Management of malignant colorectal polyps in New Zealand

In comparison with polypectomy, colorectal resection is associated with improved survival for patients diagnosed with malignant polyps

AIM

Patients diagnosed with a malignant polyp generally have favourable overall survival (OS) and cancer-specific survival (CSS). However, it is unclear how choice in management for malignant polyps may affect survival.

METHODS

Data from the Queensland Oncology Repository was analysed to derive a population wide assessment of the impact of management strategy on OS and CSS for patients diagnosed with malignant polyps. Log-rank testing, Kaplan-Meier and Cox-regression models were performed. Patients were matched using propensity score and Mahalanobis distance matching.

RESULTS

A total of 1,646 patients were included with 240 deaths and 52 colorectal cancer related deaths until censor date. Following propensity score and Mahalanobis distance matching of patients undergoing polypectomy alone versus colorectal resection, there was no significant difference in the age groups (<60 years of age or ≥60 years of age), American Society of Anesthesiology score, comorbidity count or Association of ColoProctology of Great Britain and Ireland risk category. However, of note Log-rank testing demonstrated a significant difference in OS (p < 0.001) and CSS (p = 0.0061) between management strategies. Multivariable Cox-regression models in matched and un-matched patient cohorts demonstrated significantly lower hazards of death for OS with resection (p < 0.001). However, CSS was no longer significantly different between management groups in multivariable Cox-regression analysis (p = 0.073).

CONCLUSION

Patients who underwent colorectal resection had significantly improved OS and CSS compared with polypectomy alone. Improved OS was furthermore seen on multivariable analysis, and in matched cohorts. Future research should investigate why this unexpected finding may be the case and whether updates to guidelines should be considered.

Management of high and low risk malignant polyps: a population-wide analysis

AIM

The management of malignant polyps is a treatment dilemma in selecting between polypectomy and colorectal resection. To assist clinicians, guidelines have been developed by the Association of Coloproctology of Great Britain and Ireland (ACPGBI) to provide treatment recommendations.

METHODS

This study compared management strategy based on the ACPGBI risk categorization for malignant polyps. Univariable and multivariable statistical analysis was undertaken to assess the factors predicting management strategy. A population-wide analysis was performed of 1646 malignant polyps and the factors that predicted their management strategy, from Queensland, Australia, from 2011 to 2019.

RESULTS

Overall, 31.55% of patients with very low or low risk disease proceeded to resection. Of those with high or very high risk disease, 36.69% did not proceed to resection. In very low and low risk polyps, age (P = 0.003) and polyp location (P < 0.001) were significantly different between the colorectal resection group and the polypectomy alone group. In those with very high or high risk polyps age (P < 0.001), type of facility (public or private) for the colonoscopy (P = 0.037), right colonic polyps compared to left colonic polyps (P = 0.015) and rectal polyps (P < 0.001) and mismatch repair mutations present (P = 0.027) were predictive of resection in high risk disease using a multivariable model.

CONCLUSION

Over 30% of patients with very low and low risk malignant polyps proceeded to resection, against the advice of guidelines. Furthermore, over 35% of patients with very high or high risk malignant polyps did not proceed to resection. Education strategies may improve management decision choices. Furthermore, improvements in data collation will improve the understanding of management choices in the future.

A population-based study of the management of rectal malignant polyps and the use of trans-anal surgery

INTRODUCTION

Rectal malignant polyps can be managed by use of trans-anal resections (TAR). Traditional techniques of resection have been replaced by use of platforms such as trans-anal minimally invasive surgery (TAMIS) or trans-anal endoscopic microsurgery (TEM). This study reviewed the management of rectal malignant polyps, in particular focussing on when clinicians used TAR.

METHODS

A population wide cohort study of all malignant rectal polyps diagnosed in Queensland, Australia from 2011 to 2018 was undertaken. Patient and pathological factors were compared across the management strategies of polypectomy, TAR and rectal resection.

RESULTS

Overall 430 patients were diagnosed with a malignant rectal polyp during the study period, with 103 undergoing a TAR. There was increasing use of TAR across the study period as a management strategy (P < 0.001). Polypectomy alone was more likely to be the management strategy over TAR or rectal resection if there were clear margins (P < 0.001). The distance to the closest polypectomy margin was also significantly higher in the polypectomy group with mean clearance 2.09 mm in polypectomy group versus 0.86 mm in TAR group and 0.99 mm in resection group (P < 0.001). Rectal resection was more likely to be the management strategy over TAR if there was LVI (P < 0.001), depth of invasion was deeper (P < 0.001) and there was tumour budding (P = 0.001).

CONCLUSION

TAR is an effective management strategy for rectal polyps and is utilized particularly in rectal malignant polyps when there are close or involved margins. Future guideline development should consider incorporation of TAR given the advances in techniques afforded by TAMIS or TEM platforms.

Patient and pathological predictors of management strategy for malignant polyps following polypectomy: a systematic review and meta-analysis

PURPOSE

Malignant polyps present a treatment dilemma for clinicians and patients. This meta-analysis sought to identify the factors that predicted the management strategy for patients diagnosed with a malignant polyp.

METHODS

A literature search was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Cochrane Collaboration prognostic studies guidelines. Reports from 1985 onwards were included, data on patient and pathological factors were extracted and random effects meta-analysis models were used.

RESULTS

Fifteen studies were included. Seven studies evaluated lymphovascular invasion (LVI). The odds of surgery were significantly higher in malignant polyps with LVI (OR 2.20, 95% CI 1.36-3.55). Ten studies revealed the odds of surgery were significantly higher with positive polypectomy margins (OR 8.09, 95% CI 4.88-13.40). Tumour differentiation was compared in eight studies. There were significantly lower odds of surgery in malignant polyps with well/moderate differentiation compared with poor differentiation (OR 0.31, 95% CI 0.21-0.46). There were non-significant trends favouring surgical resection in younger patients, males and Haggitt 4/Kikuchi Sm3 lesions. There was considerable heterogeneity in the meta-analyses for the variables age, gender, polyp morphology and Haggitt/Kikuchi level (I² > 75%).

CONCLUSION

This meta-analysis has demonstrated that LVI, positive polypectomy resection margins, and poor tumour differentiation significantly predict malignant polypectomy patients who underwent subsequent surgery. Age and gender were important factors predicting management, but not consistently across studies, whilst polyp morphology and Haggitt/Kikuchi levels did not significantly predict the management strategy. Further research may assist in understanding the management preferences.

International validation of a risk prediction algorithm for patients with malignant colorectal polyps

AIM

The optimal management strategy for patients with endoscopically resected malignant colorectal polyps (MCP) has yet to be defined. The aim of this study was to validate a published decision-making tool, termed the Scottish Polyp Cancer Study (SPOCS) algorithm, on a large international population.

METHODS

The SPOCS algorithm allocates patients to risk groups based on just two variables: the polyp resection margin and the presence of lymphovascular invasion (LVI). The risk groups are termed low (clear margin, LVI absent), medium (clear margin, LVI present) or high (involved/non-assessable margin). The International Polyp Cancer Collaborative was formed to validate the algorithm on data from Australia, Denmark, UK and New Zealand.

RESULTS

In total, 1423 patients were included in the final dataset. 680/1423 (47.8%) underwent surgical resection and 108/680 (15.9%) had residual disease (luminal disease 8.8%, lymph node metastases 8.8%). The SPOCS algorithm classified 602 patients as low risk (in which 1.5% had residual disease), 198 patients as medium risk (in which 7.1% had residual disease) and 484 as high risk (in which 14.5% had residual disease) (P < 0.001, χ² test). Receiver operating characteristic curve analysis demonstrated good accuracy of the algorithm in predicting residual disease (area under the curve 0.732, 95% CI 0.687-0.778, P < 0.001). When patients were designated as low risk, the negative predictive value was 98.5%.

CONCLUSION

The SPOCS algorithm can be used to predict the risk of residual disease in patients with endoscopically resected MCPs. Surgery can be safely avoided in patients who have a clear margin of excision and no evidence of LVI.

Rectum versus colon: should malignant polyps be treated differently?

BACKGROUND

The management of malignant colorectal polyps removed at endoscopy remains controversial with patients either undergoing surgical resection or regular endoscopic surveillance. Lymph node (LN) metastases occur in 6-16% of patients with malignant polyps. This study assessed the rate of LN metastases in patients undergoing surgical resection for malignant polyps removed endoscopically to determine if there is a difference in the rate of LN metastases between colonic and rectal polyps.

METHODS

A retrospective review of a prospectively maintained database was performed from 2010 to 2018. All patients who underwent surgical resection following endoscopic removal of a malignant colorectal polyp were reviewed. Clinical data including patient demographics and tumour characteristics were examined.

RESULTS

A total of 177 patients underwent surgical resection in the study period. The median age at diagnosis was 65 years (range 22-88 years) with females comprising 52% of the patient cohort (n = 92/177). Polyps were located in the colon in 60.5% of cases with the remainder located in the rectum. The median number of LN harvested was 14 (range 0-44) with malignant LN (including a mesenteric tumour deposit) identified in 8.5% of resection specimens (n = 15/177). Malignant LNs were retrieved in 5.5% of right-sided tumours, 5.6% of left-sided tumours and 12.9% of rectal tumours (P = 0.090).

CONCLUSION

A small proportion of patients with malignant polyps removed endoscopically will have LN metastases. The results of this study suggest that the tumour location might be a useful predictive marker; however, a further study with increased patient numbers is required to properly establish this finding.

Current Management of Malignant Colorectal Polyps Across a Regional United Kingdom Cancer Network

BACKGROUND

The incidence of malignant colorectal polyps has increased secondary to the greater use of diagnostic colonoscopy and introduction of screening programs. Faced with the dilemma of whether major resection is required or whether polypectomy has been sufficient treatment, the clinician relies on high- and low-risk histological parameters to guide decision-making.

OBJECTIVE

The purpose of this study was to review current practice and evaluate multidisciplinary team decision-making across a United Kingdom Regional Cancer Network to establish the efficacy of previously set guidance from the Association of Coloproctology of Great Britain and Ireland (2013).

DESIGN

This was a retrospective cohort study.

SETTINGS

The study was conducted at a United Kingdom Regional Cancer Network composed of 4 separate National Health Service Hospital Trusts, covering an overall population of 1.5 million.

PATIENTS

All patients with malignant colorectal polyps who presented to the colorectal multidisciplinary team over a 3-year period (April 1, 2012 to April 1, 2015) were included.

MAIN OUTCOME MEASURES

Rate of residual disease after major resection, recurrence of cancer after polypectomy and surveillance alone, reporting of histological features, adherence to endoscopic surveillance guidelines, and outcomes of surveillance cross-sectional imaging were measured.

RESULTS

A total of 173 patients (median age = 69 y) with a malignant colorectal polyp were identified during the study period, with a median of 2.7 years of follow-up. Thirty-seven patients (21.4%) underwent primary surgical resection with a residual disease rate of 43% (16/37). The remaining 136 patients (76.8%) were managed conservatively with recurrence in 6 cases (4.4%). Endoscopic follow-up at 3 months occurred in 61% of cases. Histological reporting was varied, with tumor differentiation and resection margin being reported in 84% of cases and lymphovascular invasion and depth of invasion in 71% and 59% of cases, respectively.

LIMITATIONS

This was an observational retrospective study.

CONCLUSIONS

The residual disease rate in patients treated surgically was higher than previously reported (43.2%). Incidence of recurrence in patients treated conservatively was low (4.4%). Areas of improvements have been identified in adherence to endoscopic follow-up, histopathological reporting, and potential overuse of radiological surveillance. See Video Abstract at http://links.lww.com/DCR/B47. MANEJO ACTUAL DE PÓLIPOS COLORRECTALES MALIGNOS A TRAVÉS DE UNA RED REGIONAL DE CÁNCER DEL REINO UNIDO: La incidencia de pólipos colorrectales malignos ha aumentado secundariamente al mayor uso de la colonoscopia diagnóstica y a la introducción de programas de detección. Ante el dilema de si se requiere una resección mayor o si la polipectomía ha sido un tratamiento suficiente, el médico se basa en parámetros histológicos de alto y bajo riesgo, para guiarse en la toma de decisiones.Revisar la práctica actual y evaluar la toma de decisiones, del equipo multidisciplinario de una red regional de cáncer del Reino Unido, para establecer la eficacia de las recomendaciones previamente establecidas, por la Asociación de Coloproctología de la Gran Bretaña e Irlanda (2013).Estudio de cohorte retrospectivo.Red Regional del Cáncer del Reino Unido, que comprende cuatro Fideicomisos Hospitalarios del Servicio Nacional de Salud y que cubren una población general de 1,5 millones de personas.Todos los pacientes con pólipos colorrectales malignos presentados al equipo colorrectal multidisciplinario durante un período de 3 años (01/04/2012-01/04/2015).Tasa de enfermedad residual después de una resección mayor, recurrencia de cáncer después de polipectomía y vigilancia sola, informe de características histológicas, adherencia a directrices de vigilancia endoscópica y resultados de la vigilancia de la imagen transversal.Se identificaron un total de 173 pacientes (mediana de edad de 69 años) con pólipo colorrectal maligno durante el período de estudio, con una mediana de seguimiento de 2.7 años. 37 pacientes (21,4%) fueron sometidos a resección quirúrgica primaria con tasa de enfermedad residual del 43% (16/37). Los 136 pacientes restantes (76.8%) fueron manejados conservadoramente, con recurrencia en 6 casos (4.4%). El seguimiento endoscópico a los 3 meses, ocurrió en el 61% de los casos. El reporte histológico varió con la diferenciación tumoral. El margen de resección se informó en el 84% de los casos. La invasión linfovascular y la profundidad de la invasión fue del 71% y 59% de los casos.Estudio observacional retrospectivo.La tasa de enfermedad residual en pacientes tratados quirúrgicamente, fue más alta que la reportada previamente (43.2%). La incidencia de recurrencia en pacientes tratados de forma conservadora fue baja (4,4%). Se han identificado áreas de mejoras en cumplimiento del seguimiento endoscópico, informe histopatológico y el posible uso excesivo de la vigilancia radiológica. Vea el Resumen del Video en http://links.lww.com/DCR/B47.

Role of Endoscopic Resection Versus Surgical Resection in Management of Malignant Colon Polyps: a National Cancer Database Analysis

BACKGROUND

Endoscopic resection (polypectomy) or surgery, are the main approaches in management of malignant colon polyps. There are very few large population-based studies comparing outcomes between the two.

METHODS

Using the National Cancer Database, we identified patients ≥ 18 years with the first diagnosis of T1N0M0 malignant polyp from 2004 to 2015. Patients with a positive resection margin were excluded. Outcomes were compared between those who had surgery versus those who had polypectomy. Overall survival was compared using Kaplan-Meier curves. Multivariate Cox proportional hazards analysis was performed to generate hazard ratios, adjusted for patient, demographic, and tumor factors.

RESULTS

A total of 31,062 patients met the inclusion criteria, out of which 2593 (8.3%) underwent polypectomy alone and 28,469 (91.7%) had surgery. Overall survival was significantly better in the surgical group compared with the polypectomy group. One-year and 5-year survival for surgery were 95.8% and 86.1% respectively compared with 94.2% and 80.6% for polypectomy (p < .0001). Hazard ratio for surgery after adjusting for various clinical-, demographic-, and tumor-level factors was 0.53 (p < .0001).

CONCLUSION

Our study is the largest population-based analysis of patients with T1N0M0 malignant colon polyps. Overall survival was higher in patients who underwent surgery compared with polypectomy. This remained consistent even after adjusting for multiple patient and tumor factors between the two groups.

Revising the definition of vertical margin involvement following endoscopic polypectomy may reduce unnecessary surgery in patients with malignant colorectal polyps

Background and Study Aims

Endoscopically resected malignant colorectal polyps (MCPs) present a dilemma regarding whether the risk of residual disease justifies a major bowel resection. Overtreatment is common, and the vast majority of patients who undergo resection have no residual tumor. The aim of this study was to investigate whether revising the definition of vertical margin involvement following MCP polypectomy could reduce unnecessary surgery.

Patients and Methods

This was a cohort study of consecutive patients with MCPs treated at a tertiary hospital between 2004 and 2018. Data on demographics, index colonoscopy, polyp pathology, and any subsequent surgical resection were analyzed. Polypectomy resection margins were reviewed and measured to the nearest decimal place. The ability of existing guidelines (requiring a margin clearance of ≥ 1 mm) to predict residual disease was compared to a revised version requiring a margin clearance of ≥ 0.1 mm.

Results

A total of 129 patients with an MCP were included. Of these 129 patients, 77 (60%) underwent surgical resection, of which 62 (81%) had no residual tumor. Existing guidelines, requiring a margin clearance of ≥ 1 mm, classified 28 patients as being at “low risk” for residual disease. Of these, four underwent surgery, but none had residual tumor (P = 0.031). Revised guidelines, requiring a margin clearance of ≥ 0.1 mm, classified 44 patients as “low risk.” Of these, in the 13 that had surgery, no residual tumor was found (P = 0.003).

Conclusions

Revising the definition of vertical margin involvement leads to more patients being correctly classified as being at low risk of residual disease. This has the potential to reduce unnecessary surgery in patients with MCPs.

Malignant colorectal polyps: endoscopic polypectomy and watchful waiting is not inferior to subsequent bowel resection. A nationwide propensity score-based analysis

BACKGROUND AND AIMS

The optimal treatment of patients with malignant colorectal polyps is unsettled. The surgical dilemma following polypectomy is selecting between watchful waiting (WW) and subsequent bowel resection (SBR), but the long-term survival outcomes have not been established yet. This nationwide study compared survival of patients after WW or SBR.

METHODS

Danish nationwide study with 100% follow-up of all patients with malignant colorectal polyps (the Danish Colorectal Cancer Group database) in a 10-year period from 2001 to 2011. All patients' charts and histological reports were individually reviewed. Survival rates were calculated with Cox proportional hazard model after propensity score matching.

RESULTS

A total of 692 patients were included (WW, 424 (61.3%), SBR, 268 (38.7%)) with a mean follow-up of 7.5 years (3-188 months). Following propensity score matching, there was no significant difference in overall or disease-free survival (p = 0.344 and p = 0.184) or rate of local recurrence (WW, 7.2%, SBR, 2%, p = 0.052) or distant metastases (WW, 3.3%, SBR, 4.6%, p = 0.77). In the SBR group, there was no residual tumor or lymph node metastases in the resected specimen in 82.5% of the patients.

CONCLUSION

Subsequent bowel resection may not be superior to endoscopic polypectomy and watchful waiting with regard to overall and disease-free survival in patients with malignant colorectal polyps.