randomised trial corroborate the 3-year results, providing no evidence of difference in oncological outcomes between local excision and total mesorectal excision. Local excision can be proposed in selected patients having a small T2T3 low rectal cancer with a good clinical response after chemoradiotherapy.

FUNDING

National Cancer Institute of France.

Trends of National and Subnational Incidence of Childhood Cancer Groups in Iran: 1990-2016

Background: Childhood cancer is a double-edged sword, considering its high rate of response to treatment despite a high vulnerability to develop future malignancies in survivors. Thus, multidisciplinary preventive, curative, and supportive strategies must be incorporated in childhood cancer care that require understanding the distribution and trend of cancer in the target population. In this article, we aimed to report the national and subnational trends of childhood cancer incidence in Iran from 1990 to 2016, and mortality/incidence ratio (MIR), which, to our knowledge, have not been reported in previous literature.

Method: Data on the incidence and mortality rates were collected from the National and Subnational Burden of Diseases project. We employed a two-stage spatiotemporal model to estimate cancer incidences by sex, age, province, and year based on the primary dataset of national death registration system. National and subnational age and gender-specific trends as well as MIR were calculated.

Result: The age-standardized incidence rate had a steady increasing trend for cancers in both female [annual percent change (APC), 1.6%] and male (APC, 2.1%) patients. Not only there was an increasing trend in most provinces but also there was a 40% divergence in age-standardized incidence rate at subnational levels. Leukemia, lymphoma, neoplasms of the central nervous system (CNS), digestive tract, endocrine gland, and urinary tract were the leading causes of cancer comprising more than half of all cancers. There was a remarkable general decrease in MIR by 75% as a proxy of care quality.

Conclusion: Regarding the increased trend of childhood cancer incidence, there is an essential need to address the etiologic factors and establish preventive plans for childhood cancers. Despite the favorable outcomes observed in cancer care, commensurate health resource allocation must be applied to diminish the subnational disparities.

Prognosis comparison between wait and watch and surgical strategy on rectal cancer patients after treatment with neoadjuvant chemoradiotherapy: a meta-analysis

BACKGROUND

After achieving a clinical complete response through neoadjuvant chemoradiotherapy, a nonoperative management approach for rectal cancer patients known as Wait and Watch (W&W) has gained increasing attention. However, the W&W strategy has been related to higher local recurrence and ambiguous long-term survival. This meta-analysis compared key prognosis indicators between W&W and surgical treatment in an effort to clarify some long-standing points of confusion.

METHODS

Pubmed, Web of Science, EMbase, Cochrane Library were searched for relevant researches comparing W&W with surgery treatment, with a time criteria set from 1 January 2002 to 4 July 2019. Endpoints were 2-year local regrowth/recurrence, 2-year distant metastasis (plus local regrowth/recurrence), 3- and 5-year disease-free survival (DFS), and overall survival (OS).

RESULTS

In total, nine studies with 801 patients were enrolled, of which 348 were managed by W&W and 453 by surgery. Surgery patients were further divided into a pathological complete response (pCR) group (all included patients achieved pCR) and a surgery group (consisting of both pCR and non-pCR patients without deliberate screening). Compared with the surgery group, W&W patients have higher 3- and 5-year OS, and are not inferior on 2-year local regrowth (LR), 2-year distant metastasis (DM)/DM+LR, and 3- and 5-year DFS. On the other hand, compared with the pCR group, the W&W group is inferior on 2-year LR, 3- and 5-year DFS, and 5-year OS, and not inferior on 2-year DM/DM+LR and 3-year OS.

CONCLUSIONS

In contrast with patients undergoing surgical treatment, the W&W group has higher 3- and 5-year OS, and is not inferior on other major prognostic indicators, which, however, is based on the fact that the tumor stage in the W&W group is generally earlier. Versus surgically treated patients who acquired pCR, W&W group is inferior on all major prognostic indicators except 2-year DM/DM+LR and 3-year OS. Additionally, by comparison of cCR definitions across different studies, we conclude that implementation of the strictest cCR criteria is critical for W&W patients to acquire maximum prognostic benefit.

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.

Evaluating Surveillance Patterns after Chemoradiation-Only Compared with Conventional Management for Older Patients with Rectal Cancer

BACKGROUND

Upfront chemoradiation with omission of surgery (CR-only) is increasingly being used to treat rectal cancer. When CR-only is used with curative intent, intense surveillance is recommended. We hypothesized that in practice, few patients treated with CR-only receive intensive post-treatment surveillance.

STUDY DESIGN

Using Surveillance, Epidemiology, and End Results (SEER)-Medicare, all nonmetastatic rectal cancer patients (≥66 years old) diagnosed from 2004 to 2012, who received upfront chemoradiation, were included. Patients who received CR-only were compared with patients receiving neoadjuvant therapy plus proctectomy. In the 24 months after treatment, markers of surveillance, including carcinoembryonic antigen testing (CEA), endoscopy, and imaging, were compared between groups.

RESULTS

A total of 2,482 individuals met the inclusion criteria: 21% (n = 514) had CR-only and 79% had conventional treatment (ie chemoradiation plus proctectomy). Only 2.5% and 3.4% of those in the CR-only and conventional treatment groups, respectively, were in complete compliance with National Comprehensive Cancer Network surveillance guidelines during the first 2 years post-treatment (p < 0.01). The CR-only group was less likely than the conventional treatment group to receive: CEA (adjusted risk ratio [aRR] 0.57; 95% CI 0.50 to 0.65), endoscopy (aRR 0.76; 95% CI 0.66 to 0.87), and office visits (aRR 0.88; 95% CI 0.84 to 0.92), respectively. However, there were similar rates of cross-sectional imaging between groups (aRR 1.31; 95% CI 0.93 to 1.85).

CONCLUSIONS

Adherence to guideline-recommended surveillance was poor for all Medicare patients with rectal cancer. Despite recommendations for closer follow-up, patients treated with CR-only were less likely to receive surveillance than those treated with conventional treatment. Efforts should be made to increase adherence to surveillance guidelines for all rectal cancer patients treated with curative intent, but particularly for those with higher risk of recurrence, such as those treated with CR-only.

'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.

Do clinical criteria reflect pathologic complete response in rectal cancer following neoadjuvant therapy?

BACKGROUND

Clinical complete response (cCR) in rectal cancer is being evaluated as a tool to identify patients who would not require surgery in the curative management of rectal cancer. Our study reviews mucosal changes after neoadjuvant therapy for rectal cancer in patients treated at our center.

METHODS

Pathology reports were retrieved for patients treated with neoadjuvant chemoradiation therapy (CRT) or high-dose rate brachytherapy (HDRBT). The macroscopic appearance of the specimen was compared with pathologic staging.

RESULTS

This study included 282 patients: 88 patients underwent neoadjuvant CRT and 194 patients underwent HDRBT; all patients underwent total mesorectal excision (TME). There were 160 male and 122 female patients with a median age of 65 years (range 29-87). The median time between neoadjuvant therapy and surgery was 50 and 58 days. Sixty patients (21.2%) were staged as ypT0N0, 21.2% had a pathologic complete response (pCR), and only 3.2% had a cCR. Of the 67 patients with initial involvement of the circumferential radial margin (CRM), 44 converted to pathologic CRM-. Two hundred seventy-three patients (96.8%) had mucosal abnormalities. Of the 222 patients with residual tumor, 70 patients had no macroscopic tumor visualized but an ulcer in its place.

CONCLUSION

Most patients undergoing neoadjuvant therapy for rectal cancer have residual mucosal abnormalities which preclude to a cCR as per published criteria from Brazil. Further studies are required to optimize clinical evaluation and MRI imaging in selected patients.

Assessment of remaining tumour involved lymph nodes with MRI in patients with complete luminal response after neoadjuvant treatment of rectal cancer

OBJECTIVE

To assess the accuracy of MRI to predict remaining lymph node metastases in patients with complete pathological luminal response (ypT0) after neoadjuvant therapy.

METHODS

Data from a national registry were used. 19 patients with histopathologically remaining lymph node metastases (ypT0N+) were identified. Another 19 patients without lymph node metastases (ypT0N0) were used as matched controls. Two radiologists blinded to all patient information evaluated staging and restaging MRI that was compared to histopathological findings of the resected specimen.

RESULTS

The average size of the largest lymph node on restaging MRI was significantly larger (4.5 mm) in the ypT0N+ group than in the ypT0N0 group (2.6 mm) (p = 0.04). Presence of ypN+ was correctly predicted by MRI in 7 of 19 patients. In patients without lymph node metastases (ypT0N0), these were correctly classified by MRI in 16 of 19 patients. All patients who had MR-identified lymph nodes larger than 8 mm at restaging were ypTN+. The sensitivity, specificity, positive predictive value and negative for prediction of remaining lymph node metastasis with MRI were 37, 84, 70 and 57%.

CONCLUSION

In patients with ypT0 in rectal cancer after neoadjuvant treatment, remaining regional lymph node metastases cannot safely be predicted by restaging MRI alone using presently known criteria. Presence of a lymph node over 8 mm on restaging MRI strongly indicates yPN+. Advances in knowledge: This is one of the first studies on MRI lymph node assessment after chemo-radiotherapy (CRT) in luminal complete response.

Organ-Preserving Strategies for the Management of Near-Complete Responses in Rectal Cancer after Neoadjuvant Chemoradiation

In recent years, organ preservation has been considered a feasible alternative to total mesorectal excision for patients with locally advanced rectal cancer with a clinical complete response to neoadjuvant therapy. However, the degree of tumor response to neoadjuvant therapy is variable. A fraction of the patients who did not achieve a complete response had grossly visible tumors. These patients, with clearly incomplete clinical response, need a total mesorectal excision. In addition, some patients with a significant tumor response still have some abnormalities in the bowel wall, such as superficial ulceration or tissue nodularity, which, while not conclusive for the presence of a tumor, are indicative of the possibility of a residual tumor in the bowel wall or in mesorectal lymph nodes. The management of patients with a so-called near-complete clinical response to neoadjuvant therapy is controversial. In this article, we will review the clinical and radiological criteria that define a clinical response to neoadjuvant therapy, possible treatment strategies, and follow-up protocols. We will also discuss patient and tumor characteristics that in our opinion can be useful in selecting the most appropriate treatment alternative. Although organ preservation and quality of life are important, the primary goal of treatment for these patients should be local tumor control and long-term survival.

Moderate dose escalation with volumetric modulated arc therapy improves outcome in rectal cancer

BACKGROUND

Locally advanced rectal cancer is frequently treated with a long course of preoperative chemoradiotherapy. We investigated the effect of moderate dose escalation with volumetric modulated arc therapy (VMAT) up to 50 Gy in 25 fractions compared to 3D conformal radiotherapy (3D-CRT) to 45 Gy in 25 fractions in rectal cancer patients. Dose-volume parameters, acute toxicity, and complete response rates were compared.

MATERIAL AND METHODS

For both groups, 65 patients were selected from our database through availability. Dose-volume parameters and acute toxicity data were compared using a Mann-Whitney U-test. Univariate and multivariate analyses correcting for tumor and nodal stage, distance to the mesorectal fascia and interval to surgery were used to compare complete response rates.

RESULTS

Lower mean doses to the small and large bowel were observed in the VMAT group compared to the 3D-CRT group (21 Gy vs. 29 Gy [p < .001] and 26 Gy vs. 30 Gy [p = .002], respectively). Similar beneficial dose-volume parameters were observed for the bladder, sacrum and femoral heads. Furthermore, patients receiving VMAT experienced significantly less diarrhea, flatulence, non-infective cystitis, urinary frequency, dermatitis, and fatigue. In univariate analysis, a significant increase in complete response rate after moderate dose escalation with VMAT was observed (34% vs. 15%, p = .015). However, this did not remain significant when corrected for tumor and nodal stage, distance to the mesorectal fascia, and interval to surgery.

CONCLUSIONS

Moderate dose escalation with VMAT resulted in superior dose-volume parameters compared to 3D-CRT, translating into lower acute toxicity. Additionally, improved tumor response after VMAT up to 50 Gy might contribute to a higher percentage of patients achieving a complete response.

Comparison of volumetric-modulated arc therapy using simultaneous integrated boosts (SIB-VMAT) of 45 Gy/55 Gy in 25 fractions with conventional radiotherapy in preoperative chemoradiation for rectal cancers: a propensity score case-matched analysis

Background and purpose

The aim of this retrospective study was to compare volumetric-modulated arc therapy using simultaneous integrated boosts (SIB-VMAT) of 45 Gy/55 Gy in 25 fractions with three-dimensional conformal radiotherapy (3D–CRT) in preoperative chemoradiation for rectal cancers.

Methods and materials

In the propensity score-matching analysis of 1:2, we selected 60 patients from the SIB-VMAT group and 120patients from the 3D–CRT group matched pairings out of 145 patients between 2005 and 2015. The regimen of concurrent combined chemotherapy was oral uracil/tegafur plus leucovorin with/without irinotecan.

Results

There were no significant differences between the two groups, in pathological complete response rates (pCR) (11% in the 3D–CRT group vs. 17% in the SIB-VMAT group, P = 0.39), pathological response rates (44% vs. 60%, P = 0.77), disease-free survival (P = 0.32), or local control (P = 0.52). The SIB-VMAT method marginally improved the rate of pathological grade 2–3 effects and the OS was significantly better in patients with grade 2–3 effects. Recurrence was seen in 36 patients (30%) in the 3D–CRT group and 19 patients (32%) in the SIB-VMAT group. The first distant recurrence site in the SIB-VMAT group was liver in 6 patients and lung in 8 patients. The obvious radiation-induced late toxicity in the SIB-VMAT group was recto-vesical fistula in two patients.

Conclusions

The SIB-VMAT may be a promising method for preoperative CRT of rectal cancer.

A watch-and-wait approach for locally advanced rectal cancer after a clinical complete response following neoadjuvant chemoradiation: a systematic review and meta-analysis

BACKGROUND

A watch-and-wait approach for patients with clinical complete response to neoadjuvant chemoradiation could avoid the morbidity of conventional surgery for rectal cancer. However, the safety of this approach is unclear. We synthesised the evidence for watch-and-wait as a treatment for rectal cancer.

METHODS

We systematically searched MEDLINE, Embase, and the grey literature (up to June 28, 2016) for studies of patients with rectal adenocarcinoma managed by watch-and-wait after complete clinical response to neoadjuvant chemoradiation. We determined the proportion of 2-year local regrowth after watch-and-wait. We assessed non-regrowth recurrence, cancer-specific mortality, disease-free survival, and overall survival from studies comparing patients who had watch-and-wait versus those who had radical surgery after detection of clinical complete response or versus patients with pathological complete response.

FINDINGS

We identified 23 studies including 867 patients with median follow-up of 12-68 months. Pooled 2-year local regrowth was 15·7% (95% CI 11·8-20·1); 95·4% (95% CI 89·6-99·3) of patients with regrowth had salvage therapies. There was no significant difference between patients managed with watch-and-wait after a clinical complete response and patients with pathological complete response identified at resection with respect to non-regrowth recurrence (risk ratio [RR] 1·46, 95% CI 0·70-3·05) or cancer-specific mortality (RR 0·87, 95% CI 0·38-1·99). Although there was no significant difference in overall survival between groups (hazard ratio [HR] 0·73, 95% CI 0·35-1·51), disease-free survival was better in the surgery group (HR 0·47, 95% CI 0·28-0·78). We found no significant difference between patients managed with watch-and-wait and patients with clinical complete response treated with surgery in terms of non-regrowth recurrence (RR 0·58, 95% CI 0·18-1·90), cancer-specific mortality (RR 0·58, 95% CI 0·06-5·84), disease-free survival (HR 0·56, 95% CI 0·20-1·60), or overall survival (HR 3·91, 95% CI 0·57-26·72).

INTERPRETATION

Most patients treated by watch-and-wait avoid radical surgery and of those who have regrowth almost all have salvage therapy. Although we detected no significant differences in non-regrowth cancer recurrence or overall survival in patients treated with watch-and-wait versus surgery, few patients have been studied and more prospective studies are needed to confirm long-term safety.

FUNDING

None.

Perfusion CT measurements predict tumor response in rectal carcinoma

PURPOSE

To evaluate the capacity of perfusion CT imaging to distinguish between complete and incomplete responders after neoadjuvant chemoradiation therapy for rectal carcinoma, with particular attention to segmentation technique.

MATERIALS AND METHODS

17 patients were evaluated in this prospective IRB-approved study. For each patient, a perfusion CT acquisition was obtained prior to the initiation of chemoradiation, at 1-2 weeks after the start of chemoradiation, and at 12 weeks after the start of chemoradiation therapy. From each dataset, three perfusion parameters were measured, each in two different ways: a region of interest incorporating only "hot spots" of greatest enhancement and whole-tumor measurements.

RESULTS

In univariate analysis, blood volume and permeability differed significantly between responders and non-responders. In logistic regression analysis evaluating predictors of the "complete response" outcome, only two predictors were retained as statistically significant: peak hot spot blood volume 1-2 weeks into therapy (OR 10.25, p = 0.0026) and hot spot permeability decline at 12 weeks after the initiation of therapy (OR 5.62, p = 0.03). The overall likelihood ratio test for this model supported the conclusion that hot spot blood volume and hot spot permeability decline were significant predictors of the complete pathologic response outcome (p < 0.0001).

CONCLUSION

In this pilot study, peak tumor blood volume and decline in tumor permeability, when measured in "hot spots" of greatest enhancement, were strong predictors of complete therapeutic response in rectal cancer after neoadjuvant therapy.

Nonoperative Management or 'Watch and Wait' for Rectal Cancer with Complete Clinical Response After Neoadjuvant Chemoradiotherapy: A Critical Appraisal

BACKGROUND

There is increasing interest in nonoperative management (NOM) for rectal cancer with complete clinical response (cCR) after neoadjuvant chemoradiation (nCRT).

OBJECTIVE

The aim of this systematic review was to summarize the available data on NOM, with the intention of formulating standardized protocols on which to base future investigations.

METHODS

A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted. A highly sensitive literature search identified all relevant studies published between January 2004 and December 2016. Data extraction and quality assessment was performed independently by two authors, and resolved by consensus with a third reviewer.

RESULTS

In total, 15 studies, including 920 patients, met the inclusion criteria; 575 (62.5%) of these patients underwent NOM after cCR, with the remaining patients forming a surgical control group. The weighted mean follow-up was 39.4 (12.7) months in the NOM group and 39.8 (5.1) months in the surgery group. The pooled regrowth rate in the NOM group was 21.3% at a mean of 15.6 (7.0) months. Surgical salvage was possible and was undertaken in 93.2% of these patients. Overall survival in the NOM group was 91.7%, while disease-free survival was 82.7%. For the comparison proctectomy group, pooled rates of local recurrence, overall survival, and disease-free survival were 8.4, 92.4, and 87.5%, respectively.

CONCLUSION

NOM may be a feasible option for surgically eligible rectal cancer patients with cCR after nCRT. Before such a strategy can be widely implemented, further prospective data are required with standardized definitions, diagnostic criteria, and management protocols, with an emphasis on shared patient-provider decision making and patient-centered outcomes.

Techniques and Outcome of Surgery for Locally Advanced and Local Recurrent Rectal Cancer

Locally advanced primary rectal cancer is variably defined, but generally refers to T3 and T4 tumours. Radical surgery is the mainstay of treatment for these tumours but there is a high-risk for local recurrence. National Institute for Health and Care Excellence (2011) guidelines recommend that patients with these tumours be considered for preoperative chemoradiotherapy and this is the starting point for any discussion, as it is standard care. However, there are many refinements of this pathway and these are the subject of this overview. In surgical terms, there are two broad settings: (i) patients with tumours contained within the mesorectal envelope, or in the lower rectum, limited to invading the sphincter muscles (namely some T2 and most T3 tumours); and (ii) patients with tumours directly invading or adherent to pelvic organs or structures, mainly T4 tumours - here referred to as primary rectal cancer beyond total mesorectal excision (PRC-bTME). Major surgical resection using the principles of TME is the mainstay of treatment for the former. Where anal sphincter sacrifice is indicated for low rectal cancers, variations of abdominoperineal resection - referred to as tailored excision - including the extralevator abdominoperineal excision (ELAPE), are required. There is debate whether or not plastic reconstruction or mesh repair is required after these surgical procedures. To achieve cure in PRC-bTME tumours, most patients require extended multivisceral exenterative surgery, carried out within specialist multidisciplinary centres. The surgical principles governing the treatment of recurrent rectal cancer (RRC) parallel those for PRC-bTME, but typically only half of these patients are suitable for this type of major surgery. Peri-operative morbidity and mortality are considerable after surgery for PRC-bTME and RRC, but unacceptable levels of variation in clinical practice and outcome exist globally. To address this, there are now major efforts to standardise terminology and classifications, to allow appropriate comparisons in future studies.