Characteristics of Mismatch Repair-Deficient Colon Cancer in Relation to Mismatch Repair Protein Loss, Hypermethylation Silencing, and Constitutional and Biallelic Somatic Mismatch Repair Gene Pathogenic Variants.

BACKGROUND: Mismatch repair-deficient colon cancer is heterogeneous. Differentiating inherited constitutional variants from somatic genetic alterations and gene silencing is important for surveillance and genetic counseling. OBJECTIVE: This study aimed to determine the extent to which the underlying mechanism of loss of mismatch repair influences molecular and clinicopathologic features of microsatellite instability-high colon cancer. DESIGN: This is a retrospective analysis. SETTINGS: This study was conducted at a comprehensive cancer center. PATIENTS: Patients with microsatellite instability-high colon cancer of stage I, II, or III were included. INTERVENTION: Patients underwent a curative surgical resection. MAIN OUTCOME MEASURES: The main outcome measures were hypermethylation of the MLH1 promoter, biallelic inactivation, constitutional pathogenic variants, and loss of specific mismatch repair proteins. RESULTS: Of the 157 identified tumors with complete genetic analysis, 66% had hypermethylation of the MLH1 promoter, 18% had constitutional pathogenic variants, (Lynch syndrome), 11% had biallelic somatic mismatch repair gene pathogenic variants, and 6% had unexplained high microsatellite instability. The distribution of mismatch repair loss was as follows: MLH1 and PMS2 co-loss, 79% of the tumors; MSH2 and MSH6 co-loss, 10%; MSH6 alone, 3%; PMS2 alone, 2%; other combinations, 2%; no loss, 2%. Tumor mutational burden was lowest in MLH1- and PMS2-deficient tumors. MSH6-deficient tumors had the lowest levels of tumor-infiltrating lymphocytes, lowest MSI scores, and fewest frameshift deletions. Patients with MLH1 promoter hypermethylation were significantly more likely to be older and female and to have right-sided colon lesions than patients with biallelic inactivation. Mutation was the most prevalent second hit in tumors with biallelic inactivation and tumors of patients with Lynch syndrome. LIMITATIONS: This study was limited by potential selection or referral bias, missing data for some patients, and relatively small sizes of some subgroups. CONCLUSIONS: Clinical characteristics of mismatch repair-deficient colon cancer vary with the etiology of microsatellite instability, and its molecular characteristics vary with the affected mismatch repair protein. See Video Abstract at http://links.lww.com/DCR/B984 . CARACTERSTICAS DEL CNCER DE COLON CON DEFICIENCIA EN LA REPARACIN DE ERRORES DE EMPAREJAMIENTO EN RELACIN CON LA PRDIDA DE PROTENAS MMR, SILENCIAMIENTO DE LA HIPERMETILACIN Y LAS VARIANTES PATGENAS SOMTICAS DE GENES MMR CONSTITUCIONAL Y BIALLICO: ANTECEDENTES:El cáncer de colon deficiente en la reparación de errores de emparejamiento es heterogéneo. La diferenciación de las variantes constitucionales heredadas de las alteraciones genéticas somáticas y el silenciamiento de genes es importante para la vigilancia y el asesoramiento genético.OBJETIVO:Determinar hasta qué punto el mecanismo subyacente de pérdida de reparación de desajustes influye en las características moleculares y clinicopatológicas del cáncer de colon con alta inestabilidad de microsatélites.DISEÑO:Análisis retrospectivo.ESCENARIO:Centro integral de cáncer.PACIENTES:Pacientes con cáncer de colon con inestabilidad de microsatélites alta en estadio I, II, o III.INTERVENCIÓN:Resección quirúrgica con intención curativa.PRINCIPALES RESULTADOS Y MEDIDAS:Hipermetilación del promotor MLH1, inactivación bialélica, variante patógena constitucional y pérdida de proteínas específicas reparadoras de desajustes.RESULTADOS:De los 157 tumores identificados con un análisis genético completo, el 66 % tenía hipermetilación del promotor MLH1, el 18 % tenía una variante patogénica constitucional (síndrome de Lynch), el 11 % tenía variantes patogénicas somáticas bialélicas de algún gen MMR y el 6 % tenía una alta inestabilidad de microsatélites sin explicación. La distribución de la pérdida según la proteína de reparación del desajuste fue la siguiente: pérdida conjunta de MLH1 y PMS2, 79 % de los tumores; co-pérdida de MSH2 y MSH6, 10%; MSH6 solo, 3%; PMS2 solo, 2%; otras combinaciones, 2%; sin pérdida, 2%. La carga mutacional del tumor fue más baja en los tumores deficientes en MLH1 y PMS2. Los tumores con deficiencia de MSH6 tenían los niveles más bajos de linfocitos infiltrantes de tumores, las puntuaciones más bajas del sensor de IMS y la menor cantidad de deleciones por cambio de marco. Los pacientes con hipermetilación del promotor MLH1 tenían significativamente más probabilidades de ser mayores y mujeres y de tener lesiones en el colon derecho que los pacientes con inactivación bialélica. La mutación fue el segundo golpe más frecuente en tumores con inactivación bialélica y tumores de pacientes con síndrome de Lynch.LIMITACIONES:Sesgo potencial de selección o referencia, datos faltantes para algunos pacientes y tamaños relativamente pequeños de algunos subgrupos.CONCLUSIONES:Las características clínicas del cáncer de colon deficiente en reparación de desajustes varían con la etiología de la inestabilidad de microsatélites, y sus características moleculares varían con la proteína de reparación de desajustes afectada. Vea Resumen de video en http://links.lww.com/DCR/B984 . (Traducción-Dr. Felipe Bellolio ).

The Benefits and Drawbacks of Staging Pelvic Pouches.

Since the mid-20th century, physicians have searched for way to improve the lives of patients with ulcerative colitis (UC). Early attempts of curative resection left the patients with a permanent stoma with only primitive stoma appliances available. Gradually, stoma care improved and operations were devised to give the patient bowel continuity without the need for a permanent ostomy. As these operations were evolving, benefits and drawbacks related to fertility, ease of small bowel reach to the pelvis, and postoperative pelvic sepsis were observed. In this article, we will elucidate the various ways pelvic pouches are used to treat UC and the rationale for the timing of surgery as well as the evolution of stoma care.

Underrepresented Minorities in Surgical Residencies: Where are They? A Call to Action to Increase the Pipeline.

OBJECTIVE: To describe and evaluate trends of general surgery residency applicants, matriculants, and graduates over the last 13 years. SUMMARY OF BACKGROUND DATA: The application and matriculation rates of URMs to medical school has remained unchanged over the last three decades with Blacks and Hispanics representing 7.1% and 6.3% of matriculants, respectively. With each succession along the surgical career pathway, from medical school to residency to a faculty position, the percentage of URMs decreases. METHODS: The Electronic Residency Application Service to General Surgery Residency and the Graduate Medical Education Survey of residents completing general surgery residency were retrospectively analyzed (2005-2018). Data were stratified by race, descriptive statistics were performed, and time series were charted. RESULTS: From 2005 to 2018, there were 71,687 Electronic Residency Application Service applicants to general surgery residencies, 26,237 first year matriculants, and 24,893 general surgery residency graduates. Whites followed by Asians represented the highest percentage of applicants (n = 31,197, 43.5% and n = 16,602, 23%), matriculants (n = 16,395, 62.5% and n = 4768, 18.2%), and graduates (n = 15,239, 61% and n = 4804, 19%). For URMs, the applicants (n = 8603, 12%, P < 0.00001), matriculants (n = 2420, 9.2%, P = 0.0158), and graduates (n = 2508, 10%, P = 0.906) remained significantly low and unchanged, respectively, whereas the attrition was significantly higher (3.6%, P = 0.049) when compared to Whites (2.6%) and Asians (2.9%). CONCLUSION: Significant disparities in the application, matriculation, graduation, and attrition rates for general surgery residency exists for URMs. A call to action is needed to re-examine and improve existing recommendations/paradigms to increase the number of URMs in the surgery training pipeline.

The Impact of Primary Care Providers on Patient Screening Mammography and Initial Presentation in an Underserved Clinical Setting.

INTRODUCTION: Cancer screening is a key component of primary care, and access to regular screening mammography (SMG) is highly dependent on recommendation and referral by a primary care provider (PCP). Women with no health insurance or who are underinsured often lack access to a regular PCP and thus access to routine screening. METHODS: We retrospectively reviewed the charts of 173 surgical patients diagnosed between January 2012 and December 2013. The main outcome variables were PCP status, method of cancer detection, and breast cancer stage at diagnosis. Additional variables included race, age at diagnosis, family history of breast and ovarian cancer, and medical comorbidities. RESULTS: Patients with a PCP received more mammograms (SMG) compared with patients without a PCP (61 vs. 37 %; p = 0.003). The majority (73 %) of patients without a PCP presented symptomatically with a palpable mass versus 42 % of patients with a PCP. A significant difference was noted with regard to final pathologic stage of breast cancer between the two groups (p = 0.019), and Caucasian and African American patients were more likely to have locally advanced breast cancer. CONCLUSIONS: Underserved patients with a PCP are more likely to present asymptomatically and at an earlier stage of breast cancer compared with patients without a PCP. Community engagement programs that build relationships with patients may help bring vulnerable patients into the healthcare system for routine screening. Moreover, PCP education regarding the subtleties of breast cancer screening guidelines and referral to a breast specialist is also critical in improving outcomes of underserved patients.

A Call to Action to Train Underrepresented Minorities in Surgical Subspecialties and Fellowships.

BACKGROUND: With each succession along the surgical career pathway, from medical school to faculty, the percentage of those who identify as underrepresented in medicine (URiM) decreases. We sought to evaluate the demographic trend of surgical fellowship applicants, matriculants, and graduates over time. STUDY DESIGN: The Electronic Residency Application Service and the Graduate Medical Education Survey for general surgery fellowships in colorectal surgery, surgical oncology, pediatric surgery, thoracic surgery, and vascular surgery were retrospectively analyzed (2005 to 2020). The data were stratified by race and gender, descriptive statistics were performed, and time series were evaluated. Race/ethnicity groups included White, Asian, other, and URiM, which is defined as Black/African American, Hispanic/Latino(a), Alaskan or Hawaiian Native, and Native American. RESULTS: From 2005 to 2020, there were 5,357 Electronic Residency Application Service applicants, 4,559 matriculants, and 4,178 graduates to surgery fellowships. Whites, followed by Asians, represented the highest percentage of applicants (62.7% and 22.3%, respectively), matriculants (65.4% and 23.8% respectively), and graduates (65.4% and 24.0%, respectively). For URiMs, the applicants (13.4%), matriculants (9.1%), and graduates (9.1%) remained significantly low (p < 0.001). When stratified by both race and gender, only 4.6% of the applicants, 2.7% of matriculants, and 2.4% of graduates identified as both URiM and female compared to White female applicants (20.0%), matriculants (17.9%), and graduates (16.5%, p < 0.001). CONCLUSIONS: Significant disparities exist for URiMs in general surgery subspecialty fellowships. These results serve as a call to action to re-examine and improve the existing processes to increase the number of URiMs in the surgery subspecialty fellowship training pathway.

Intratumoral T-cell repertoires in DNA mismatch repair-proficient and -deficient colon tumors containing high or low numbers of tumor-infiltrating lymphocytes.

Colon tumors with deficient DNA mismatch repair (dMMR) are generally infiltrated by T cells more densely than tumors with proficient mismatch repair (pMMR). However, high numbers of tumor-infiltrating lymphocytes (TILs) are found in select pMMR tumors, and low numbers of TILs are seen in select dMMR tumors. In this study, we compared T-cell repertoires in 20 pMMR and 27 dMMR colon tumors with high and low TIL counts. We found that T cells in dMMR tumors are more clonal and their repertoire is less rich compared with T cells in pMMR tumors. In the dMMR group, T cells in TIL-high tumors were more clonal and their repertoire was less rich compared with T cells in TIL-low tumors, but in the pMMR group, T-cell diversity in TIL-high tumors was comparable to T-cell diversity in TIL-low tumors. These findings suggest that T cells clonally expand in dMMR tumors, possibly in response to MMR deficiency-induced tumor neoantigens.

Examination of Intersectionality and the Pipeline for Black Academic Surgeons.

IMPORTANCE: The lack of underrepresented in medicine physicians within US academic surgery continues, with Black surgeons representing a disproportionately low number. OBJECTIVE: To evaluate the trend of general surgery residency application, matriculation, and graduation rates for Black trainees compared with their racial and ethnic counterparts over time. DESIGN, SETTING, AND PARTICIPANTS: In this nationwide multicenter study, data from the Electronic Residency Application Service (ERAS) for the general surgery residency match and Graduate Medical Education (GME) surveys of graduating general surgery residents were retrospectively reviewed and stratified by race, ethnicity, and sex. Analyses consisted of descriptive statistics, time series plots, and simple linear regression for the rate of change over time. Medical students and general surgery residency trainees of Asian, Black, Hispanic or Latino of Spanish origin, White, and other races were included. Data for non-US citizens or nonpermanent residents were excluded. Data were collected from 2005 to 2018, and data were analyzed in March 2021. MAIN OUTCOMES AND MEASURES: Primary outcomes included the rates of application, matriculation, and graduation from general surgery residency programs. RESULTS: Over the study period, there were 71 687 applicants, 26 237 first-year matriculants, and 24 893 graduates. Of 71 687 applicants, 24 618 (34.3%) were women, 16 602 (23.2%) were Asian, 5968 (8.3%) were Black, 2455 (3.4%) were Latino, and 31 197 (43.5%) were White. Women applicants and graduates increased from 29.4% (1178 of 4003) to 37.1% (2293 of 6181) and 23.5% (463 of 1967) to 33.5% (719 of 2147), respectively. When stratified by race and ethnicity, applications from Black women increased from 2.2% (87 of 4003) to 3.5% (215 of 6181) (P < .001) while applications from Black men remained unchanged (3.7% [150 of 4003] to 4.6% [284 of 6181]). While the matriculation rate for Black women remained unchanged (2.4% [46 of 1919] to 2.3% [52 of 2264]), the matriculation rate for Black men significantly decreased (3.0% [57 of 1919] to 2.4% [54 of 2264]; P = .04). Among Black graduates, there was a significant decline in graduation for men (4.3% [85 of 1967] to 2.7% [57 of 2147]; P = .03) with the rate among women remaining unchanged (1.7% [33 of 1967] to 2.2% [47 of 2147]). CONCLUSIONS AND RELEVANCE: Findings of this study show that the underrepresentation of Black physicians at every stage in surgical training pipeline persists. Black men are especially affected. Identifying factors that address intersectionality and contribute to the successful recruitment and retention of Black trainees in general surgery residency is critical for achieving racial and ethnic as well as gender equity.

Ileoanal Pouch: Pelvic Sepsis and Poor Function-Now What?

Pelvic sepsis is a dreadful complication after ileal pouch creation. It is mostly treated conservatively, and the ileal pouch can be salvaged if sepsis is detected and treated in a timely manner. Even under the best circumstances, pelvic sepsis is often associated with poor functional outcomes. If pelvic sepsis becomes chronic, it could lead to pouch failure. Redo ileal pouch-anal anastomosis (IPAA) is a viable option in the setting of chronic pelvic sepsis to preserve gastrointestinal continuity in motivated patients. It is associated with similar surgical morbidity, acceptable functional outcomes, and good quality of life. Patients should be involved in the decision-making process after ileal pouch failure. In the setting of ileal pouch failure, surgeons with limited experience may not be comfortable offering patients redo IPAA. Redo IPAA requires subspecialization and patients with ileal pouch failure should be treated at specialized high-volume centers.

Advances in the treatment of locally advanced rectal cancer.

Locally advanced rectal cancer requires multidisciplinary care. In the United States, most patients are treated with neoadjuvant chemoradiation delivered over 25-28 days, total mesorectal excision, and 4 months of adjuvant chemotherapy. While effective, this trimodal approach is arduous. Alternative approaches have emerged to streamline treatment without sacrificing oncologic outcomes. These approaches include preoperative chemotherapy with selective use of radiation, short-course radiotherapy delivered over 5 days, and total neoadjuvant therapy with attempted nonoperative organ-preserving management (watch and wait). Ongoing trials are assessing the efficacies of these approaches in combination with various risk stratification strategies.

Tumor-Infiltrating Lymphocytes, Tumor Mutational Burden, and Genetic Alterations in Microsatellite Unstable, Microsatellite Stable, or Mutant POLE/POLD1 Colon Cancer.

To characterize the relationship between tumor-infiltrating lymphocytes (TIL), tumor mutational burden (TMB), and genetic alterations in microsatellite stable (MSS), microsatellite instability (MSI), or mutant POLE/POLD1 colon cancer. MATERIALS AND METHODS: Four hundred ninety-nine resected stage I-III colon tumors treated between 2014 and 2019 were assessed for TIL; somatic mutations, copy number alterations, and structural changes in > 400 oncogenes; and MSI status. RESULTS: Of the 499 tumors analyzed, 313 were MSS, 175 were MSI, and 11 had POLE/POLD1 pathogenic mutations. Both the percentage of tumors with a high level of TIL (≥ 4 lymphocytes per high-power field) and the median TMB differed significantly between the three phenotypes: MSS, 4.5% and 6 mutations/Mb; MSI, 68% and 54 mutations/Mb; POLE/POLD1, 82% and 158 mutations/Mb (P < .05). Within each phenotype, TMB did not vary significantly with TIL level. Among MSI tumors, the median number of frameshift indels was significantly higher in tumors with high levels of TIL (20 v 17; P = .018). In the MSS group, significantly higher proportions of tumors with high levels of TIL had mutations in the transforming growth factor-ß (36% v 12%; P = .01), RAS (86% v 54%; P = .02), and Hippo (7% v 1%; P = .046) pathways; in contrast, TP53 alterations were associated with low levels of TIL (74% v 43%; P = .01). CONCLUSION: The association between TIL, TMB, and genetic alterations varies significantly between MSI, MSS, and mutant POLE/POLD1 colon tumors. These differences may help explain tumoral immunity and lead to predictors of response to immunotherapy.

Development and Assessment of a Clinical Calculator for Estimating the Likelihood of Recurrence and Survival Among Patients With Locally Advanced Rectal Cancer Treated With Chemotherapy, Radiotherapy, and Surgery.

Importance: Predicting outcomes in patients receiving neoadjuvant therapy for rectal cancer is challenging because of tumor downstaging. Validated clinical calculators that can estimate recurrence-free survival (RFS) and overall survival (OS) among patients with rectal cancer who have received multimodal therapy are needed. Objective: To develop and validate clinical calculators providing estimates of rectal cancer recurrence and survival that are better for individualized decision-making than the American Joint Committee on Cancer (AJCC) staging system or the neoadjuvant rectal (NAR) score. Design, Setting, and Participants: This prognostic study developed risk models, graphically represented as nomograms, for patients with incomplete pathological response using Cox proportional hazards and multivariable regression analyses with restricted cubic splines. Because patients with complete pathological response to neoadjuvant therapy had uniformly favorable outcomes, their predictions were obtained separately. The study included 1400 patients with stage II or III rectal cancer who received treatment with chemotherapy, radiotherapy, and surgery at 2 comprehensive cancer centers (Memorial Sloan Kettering [MSK] Cancer Center and Siteman Cancer Center [SCC]) between January 1, 1998, and December 31, 2017. Patients from the MSK cohort received chemoradiation, surgery, and adjuvant chemotherapy from January 1, 1998, to December 31, 2014; these patients were randomly assigned to either a model training group or an internal validation group. Models were externally validated using data from the SCC cohort, who received either chemoradiation, surgery, and adjuvant chemotherapy (chemoradiotherapy group) or short-course radiotherapy, consolidation chemotherapy, and surgery (total neoadjuvant therapy with short-course radiotherapy group) from January 1, 2009, to December 31, 2017. Data were analyzed from March 1, 2020, to January 10, 2021. Exposures: Chemotherapy, radiotherapy, chemoradiotherapy, and surgery. Main Outcomes and Measures: Recurrence-free survival and OS were the outcome measures, and the discriminatory performance of the clinical calculators was measured with concordance index and calibration plots. The ability of the clinical calculators to predict RFS and OS was compared with that of the AJCC staging system and the NAR score. The models for RFS and OS among patients with incomplete pathological response included postoperative pathological tumor category, number of positive lymph nodes, tumor distance from anal verge, and large- and small-vessel venous and perineural invasion; age was included in the risk model for OS. The final clinical calculators provided RFS and OS estimates derived from Kaplan-Meier curves for patients with complete pathological response and from risk models for patients with incomplete pathological response. Results: Among 1400 total patients with locally advanced rectal cancer, the median age was 57.8 years (range, 18.0-91.9 years), and 863 patients (61.6%) were male, with tumors at a median distance of 6.7 cm (range, 0-15.0 cm) from the anal verge. The MSK cohort comprised 1069 patients; of those, 710 were assigned to the model training group and 359 were assigned to the internal validation group. The SCC cohort comprised 331 patients; of those, 200 were assigned to the chemoradiotherapy group and 131 were assigned to the total neoadjuvant therapy with short-course radiotherapy group. The concordance indices in the MSK validation data set were 0.70 (95% CI, 0.65-0.76) for RFS and 0.73 (95% CI, 0.65-0.80) for OS. In the external SCC data set, the concordance indices in the chemoradiotherapy group were 0.71 (95% CI, 0.62-0.81) for RFS and 0.72 (95% CI, 0.59-0.85) for OS; the concordance indices in the total neoadjuvant therapy with short-course radiotherapy group were 0.62 (95% CI, 0.49-0.75) for RFS and 0.67 (95% CI, 0.46-0.84) for OS. Calibration plots confirmed good agreement between predicted and observed events. These results compared favorably with predictions based on the AJCC staging system (concordance indices for MSK validation: RFS = 0.69 [95% CI, 0.64-0.74]; OS = 0.67 [95% CI, 0.58-0.75]) and the NAR score (concordance indices for MSK validation: RFS = 0.56 [95% CI, 0.50-0.63]; OS = 0.56 [95% CI, 0.46-0.66]). Furthermore, the clinical calculators provided more individualized outcome estimates compared with the categorical schemas (eg, estimated RFS for patients with AJCC stage IIIB disease ranged from 7% to 68%). Conclusions and Relevance: In this prognostic study, clinical calculators were developed and validated; these calculators provided more individualized estimates of the likelihood of RFS and OS than the AJCC staging system or the NAR score among patients with rectal cancer who received multimodal treatment. The calculators were easy to use and applicable to both short- and long-course radiotherapy regimens, and they may be used to inform surveillance strategies and facilitate future clinical trials and statistical power calculations.

Discordant DNA mismatch repair protein status between synchronous or metachronous gastrointestinal carcinomas: frequency, patterns, and molecular etiologies.

The widespread use of tumor DNA mismatch repair (MMR) protein immunohistochemistry in gastrointestinal tract (GIT) carcinomas has unveiled cases where the MMR protein status differs between synchronous/metachronous tumors from the same patients. This study aims at examining the frequency, patterns and molecular etiologies of such inter-tumoral MMR discordances. We analyzed a cohort of 2159 colorectal cancer (CRC) patients collected over a 5-year period and found that 1.3% of the patients (27/2159) had ≥ 2 primary CRCs, and 25.9% of the patients with ≥ 2 primary CRCs (7/27) exhibited inter-tumoral MMR discordance. We then combined the seven MMR-discordant CRC patients with three additional MMR-discordant GIT carcinoma patients and evaluated their discordant patterns and associated molecular abnormalities. The 10 patients consisted of 3 patients with Lynch syndrome (LS), 1 with polymerase proofreading-associated polyposis (PAPP), 1 with familial adenomatous polyposis (FAP), and 5 deemed to have no cancer disposing hereditary syndromes. Their MMR discordances were associated with the following etiologies: (1) PMS2-LS manifesting PMS2-deficient cancer at an old age when a co-incidental sporadic MMR-proficient cancer also occurred; (2) microsatellite instability-driven secondary somatic MSH6-inactivation occurring in only one-and not all-PMS2-LS associated MMR-deficient carcinomas; (3) "compound LS" with germline mutations in two MMR genes manifesting different tumors with deficiencies in different MMR proteins; (4) PAPP or FAP syndrome-associated MMR-proficient cancer co-occurring metachronously with a somatic MMR-deficient cancer; and (5) non-syndromic patients with sporadic MMR-proficient cancers co-occurring synchronously/metachronously with sporadic MMR-deficient cancers. Our study thus suggests that inter-tumoral MMR discordance is not uncommon among patients with multiple primary GIT carcinomas (25.9% in patients with ≥ 2 CRCs), and may be associated with widely varied molecular etiologies. Awareness of these patterns is essential in ensuring the most effective strategies in both LS detection and treatment decision-making. When selecting patients for immunotherapy, MMR testing should be performed on the tumor or tumors that are being treated.

Clinical Calculator Based on Molecular and Clinicopathologic Characteristics Predicts Recurrence Following Resection of Stage I-III Colon Cancer.

PURPOSE: Clinical calculators and nomograms have been endorsed by the American Joint Committee on Cancer (AJCC), as they provide the most individualized and accurate estimate of patient outcome. Using molecular and clinicopathologic variables, a third-generation clinical calculator was built to predict recurrence following resection of stage I-III colon cancer. METHODS: Prospectively collected data from 1,095 patients who underwent colectomy between 2007 and 2014 at Memorial Sloan Kettering Cancer Center were used to develop a clinical calculator. Discrimination was measured with concordance index, and variability in individual predictions was assessed with calibration curves. The clinical calculator was externally validated with a patient cohort from Washington University's Siteman Cancer Center in St Louis. RESULTS: The clinical calculator incorporated six variables: microsatellite genomic phenotype; AJCC T category; number of tumor-involved lymph nodes; presence of high-risk pathologic features such as venous, lymphatic, or perineural invasion; presence of tumor-infiltrating lymphocytes; and use of adjuvant chemotherapy. The concordance index was 0.792 (95% CI, 0.749 to 0.837) for the clinical calculator, compared with 0.708 (95% CI, 0.671 to 0.745) and 0.757 (0.715 to 0.799) for the staging schemes of the AJCC manual's 5th and 8th editions, respectively. External validation confirmed robust performance, with a concordance index of 0.738 (95% CI, 0.703 to 0.811) and calibration plots of predicted probability and observed events approaching a 45° diagonal. CONCLUSION: This third-generation clinical calculator for predicting cancer recurrence following curative colectomy successfully incorporates microsatellite genomic phenotype and the presence of tumor-infiltrating lymphocytes, resulting in improved discrimination and predictive accuracy. This exemplifies an evolution of a clinical calculator to maintain relevance by incorporating emerging variables as they become validated and accepted in the oncologic community.

Quantitative assessment of tumor-infiltrating lymphocytes in mismatch repair proficient colon cancer.

Tumor infiltrating lymphocytes (TIL), which represent host adaptive response to the tumor, were first identified at scanning magnification to select areas with the highest counts on hematoxylin and eosin slides, quantitated per high-power field (HPF), and analyzed for association with recurrence-free survival (RFS) in 848 patients. Highest TIL in a single HPF was analyzed as a continuous and categorical variable, and optimal cutoff analysis was performed to predict RFS. Highest TIL count in a single HPF ranged from 0 to 45, and the optimal cutoff for TIL high vs TIL low was determined to be ≥ 3 vs < 3 with a concordance probability estimate of 0.74. In the entire cohort, 5-year RFS was 90.2% (95% CI = 83.7-94.2) in TIL high compared to 78.9% (95% CI = 74.1-82.9) in TIL low (log rank P < .0001). TIL remained significant in the mismatch repair-proficient (pMMR) cohort where 5-year RFS was 94.6% (95% CI = 88.3-97.5) in TIL high compared to 77.9% (95% CI = 69.2-84.4) in TIL low (P = .008). On multivariable analysis, TIL and AJCC Stage were independently associated with RFS in the pMMR cohort. Qualitatively in the pMMR cohort, RFS in Stage II TIL high patients was similar to that in Stage I patients and RFS in Stage III TIL high was similar to that in Stage II TIL low patients. Assessment of TIL in a single HPF using standard H&E slides provides important prognostic information independent of MMR status and AJCC stage.