Neoadjuvant Immune Checkpoint Inhibition Improves Organ Preservation in T4bM0 Colorectal Cancer With Mismatch Repair Deficiency: A Retrospective Observational Study.

BACKGROUND: Colorectal cancer with mismatch repair deficiency is usually less aggressive and associated with a lower risk of distant metastasis. Immune checkpoint inhibition, rather than traditional chemoradiotherapy, has shown great advantages in treating such patients. OBJECTIVE: This study aimed to verify the hypothesis that locally very advanced (T4b) colorectal cancer without distant metastases might present with higher probability of mismatch repair deficiency and be more sensitive to neoadjuvant immune checkpoint inhibition. DESIGN: This study was designed as a single-center retrospective observational study. SETTINGS: The study was conducted in a tertiary referral center in China. PATIENTS: The study included patients who were clinically diagnosed with T4bM0 colorectal cancer from 2008 to 2019. MAIN OUTCOME MEASURES: Clinicopathological characteristics, mismatch repair status, and survival outcomes of patients with mismatch repair deficiency were analyzed. RESULTS: A total of 268 patients were included. The incidence of patients with mismatch repair deficiency in the T4bM0 population was 27.6% (75/268), with 84.0% (63/75) in the colon and 16.0% (12/75) in the rectum. For tumors located in the proximal colon, 45.0% (50/111) exhibited mismatch repair deficiency, whereas the incidence of mismatch repair deficiency in sigmoid colon cancer and rectal cancer was only 15.9% (25/157). Neoadjuvant immune checkpoint inhibition significantly reduced the open surgery rate ( p = 0.000) and multivisceral resection rate ( p = 0.025). The pathological complete remission rate in the neoadjuvant immune checkpoint inhibition group was significantly higher than that in neoadjuvant chemoradiotherapy/chemotherapy group (70.0% vs 0%; p = 0.004). No tumor downstaging was observed after neoadjuvant chemotherapy. Neoadjuvant immune checkpoint inhibition provided significantly better disease-free survival ( p = 0.0078) and relatively longer overall survival ( p = 0.15) than other groups. LIMITATIONS: This study is limited by the possible selection bias and small sample size. CONCLUSIONS: Our data depicted the high incidence of mismatch repair deficiency in T4bM0 mismatch repair deficiency and the effectiveness of the neoadjuvant immune checkpoint inhibition group in organ preservation. Precision oncology requires identification of the protein status of mismatch repair at initial diagnosis to make a rational treatment decision for these patients. See Video Abstract at http://links.lww.com/DCR/B952 . LA INHIBICIN DEL PUNTO DE CONTROL INMUNITARIO NEOADYUVANTE MEJORA LA PRESERVACIN DE RGANOS EN EL CNCER COLORRECTAL TBM CON DEFICIENCIA DE REPARACIN DE ERRORES DE COINCIDENCIA UN ESTUDIO OBSERVACIONAL RETROSPECTIVO: ANTECEDENTES:Los pacientes con cáncer colorrectal con deficiencia en la reparación de desajustes suelen (dMMR) ser menos agresivos y se asocian con un menor riesgo de metástasis a distancia. La inhibición del punto de control inmunitario, en lugar de la quimiorradioterapia tradicional, ha mostrado grandes ventajas en el tratamiento de estos pacientes.OBJETIVO:Este estudio tuvo como objetivo verificar nuestra hipótesis de que el CCR localmente muy avanzado (T4b) sin metástasis a distancia podría presentarse con una mayor probabilidad de dMMR y ser más sensible a la inhibición del punto de control inmunitario neoadyuvante.DISEÑO:Este estudio fue diseñado como un estudio observacional retrospectivo de un solo centro.CONFIGURACIÓN:El estudio se realizó en un centro de referencia terciario en China.PACIENTES:Se incluyeron pacientes con diagnóstico clínico de CCR T4bM0 desde 2008 hasta 2019.PRINCIPALES MEDIDAS DE RESULTADO:Se analizaron las características clinicopatológicas, el estado de MMR y los resultados de supervivencia de los pacientes con dMMR.RESULTADOS:Se incluyeron un total de 268 pacientes. La incidencia de dMMR en la población T4bM0 fue del 27,6% (75/268), con un 84,0% (63/75) en colon y un 16,0% (12/75) en recto. Para los tumores ubicados en el colon proximal, el 45,0% (50/111) exhibió dMMR, mientras que la incidencia de dMMR en el cáncer de colon sigmoideo y el cáncer de recto fue solo del 15,9% (25/157). La inhibición del punto de control inmunitario neoadyuvante redujo significativamente la cirugía abierta y la tasa de resección multivisceral ( p = 0,000 y p = 0,025, respectivamente). La tasa de PCR en el grupo de inhibición del punto de control inmunitario neoadyuvante fue significativamente mayor que en el grupo de quimiorradioterapia/quimioterapia neoadyuvante (70,0% frente a 0%, p = 0,004). No se observó reducción del estadio del tumor después de la quimioterapia neoadyuvante. La inhibición del punto de control inmunitario neoadyuvante proporcionó una supervivencia sin enfermedad significativamente mejor ( p = 0,0078) y una supervivencia general relativamente más larga ( p = 0,15) que otros grupos.LIMITACIONES:Este estudio está limitado por el posible sesgo de selección y el pequeño tamaño de la muestra.CONCLUSIONES:Nuestros datos representan la alta incidencia de dMMR en T4bM0 CRC y la eficacia del grupo de inhibición del punto de control inmunitario neoadyuvante en la preservación de órganos. La oncología de precisión requiere la identificación del estado de la proteína MMR en el diagnóstico inicial para tomar una decisión de tratamiento racional para estos pacientes especiales. Consulte el Video Resumen en http://links.lww.com/DCR/B952 . (Traducción-Dr. Yesenia Rojas-Khalil ).

Low prevalence of mismatch repair deficiency in Chinese colorectal cancers: a multicenter study.

BACKGROUND: Although universal testing for mismatch repair deficiency (dMMR) has been recommended to all colorectal cancer (CRC) patients, related evidence for the Chinese population is lacking. Here, we investigated the prevalence and clinicopathological features of dMMR patients in a large Chinese CRC cohort. METHODS: We included 7,373 CRC patients treated at four Chinese medical centers between August 2010 and September 2016. Patients' baseline characteristics and pathological features were recorded. The clinicopathological features were compared between patients with MLH1/PMS2 deficiency (dMLH1/PMS2) and MSH2/MSH6 deficiency (dMSH2/MSH6). RESULTS: Among the investigated patients, 654 (8.9%) were identified with dMMR CRCs and, of them, 401 (61.3%) were males, with a median age of 55 years (range, 22-87 years); 355 (54.3%) had stage II CRC based on American Joint Committee on Cancer 8th edition. The prevalence of the dMLH1/PMS2 group and the dMSH2/MSH6 group were 51.5% (337/654) and 25.1% (164/654), respectively. Compared with dMSH2/MSH6 patients, those with dMLH1/PMS2 were older (57 vs 52 years, P < 0.001), more likely to be female (45.7% vs 31.5%, P = 0.004), prone to having tumors located in the right-hand side of the colon (59.0% vs 47.6%, P = 0.015), and less likely to have a family history of tumors (29.7% vs 43.3%, P = 0.003). CONCLUSIONS: The prevalence of dMMR in Chinese CRC patients was low, especially in the dMLH1/PMS2 group. The clinicopathological features were different between dMMR subgroups.

PD-1 blockade in neoadjuvant setting of DNA mismatch repair-deficient/microsatellite instability-high colorectal cancer.

Background: Although PD-1 blockade has significantly improved the survival of metastatic colorectal cancer with DNA Mismatch Repair-Deficient/Microsatellite Instability-High (MSI-H), the data on neoadjuvant setting is limited. Methods: In this retrospective study, we enrolled eight patients with advanced MSI-H colorectal cancer from three hospitals. Four patients are locally advanced and four are metastatic. All the patients received at least two doses of PD-1 antibody with or without chemotherapy as neoadjuvant therapy. The aim of the present study was to evaluate the short-term efficacy and toxicities of this strategy. Results: All the enrolled eight patients had a major response in imaging and/or pathological evaluation. Five of the seven resected patients were evaluated as pathological complete response. One patient without surgery has a clinical complete response (cCR) tumor response. Conclusions: Neoadjuvant PD-1 blockade induced tumor regression with a major clinical and pathological response in advanced dMMR/MSI-H colorectal cancer. Further studies are required to evaluate the long-term effect of this strategy.

A frameshift mutation in exon 19 of MLH1 in a Chinese Lynch syndrome family: a pedigree study.

Lynch syndrome (LS), an autosomal dominantly inherited disease previously known as hereditary non-polyposis colorectal cancer (HNPCC), leads to a high risk of colorectal cancer (CRC) as well as malignancy at certain sites including endometrium, ovary, stomach, and small bowel (Hampel et al., 2008; Lynch et al., 2009). Clinically, LS is considered the most common hereditary CRC-predisposing syndrome, accounting for about 3% of all CRC cases (Popat et al., 2005). LS is associated with mutations of DNA mismatch repair (MMR) genes such as MLH1, MSH2, MSH6, PMS2, and EPCAM (Ligtenberg et al., 2009; Lynch et al., 2009), which can trigger a high frequency of replication errors in both microsatellite regions and repetitive sequences in the coding regions of various cancer-related genes. Immunohistochemistry (IHC) tests followed by genetic analysis of these mutations play a significant role in diagnosis, treatment determination, and therapeutic response prediction of LS (Lynch et al., 2009; Alex et al., 2017; Ryan et al., 2017). Here, we report substitution of one base-pair in exon 1 of MLH3 (c.1397C>A) and a frameshift mutation in exon 19 of MLH1 (c.2250_2251ins AA) in a 43-year-old Chinese male with an LS pedigree.

Lymphocyte-to-monocyte ratio before chemoradiotherapy represents a prognostic predictor for locally advanced rectal cancer.

Research indicates that cancer-triggered inflammation plays a pivotal role in carcinogenesis. Here, we aimed to evaluate the correlation of lymphocyte-to-monocyte ratio (LMR) before neoadjuvant chemoradiotherapy (CRT) with clinical outcomes in patients with locally advanced rectal cancer (LARC). We retrospectively enrolled 317 consecutive patients with LARC between 2004 and 2013. The optimal cutoff values of LMR were determined using receiver operating curve analysis. Overall survival (OS) and disease-free survival related to the LMR were analyzed using the log-rank test and multivariate Cox regression methods. We found that a low LMR (≤4.91) was prominently correlated with worse prognostic features and a shorter 3-year survival rate of LARC. Moreover, multivariate Cox analysis revealed that elevated LMR was an independent factor for better OS (hazard ratio 0.538, 95% confidence interval 0.292-0.991, P=0.047). In addition, univariate logistic regression analysis showed that the LMR was not associated with tumor pathologic regression. In conclusion, LMR is identified as a valuable prognostic marker for predicting the OS of LARC patients receiving CRT.