Disparities in Clinical Trial Enrollment and Reporting in Rectal Cancer: A Systematic Review and Demographic Comparison to the National Cancer Database

BACKGROUND

Cancer care guidelines based on clinical trial data in homogenous populations may not be applicable to all rectal cancer patients. The aim of this study was to evaluate whether patients enrolled in rectal cancer clinical trials (CTs) are representative of United States (U.S.) rectal cancer patients.

METHODS

Prospective rectal cancer CTs from 2010 to 2019 in the United States were systematically reviewed. In trials with multiple arms reporting separate demographic variables, each arm was considered a separate CT group in the analysis. Demographic variables considered in the analysis were age, sex, race/ethnicity, facility location throughout the United States, rural vs urban geography, and facility type. Participant demographics from trial and the National Cancer Database (NCDB) participants were compared using chi-squared goodness of fit and one-sample t-test where applicable.

RESULTS

Of 50 CT groups identified, 42 (82%) studies reported mean or median age. Trial participants were younger compared to NCDB patients (P < .001 all studies). All but three trials had fewer female patients than NCDB (48.2% female, P < .001). Less than half the CT groups reported on race or ethnicity. Eighteen out of 22 trials (82%) had a smaller percentage of Black patients and 4 out of 8 (50%) trials had fewer Hispanic or Spanish origin patients than the NCDB. No CTs reported comorbidities, socioeconomic factors, or education. CT primary sites were largely at academic centers and in urban areas.

CONCLUSION

The present study supports the need for improved demographic representation and transparency in rectal cancer clinical trials.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

A preoperative prediction model for anastomotic leakage after rectal cancer resection based on 13.175 patients

INTRODUCTION

This study aims to develop a robust preoperative prediction model for anastomotic leakage (AL) after surgical resection for rectal cancer, based on established risk factors and with the power of a large prospective nation-wide population-based study cohort.

MATERIALS AND METHODS

A development cohort was formed by using the DCRA (Dutch ColoRectal Audit), a mandatory population-based repository of all patients who undergo colorectal cancer resection in the Netherlands. Patients aged 18 years or older were included who underwent surgical resection for rectal cancer with primary anastomosis (with or without deviating ileostomy) between 2011 and 2019. Anastomotic leakage was defined as clinically relevant leakage requiring reintervention. Multivariable logistic regression was used to build a prediction model and cross-validation was used to validate the model.

RESULTS

A total of 13.175 patients were included for analysis. AL was diagnosed in 1319 patients (10%). A deviating stoma was constructed in 6853 patients (52%). The following variables were identified as significant risk factors and included in the prediction model: gender, age, BMI, ASA classification, neo-adjuvant (chemo)radiotherapy, cT stage, distance of the tumor from anal verge, and deviating ileostomy. The model had a concordance-index of 0.664, which remained 0.658 after cross-validation. In addition, a nomogram was developed.

CONCLUSION

The present study generated a discriminative prediction model based on preoperatively available variables. The proposed score can be used for patient counselling and risk-stratification before undergoing rectal resection for cancer.

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

BACKGROUND

Standard total mesorectal resection has become an important treatment option for locally advanced or high-risk rectal cancer after neoadjuvant chemo-radiotherapy. 15-27% of patients can achieve pathological complete response (PCR) after neoadjuvant chemo-radiotherapy (nCRT). However, the relationship between PCR and postoperative complications remains an important unsolved problem. The objective of this study was to determine whether PCR was associated with the rate of postoperative complications.

METHODS

This meta-analysis was implemented following the recommendations from Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We searched electronic literature by PubMed, EMBASE, and Google Scholar. Major outcomes of interest included anastomotic leakage, surgical-site infection, reoperation, and any postoperative complications. Other outcomes comprised postoperative hemorrhage, ileus, and mortality.

RESULTS

Eleven thousand two hundred ninety patients in 9 studies were included in the meta-analysis. The pooled analysis revealed that patients with PCR did not have a higher risk of anastomotic leakage (OR = 1.22, 95% CI 0.92-1.62, p = 0.17), reoperation (OR = 1.13, 95% CI 0.93-1.37, p = 0.22), and any postoperative complications (OR = 1.02, 95% CI 0.91-1.15, p = 0.72) than patients with non-PCR. However, the meta-analysis showed that the PCR group was superior to the non-PCR group in terms of surgical-site infection (9.38% vs. 12.44%OR = 0.68, 95% CI 0.47-0.98; p = 0.04).

CONCLUSION

PCR might not be related to the occurrence of postoperative complications in rectal cancer patients following nCRT. In addition, PCR might be associated with a lower risk of surgical-site infection.

Anastomotic leak risk in complete responders to neoadjuvant therapy for rectal cancer: a systematic review

PURPOSE

The oncological benefits of achieving a complete pathological response following neoadjuvant chemoradiotherapy for rectal cancer are well defined. How a pathological response affects anastomotic healing or leak rates is not clear. The aim of this systematic review was to compare anastomotic leak rates among patients who did and did not achieve a complete pathological response.

METHODS

Three major databases (PubMed, Embase, and Scopus) were searched. Predetermined inclusion criteria included prospective and retrospective articles published in English reporting complete pathological response and anastomotic leak rates following total mesorectal excision in ≥ 30 patients with rectal cancer who underwent neoadjuvant chemoradiotherapy and total mesorectal excision. The primary outcomes measured included complete pathological response and 30-day postoperative morbidity.

RESULTS

From a total of 8919 patients with rectal cancer in 7 studies, 4165 fulfilled the criteria for inclusion. The majority (> 80%) of patients had clinical stage II or III disease. A defunctioning loop ileostomy was formed in 76.5%. A total of 589 (14.1%) patients achieved a pCR of whom 63 (10.7%) developed an anastomotic leak compared to 272/3576 (7.6%) patients without a pCR (p = 0.02).

CONCLUSION

Patients with complete pathological response following neoadjuvant chemoradiotherapy and total mesorectal excision may be at higher risk of anastomotic leak than incomplete responders. This may need to be taken into account when counseling patients about the relative risks of organ preservation versus anterior resection.

Pathologic complete response is associated with decreased morbidity following rectal cancer resection

BACKGROUND

There are conflicting data regarding the relationship between pathologic complete response (pCR) and post-operative complications following rectal cancer resection. The objective of this study was to compare the rates of morbidity among pCR patients and non-pCR patients and to identify factors that predict pCR morbidity in a large national database.

METHODS

This is a retrospective study using American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) targeted proctectomy data (2016-18). Patients with neoadjuvant chemoradiation therapy followed by proctectomy were included, and divided into pCR and non-pCR groups according to final stage. The groups were compared with Student's t-test, Chi-squared or Fisher's exact test. Multivariate logistic regression models were constructed to estimate the association between pCR status and post-operative morbidity while adjusting for key covariates.

RESULTS

244 pCR and 1656 non-pCR patients were included. pCR patients had higher body mass index (28.1 ± 6.2 vs. 29.1 ± 5.9 kg/m²; p = 0.01) and lower pre-operative stage (T stage, p = 0.03; N stage, p < 0.001). The groups were equivalent with respect to surgical approach, type of surgery, and operative time (p > 0.05). Post-operative complications in pCR patients were less frequent than in non-pCR patients (23.0% vs. 29.3%; p = 0.04). This association was robust to adjustment for confounders in logistic regression, as patients with pCR had decreased odds of post-operative morbidity (OR 0.66, CI [0.43, 0.96], p = 0.04).

CONCLUSION

pCR is associated with fewer post-operative complications compared to non-pCR, suggesting that pCR is not a marker of severe pelvic fibrosis. This difference may be due to underlying tumor biology, and associated increased technical challenges resecting larger, non-responsive tumors.

Predictors for complete pathological response for stage II and III rectal cancer following neoadjuvant therapy - A systematic review and meta-analysis

BACKGROUND

There has been an increasing interest in the complete pathological response (pCR) in rectal cancers following neoadjuvant therapy. The aim of this study was to identify predictive factors of pCR in locally advanced rectal cancer following neoadjuvant therapy.

METHODS

The studies identified were appraised with standard selection criteria. The selection criteria included studies on patients with stage II or III rectal cancer who underwent neoadjuvant therapy.

RESULTS

Patients with pCR are more likely to be older (p = 0.0002), have cancers closer distance to the anal verge (p < 0.00001), smaller tumors (P < 0.0001), no clinical lymph nodes involvement (p=<0.00001) and waited more than eight weeks until definitive surgery (p = 0.002). There was no difference in gender (p = 0.15) and tumor differentiation (p = 0.21).

CONCLUSIONS

The 'Watch and Wait' approach may be appropriate for selected patients. Patients with lower rectal cancers, smaller tumors, and negative clinical lymph node involvement may be more likely to achieve pCR following neoadjuvant therapy.

Population-based study of morbidity risk associated with pathological complete response after chemoradiotherapy for rectal cancer

Background

Neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer may induce a pathological complete response (pCR) but increase surgical morbidity due to radiation-induced fibrosis. In this study the association between pCR and postoperative surgical morbidity was investigated.

Methods

Patients in the Netherlands with rectal cancer who underwent nCRT followed by total mesorectal excision between 2009 and 2017 were included. Data were stratified into patients who underwent resection with creation of a primary anastomosis and those who had a permanent stoma procedure. The association between pCR and postoperative morbidity was investigated in univariable and multivariable logistic regression analyses.

Results

pCR was observed in 976 (12·2 per cent) of 8003 patients. In 3472 patients who had a primary anastomosis, the presence of pCR was significantly associated with surgical complications (122 of 443 (27·5 per cent) versus 598 of 3029 (19·7 per cent) in those without pCR) and anastomotic leak (35 of 443 (7·9 per cent) versus 173 of 3029 (5·7 per cent) respectively). Multivariable analysis also showed associations between pCR and surgical complications (adjusted odds ratio (OR) 1·53, 95 per cent c.i. 1·22 to 1·92) and pCR and anastomotic leak (adjusted OR 1·41, 1·03 to 2·05). Of 4531 patients with a permanent stoma, surgical complications were observed in 120 (22·5 per cent) of 533 patients with a pCR, compared with 798 (20·0 per cent) of 3998 patients with no pCR (adjusted OR 1·17, 0·94 to 1·46).

Conclusion

Patients with a pCR in whom an anastomosis was created were at increased risk of developing an anastomotic leak.

A Phase I Clinical Trial of the Phosphatidylserine-targeting Antibody Bavituximab in Combination With Radiation Therapy and Capecitabine in the Preoperative Treatment of Rectal Adenocarcinoma

OBJECTIVES

There is interest in improving the tumoricidal effects of preoperative radiotherapy for rectal carcinoma by studying new radiosensitizers. The safety and toxicity profile of these combination regimens needs rigorous clinical evaluation. The primary objective of this study was to evaluate the toxicity of combining bavituximab, an antibody that targets exposed phosphatidylserine, with capecitabine and radiation therapy.

MATERIALS AND METHODS

Patients with stage II or III rectal adenocarcinoma were enrolled on a phase I study combining radiation therapy, capecitabine, and bavituximab. A standard 3+3 trial designed was used.

RESULTS

In general, bavituximab was safe and well tolerated in combination with radiation therapy and capecitabine in the treatment of rectal adenocarcinoma. One patient at the highest dose level experienced a grade III infusion reaction related to the bavituximab. One tumor demonstrated a complete pathologic response to the combination treatment.

CONCLUSIONS

Bavituximab is safe in combination with capecitabine and radiation therapy at the doses selected for the study. Further clinical investigation would be necessary to better define the efficacy of this combination.

Pathologic response grade after long-course neoadjuvant chemoradiation does not influence morbidity in locally advanced mid-low rectal cancer resected by laparoscopy

PURPOSE

Patients with locally advanced rectal cancer and pathologic complete response to neoadjuvant chemoradiation therapy have lower rates of recurrence compared to those who do not. However, the influences of the pathologic response on surgical complications and survival remain unclear. This study aimed to investigate the influence of neoadjuvant therapy for rectal cancer on postoperative morbidity and long-term survival.

METHODS

This was a comparative study of consecutive patients who underwent laparoscopic total mesorectal excision for rectal cancer in two European tertiary hospitals between 2004 and 2014. Patients with and without pathologic complete responses were compared in terms of postoperative morbidity, mortality, and survival.

RESULTS

Fifty patients with complete response (ypT0N0) were compared with 141 patients who exhibited non-complete response. No group differences were observed in the postoperative mortality or morbidity rates. The median follow-up time was 57 months (range 1-121). Over this period, 11 (5.8 %) patients, all of whom were in the non-complete response group, exhibited local recurrence. The 5-year overall survival and disease-free survival were significantly better in the complete response group, 92.5 vs. 75.3 % (p = 0.004) and 89 vs. 73.4 % (p = 0.002), respectively.

CONCLUSIONS

Postoperative complication rate after laparoscopic total mesorectal excision is not associated with the pathologic response grade to neoadjuvant chemoradiation therapy.

Predictors of Pathologic Complete Response Following Neoadjuvant Chemoradiotherapy for Rectal Cancer

BACKGROUND

Some patients with rectal cancer who receive neoadjuvant chemoradiotherapy (nCRT) achieve a pathologic complete response (pCR) and may be eligible for less radical surgery or non-operative management. The aim of this study was to identify variables that predict pCR after nCRT for rectal cancer and to examine the impact of pCR on postoperative complications.

METHODS

A retrospective review was performed of the NCDB from 2006 to 2011. Patients with rectal cancer who received nCRT followed by radical resection were included in this study. Multivariable analysis of the association between clinicopathologic characteristics and pCR was performed, and propensity-adjusted analysis was used to identify differences in postoperative morbidity between pCR and non-pCR patients.

RESULTS

A total of 23,747 patients were included in the study. Factors associated with pCR included lower tumor grade, lower clinical T and N stage, higher radiation dose, and delaying surgery by more than 6-8 weeks after the end of radiation, while lack of health insurance was linked with a lower likelihood of pCR. Complete response was not associated with an increased risk of major postoperative complications.

CONCLUSIONS

Several clinical, pathologic, and treatment variables can help to predict which patients are most likely to have pCR after nCRT for rectal cancer. Awareness of these variables can be valuable in counseling patients regarding prognosis and treatment options.

The Impact of Surgical Diversion Before Neoadjuvant Therapy for Rectal Cancer

Up-front fecal diversion can palliate emergent symptoms related to locally advanced rectal cancer (LARC) allowing patients to receive neoadjuvant chemoradiation therapy (nCRT). We analyzed outcomes of pretreatment-diverted LARC patients relative to nondiverted patients to define the impact of this management strategy. We retrospectively collected data on 103 LARC patients treated with nCRTand surgery. Medical records were reviewed for patient characteristics, staging, treatment plan, and outcomes. Thirteen LARC patients underwent pretreatment diversion for urgent symptoms and 90 LARC patients proceeded directly to nCRT. In all, 50 per cent of diverted patients presented with T4 tumor compared with 14 per cent in the nondiverted patients ( P = 0.003). Diverted patients experienced a delay in time-to-treatment initiation of 12 days, although this difference was not statistically significant. Similar rates of chemoradiation and surgical toxicities were observed. Even though diverted patients demonstrated less pathologic response to nCRT compared with nondiverted patients ( P = 0.04), there was no significant difference in overall survival. In conclusion, our study demonstrates the effectiveness of up-front fecal diversion at managing emergent obstructive symptoms related to advanced rectal cancer without additional complications, allowing patients to proceed with nCRT followed by radical surgery.

Prognostic factors for postoperative morbidity and tumour response after neoadjuvant chemoradiation followed by resection for rectal cancer

BACKGROUND AND PURPOSE

In patients with locally advanced rectal cancer treated with neoadjuvant chemoradiation followed by rectal resection, postoperative morbidity is a significant clinical problem. Pathologic complete tumour response seems to give the best prognosis in the long term. Little is known about the factors that are associated with postoperative complications and pathologic complete response. The aim of this retrospective study was to identify and describe these factors.

METHODS

Ninety-nine consecutive patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiation (50 Gy and capecitabine) followed by surgery at our institute between January 2007 and May 2012 were identified. Postoperative complications were graded according to the Clavien-Dindo classification. Pathologic tumour response was categorized as complete response or no/partial response.

RESULTS

Postoperative complications occurred in 68 patients (69%) and grade 3-5 complications in 25 patients (25%). The 30-day and 90-day mortality were 1% (n = 1) and 2% (n = 2), respectively. A young age (p = 0.021) and a preoperative or postoperative blood transfusion (p = 0.015) independently predicted complications. Intraoperative or postoperative blood transfusion (p = 0.007) and ypT0-1 stage (p = 0.037) were independent predictors for grade 3-5 complications. Complete response rate was 22% (n = 22); 4% (n = 4) of patients showed no response. No independent factors predicting complete response were found.

CONCLUSIONS

Neoadjuvant chemoradiation followed by rectal resection is associated with significant postoperative morbidity but minimal postoperative mortality. A complete response rate of 22% was achieved.

Does pathologic response of rectal cancer influence postoperative morbidity after neoadjuvant radiochemotherapy and total mesorectal excision?

BACKGROUND

A pathologic complete response (pCR) can be observed in up to 25% of patients after preoperative chemoradiotherapy for rectal cancer and is associated with an improved long-term prognosis. However, few data are available regarding the effect of pCR on postoperative morbidity. This study aimed to assess the impact of the pCR on postoperative outcomes after laparoscopic total mesorectal excision (TME).

METHODS

A prospectively maintained database (2006-2011) was reviewed for all consecutive patients (n = 143) undergoing laparoscopic TME for mid or low rectal cancer after neoadjuvant chemoradiotherapy. Postoperative data were compared for pCR-group and non-pCR-group. A pCR was defined as the absence of gross and microscopic tumor in the specimen, irrespective of the nodal status (ypT0).

RESULTS

Thirty-three patients (23%) had a pCR. Median operating time was greatly shorter in the pCR-group (230 minutes, 180-360), compared with the non-pCR-group (240 minutes, 130-420, P = .02). Lymph node involvement was noted for 12% of the patients in the pCR-group and 33% of the patients in the non-pCR-group (P = .91). Clavien Dindo grade 3 and 4 complications (6% vs 22%, P = .04), infection related morbidity (47% vs 76%, P = .04), and clinical anastomotic leakage rates (9% vs 29%, P = .02) were lesser in the pCR group compared with the non-pCR group. Mean duration of hospital stay was lesser in the pCR-group (9 vs 12 days, P = .01).

CONCLUSION

This study showed that Clavien Dindo grade 3 and 4 complications, including anastomosis leakage, and infection related complications rates were lesser in patients with pathologic complete response after RCT and laparoscopic TME for rectal cancer.