Predictors of circumferential resection margin involvement in surgically resected rectal cancer: A retrospective review of 23,464 patients in the US National Cancer Database

Incomplete Resection Is Twice as Likely in Locally Advanced Mucinous Compared to Nonmucinous Rectal Adenocarcinoma: A National Propensity-Matched Analysis

BACKGROUND AND OBJECTIVES

Rectal mucinous adenocarcinoma (MA) has poor response to neoadjuvant chemoradiation (NCR) and higher involved radial surgical margin rates than nonmucinous rectal adenocarcinoma (NMA).

METHODS

The National Cancer Database (2010-2018) was queried for adult patients with clinical stage II and III rectal cancer. Patients with MA and NMA treated with NCR and total mesorectal excision (TME) were identified. We sought to evaluate differences in pathologic downstaging and completeness of resection between MA and NMA rectal adenocarcinoma.

RESULTS

We identified 13 294 patients, 12 655 (95.2%) NMA and 639 (4.8%) MA. After 3:1 propensity score matching for pathologic outcomes, 1707 NMA and 569 MA patients were included. MA patients had more involved distal (2.1% vs. 1.1%, p = 0.047) and radial (29% vs. 15%, p < 0.001) margins, and less pathologic downstaging (49% vs. 55%, p = 0.015). Among MA patients, minimally invasive resection had higher distal (2.1% vs. 1.4%, p = 0.65) and radial margin involvement (35% vs. 26%, p = 0.09) compared to open resection. Incomplete resection rates were similar between low anterior and abdominoperineal resection.

CONCLUSIONS

TME of locally advanced rectal MA treated with NCR resulted in nearly double the involved radial surgical margins compared to NMA. Operative approach should be carefully considered. Extended or extra-mesorectal resection may reduce the risk of incomplete resection.

Rectal Cancer Tissue Lipidome Differs According to Response to Neoadjuvant Therapy

Rectal cancer (RC) is a gastrointestinal cancer with a poor prognosis. While some studies have shown metabolic reprogramming to be linked to RC development, it is difficult to define biomolecules, like lipids, that help to understand cancer progression and response to therapy. The present study investigated the relative lipid abundance in tumoral tissue associated with neoadjuvant therapy response using untargeted liquid chromatography-mass spectrometry lipidomics. Locally advanced rectal cancer (LARC) patients (n = 13), clinically staged as T3-4 were biopsied before neoadjuvant chemoradiotherapy (nCRT). Tissue samples collected before nCRT (staging) and afterwards (restaging) were analyzed to discover lipidomic differences in RC cancerous tissue from Responders (n = 7) and Non-responders (n = 6) to nCRT. The limma method was used to test differences between groups and to select relevant feature lipids from tissue samples. Simple glycosphingolipids and differences in some residues of glycerophospholipids were more abundant in the Non-responder group before and after nCRT. Oxidized glycerophospholipids were more abundant in samples of Non-responders, especially those collected after nCRT. This work identified potential lipids in tissue samples that take part in, or may explain, nCRT failure. These results could potentially provide a lipid-based explanation for nCRT response and also help in understanding the molecular basis of RC and nCRT effects on the tissue matrix.

Downstaging in Advanced Rectal Cancers: A Propensity-Matched Comparison Between Short-Course Radiotherapy Followed by Chemotherapy and Long-Course Chemoradiotherapy

BACKGROUND

Short-course radiotherapy followed by chemotherapy has not been widely evaluated as an alternative to traditional long-course chemoradiotherapy in locally advanced rectal cancer.

OBJECTIVE

This study compared the oncological and short-term outcomes between short-course radiotherapy + chemotherapy and long-course chemoradiotherapy in locally advanced rectal cancer.

DESIGN

This is a retrospective propensity-matched study.

SETTINGS

The study was conducted in a colorectal department at a tertiary care oncology center in India.

PATIENTS

There were 173 patients. Group A had 47 patients and group B had 126 patients. A 1:2.7 matching was done for age, sex, distance of tumor from the anal verge, sphincter preservation surgeries, MRI-based pretreatment T stage, and circumferential resection margin.

INTERVENTIONS

The interventions performed were short-course radiotherapy + chemotherapy (group A) and long-course chemoradiotherapy (group B) in locally advanced rectal cancer.

MAIN OUTCOME MEASURES

The primary measures were pathological circumferential resection margin positivity, downstaging, tumor regression grade, and postoperative complications.

RESULTS

Of the patients, 52% had a positive circumferential resection margin on MRI, 57% had low rectal tumors, and 20% had T4 tumors. Distribution of rectal surgeries was similar between the 2 groups. pT downstaging and tumor regression scores were significantly better in group B ( p = 0.028 and 0.026). Pathological circumferential resection margin, distal resection margin, and nodal yield were similar. On multivariate analysis, pretreatment N status was the only independent predictive factor for pathological circumferential resection margin status. Grade 3 to 4 Clavien-Dindo complications, anastomotic leak rates, and hospital stay were similar between the 2 groups.

LIMITATIONS

This was a retrospective study. Although propensity matching was performed, selection bias cannot be eliminated completely, as seen in the difference in the surgical approaches between the 2 groups.

CONCLUSIONS

In a cohort containing a significant portion of MRI circumferential resection margin-positive low rectal cancers, short-course radiotherapy + chemotherapy followed by delayed surgery resulted in lower T downstaging and lower tumor regression scores compared with long-course chemoradiotherapy, but pathological circumferential margin status, distal resection margin, nodal yield, and perioperative morbidity were similar between the 2 groups. This suggests that short-course radiotherapy + chemotherapy could be a viable alternative to long-course chemoradiotherapy in locally advanced rectal cancers. See Video Abstract at http://links.lww.com/DCR/B855 .

REDUCCIN DEL ESTADIO EN LOS CNCERES RECTALES AVANZADOS UNA COMPARACIN DE PROPENSIN EQUIPARADA ENTRE LA RADIACIN DE CICLO CORTO SEGUIDA DE QUIMIOTERAPIA Y LA QUIMIO RADIACIN DE CICLO LARGO

ANTECEDENTES:La radioterapia de ciclo corto seguida de quimioterapia no ha sido evaluada ampliamente como una alternativa a la tradicional quimio radioterapia de ciclo largo en el cáncer de recto localmente avanzado.OBJETIVO:Estudio que compara los resultados oncológicos y a corto plazo entre la radioterapia de ciclo corto + quimioterapia y la quimio radioterapia de ciclo largo en el cáncer de recto localmente avanzado.DISEÑO:Estudio comparado de propensión de manera retrospectiva.AJUSTE:Departamento colorrectal en un centro de atención oncológica de tipo terciario en la India.PACIENTES:Hubo 173 pacientes. El grupo A tenía 47 y el grupo B tenía 126 pacientes. Se realizó una comparación de 1: 2,7 para edad, sexo, distancia del tumor desde el margen anal, cirugías de preservación del esfínter, estadio T previo al tratamiento basada en resonancia magnética y margen de resección circunferencial (CRM).INTERVENCIONES:Radioterapia de ciclo corto + quimioterapia (grupo A) y quimio radioterapia de ciclo largo (grupo B) en cáncer de recto localmente avanzado (LARC).PRINCIPALES MEDIDAS DE RESULTADO:Positividad histopatológica de CRM, reducción del estadio tumoral, grado de regresión tumoral, complicaciones posoperatorias.RESULTADOS:El 52% de los pacientes han tenido un margen de resección circunferencial positivo en la resonancia magnética, 57% de tumores rectales bajos, 20% de tumores T4. La distribución de cirugías rectales fue similar entre los 2 grupos. Las puntuaciones de regresión tumoral y de reducción del estadio de pT fueron significativamente mejores en el grupo B ( p = 0.028 y 0.026 respectivamente). El margen de resección circunferencial patológico, el margen de resección distal y los ganglios arrojados fueron similares. En el análisis multivariado, el estadio N previo al tratamiento fue el único factor predictivo independiente para el estadio de pCRM. Las complicaciones Clavien-Dindo de grado 3-4, las tasas de fuga anastomótica y la estancia hospitalaria fueron similares entre los dos grupos.LIMITACIONES:Retrospectiva; aunque la propensión coincide, existe potencial sesgo de selección.CONCLUSIONES:En una cohorte que contenía una porción significativa de cánceres rectales bajos con margen de resección circunferencial positivo por resonancia magnética, la radioterapia de ciclo corto + quimioterapia seguida de cirugía tardía dio como resultado una mayor reducción del estadio T y de regresión tumoral en comparación con la quimio radioterapia de ciclo largo. Pero el estatus histopatológico del margen circunferencial, el margen de resección distal, el rendimiento ganglionar y la morbilidad perioperatoria fueron similares entre los dos grupos. Esto sugiere que la radioterapia de ciclo corto + quimioterapia podría ser una alternativa viable a la quimio radioterapia de ciclo largo en cánceres rectales localmente avanzados. Consulte Video Resumen en http://links.lww.com/DCR/B855 . (Traducción-Dr. Osvaldo Gauto ).

Assessment of mesorectal fascia status in MRI compared with circumferential resection margin after total mesorectal excision and predictors of involved margins

BACKGROUND

Circumferential resection margin is an important prognosticator for total mesorectal excision outcome. We investigated the status of mesorectal fascia on magnetic resonance imaging compared with circumferential resection margin on pathology and factors associated with status change.

METHODS

This was a retrospective analysis of a prospective database of rectal cancer patients who underwent surgery. Mesorectal fascia status on magnetic resonance imaging done before neoadjuvant therapy and circumferential resection margin status on pathology were compared. The study outcomes were factors associated with a margin status conversion between magnetic resonance imaging and pathology, and predictors of involved circumferential resection margin.

RESULTS

In total, 244 patients (average follow-up of 25.4 months) were included. Eighty-one (33.2%) patients had potentially involved mesorectal fascia in magnetic resonance imaging and 12 (4.9%) had involved circumferential resection margin in pathology. A total of 2.8% of patients had a conversion of clear mesorectal fascia in magnetic resonance imaging to involved circumferential resection margin. Abdominoperineal resection was significantly associated with this status change (odds ratio: 25, 95% confidence interval: 2.4-255.8, P = .007). In total, 7.4% of patients with potentially involved mesorectal fascia had persistently involved circumferential resection margin. Lack of total neoadjuvant therapy was associated with higher, yet statistically insignificant, odds of persistently involved circumferential resection margin (odds ratio: 12, 95% confidence interval: 0.65-220.8, P = .09). The significant independent predictors of involved circumferential resection margin were body mass index (odds ratio: 1.2, P = .016) and abdominoperineal resection (odds ratio: 4.22, P = .04).

CONCLUSION

Change of clear mesorectal fascia in magnetic resonance imaging to an involved circumferential resection margin in pathology was recorded in 2.8% of patients; abdominoperineal resection might be associated with this change. Approximately 7% of patients had persistent involvement of circumferential resection margin as determined by pathology. Omission of total neoadjuvant therapy might be associated with persistent margin involvement.

Transanal total mesorectal excision for abdominoperineal resection is associated with poor oncological outcomes in rectal cancer patients: A word of caution from a multicentric Canadian cohort study

AIM

The main objective of this study was to compare the oncological outcomes of patients undergoing abdominoperineal resection (APR) versus low anterior resection (LAR) through a transanal total mesorectal excision (taTME) approach.

METHOD

A total of 360 adult patients with a diagnosis of rectal cancer were enrolled at participating centres from the Canadian taTME Expert Collaboration. Forty-three patients received taTME-APR and received 317 taTME-LAR. Demographic, operative, pathological and follow-up data were collected and merged into a single database. Results are presented as hazard ratio (HR) and 95% confidence interval. All analyses were performed in the R environment (v.3.6).

RESULTS

The proportion of patients with a positive circumferential radial margin status was higher in the taTME-APR group than the taTME-LAR group (21% vs. 9%, p = 0.001). Complete TME was achieved in 91% of those undergoing APR compared with 96% of those undergoing LAR (p = 0.25). APR was associated with a greater rate of local recurrence relative to LAR, although it was not significant [crude HR = 3.53 (95% CI 0.92-13.53)]. Circumferential margin positivity was significantly associated with a higher rate of systemic recurrence [crude HR = 3.59 (95% CI 1.38-9.3)].

CONCLUSION

Our results demonstrate inferior outcomes in those undergoing taTME-APR compared with taTME-LAR. The use of this technique for this particular indication needs to be carefully considered.

Endorectal Ultrasonography and Pelvic Magnetic Resonance Imaging Show Similar Diagnostic Accuracy in Local Staging of Rectal Cancer: An Update Systematic Review and Meta-Analysis

BACKGROUND

Endorectal Ultrasonography (EUS-ERUS) and pelvic magnetic resonance imaging (MRI) are world-wide performed for the local staging of rectal cancer (RC), but no clear consensus on their indications is present, there being literature in support of both. The aim of this meta-analysis is to give an update regarding the diagnostic test accuracy of ERUS and pelvic MRI about the local staging of RC.

MATERIALS AND METHODS

A systematic literature search from November 2020 to October 2021 was performed to select studies in which head-to-head comparison between ERUS and MRI was reported for the local staging of rectal cancer. Quality and risk of bias were assessed with the QUADAS-2 tool. Our primary outcome was the T staging accuracy of ERUS and MRI for which pooled accuracy indices were calculated using a bivariable random-effects model. In addition, a hierarchical summary receiver operating characteristic curve (hSROC) was created to characterize the accuracy of ERUS and MRI for the staging of T and N parameters. The area under the hSROC curve (AUChSROC) was determined as a measure of diagnostic accuracy.

RESULTS

Seven studies and 331 patients were included in our analysis. ERUS and MRI showed a similar accuracy for the T staging, with AUChSROC curves of 0.91 (95% C.I., 0.89 to 0.93) and 0.87 (95% C.I., 0.84 to 0.89), respectively (p = 0.409). For T staging, ERUS showed a pooled sensitivity of 0.82 (95% C.I. 0.72 to 0.89) and pooled specificity of 0.91 (95% C.I. 0.77-0.96), while MRI had pooled sensitivity and specificity of 0.69 (95% C.I. 0.55-0.81) and 0.88 (95% C.I. 0.79-0.93), respectively. ERUS and MRI showed a similar accuracy in the N staging too, with AUChSROC curves of 0.92 (95% C.I., 0.89 to 0.94) and 0.93 (95% C.I., 0.90 to 0.95), respectively (p = 0.389).

CONCLUSIONS

In conclusion, ERUS and MRI are comparable imaging techniques for the local staging of rectal cancer.

Significant decrease of the pathological stage I rectal carcinoma in the era of neoadjuvant therapy-A matter of concern

BACKGROUND

Neoadjuvant treatment (nTx) for rectal cancer is commonly reserved for UICC stages II/III. Patients with stage I tumours (T1-2N0M0) are not candidates for nTx. The accuracy of treatment allocation depends on the precision of clinical staging, which is liable to understaging and overstaging. The study aimed at exploring changes in the proportion of stage pI patients with the introduction of nTx over a 26-year period.

MATERIALS AND METHODS

All consecutive patients with histologically proven rectal cancer excluding carcinoma in situ were retrieved from a prospective database of our colorectal unit. Time periods were defined as per the use of nTx: baseline phase 1994-1997; implementation phase 1998-2005 and guideline phase 2006-2019. Trends over time regarding proportion of applied nTx and stage pI tumours were investigated.

RESULTS

Overall, 1468 patients met the inclusion criteria. There were no major differences in patients' characteristics, especially proportion of synchronous metastases (stage IV) over time. nTx was applied to 1.2% of patients without metastases in the baseline phase, to 29.6% in the implementation phase, and to 59.6% in the guideline phase (p < 0.001). Corresponding proportions for patients with stage pI were 31.0%, 26.3% and 14.2%, respectively (p < 0.001).

CONCLUSION

With a stable proportion of stage IV carcinomas indicating no major changes in the patient cohorts, we could document a significant decrease of stage pI patients with increasing use of nTx. This trend clearly signals overtreatment caused by clinical T- and N-staging. More precise criteria are needed to better select patients with rectal cancer for nTx.

Can Post-Treatment MRI Features Predict Pathological Circumferential Resection Margin (pCRM) Involvement in Low Rectal Tumors

The MERCURY II study demonstrated the use of MRI-based risk factors such as extramural venous invasion (EMVI), tumor location, and circumferential resection margin (CRM) involvement to preoperatively predict pCRM (pathological CRM) outcomes for lower rectal tumors in a mixed group of upfront operated patients and patients who received neoadjuvant treatment. We aim to study the applicability of results of MERCURY II study in a homogeneous cohort of patients who received neoadjuvant chemoradiation (NACTRT) prior to surgery. After Institutional Review Board approval, post NACTRT restaging MRI of 132 patients operated for low rectal cancer between 2014 and 2018 were retrospectively reviewed by two radiologists for site of tumor, EMVI status, distance from anal verge (< 4 or > 4 cm), and mrCRM positivity. Findings were compared with post surgery pCRM outcomes using Fisher's exact test. Only 9/132(7%) patients showed pCRM involvement on histopathology, 8 of them being CRM positive on MRI (p = 0.01). The positive predictive value (PPV) of mrCRM positive status and pCRM status was 12.7% (95% CI: 9.7-16.5%), while the negative predictive value was 98.5% (95% CI: 91.4-99.8%) (p = 0.01). EMVI positive and anteriorly located tumors showed higher incidence of pCRM positivity but were not found to be significant (15% vs 5.2% and p = 0.13 and 8.6% vs 2.1% and p = 0.28, respectively). Unsafe mrCRM was the only factor significantly associated with pCRM positivity on post neoadjuvant restaging MRI. Tumors less than 4 cm from anal verge, anterior tumor location, and mrEMVI positivity did not show statistically significant results to predict pCRM involvement.

The Role of Micro-RNAs and Circulating Tumor Markers as Predictors of Response to Neoadjuvant Therapy in Locally Advanced Rectal Cancer

The response to neoadjuvant chemoradiation (nCRT) is a critical step in the management of locally advanced rectal cancer (LARC) patients. Only a minority of LARC patients responds completely to neoadjuvant treatments, thus avoiding invasive radical surgical resection. Moreover, toxic side effects can adversely affect patients' survival. The difficulty in separating in advances responder from non-responder patients affected by LARC highlights the need for valid biomarkers that guide clinical decision-making. In this context, microRNAs (miRNAs) seem to be promising candidates for predicting LARC prognosis and/or therapy response, particularly due to their stability, facile detection, and disease-specific expression in human tissues, blood, serum, or urine. Although a considerable number of studies involving potential miRNA predictors to nCRT have been conducted over the years, to date, the identification of the perfect miRNA signatures or single miRNA, as well as their use in the clinical practice, is still representing a challenge for the management of LARC patients. In this review, we will first introduce LARC and its difficult management. Then, we will trace the scientific history and the key obstacles for the identification of specific miRNAs that predict responsiveness to nCRT. There is a high potential to identify non-invasive biomarkers that circulate in the human bloodstream and that might indicate the LARC patients who benefit from the watch-and-wait approach. For this, we will critically evaluate recent advances dealing with cell-free nucleic acids including miRNAs and circulating tumor cells as prognostic or predictive biomarkers.

A Multicenter Matched Comparison of Transanal and Robotic Total Mesorectal Excision for Mid and Low-rectal Adenocarcinoma

OBJECTIVE

To compare the quality of surgical resection of transanal total mesorectal excision (TA-TME) and robotic total mesorectal excision (R-TME).

BACKGROUND

Both TA-TME and R-TME have been advocated to improve the quality of surgery for rectal cancer below 10 cm from the anal verge, but there are little data comparing TA-TME and R-TME.

METHODS

Data of patients undergoing TA-TME or R-TME for rectal cancer below 10 cm from the anal verge and a sphincter-saving procedure from 5 high-volume rectal cancer referral centers between 2011 and 2017 were obtained. Coarsened exact matching was used to create balanced cohorts of TA-TME and R-TME. The main outcome was the incidence of poor-quality surgical resection, defined as a composite measure including incomplete quality of TME, or positive circumferential resection margin (CRM) or distal resection margin (DRM).

RESULTS

Out of a total of 730 patients (277 TA-TME, 453 R-TME), matched groups of 226 TA-TME and 370 R-TME patients were created. These groups were well-balanced. The mean tumor height from the anal verge was 5.6 cm (SD 2.5), and 70% received preoperative radiotherapy. The incidence of poor-quality resection was similar in both groups (TA-TME 6.9% vs R-TME 6.8%; P = 0.954). There were no differences in TME specimen quality (complete or near-complete TA-TME 99.1% vs R-TME 99.2%; P = 0.923) and CRM (5.6% vs 6.0%; P = 0.839). DRM involvement may be higher after TA-TME (1.8% vs 0.3%; P = 0.051).

CONCLUSIONS

High-quality TME for patients with rectal adenocarcinoma of the mid and low rectum can be equally achieved by transanal or robotic approaches in skilled hands, but attention should be paid to the distal margin.

Circumferential Resection Margin After Laparoscopic and Open Rectal Resection: A Nationwide Propensity Score Matched Cohort Study

BACKGROUND

Recent studies suggest better oncological results after open versus laparoscopic rectal resection for cancer. The external validity of these results has not been tested on a nationwide basis.

OBJECTIVE

This study aimed to identify risk factors for positive circumferential resection margin in patients undergoing surgery for rectal cancer with special emphasis on surgical approach.

DESIGN

This database study was based on the Danish nationwide colorectal cancer database. To identify risk factors for positive circumferential resection margin, we performed uni- and multivariate logistic regression analyses. To assess the role of surgical approach, a propensity score-matched analysis was performed.

SETTINGS

This study was conducted at public hospitals across Denmark.

PATIENTS

Patients undergoing elective rectal resection from October 2009 through December 2013 were included.

MAIN OUTCOME MEASURES

The primary outcome measured was the risk of a positive circumferential resection margin.

RESULTS

Included in the final analyses were 2721 cases (745 operated on by an open approach; 1976 by laparoscopy). On direct comparison, positive circumferential resection margin occurred more often after open resection (6.3% vs 4.7%; p = 0.047). After multivariate analyses, tumors located low in the rectum, neoadjuvant chemoradiation therapy, increasing T and N stage, tumor fixated in the pelvis, and dissection in the muscularis plane increased the risk of a positive circumferential resection margin. In the propensity score-matched sample (541 exact matched pairs), the laparoscopic approach did not influence the risk of a positive circumferential resection margin (OR, 0.9; 95% CI, 0.6-1.5; p = 0.77).

LIMITATIONS

This was a retrospective review of prospectively collected data, and thereby contained possible selection bias.

CONCLUSIONS

Based on this nationwide database study, and after multivariate and propensity score-matched analyses, there was no increased risk of positive circumferential resection margin after laparoscopic vs open rectal resection. See Video Abstract at http://links.lww.com/DCR/A996. MARGEN DE RESECCIÓN CIRCUNFERENCIAL DESPUÉS DE LA RESECCIÓN RECTAL LAPAROSCÓPICA Y ABIERTA: UN ESTUDIO DE COHORTE DE PUNTUACIÓN DE PROPENSIÓN A NIVEL NACIONAL: Estudios recientes sugieren mejores resultados oncológicos después de la resección rectal abierta versus laparoscópica. La validez de estos resultados no se ha probado a nivel nacional.

OBJETIVO

Identificar los factores de riesgo del margen de resección circunferencial positivo en pacientes sometidos a cirugía por cáncer de recto con especial énfasis en el abordaje quirúrgico. DISEÑO:: Estudio de la base de datos nacional de Dinamarca de cáncer colorrectal. Para identificar los factores de riesgo del margen de resección circunferencial positivo, realizamos análisis de regresión logística uni y multivariable. Para evaluar el papel del abordaje quirúrgico, se realizó un análisis emparejado de puntuación de propensión.

AJUSTES

Hospitales públicos en toda Dinamarca.

PACIENTES

Pacientes sometidos a resección rectal electiva en el período comprendido entre octubre de 2009 y diciembre de 2013.

PRINCIPALES MEDIDAS DE RESULTADOS

Riesgo del margen de resección circunferencial positivo.

RESULTADOS

2721 casos (745 operados por abordaje abierto; 1976 por laparoscopia) se incluyeron en el análisis final. En la comparación directa, el margen de resección circunferencial positivo ocurrió más a frecuentemente, después de la resección abierta (6.3 vs 4.7%; p = 0.047). Posterior a los análisis multivariados, tumores localizados en el recto bajo, quimioterapia con radioterapia neoadyuvante, incremento de etapas T y la N, tumor fijo en pelvis y la disección en el plano muscular, aumentaron el riesgo del margen de resección circunferencial positivo. En la muestra emparejada del puntaje de propensión (541 pares coincidentes exactos), el abordaje laparoscópico no influyó en el riesgo del margen de resección circunferencial positivo (razón de probabilidades (IC 95%) 0.9 (0.6-1.5); p = 0.77).

LIMITACIONES

Revisión retrospectiva de los datos recopilados prospectivamente y por lo tanto, posible sesgo de selección.

CONCLUSIONES

El estudio de la base de datos a nivel nacional y después de los análisis emparejados multivariados y de puntuación de propensión, no hubo un mayor riesgo del margen de resección circunferencial positivo después de la resección laparoscópica versus resección abierta. Vea el Resumen del video en http://links.lww.com/DCR/A996.

Hospital and surgeon variation in positive circumferential resection margin among rectal cancer patients

BACKGROUND

The objective of this study was to evaluate variation in positive CRM at the surgeon and hospital levels and assess impact on disease-specific survival.

METHODS

Patients with stage I-III rectal cancer were identified in New York State. Bayesian hierarchical regressions estimated observed-to-expected (O/E) ratios for each surgeon/hospital. Competing-risks analyses estimated disease-specific survival among patients who were treated by surgeons/hospitals with O/E > 1 compared to those with O/E ratio ≤ 1.

RESULTS

Among 1,251 patients, 208 (17%) had a positive CRM. Of the 345 surgeons and 118 hospitals in the study, 99 (29%) and 48 (40%) treated a higher number of patients with CRM than expected, respectively. Patients treated by surgeons with O/E > 1 (HR = 1.38, 95% CI = 1.16, 1.67) and those treated at hospitals with O/E > 1 (HR = 1.44, 95% CI = 1.11, 1.85) had worse disease-specific survival.

DISCUSSION

Surgeon and hospital performance in positive CRM is associated with worse prognosis suggesting opportunities to enhance referral patterns and standardize care.

Nomograms for estimating survival in patients with liver-only colorectal metastases: A retrospective study

BACKGROUND

The aim of this study was to develop and validate nomograms for individual risk prediction in patients with liver-only colorectal metastases (CRLM).

METHODS

Histologically confirmed CRLM diagnosed between 2010 and 2015 were analysed from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate analyses were used to obtain independent prognostic factors to build nomograms for predicting 1- and 3-year overall survival (OS) and cancer-specific survival (CSS). The predictive accuracy of the nomogram was determined by concordance index (C-index) and calibration plots.

RESULTS

A total of 9615 patients with CRLM were included in the study. A nomogram predicting OS was constructed according to 9 independent clinicopathological factors. A nomogram predicting CSS was constructed based on the same 9 factors. The C-indexes of the nomograms were significantly better than the TNM staging system (7th edition) in both sets for predicting both OS and CSS. The calibration plots displayed an optimal agreement between the predictive results and the actual observed outcomes.

CONCLUSIONS

The proposed nomograms can help clinicians calculate the probability in patients with CRLM.

Superior mesenteric artery margin in pancreaticoduodenectomy for pancreatic adenocarcinoma

The aim of this study is trying to describe more details of superior mesenteric artery margin in pancreaticoduodenectomy for pancreatic ductal adenocarcinoma, to evaluate biological and prognostic implications of tumor budding in this margin, and to provide more evidence for evaluation of R0 surgery in pancreaticoduodenectomy. 46 patients in 5-years period are included in this study. Immunochemistry and immunofluorescence are used to analyze tumor budding and epithelial-mesenchymal transition. Superior mesenteric artery margin might be described from four aspects including location, gross appearance, microscopic appearance and tumor budding. We find that 1mm rule for R1 surgery is more appropriate to predict prognosis (P = 0.009) than 0mm rule (P = 0.141). Expression of cytokeratin in tumor budding is significantly lower than primary tumor (P = 0.001), and it suggests that tumor budding may participate the procedure of epithelial-mesenchymal transition. High-grade tumor budding and decreasing cytokeratin of tumor budding correlate with distant metastasis and has negative influence on prognosis. So superior mesenteric artery margin might be not only an area that tumor cells may invade, but also a pathway for distant metastasis. It is necessary to evaluate superior mesenteric artery margin in pancreaticoduodenectomy for pancreatic cancer.