Need for objective and reproducible criteria in histopathological assessment of total mesorectal excision specimens: lessons from a national improvement project

Discordance in Total Mesorectal Excision Specimen Grading in a Prospective Phase 2 Multicenter Rectal Cancer Trial: Are We Overestimating the Quality of Our Resections?

OBJECTIVES

To report the results of a rigorous quality control (QC) process in the grading of total mesorectal excision (TME) specimens during a multicenter prospective phase 2 trial of transanal TME.

BACKGROUND

Grading of TME specimens is based on the macroscopic assessment of the mesorectum and standardized through synoptic pathology reporting. TME grade is a strong predictor of outcomes with incomplete (IC) TME associated with increased rates of local recurrence relative to complete or near complete (NC) TME. Although TME grade serves as an endpoint in most rectal cancer trials, in protocols incorporating centralized review of TME specimens for quality assurance, discordance in grading and the management thereof has not been previously described.

METHODS

A phase 2 prospective transanal TME trial was conducted from 2017 to 2022 across 11 North American centers with TME quality as the primary study endpoint. QC measures included (1) training of site pathologists in TME protocols, (2) blinded grading of de-identified TME specimen photographs by central pathologists, and (3) reconciliation of major discordance before trial reporting. Cohen Kappa statistic was used to assess agreement in grading.

RESULTS

Overall agreement in grading of 100 TME specimens between site and central reviewer was rated as fair, (κ = 0.35; 95% CI: 0.10-0.61; P < 0.0001). Concordance was noted in 54%, with minor and major discordance in 32% and 14% of cases, respectively. Upon reconciliation, 13/14 (93%) major discordances were resolved. Pre versus postreconciliation rates of complete or NC and IC TME are 77%/16% and 7% versus 69%/21% and 10%. Reconciliation resulted in a major upgrade (IC-NC; N = 1) or major downgrade (NC/C-IC, N = 4) in 5 cases overall (5%).

CONCLUSIONS

A 14% rate of major discordance was observed in TME grading between the site and central reviewers. The resolution resulted in a major change in final TME grade in 5% of cases, which suggests that reported rates or TME completeness are likely overestimated in trials. QC through a central review of TME photographs and reconciliation of major discordances is strongly recommended.

Standard Lymphadenectomy for Esophageal and Lung Cancer: Variability in the Number of Examined Lymph Nodes Among Pathologists and Its Survival Implication

AIM

We compared variability in number of examined lymph nodes between pathologists and analyzed survival implications in lung and esophageal cancer after standardized lymphadenectomy.

METHODS

Outcomes of 294 N2 dissected lung cancer patients and 132 2-field dissected esophageal cancer patients were retrospectively examined. The primary outcome was difference in reported lymph node count among pathologists. Secondary outcomes were overall and disease-specific survival related to this count and survival related to the 50% probability cut-off value of detecting metastasis based on the number of examined lymph nodes.

RESULTS

The median number of examined lymph nodes in lung cancer was 13 (IQR 9-17) and in esophageal cancer it was 22 (18-29). The pathologist with the highest median number of examined nodes had > 50% higher lymph node yield compared with the pathologist with the lowest median number of nodes in lung (15 vs. 9.5, p = 0.003), and esophageal cancer (28 vs. 17, p = 0.003). Survival in patients stratified by median reported lymph node count in both lung (adjusted RMST ratio < 14 vs. ≥ 14 lymph nodes 0.99, 95% CI 0.88-1.10; p = 0.810) and esophageal cancer (adjusted RMST ratio < 25 vs. ≥ 25 lymph nodes 0.95, 95% CI 0.79-1.15, p = 0.612) was similar. The cut-off value for 50% probability of detecting metastasis by number of examined lymph nodes in lung cancer was 15.7 and in esophageal cancer 21.8. When stratified by this cut-off, no survival differences were seen.

CONCLUSION

The quality of lymphadenectomy based on lymph node yield is susceptible to error due to detected variability between pathologists in the number of examined lymph nodes. This variability in yield did not have any survival effect after standardized lymphadenectomy.

Crohn's versus Cancer: Comparison of Functional and Surgical Outcomes after Right-Sided Resections

BACKGROUND

The objective of this study was to compare functional and surgical outcomes of patients undergoing ileocecal resection for Crohn's disease (CD) to patients undergoing oncological right colectomy.

METHODS

Retrospective single-center cohort study including consecutive patients undergoing right colectomy for adenocarcinoma (oncological resection) or CD (mesentery-sparing resection) between July 2011 and November 2017. Outcome measures were pathological details (lymph node yield), postoperative recovery (pain levels, return to flatus and stool, intake of fluids, weight change, and mobilization), and early (30-day) outcomes (surgical/medical complications, hospital stay, readmissions).

RESULTS

A total of 195 patients (153 [78%] with cancer and 42 [22%] with CD) were included. Overall compliance with the institutional enhanced recovery protocol was comparable between the 2 groups (compliance ≥70%: 60% in CD patients vs. 62% in cancer, p = 0.458). The adenocarcinoma group had a larger lymph node yield than the CD group (26 ± 13 vs. 2.4 ± 5, respectively, p < 0.001). While the CD group experienced significantly more pain (3.7 ± 1.9/10 vs. 2.8 ± 2.5/10, p = 0.007, patients requiring opioids: 65 vs. 28%, p = 0.001), return of flatus (2.3 ± 1.2 days vs. 2.4 ± 2.8 days, p = 0.642) and stool (4.1 ± 6.0 vs. 3.0 ± 1.8 days, p = 0.292) was no different in both groups. No difference was observed regarding postoperative complications, length of stay, and readmission rate.

CONCLUSION

This study revealed no differences in both functional and surgical outcomes in CD and cancer patients undergoing mesentery-sparing or formal oncological right colectomy, respectively.

Uptake of Total Mesorectal Excision and Total Mesorectal Excision Grading for Rectal Cancer: A Statewide Study

BACKGROUND

Total mesorectal excision is associated with decreased local recurrence and improved disease-free survival following rectal cancer resection. The extent to which total mesorectal excision has been adopted in the United States is unknown.

OBJECTIVE

We sought to assess trends in total mesorectal excision performance and grading in Michigan hospitals.

DESIGN

This is a retrospective cohort study from the Michigan Surgical Quality Collaborative. Trends in total mesorectal excision performance and grade assignment were analyzed by using χ tests and linear regression.

SETTINGS

Participating hospitals (initially 14 hospitals, now 38) abstracted medical records data for rectal cancer cases from 2007 to 2016.

PATIENTS

Patients who underwent rectal cancer resection were included.

MAIN OUTCOME MEASURE

The main outcome measures were surgeon-documented total mesorectal excision performance and pathologist-reported total mesorectal excision grade.

RESULTS

Of 510 rectal cancer cases, 367 (72.0%) had surgeon-reported total mesorectal excision performance and 78 (15.3%) had pathologist-reported total mesorectal excision grade. Between-hospital variability in total mesorectal excision performance ranged from 0% to 97% and total mesorectal excision grading ranged from 0% to 90%. Total mesorectal excision grading was associated with a higher likelihood of also having adequate lymph node assessment (88.5% versus 71.9%, p = 0.002). There has been a statistically significant trend toward an increase in total mesorectal excision grading in the original 14 hospitals (p = 0.001), but not in the complete cohort of all hospitals (p = 0.057).

LIMITATIONS

This is a retrospective cohort design with sampled rectal cancer cases. In addition, there is insufficient granularity to capture all factors associated with total mesorectal excision performance or grade assignment.

CONCLUSIONS

The rates of total mesorectal excision performance and grade assignment are widely variable throughout the state of Michigan. Overall, grade assignment remains very low. This suggests an opportunity for quality improvement projects to increase total mesorectal excision performance and grading, involving both the surgeons and pathologists for effective implementation. See Video Abstract at http://links.lww.com/DCR/B53. IMPLEMENTACIÓN DE LA ESCISIÓN MESORRECTAL TOTAL Y LA CLASIFICACIÓN POR ESCISIÓN MESORRECTAL TOTAL PARA EL CÁNCER RECTAL: UN ESTUDIO A NIVEL ESTATAL.: La escisión mesorrectal total se asocia con una menor recurrencia local y una mejor supervivencia libre de enfermedad después de la resección del cáncer rectal. Se desconoce hasta que punto se ha adoptado la escisión mesorrectal total en los Estados Unidos.Se intento evaluar las tendencias en el rendimiento y la clasificación de la escisión mesorrectal total en los hospitales de Michigan.Este es un estudio de cohorte retrospectivo de la "Michigan Surgical Quality Collaborative". Las tendencias en el rendimiento de la escisión mesorrectal total y la asignación de grado se analizaron mediante pruebas de chi-cuadrada y regresión lineal.Los hospitales participantes (inicialmente 14 hospitales, ahora 38) extrajeron datos de registros médicos de los casos de cáncer rectal desde 2007 hasta 2016.Pacientes que se sometieron a resección de cáncer rectal.Las principales medidas de resultado fueron el rendimiento de la escisión mesorrectal total documentado por el cirujano y el grado de escisión mesorrectal total informada por el patólogo.De 510 casos de cáncer rectal, 367 (72.0%) tenían un rendimiento de escisión mesorrectal total reportado por el cirujano y 78 (15.3%) tenían un grado de escisión mesorrectal total reportado por el patólogo. La variabilidad entre hospitales en el rendimiento de la escisión mesorrectal total varió del 0 al 97% y la clasificación de la escisión mesorrectal total varió del 0 al 90%. La clasificación de la escisión mesorrectal total se asoció con una mayor probabilidad de tener también una evaluación adecuada de los ganglios linfáticos (88.5% versus 71.9%, p = 0.002). Ha habido una tendencia estadísticamente significativa hacia un aumento en la clasificación de la escisión mesorrectal total en los 14 hospitales originales (p = 0.001), pero no en la cohorte completa de todos los hospitales (p = 0.057).Diseño de cohorte retrospectivo con casos de cáncer rectal muestreados. Además, no hay suficiente granularidad para capturar todos los factores asociados con el rendimiento de la escisión mesorrectal total o la asignación de grados.Las tasas de rendimiento de escisión mesorrectal total y asignación de grado son muy variables en todo el estado de Michigan. En general, la asignación de calificaciones sigue siendo muy baja. Esto sugiere una oportunidad para que los proyectos de mejora de la calidad aumenten el rendimiento y la clasificación de la escisión mesorrectal total, involucrando tanto a los cirujanos como a los patólogos para una implementación efectiva. Vea el resumen del video en http://links.lww.com/DCR/B53.

Effect of abdominopelvic sepsis on cancer outcome in patients undergoing sphincter saving surgery for rectal cancer

BACKGROUND

In rectal cancer, the significance of abdominopelvic sepsis (APS) on metastatic tumor growth remains uncertain. We aimed to analyze the effect of abdominopelvic sepsis on long-term survival in patients undergoing restorative rectal cancer surgery.

METHODS

Data were used from the Belgian PROCARE rectal cancer registry. The effect of abdominopelvic infection on survival was assessed in uni- and multivariable Cox regression models. The effect of clinical and pathological covariates was controlled by propensity score-based matching of cases with controls. The effect of abdominopelvic sepsis on the rate of local and metastatic recurrence was evaluated using crosstabulation and the Pearson χ² test.

RESULTS

In univariable analysis, the presence of APS was associated with significantly worse overall survival (HR 1.3, P = 0.025). After propensity score matching including age, BMI, tumor level, pTstage, pN stage, CRM, tumor grade, number of lymph nodes, and presence of lymphovascular invasion, the association of APS with OS was no longer significant (HR 1.26, 95%CI 0.92-1.74, P = 0.15). No differences were observed in the risk of local or metastatic recurrence (3.6% vs 2.9% and 13% vs 16.5%).

CONCLUSIONS

In this analysis APS after rectal cancer resection was not significantly associated with OS, metastatic, or local recurrence.

Effect of increasing radiation dose on pathologic complete response in rectal cancer patients treated with neoadjuvant chemoradiation therapy

BACKGROUND

Neoadjuvant chemoradiation therapy (CRT) increases pathological complete response (pCR) rates compared to radiotherapy alone in patients with stage II-III rectal cancer. Limited evidence addresses whether radiotherapy dose escalation further improves pCR rates. Our purpose is to measure the effects of radiotherapy dose and other factors on post-therapy pathologic tumor (ypT) and nodal stage in rectal cancer patients treated with neoadjuvant CRT followed by mesorectal excision.

MATERIAL AND METHODS

A non-randomized comparative effectiveness analysis was performed of rectal cancer patients treated in 2000-2013 from the National Oncology Data Alliance™ (NODA), a pooled database of cancer registries from >150 US hospitals. The NODA contains the same data submitted to state cancer registries and SEER combined with validated radiotherapy and chemotherapy records. Eligible patients were treated with neoadjuvant CRT followed by proctectomy and had complete data on treatment start dates, radiotherapy dose, clinical tumor (cT) and ypT stage, and number of positive nodes at surgery (n = 3298 patients). Multivariable logistic regression was used to assess the predictive value of independent variables on achieving a pCR.

RESULTS

On multivariable regression, radiotherapy dose, cT stage, and time interval between CRT and surgery were significant predictors of achieving a pCR. After adjusting for the effect of other variates, patients treated with higher radiotherapy doses were also more likely to have negative nodes at surgery and be downstaged from cT3-T4 and/or node positive disease to ypT0-T2N0 after neoadjuvant CRT.

CONCLUSION

Our study suggests that increasing dose significantly improved pCR rates and downstaging in rectal cancer patients treated with neoadjuvant CRT followed by surgery.

Significant Individual Variation Between Pathologists in the Evaluation of Colon Cancer Specimens After Complete Mesocolic Excision

BACKGROUND

After the introduction of complete mesocolic excision, a new pathological evaluation of the resected colon cancer specimen was introduced. This concept has quickly gained acceptance and is often used to compare surgical quality. The grading of colon cancer specimens is likely to depend on both surgical quality and the training of the pathologist.

OBJECTIVE

The purpose of this study was to validate the principles of the pathological evaluation of colon cancer specimens.

DESIGN

This was an exploratory study.

SETTINGS

The study was conducted in Aarhus, Denmark, and Leeds, United Kingdom.

PATIENTS

Colon cancers specimens were used.

MAIN OUTCOME MEASURES

The agreement of gradings between participants was of interest. Four specialist GI pathologists and 2 abdominal surgeons evaluated 2 rounds of colon cancer specimens, each at 2 separate time points. Each round contained 50 specimens. After the first round, a protocol of detailed principles for the grading procedure was agreed on. Results from an experienced pathologist were considered as the reference results.

RESULTS

In the first round, the distribution of gradings between participants showed substantial variation. In the second round, the variation was reduced. Intraobserver agreement was mostly fair to good, whereas interobserver agreement was frequently poor. This did not significantly change from round 1 to round 2.

LIMITATIONS

The small sample size of 100 specimens provided a very small number of specimens resected in the muscularis propria plane, which renders the evaluation of this group potentially unreliable. The evaluations were made on photos and not on fresh specimens.

CONCLUSIONS

This study demonstrates significant variation in the pathological evaluation of colon cancer specimens. It demonstrates that it cannot be used in clinical studies, and care should be taken when comparing results between different hospitals.

Review of the quality of total mesorectal excision does not improve the prediction of outcome

AIM

A fair to moderate concordance in grading of the total mesorectal excision (TME) surgical specimen by local pathologists and a central review panel has been observed in the PROCARE (Project on Cancer of the Rectum) project. The aim of the present study was to evaluate the difference, if any, in the accuracy of predicting the oncological outcome through TME grading by local pathologists or by the review panel.

METHOD

The quality of the TME specimen was reviewed for 482 surgical specimens registered on a prospective database between 2006 and 2011. Patients with a Stage IV tumour, with unknown incidence date or without follow-up information were excluded, resulting in a study population of 383 patients. Quality assessment of the specimen was based on three grades including mesorectal resection (MRR), intramesorectal resection (IMR) and muscularis propria resection (MPR). Using univariable Cox regression models, local and review panel histopathological gradings of the quality of TME were assessed as predictors of local recurrence, distant metastasis and disease-free and overall survival. Differences in the predictions between local and review grading were determined.

RESULTS

Resection planes were concordant in 215 (56.1%) specimens. Downgrading from MRR to MPR was noted in 23 (6.0%). There were no significant differences in the prediction error between the two models; local and central review TME grading predicted the outcome equally well.

CONCLUSION

Any difference in grading of the TME specimen between local histopathologists and the review panel had no significant impact on the prediction of oncological outcome for this patient cohort. Grading of the quality of TME as reported by local histopathologists can therefore be used for outcome analysis. Quality control of TME grading is not warranted provided the histopathologist is adequately trained.

Effect of Neoadjuvant Radiation Dose and Schedule on Nodal Count and Its Prognostic Impact in Stage II-III Rectal Cancer

BACKGROUND

It is unknown how neoadjuvant treatment schedule affects lymph node count (LNC) and lymph node ratio (LNR) and how these correlate with overall survival (OS) in rectal cancer (RC).

METHODS

Data were used from the Belgian PROCARE rectal cancer registry on RC patients treated with surgery alone, short-term radiotherapy with immediate surgery (SRT), or chemoradiation with deferred surgery (CRT). The effect of neoadjuvant therapy on LNC was examined using Poisson log-linear analysis. The association of LNC and LNR with overall survival (OS) was studied using Cox proportional hazards models.

RESULTS

Data from 4037 patients were available. Compared with surgery alone, LNC was reduced by 12.3 % after SRT and by 31.3 % after CRT (p < 0.001). In patients with surgery alone, the probability of finding node-positive disease increased with LNC, while after SRT and CRT no increase was noted for more than 12 and 18 examined nodes, respectively. Per node examined, we found a decrease in hazard of death of 2.7 % after surgery alone and 1.5 % after SRT, but no effect after CRT. In stage III patients, the LNR but not (y)pN stage was significantly correlated with OS regardless of neoadjuvant therapy. Specifically, a LNR > 0.4 was associated with a significantly worse outcome.

CONCLUSIONS

Nodal counts are reduced in a schedule-dependent manner by neoadjuvant treatment in RC. After chemoradiation, the LNC does not confer any prognostic information. A LNR of >0.4 is associated with a significantly worse outcome in stage III disease, regardless of neoadjuvant therapy type.

Impact of Total Lymph Node Count on Staging and Survival After Neoadjuvant Chemoradiation Therapy for Rectal Cancer

PURPOSE

Current guidelines recommend that a minimum of 12 lymph nodes (LNs) be dissected to accurately stage rectal cancer patients. Neoadjuvant chemoradiation therapy (CRT) decreases the number of LNs retrieved at surgery. The purpose of this study was to assess the impact of the number of LNs dissected on overall survival (OS) for localized rectal cancer patients treated with neoadjuvant CRT.

METHODS

Treatment data were obtained on all patients treated for rectal cancer (2000-2013) in the National Oncology Data Alliance™, a proprietary database of merged tumor registries. Eligible patients were treated with neoadjuvant CRT followed by surgery and had complete data on number of positive LNs, number of LNs examined, and treatment dates (n = 4565).

RESULTS

Hazard ratios for OS decreased sequentially with increasing number of LNs examined until a maximum benefit was achieved with examination of eight LNs. On multivariate analysis, age, sex, race, marital status, grade, ypT stage, ypN stage, type of surgery, margin status, presence of pathologically confirmed metastasis at surgery, and number of LNs examined were significant predictors of OS.

CONCLUSIONS

Examination of eight or more LNs in rectal cancer patients treated with neoadjuvant CRT resulted in accurate staging and assignment into prognostic groups with an ensuing improvement in OS by stage. This study suggests that eight LNs is the threshold for an adequate lymph node dissection after neoadjuvant CRT.

Pathologic processing of the total mesorectal excision

Total mesorectal excision (TME) is the current optimal surgical treatment for patients with rectal carcinoma. A complete TME is related to lower local recurrence rates and increased patient survival. Many confounding factors in the patient's anatomy and prior therapy can make it difficult to obtain a perfect plane, and thus a complete TME. The resection specimen can be thoroughly evaluated, grossly and microscopically, to identify substandard surgical outcomes and increased risk of local recurrence. Complete and accurate data reporting is critical for patient care and helps surgeons improve their technique.