Modern multidisciplinary treatment of rectal cancer based on staging with magnetic resonance imaging leads to excellent local control, but distant control remains a challenge

Pretreatment MRI-detected extramural venous invasion as a prognostic and predictive biomarker for neoadjuvant chemoradiotherapy in non-metastatic rectal cancer: a propensity score matched analysis

OBJECTIVES

This study evaluated pretreatment magnetic resonance imaging (MRI)-detected extramural venous invasion (pmrEMVI) as a predictor of survival after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

Medical records of 1184 patients with rectal adenocarcinoma who underwent TME between January 2011 and December 2016 were reviewed. MRI data were collected from a computerized radiologic database. Cox proportional hazards analysis was used to assess local, systemic recurrence, and disease-free survival risk based on pretreatment MRI-assessed tumor characteristics. After propensity score matching (PSM) for pretreatment MRI features, nCRT therapeutic outcomes according to pmrEMVI status were evaluated. Cox proportional hazards analysis was used to identify risk factors for early recurrence in patients receiving nCRT.

RESULTS

Median follow-up was 62.8 months. Among all patients, the presence of pmrEMVI was significantly associated with worse disease-free survival (DFS; HR 1.827, 95% CI 1.285-2.597, p = 0.001) and systemic recurrence (HR 2.080, 95% CI 1.400-3.090, p < 0.001) but not local recurrence. Among patients with pmrEMVI, nCRT provided no benefit for oncological outcomes before or after PSM. Furthermore, pmrEMVI( +) was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT.

CONCLUSIONS

pmrEMVI is a poor prognostic factor for DFS and SR in patients with non-metastatic rectal cancer and also serves as a predictive biomarker of poor DFS and SR following nCRT in LARC. Therefore, for patients who are positive for pmrEMVI, consideration of alternative treatment strategies may be warranted.

CLINICAL RELEVANCE STATEMENT

This study demonstrated the usefulness of pmrEMVI as a predictive biomarker for nCRT, which may assist in initial treatment decision-making in patients with non-metastatic rectal cancer.

KEY POINTS

• Pretreatment MRI-detected extramural venous invasion (pmrEMVI) was significantly associated with worse disease-free survival and systemic recurrence in patients with non-metastatic rectal cancer. • pmrEMVI is a predictive biomarker of poor DFS following nCRT in patients with LARC. • The presence of pmrEMVI was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT.

Risk Factors for Distant Metastasis in T3 T4 Rectal Cancer

Background

Distant metastasis is the leading cause of death in patients with rectal cancer. This study aims to comprehensively analyze the risk factors of distant metastasis in T3 T4 rectal cancer using magnetic resonance imaging (MRI), pathological features, and serum indicators.

Methods

The clinicopathological data of 146 cases of T3 T4 rectal cancer after radical resection from January 2015 to March 2023 were retrospectively analyzed. Pre- and postoperative follow-up data of all cases were collected to screen for distant metastatic lesions. Univariate and multivariate Logistic regression methods were used to analyze the relationship between MRI features, pathological results, serum test indexes, and distant metastasis.

Results

Of the 146 included patients, synchronous or metachronous distance metastasis was confirmed in 43 (29.4%) cases. The patients' baseline data and univariate analysis showed that mrEMVI, maximum tumor diameter, mr T Stage, pathological N stage, number of lymph node metastasis, cancer nodules, preoperative serum CEA, (Carcinoembryonic antigen) and CA199 were associated with distant metastasis. In the multiple logistic regression model, mrEMVI, pathological N stage, number of lymph node metastasis, maximum tumor diameter, and preoperative serum CEA were identified as independent risk factors for distant metastasis: mrEMVI [odds ratio (OR) = 3.06], pathological N stage (OR = 6.52 for N1 vs N0; OR = 63.47 for N2 vs N0), preoperative serum CEA (OR = 0.27), tumor maximum diameter (OR = 1.03), number of lymph nodes metastasis (OR = 0.62). And, the receiver operating characteristic (ROC) curve was plotted and the area under the curve was calculated (area under the curve [AUC) = 0.817, 95% CI = 0.744-0.890, P < .001].

Conclusions

mrEMVI, pathological N stage, number of lymph node metastasis, maximum tumor diameter and preoperative serum CEA are the independent risk factors for distant metastasis in T3 T4 rectal cancer. A comprehensive analysis of the risk factors for distant metastasis in rectal cancer can provide a reliable basis for formulating individualized treatment strategies, follow-up plans, and evaluating prognosis.

Disparities in Diagnostic Imaging for Initial Local Staging for Rectal Cancer

OBJECTIVE

To assess the presence, quality, and timeliness of initial staging imaging for rectal cancer patients, and to evaluate demographic factors associated with disparities.

METHODS

We conducted a chart review of consecutive rectal adenocarcinoma cancer registry cases from a single institution for the period from 2015 to 2020. We recorded whether initial staging MRI or endoscopic ultrasound (EUS) was performed, and whether it was performed in or outside the institution. MRI quality was assessed based on compliance to the Society of Abdominal Radiology rectal cancer disease-focused panel protocol recommendations. The times between diagnosis and imaging were calculated. Patients' age, race, ethnicity, sex, body mass index, address, and primary payer were acquired from the electronic medical record. Descriptive analysis, odds ratios, and Student's t tests were used for analysis.

RESULTS

Of 346 patients, 39% were female, and the average age was 59 years. A total of 93 patients (26.8%) had no initial staging MRI or endoscopic ultrasound. Of the 142 MRIs evaluated for image quality, 100 patient exams (72.4%) met the criteria for adequate quality. The mean time interval from diagnosis to imaging was 30.9 days. A lower likelihood of receiving initial local staging was associated with being of Hispanic ethnicity (P < .01), having Medicaid or no insurance (P < .01), and residing in a low-income census block (P < .01). Higher quality of imaging was associated with residence in a census block with high median income (P < 0.01), more recent diagnosis (P < .01), and MRI performed at the institution presented (P < .01).

CONCLUSIONS

Although radiologic workup variability was found across all demographics, sociodemographic factors have an effect on local initial imaging of rectal cancer, emphasizing the need to improve image acquisition for underserved patients and improve quality standardization at low-volume centers.

Neoadjuvant chemotherapy (CAPOX) alone for low- and intermediate-risk stage II/III rectal cancer: Long-term follow-up of a prospective single-arm study

BACKGROUND

Stratified treatment has been recommended for rectal cancer. Our previous multicenter randomized trial showed that low-/intermediate-risk rectal cancer patients did not benefit much from neoadjuvant chemoradiotherapy. In our phase II study, we found that stage II/III rectal cancer patients with low-/intermediate risks can be managed by neoadjuvant chemotherapy alone and achieve a good response. The current study aimed to report the long-term survival outcomes in the expanded phase II trial.

METHOD

Consecutive patients diagnosed with mid-low stage II/III rectal cancer with low/intermediate risk factors were included. Four cycles of neoadjuvant chemotherapy (CAPOX) were given, and MRI was used for tumour response detection. The primary endpoint was disease-free survival. The secondary endpoints were tumour response to NCT, tumour-related death, and overall survival.

RESULTS

This study enrolled 121 eligible patients. The good tumour response rate based on MRI was 82.6 %, with a pathological complete response (pCR) rate of 18.3 %. The disease-free survival rate was 82.6 %, and the overall survival rate was 96.7 % after a median follow-up time of 40 months. Two patients (1.7 %) suffered local recurrence, and 15 patients (12.4 %) suffered distant metastasis. The median disease-free survival and overall survival were 37 (9-60) and 40 (16-60) months, respectively. Tumour longitudinal length reduction and tumour regression grade on MRI were identified as predictors for poor tumour response to neoadjuvant chemotherapy.

CONCLUSION

In stage II/III rectal cancer patients with low-/intermediate risks, neoadjuvant chemotherapy alone may result in an acceptable tumour response and disease-free survival. Tumour response might be predicted early.

A Prospective Study on the Roles of the Lymphocyte-to-Monocyte Ratio (LMR), Neutrophil-to-Lymphocyte Ratio (NLR), and Platelet-to-Lymphocyte Ratio (PLR) in Patients with Locally Advanced Rectal Cancer

Rectal cancer constitutes over one-third of all colorectal cancers (CRCs) and is one of the leading causes of cancer-related deaths in developed countries. In order to identify high-risk patients and better adjust therapies, new markers are needed. Systemic inflammatory response (SIR) markers such as LMR, NLR, and PLR have proven to be highly prognostic in many malignancies, including CRC; however, their roles in locally advanced rectal cancer (LARC) are conflicting and lack proper validation. Sixty well-selected patients with LARC treated at the Maria Sklodowska-Curie National Research Institute of Oncology in Warsaw, Poland, between August 2017 and December 2020 were prospectively enrolled in this study. The reproducibility of the pre-treatment levels of the SIR markers, their correlations with clinicopathological characteristics, and their prognostic value were evaluated. There was a significant positive correlation between LMR and cancer-related inflammatory infiltrate (r = 0.38, p = 0.044) and PD-L1 expression in tumor cells, lymphocytes, and macrophages (combined positive score (CPS)) (r = 0.45, p = 0.016). The PLR level was correlated with nodal involvement (p = 0.033). The SIR markers proved to be only moderately reproducible and had no significant prognostic value. In conclusion, the LMR was associated with local cancer-related inflammation and PD-L1 expression in tumor microenvironments. The validity of SIR indices as biomarkers in LARC requires further investigation.

The Incidence and Prognosis Value of Perineural Invasion in Rectal Carcinoma: From Meta-Analyses and Real-World Clinical Pathological Features

AIMS

Perineural invasion (PNI) is a special type of metastasis of several cancers and has been reported as being a factor for poor prognosis in colorectal carcinoma. However, investigations of PNI in only rectal cancer and a comprehensive analysis combining meta-analyses with real-world case studies remain lacking.

MATERIALS AND METHODS

First, articles from 2000 to 2020 concerning the relationship between PNI and rectal cancer prognoses and clinical features were meta-analysed. Subsequently, we carried out a retrospective analysis of 312 rectal cancer cases that underwent radical surgery in the real world. The incidence of PNI and the relationship between PNI and prognosis, as well as clinicopathological factors, were investigated.

RESULTS

The incidence of PNI was 23.09% and 33.01% in the meta-analysis and clinical cases, respectively. PNI occurred as early as stage I (2.94%). Moreover, neoadjuvant therapy significantly reduced the PNI-positive rate (20.34% versus 26.54%). Both meta-analysis and real-world clinical case studies suggested that PNI-positive patients had poorer prognoses than PNI-negative patients. We established an effective risk model consisting of T stage, differentiation and lymphovascular invasion to predict PNI in rectal cancer.

CONCLUSION

PNI is a poor prognostic factor for rectal cancer and could occur even in stage I. Additionally, neoadjuvant therapy could sufficiently reduce the PNI-positive rate. T stage, lymphovascular invasion and differentiation grade were independent risk factors for PNI and the risk model that included these factors could predict the probability of PNI.

Prognostic Value of the Circumferential Resection Margin After Curative Surgery for Rectal Cancer: A Multicenter Propensity Score-Matched Analysis

BACKGROUND

Recently, positive circumferential resection margin has been found to be an indicator of advanced disease with a high risk of distant recurrence rather than local recurrence.

OBJECTIVE

The study aimed to analyze the prognostic impact of the circumferential resection margin on long-term oncological outcomes in patients with rectal cancer.

DESIGN

This was a multicenter, propensity score-matched (2:1) analysis comparing the positive and negative circumferential resection margins.

SETTINGS

The study was conducted at 5 high-volume centers in Spain.

PATIENTS

Patients who underwent total mesorectal excision with curative intent for middle-low rectal cancer between 2006 and 2014 were included.

MAIN OUTCOME MEASURES

The main outcomes were local recurrence, distant recurrence, overall survival, and disease-free survival.

RESULTS

The unmatched initial cohort consisted of 1599 patients, of whom 4.9% had a positive circumferential resection margin. After matching, 234 patients were included (156 with a negative circumferential margin and 78 with a positive circumferential margin). The median follow-up period was 52.5 (22.0-69.5) months. Local recurrence was significantly higher in patients with a positive circumferential margin (33.3% vs 11.5%; p < 0.001). Distant recurrence was similar in both groups (46.2% vs 42.3%; p = 0.651). There were no statistically significant differences in 5-year overall survival (48.6% vs 43.6%; p = 0.14). Disease-free survival was lower in patients with a positive circumferential margin (36.1% vs 52.3%; p = 0.026).

LIMITATIONS

This study was limited by its retrospective design. The different neoadjuvant treatment options were not included in the propensity score.

CONCLUSIONS

The positive circumferential resection margin was associated with a higher local recurrence rate and worse disease-free survival in comparison with the negative circumferential resection margin. However, the positive circumferential resection margin was not a prognostic indicator of distant recurrence and overall survival. See Video Abstract at http://links.lww.com/DCR/B950 .

VALOR PRONSTICO DEL MARGEN DE RESECCIN CIRCUNFERENCIAL DESPUS DE LA CIRUGA CURATIVA PARA EL CNCER DE RECTO UN ANLISIS MULTICNTRICO EMPAREJADO POR PUNTAJE DE PROPENSIN

ANTECEDENTES:En los últimos años, se ha encontrado que el margen de resección circunferencial positivo es un indicador de enfermedad avanzada con alto riesgo de recurrencia a distancia más que de recurrencia local.OBJETIVO:El objetivo fue analizar el impacto pronóstico del margen de resección circunferencial sobre la recidiva local, a distancia y las tasas de supervivencia en pacientes con cáncer de recto.DISEÑO:Este fue un análisis multicéntrico emparejado por puntaje de propensión 2: 1 que comparó el margen de resección circunferencial positivo y negativo.AJUSTES:El estudio se realizó en 5 centros Españoles de alto volumen.PACIENTES:Se incluyeron pacientes sometidos a escisión total de mesorrecto con intención curativa por cáncer de recto medio-bajo entre 2006-2014. Las características clínicas e histológicas se utilizaron para el emparejamiento.PRINCIPALES MEDIDAS DE RESULTADO:Los resultadoes principales fueron la recurrencia local, la recurrencia a distancia, la supervivencia global y libre de enfermedad.RESULTADOS:La cohorte inicial no emparejada consistió en 1599 pacientes; El 4,9% tuvo un margen de resección circunferencial positivo. Tras el emparejamiento se incluyeron 234 pacientes (156 con margen circunferencial negativo y 78 con margen circunferencial positivo). La mediana del período de seguimiento fue de 52,5 meses (22,0-69,5). La recurrencia local fue significativamente mayor en pacientes con margen circunferencial positivo, 33,3% vs 11,5% [HR 3,2; IC 95%: 1,83-5,43; p < 0,001]. La recidiva a distancia fue similar en ambos grupos (46,2 % frente a 42,3 %) [HR 1,09, IC 95 %: 0,78-1,90; p = 0,651]. No hubo diferencias significativas en la supervivencia global a 5 años (48,6 % frente a 43,6 %) [HR 1,09, IC 95 %: 0,92-1,78; p = 0,14]; La supervivencia libre de enfermedad fue menor en pacientes con margen circunferencial positivo, 36,1% vs 52,3% [HR 1,5; IC 95%: 1,05-2,06; p = 0,026].LIMITACIONES:Este estudio estuvo limitado por el diseño retrospectivo. Las diferentes opciones de tratamientos neoadyuvantes no se han incluido en la puntuación de propensión.CONCLUSIONES:El margen de resección circunferencial positivo se asocia con una mayor tasa de recurrencia local y peor supervivencia libre de enfermedad en comparación con el margen de resección circunferencial negativo. Sin embargo, el margen de resección circunferencial positivo no fue un indicador pronóstico de recidiva a distancia ni de supervivencia global. Consulte el Video del Resumen en http://links.lww.com/DCR/B950 . (Traducción- Dr. Yesenia Rojas-Khalil ).

Development and validation of a prognostic nomogram for rectal cancer patients who underwent surgical resection

Objective: The purpose of this study was to develop and validate a nomogram model for the prediction of survival outcome in rectal cancer patients who underwent surgical resection. Methods: A total of 9,919 consecutive patients were retrospectively identified using the Surveillance, Epidemiology, and End Results (SEER) database. Significant prognostic factors were determined by the univariate and multivariate Cox analysis. The nomogram model for the prediction of cancer-specific survival (CSS) in rectal cancer patients were developed based on these prognostic variables, and its predictive power was assessed by the concordance index (C-index). Calibration curves were plotted to evaluate the associations between predicted probabilities and actual observations. The internal and external cohort were used to further validate the predictive performance of the prognostic nomogram. Results: All patients from the SEER database were randomly split into a training cohort (n = 6,944) and an internal validation cohort (n = 2,975). The baseline characteristics of two cohorts was comparable. Independent prognostic factors were identified as age, pT stage, lymph node metastasis, serum CEA level, tumor size, differentiation type, perineural invasion, circumferential resection margin involvement and inadequate lymph node yield. In the training cohort, the C-index of the nomogram was 0.719 (95% CI: 0.696-0.742), which was significantly higher than that of the TNM staging system (C-index: 0.606, 95% CI: 0.583-0.629). The nomogram had a C-index of 0.726 (95% CI: 0.691-0.761) for the internal validation cohort, indicating a good predictive power. In addition, an independent cohort composed of 202 rectal cancer patients from our institution were enrolled as the external validation. Compared with the TNM staging system (C-index: 0.573, 95% CI: 0.492-0.654), the prognostic nomogram still showed a better predictive performance, with the C-index of 0.704 (95% CI: 0.626-0.782). Calibration plots showed a good consistency between predicted probability and the actual observation in the training and two validation cohorts. Conclusion: The nomogram showed an excellent predictive ability for survival outcome of rectal cancer patients, and it might provide an accurate prognostic stratification and help clinicians determine individualized treatment strategies.

The value of diffusion kurtosis imaging and intravoxel incoherent motion quantitative parameters in predicting synchronous distant metastasis of rectal cancer

BACKGROUND

The incidence and mortality rate of rectal cancer are still high, the metastasis of rectal cancer are main causes of death. The control of the distant metastasis is one of the main concerns in the treatment of locally advanced rectal cancer, but there are few studies on predicting synchronous distant metastasis (SDM) of rectal cancer.

METHOD

The data of patients with rectal adenocarcinoma confirmed by endoscopic biopsy or postoperative pathology from September 2015 to May 2020 in hospital A (center 1) and hospital B (center 2) were analyzed retrospectively, including age, sex, carcinoembryonic antigen, carbohydrate antigen 19-9, tumor location, tumor length, image staging and characteristics. The average age of the 169 patients consisting of 105 males and 64 females in study is 61.2 years. All patients underwent rectal routine rectal MRI, DKI and IVIM examinations on a 3.0-T scanner. Two radiologists sketched regions of interest (ROIs) on b = 1000 s/mm² DKI and IVIM images to obtain quantitative parameters with FireVoxel manually. We evaluated the difference of histogram analysis, clinical and image data between SDM group and non-SDM group, and evaluated the efficacy of each index in predicting SDM of rectal cancer.

RESULTS

The 90th percentile of f values in the SDM group is lower than that in the non-SDM group (29.4 ± 8.4% vs. 35 ± 17.8%, P = 0.005). CA19-9 in the SDM group is higher than that in the non-SDM group (P = 0.003). Low and high rectal cancer are more likely to develop SDM than middle rectal cancer (P = 0.05 and P = 0.047). The combination of these three indexes has a greater area under the curve (AUC) than any one index (0.801 vs. 0.685 (f (90th percentile)) and 0.627 (CA19-9), P = 0.0075 and 0.0058, respectively), and its specificity and sensitivity are 80.0% and 71.6%, respectively. When this combination is incorporated into the predictive nomogram model, the c-index is 0.801 (95% confidence interval (CI): 0.730-0.871).

CONCLUSIONS

IVIM quantitative parameters combine with CA19-9 and tumor location can better predict the risk of SDM of rectal cancer.

RING finger protein 128 (RNF128) regulates malignant biological behaviors of colorectal cancer cells via PI3K/AKT signaling pathway

This study was designed and conducted to clarify the impact of RNF128 expression on malignant biological behaviors of colorectal cancer (CRC) cells and the underlying mechanism. The expression of RNF128 in CRC tissues was analyzed using mRNA sequencing data of TCGA database and was validated by Western blot assay. The experimental studies on biological functions of RNF128 in vitro were conducted to assess its impact on the proliferation, apoptosis, and metastasis of CRC cells. Furthermore, tumor xenograft models in nude mice were established to investigate the relationship between RNF128 expression and tumor growth in vivo. The expression levels of both RNF128 mRNA and protein were significantly increased in CRC tissues (p < .001). The knockdown of RNF128 markedly suppressed the malignant phenotype of HCT116 and SW480 cells in vitro, including cell growth, antiapoptosis, migration, and invasion (p < .001). On the other hand, knockdown of RNF128 exerted a remarkable effect on the growth inhibition of tumor xenografts in vivo (p < .001). Further investigation revealed that RNF128 knockdown lead to a significant decrease in the expression of p-AKT and p-PI3K protein. More importantly, the proliferative, antiapoptotic, metastatic abilities of RNF128-knockdown cells were markedly increased by 740 Y-P treatment (p < .001). These findings further suggested that PI3K/AKT signaling pathway played a key role in RNF128-mediated aggressive phenotype of CRC cells. RNF128 functions as a tumor promoter in the pathogenesis of CRC via regulating PI3K/AKT pathway, and it could be a valuable target for CRC treatment.

ACR Appropriateness Criteria® Staging of Colorectal Cancer: 2021 Update

Preoperative imaging of rectal carcinoma involves accurate assessment of the primary tumor as well as distant metastatic disease. Preoperative imaging of nonrectal colon cancer is most beneficial in identifying distant metastases, regardless of primary T or N stage. Surgical treatment remains the definitive treatment for colon cancer, while organ-sparing approach may be considered in some rectal cancer patients based on imaging obtained before and after neoadjuvant treatment. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Benchmarking Outcomes for Definitive Treatment of Young-Onset, Locally Advanced Rectal Cancer

PURPOSE

There has been an increase in the incidence of rectal cancer diagnosed in young adults (age < 50 years). We evaluated outcomes among young adults treated with pre-operative long course chemoradiation (CRT) and total mesorectal excision (TME).

METHODS

The medical records of 219 patients, age 18-49, with non-metastatic, cT3-4, or cN1-2 rectal adenocarcinoma treated from 2000 to 2017 were reviewed for demographic and treatment characteristics, as well as pathologic and oncologic outcomes. The Kaplan-Meier test, log-rank test, and Cox regression analysis were used to evaluate survival outcomes.

RESULTS

The median age at diagnosis was 44 years. CRT followed by TME and post-operative chemotherapy was the most frequent treatment sequence (n = 196), with FOLFOX (n = 115) as the predominant adjuvant chemotherapy. There was no difference in sex, stage, MSS/pMMR, or pCR by age (< 45 years [n = 111] vs. ≥ 45 years [n = 108]). The 5-year rates of DFS were 77.2% for all patients, 69.8% for age < 45 years and 84.7% for age ≥ 45 years (P = .01). The 5-year rates of OS were 89.6% for all patients, 85.1% for patients with age < 45 years and 94.3% for patients with age ≥ 45 years (P = .03). Age ≥ 45 years was associated with a lower risk of disease recurrence or death on multivariable Cox regression analysis (HR = 0.55, 95% CI 0.31-0.97, P = .04).

CONCLUSION

Among young adults, patients with age < 45 years had lower rates of DFS and OS, compared to those with age ≥ 45 years. These outcomes could serve as a benchmark by which to evaluate newer treatment approaches.

Early response to upfront neoadjuvant chemotherapy (CAPOX) alone in low- and intermediate-risk rectal cancer: a single-arm phase II trial

BACKGROUND

With local recurrence of rectal cancer continuing to decrease, distant recurrence is becoming a major concern, especially for patients with low- and intermediate-risk stage II/III rectal cancer. Therefore, a new treatment strategy is warranted for these patients. This single-arm phase II trial aimed to assess the effect of neoadjuvant chemotherapy (NCT) in low- and intermediate-risk stage II/III rectal cancer and explore candidate radiological and clinical parameters for early prediction of tumour response after two cycles of CAPOX.

METHODS

Patients with mid-low stage II/III rectal cancer with low and intermediate risk were examined. The primary outcome was defined as a clinicopathological response by integrating tumour longitudinal length reduction (TLLR) on MRI into pathological tumour regression grade (TRG). After completing NCT, patients with TRG0-2 and TRG3 with a TLLR rate greater than 30 per cent were considered to be responders. Secondary outcomes included pathological complete response (pCR), adverse events and local and distant recurrence.

RESULTS

This study enrolled 61 eligible patients. No patient was converted to neoadjuvant chemoradiotherapy owing to tumour progression. The clinicopathological response and pCR rates were 78.7 and 21.3 per cent respectively. After two cycles of CAPOX, TLLR, TRG on MRI, and mucosal lesion regression grade on endoscopy had potential discriminative ability (area under the curve greater than 0.7) for predicting both clinicopathological and pathological response.

CONCLUSION

NCT alone achieves good tumour response rates in patients with low- and intermediate-risk stage II/III rectal cancer, and predicting tumour response to NCT is feasible at an early treatment phase.

REGISTRATION NUMBER

NCT03666442 (http://www.clinicaltrials.gov).

Immune-Related lncRNAs to Construct Novel Signatures and Predict the Prognosis of Rectal Cancer

Colorectal cancer (CRC) is one of the most common cancers. Almost 1/3 of CRC are rectal cancer, and 95% of rectal cancers are rectal adenocarcinoma (READ). Increasing evidences indicated that long noncoding RNAs (lncRNAs) have important role in the genesis and development of cancers. The purpose of our present study was to identify the differential expression lncRNAs which potentially related with immune cells infiltration and establish a risk assessment model to predict the clinical outcome for READ patients. We obtained three immune-related differential expression lncRNAs (IR-DELs) (C17orf77, GATA2-AS1, and TPT1-AS1) by differential expression analysis following correlation analysis and Cox regression analysis. A risk assessment model were constructed by integrating these analysis results. We then plotted the 1-, 3-, and 5-year ROC curves depending on our risk assessment model, which suggested that all AUC values were over 0.7. In addition, we found that the risk assessment model was correlated with several immune cells and factors. This study suggested that those three signatures (C17orf77, GATA2-AS1, and TPT1-AS1) screened by pairing IR-DELs could be prognosis markers for READ patients and might benefit them from antitumor immunotherapy.

Prognostic importance of circumferential resection margin in the era of evolving surgical and multidisciplinary treatment of rectal cancer: A systematic review and meta-analysis

BACKGROUND

Circumferential resection margin is considered an important prognostic parameter after rectal cancer surgery, but its impact might have changed because of improved surgical quality and tailored multimodality treatment. The aim of this systematic review was to determine the prognostic importance of circumferential resection margin involvement based on the most recent literature.

METHODS

A systematic literature search of MEDLINE, Embase, and the Cochrane Library was performed for studies published between January 2006 and May 2019. Studies were included if 3- or 5-year oncological outcomes were reported depending on circumferential resection margin status. Outcome parameters were local recurrence, overall survival, disease-free survival, and distant metastasis rate. The Newcastle Ottawa Scale and Jadad score were used for quality assessment of the studies. Meta-analysis was performed using a random effects model and reported as a pooled odds ratio or hazard ratio with 95% confidence interval.

RESULTS

Seventy-five studies were included, comprising a total of 85,048 rectal cancer patients. Significant associations between circumferential resection margin involvement and all long-term outcome parameters were uniformly found, with varying odds ratios and hazard ratios depending on circumferential resection margin definition (<1 mm, ≤1 mm, otherwise), neoadjuvant treatment, study period, and geographical origin of the studies.

CONCLUSION

Circumferential resection margin involvement has remained an independent, poor prognostic factor for local recurrence and survival in most recent literature, indicating that circumferential resection margin status can still be used as a short-term surrogate endpoint.

Still proliferating CD44+/Ki67+ tumor cells after neoadjuvant radiochemotherapy identify rectal cancer patients with poor survival

INTRODUCTION

Distant recurrence, especially liver metastases, occurs in one-third of rectal cancer patients initially treated with curative therapy and is still an unsolved problem. The identification of patients at risk is crucial for enabling individualized treatment.

MATERIAL AND METHODS

All patients undergoing curative resection for histologically confirmed rectal cancer after neoadjuvant radiochemotherapy between January 2001 and December 2015 were included. Sections were stained for Ki67, CD44, apoptosis and CD133. Patients were categorized based on whether they were found to have (CD44⁺/Ki67⁺) or not have (CD44⁺/Ki67⁺) still proliferating tumor cells.

RESULTS

218 patients who underwent R0 resection for stage I-III rectal cancer were selected. In 37 (17%) of these patients, CD44⁺/Ki67⁺ tumor cells were found. In multivariable Cox regression analysis, patients with CD44⁺/Ki67⁺ cells had significantly impaired overall (hazard ratio (HR): 3.84, 95% CI: 1.77-8.31, p = 0.001) and relative survival (HR 3.44, 95% CI: 1.46-8.09). The previous results were confirmed after propensity-score matching. In mediation-analysis, the presence of CD44⁺/Ki67⁺ cells was associated with a substantial direct effect on overall (HR 1.92, 95% CI: 1.09-9.28) and relative survival (HR 1.63, 95% CI: 1.31-6.38).

CONCLUSIONS

The presence of still proliferating CD44⁺/Ki67⁺ tumor cells after neoadjuvant radiochemotherapy was associated with impaired oncological long-term outcomes. Characterization of these cells should be performed.

Adding Three Cycles of CAPOX after Neoadjuvant Chemoradiotherapy Increases the Rates of Complete Response for Locally Advanced Rectal Cancer

BACKGROUND AND OBJECTIVES

the total neoadjuvant chemoradiotherapy (TNT) includes different strategies, but the most appropriate model remains uncertain. The purpose of this retrospectively study was to evaluate the safety and pathological response in the consolidation chemotherapy model.

METHODS

patients with cT3/T4 or TxN + M0 rectal cancer that were receiving neoadjuvant chemoradiotherapy (CRT) (50 Gy with oral capecitabine)/TNT (CRT followed by three cycles of CAPOX) during September 2017 to September 2019 in our department were included. All of the patients were recommended to receive radical surgery.

RESULTS

a total of 197 patients were included. Eighty-one patients received CRT, while one hundred and sixteen patients received TNT. Nine patients did not undergo surgery because of the distant metastases (one patient (1.2%) in CRT group, two patients (1.7%) in TNT group) or a refusal of resection (two patients in CRT group, four patients in TNT group). The pathological complete response (pCR) rate was 32.7% in TNT compared with 12.8% in CRT (p = 0.002). There was no statistically significant difference in grade 3 acute toxicities of neoadjuvant treatment and surgical complications between the two groups.

CONCLUSIONS

the consolidation chemotherapy model is safe for patients with locally advanced rectal cancer and it has a high pCR rate. The long-term follow-up is necessary to be evaluated in a future prospective, randomized trial.

Tumor mutation burden in blood predicts benefit from neoadjuvant chemo/radiotherapy in locally advanced rectal cancer

Distant metastasis has been the major concern of prognosis in patients with locally advanced rectal cancer (LARC). The purpose of this study was to investigate the prognostic value of TMB in blood (bTMB) in LARC patients after receiving neoadjuvant chemoradiotherapy (nCRT) and surgery. Using targeted ctDNA sequencing, we revealed that bTMB level at baseline was positively correlated with recurrence-free survival (RFS). Following nCRT, the patients with decreasing TMB tends to have a longer median RFS. bTMB level after surgery was negatively correlated with RFS. The serum cytokines including IFNγ, IFNα2, IL-1β, IL-2 and MIP-1β were significantly higher in pre-nCRT serum with higher bTMB group than that of lower bTMB group. Clonal evolution analysis showed that the pre- and post-nCRT ctDNAs of most cases had shared mutations. In conclusion, we presume that bTMB could potentially improve pre- and post-treatment risk assessment and facilitate individualized therapy for patients with LARC.

Combination of radiotherapy and suppression of Tregs enhances abscopal antitumor effect and inhibits metastasis in rectal cancer

Background

Distant metastasis is the major cause of mortality in patients with locally advanced rectal cancer (LARC) following neoadjuvant chemoradiotherapy. Local radiotherapy can trigger an abscopal response to metastatic tumor cells. However, the abscopal effect is a rare event. CD4+ regulatory T (Treg) cell is a highly immune-suppressive subset which impedes immune surveillance against cancer, prevents the development of effective antitumor immunity and promotes tumor progression. We assume that the exploitation of the proimmunogenic effects of radiotherapy with anti-CD25 or anti-Cytotoxic T-Lymphocyte Associated Protein 4 (anti-CTLA4) monoclonal antibodies (mAbs) may enhance the local and abscopal effects in rectal cancer and improve the therapeutic outcome.

Methods

mRNA expression profiling of 81 pretreatment biopsy samples from LARC patients who received neoadjuvant radiotherapy (nRT) was performed to analyze the correlation between gene expression and prognosis. A retrospective analysis of patients with rectal cancer with distant metastasis or synchronous extracolonic cancers was performed to evaluate the abscopal effect of radiotherapy on rectal cancer. Two different dual-tumor mouse models were established to investigate the efficacy of single dose and dose-fractionated radiotherapy combined with anti-CD25 or anti-CTLA4 and anti-Programmed cell death 1 ligand 1 (anti-PD1) mAbs on the local tumor growth and liver metastasis. The univariate Cox regression analysis, one-way analysis of variance, Dunnett’s test, a mixed-effect linear model and Kaplan-Meier survival analysis were used to calculate p values.

Results

The proportion of Tregs in pre-nRT biopsies was negatively correlated with prognosis (p=0.007). The retrospective analysis showed that regressing liver metastases were infiltrated by CD8+ T cells. In contrast, stable/progressing metastases and synchronous extracolonic cancers were characterized by PD1+ T cells and Tregs infiltration. Animal experiment results demonstrated that the combination of radiotherapy and anti-CD25/CTLA4 mAb resulted in a significant increase in CD8+ T cells and CD8+/CD4+ ratio in primary and secondary tumors compared with the irradiation alone group (all p<0.05 or p<0.01). The combined treatment was able to decrease Tregs, PD1+CD8+ and PD1+CD4+ T cells (p<0.05), suppress locally irradiated and distal unirradiated tumor growth, and improve overall survival rate. Radiotherapy in conjunction with anti-CTLA4 reduced liver metastasis (p<0.05).

Conclusions

These data indicated that radiotherapy plus depletion of Tregs was able to improve the antitumor response and generate an abscopal effect.

MRI of rectal cancer-relevant anatomy and staging key points

Rectal cancer has the eighth highest cancer incidence worldwide, and it is increasing in young individuals. However, in countries with a high human development index, mortality is decreasing, which may reflect better patient management, imaging being key. We rely on imaging to establish the great majority of clinical tumour features for therapeutic decision-making, namely tumour location, depth of invasion, lymph node involvement, circumferential resection margin status and extramural venous invasion. Despite major improvements in technique resulting in better image quality, and notwithstanding the dissemination of guidelines and examples of standardised reports, rectal cancer staging is still challenging on the day-to-day practice, and we believe there are three reasons. First, the normal posterior pelvic compartment anatomy and variants are not common knowledge to radiologists; second, not all rectal cancers fit in review paper models, namely the very early, the very low and the mucinous; and third, the key clinical tumour features may be tricky to analyse. In this review, we discuss the normal anatomy of the rectum and posterior compartment of the pelvis, systematise all rectal cancer staging key points and elaborate on the particularities of early, low and mucinous tumours. We also include our suggested reporting templates and a discussion of its comparison to the reporting templates provided by ESGAR and SAR.

Induction chemotherapy followed by neoadjuvant chemoradiotherapy and surgery for patients with locally advanced rectal cancer: a systematic review and meta-analysis

BACKGROUND

Controversy persists about whether additional induction chemotherapy (ICT) before neoadjuvant chemoradiation (NCRT) yields improved oncological outcomes. We performed a systematic review and meta-analysis to compare ICT+ NCRT+ surgery(S) with NCRT+ S in patients with locally advanced rectal cancer (LARC).

METHODS

We searched the PubMed, EMBASE, Cochrane Library, and China Biology Medicine (CBM) databases. The data were analyzed with Stata version 12.0 software.

RESULTS

We identified 9 relevant trials that enrolled 1538 patients. We detected no significant difference in the 5-year overall survival (OS) (OR 1.50, 95% CI 0.48-4.64), disease-free survival (DFS) (OR 1.03, 95% CI 0.73-1.46), local recurrence (LR) (OR 0.80, 95% CI 0.45-1.43), and distant metastasis (DM) rates (OR 1.03, 95% CI 0.55-1.93) between patients who did and did not receive ICT. The addition of ICT before NCRT had a similar pathological complete response rate compared to NCRT (OR 1.26, 95% CI 0.90-1.77). Our findings suggest that between the ICT + NCRT+S and NCRT+S groups, ICT improved the incidence of grade 3 to 4 toxicity effects (OR 4.81, 95% CI 2.38-9.37), but between the ICT + NCRT+S and NCRT+S+ adjuvant chemotherapy (ACT) groups, ICT might reduce toxicity (OR 0.19, 95% CI 0.08-0.50). ICT had no significant impact on surgical complications (OR 0.97, 95% CI 0.63-1.51).

CONCLUSIONS

The addition of ICT before NCRT seemingly shows no survival benefit on patients with LARC, and might increase the toxicity.

Prognostic Value of Serum NPY Hypermethylation in Neoadjuvant Chemoradiotherapy for Rectal Cancer: Secondary Analysis of a Randomized Trial

OBJECTIVES

Long-term prevention of metastatic disease remains a challenge in locally advanced rectal cancer, and robust pretreatment prognostic factors for metastatic progression are lacking. We hypothesized that detecting circulating tumor-specific DNA (ctDNA) based on hypermethylation of the neuropeptide Y gene (meth-ctDNA) could be a prognostic marker in the neoadjuvant setting; we examined this in a secondary, explorative analysis of a prospective trial.

MATERIALS AND METHODS

Serum samples were prospectively collected in a phase III trial for locally advanced rectal cancer. Positivity for and fractional abundance of meth-ctDNA in baseline samples were estimated. Overall survival (OS) and the rate of distant metastases were compared between meth-ctDNA positive and negative patients; other prognostic factors were controlled for in multivariate Cox regression. Importance of quantitative load was examined by considering the fractional abundance of meth-ctDNA relative to total circulating DNA.

RESULTS

Baseline serum samples were available for 146 patients. In total, 30 patients had presence of meth-ctDNA, with no correlation with cT (P=0.8) or cN (P=0.6) stages. Median follow-up was 10.6 years for OS and 5.1 years for freedom from distant metastases. Patients with meth-ctDNA had significantly worse 5-year OS (47% vs. 69%), even when controlling for other prognostic factors (hazard ratio=2.08; 95% confidence interval, 1.23-1.51). This seemed mainly driven by disparity in the rate of distant metastases (55% vs. 72% at 5 y, P=0.01); hazard ratio=2.20 (95% confidence interval, 1.19-4.07, P=0.01) in multivariate analysis. Increased quantitative load was highly significant for worse outcomes.

CONCLUSIONS

Meth-ctDNA could be a potential prognostic marker in the neoadjuvant setting and may, if validated, identify patients at increased risk of distant metastases.

Imaging of rectal cancer

International guidelines dictate that magnetic resonance imaging (MRI) should be part of the primary standard work up of patients with rectal cancer because MRI can accurately identify the main risk factors for local recurrence and stratify patients into a differentiated treatment. The role of endoscopic ultrasound (EUS) is restricted to staging of superficial tumors because EUS is able to differentiate between T1 and T2 rectal cancer. Recent guidelines recommend the addition of diffusion-weighted (DWI) MRI to clinical and endoscopic assessment of response to preoperative radiochemotherapy (RCT). MRI is able to identify significant tumor regression which may alter the surgical approach.

Grey areas and evidence gaps in the management of rectal cancer as revealed by comparing recommendations from clinical guidelines

BACKGROUND

While the management of nonmetastatic and oligometastatic rectal cancer has rapidly evolved over the last few decades, many grey areas and highly debated topics remain that foster significant variation in clinical practice. We aimed to identify controversial points and evidence gaps in this disease setting by systematically comparing recommendations from national and international clinical guidelines.

METHODS

Twenty-six clinical questions reflecting practical challenges in the routine management of nonmetastatic and oligometastatic rectal cancer patients were selected. Recommendations from the ESMO, NCCN, JSCCR, Australian and Ontario guidelines were extrapolated and compared using a 4-tier classification system (i.e., identical/very similar, similar, slightly different, different). Overall agreement between guidelines (i.e., substantial/complete disagreement, partial disagreement, partial agreement, substantial/complete agreement) was assessed for each clinical question and compared against the highest level of available evidence by using the χ² statistic test.

RESULTS

Guidelines were in substantial/complete agreement, partial agreement, partial disagreement, and substantial/complete disagreement for 8 (30.8%), 2 (7.7%), 7 (26.9%), and 9 (34.6%) clinical questions, respectively. High level of evidence supported clinical recommendations in 3/10 cases (30%) where guidelines were in agreement and in 10/16 cases (62.5%) where guidelines were in disagreement (χ² = 2.6, p = 0.106). Agreement was frequently reached for questions regarding diagnosis, staging, and radiology/pathology pro-forma reporting, while disagreement characterised most of the treatment-related topics.

CONCLUSIONS

Substantial variation exists across clinical guidelines in the recommendations for the management of nonmetastatic and oligometastatic rectal cancer. This variation is only partly explained by the lack of supporting, high-level evidence.

An audit of performance, interpretation, and influence of pretherapeutic MRI in rectal cancer: a Swedish population-based cohort study

Background

The performance of magnetic resonance imaging (MRI) interpretation and communication of findings and its implication on treatment decisions has not fully been explored in rectal cancer.

Purpose

To investigate in a region the adherence to MRI protocol standards and the relation between MRI interpretation and selection to preoperative therapy in rectal cancer.

Material and Methods

Data on consecutive patients who underwent elective rectal cancer surgery in the region from January to June 2010 were obtained from the National Colorectal Cancer Registry. Pretherapeutic MRI images were re-evaluated. Agreement between the original reports and the re-evaluation was compared using Cohen’s kappa coefficient.

Results

Among the 94 patients included, 81 (86%) had pretherapeutic MRI in accordance with defined imaging guidelines. In 34% of the original MR reports, data on extramural venous invasion (mrEMVI) and mrT category were not reported. Complete tumor staging was not possible because of missing data in 33 (35%) of the patients. The agreement between the original MR reports and the re-evaluation regarding tumor stage was moderate (κ = 0.48). For decided treatment compared to recommended preoperative treatment according to the re-evaluation, the agreement was fair (κ = 0.33).

Conclusion

Established MRI protocol standards were not universally applied. Missing data and inadequacies in original MRI reports resulted in moderate agreement between the original report and the re-evaluation indicating a risk of inappropriate treatment selection. The results call for further educational efforts in rectal cancer MRI acquisition and repeated audits of image protocol adherence and interpretation quality.

Analysis of KRAS, NRAS, BRAF, PIK3CA and TP53 mutations in a large prospective series of locally advanced rectal cancer patients

Little information is available on the clinical significance of cancer-related genes such as KRAS, NRAS, BRAF, PIK3CA and TP53 in nonmetastatic rectal cancer. We investigated mutations of these genes in a large prospective series of locally advanced rectal cancer (LARC) patients who were recruited into two phase II trials. Mutational analyses were performed with diagnostically validated methods including polymerase chain reaction, capillary electrophoresis single-strand conformational analysis, Sanger sequencing and next-generation sequencing. Associations between single or multiple gene mutations and clinicopathological characteristics and treatment outcomes were explored. Of these 269, 210 (78%) patients were assessable. Mutations of KRAS, NRAS, BRAF, PIK3CA and TP53 occurred in 43, 9, 4, 9 and 60% of patients, respectively. Concordance between paired biopsy and resection specimens was 82% for KRAS, 95% for NRAS, 99% for BRAF, 96% for PIK3CA and 63% for TP53. TP53 mutations were associated with extramural venous invasion on baseline MRI (78% vs. 65%, p = 0.04), poor pathological tumour regression (23% vs. 36%, p = 0.05) and a trend toward a worse 5-year progression-free survival (PFS; 60% vs. 74%, HR 1.59, p = 0.06). Patients with tumours harbouring mutation of TP53 and either KRAS or NRAS (32%) had a worse 5-year PFS than those with TP53/KRAS/NRAS wild-type tumours (54% vs. 72%, HR 1.75, p = 0.02). In univariate analysis, BRAF mutation predicted poor 5-year overall survival only among patients treated without cetuximab (20% vs. 73%, HR 3.29, p = 0.03). This is one of the largest biomarker studies in a prospective, largely homogeneous, LARC population. Our findings are hypothesis generating and require validation in independent series.

Total neoadjuvant therapy in locally advanced rectal cancer: Role of systemic chemotherapy

For the past several decades, disease-related outcomes, particularly local recurrence rate, in patients with locally advanced rectal cancer have significantly improved as a result of advancement of surgical technique and implementation of neoadjuvant chemoradiation. However, distant metastasis remains unresolved, being a significant cause of cancer death. To focus on micrometastases early in the course of multimodal treatment, delivering systemic chemotherapy in the neoadjuvant setting is emerging. Also, driven by patient demand and interest in preserving quality of life, upfront chemotherapy prior to surgery serves as a strategy for organ preservation in the management of rectal cancer. Herein, currently available literature on different methods and strategies of the multimodal approach is critically appraised.

Distinct Prognosis of High Versus Mid/Low Rectal Cancer: a Propensity Score-Matched Cohort Study

BACKGROUND

Rectal cancers have long been treated as a single-entity disease; however, whether the prognosis of high rectal cancer (inferior margin located 10.1 to 15.0 cm from the anal verge) differs from that of mid/low rectal cancer (0 to 10.0 cm) remains disputed.

METHODS

Patients with stages I-III rectal adenocarcinomas undergoing curative-intent surgery were enrolled between 2007 and 2013 in this retrospective analysis. Exclusion criteria were neoadjuvant therapy or concurrent cancers. Propensity score matching and Cox regression analysis were performed to compare a 5-year overall and cancer-specific survival between patients with high and mid/low rectal cancer.

RESULTS

Of 613 patients who met the inclusion criteria, 199 (32.5%) and 414 (67.5%) had high and mid/low rectal cancer, respectively. After propensity score matching (187 cases for each group), the high group showed a better overall survival (70.9 vs. 56.9%, p = 0.042) and cancer-specific survival (77.4 vs. 60.3%, p = 0.028) at 5 years compared with the mid/low group with stage III disease. However, high rectal cancer did not demonstrate prognostic superiority in stages I-II disease. Multivariate analysis identified high tumor location as an independent prognostic factor for cancer-specific survival (hazards ratio = 0.422, 95% confidence interval 0.226-0.786, p = 0.007) and overall survival (hazards ratio = 0.613, 95% confidence interval 0.379-0.991, p = 0.046).

CONCLUSIONS

Patients with stage III high rectal adenocarcinoma demonstrated better overall and cancer-specific survival than those with mid/low type, and tumor location was an independent prognostic factor for patients with rectal carcinomas.

The Diagnostic Performance of MRI for Detection of Extramural Venous Invasion in Colorectal Cancer: A Systematic Review and Meta-Analysis of the Literature

OBJECTIVE. The purpose of this article is to perform a systematic review and meta-analysis regarding the diagnostic test accuracy of MRI for detecting extramural venous invasion (EMVI) in patients with colorectal cancer. MATERIALS AND METHODS. PubMed and EMBASE were searched up to November 9, 2018. We included diagnostic accuracy studies that used MRI for EMVI detection in patients with colorectal cancer, using pathologic analysis as the reference standard. The methodologic quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Sensitivity and specificity were pooled and plotted in a hierarchic summary ROC plot. Metaregression analysis using several clinically relevant covariates was performed. RESULTS. Fourteen studies (n = 1751 patients) were included. Study quality was moderate in general. Pooled sensitivity was 0.61 (95% CI, 0.49-0.71), and pooled specificity was 0.87 (95% CI, 0.79-0.92). There was substantial heterogeneity according to the Cochran Q test (p < 0.01) and Higgins I² heterogeneity index (98% and 95% for sensitivity and specificity, respectively). Publication bias was present (p = 0.01). Higher rates of advanced T category, use of high-resolution MRI, and use of antispasmodic drugs were shown to significantly affect heterogeneity (p < 0.01). Location of primary tumor, preoperative treatment status, study design, definition of reference standard, magnetic field strength, and use of functional MRI were not statistically significant (p = 0.17-0.92). CONCLUSION. MRI shows moderate sensitivity and good specificity for the detection of EMVI in colorectal cancer. The use of high-resolution MRI may improve diagnostic performance.

Organ Preservation Strategies After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

Standard use of neoadjuvant chemoradiotherapy, total mesorectal excision, and postoperative adjuvant chemotherapy in locally advanced rectal cancer has tremendously improved oncologic outcomes over the past several decades. However, these improvements come with costs of significant morbidity and poor quality of life. Along with developments in imaging techniques, clinical experience and evidence have identified a certain subgroup of patients that have exceptionally good clinical outcomes while preserving quality of life. Driven by patient demand and interest in preserving quality of life, numerous organ preservation treatment strategies for managing rectal cancer are rapidly evolving. Herein, the flow of research in organ preservation strategies and counter arguments are discussed.

Circumferential resection margin as a prognostic factor after rectal cancer surgery: A large population-based retrospective study

AIM

This study aimed to investigate circumferential resection margin (CRM) as a prognostic factor for long-term oncologic survival after rectal cancer surgery.

METHODS

Patients diagnosed with malignant rectal cancer between 1 January 2010 and 31 December 2014, from the Surveillance, Epidemiology, and End Results (SEER) program were identified for this study. The patients were divided into five CRM groups to compare the baseline characteristics and assess cancer-specific survival (CSS): 0-1 mm, 1.1-2.0 mm, 2.1-5.0 mm, 5.1-10.0 mm, and >10 mm. The main endpoint was CSS.

RESULTS

Circumferential resection margin ≤1 mm was independently associated with 99% increased risk of cancer-specific mortality in rectal cancer [hazard ratio (HR) = 1.990, 95% confidence interval (CI) = 1.613-2.454, P < 0.001, using CRM (1.1-2.0 mm) as a reference]. CRM (5.1-10.0 mm) was independently associated with 29.2% decreased risk of cancer-specific mortality [HR = 0.708, 95% CI = 0.525-0.954, P = 0.152, using group (2.1-5.0 mm) as reference]. CRM ≤2 mm or ≤0.4 mm was not obviously associated with CSS.

CONCLUSIONS

circumferential resection margin is an independent prognostic factor in rectal cancer. Surgeons should try to maximize the CRM. Rectal cancer patients with CRM ≤1 mm should receive more postoperative attention depending on individual situation. Also, CRM should be accurately measured in millimeters in a preoperative magnetic resonance imaging or pathological report, rather than simply described as "involved" or "clear."

MRI-based EMVI positivity predicts systemic recurrence in rectal cancer patients with a good tumor response to chemoradiotherapy followed by surgery

BACKGROUND

This study aimed to determine the prognostic value of baseline magnetic resonance imaging-based extramural vascular invasion status (EMVI) among rectal cancer patients with a good tumor response to standard chemoradiotherapy followed by surgery.

METHODS

A total of 359 patients with ypT0-2/N0 disease from The Yonsei Multicenter Colorectal Cancer Electronic Database were retrospectively included between January 2000 and December 2014. Magnetic resonance images and medical records were reviewed to investigate risk factors for tumor recurrence.

RESULTS

When we compared patients without and with EMVI, significant differences were observed in the 5-year disease-free survival rate (DFS) (80.8% vs 57.8%, P = 0.005) and in the 5-year systemic recurrence-free survival rate (SRFS) (86.9% vs 64.3%, P = 0.007). In the multivariate analysis, both mrEMVI and APR independently predicted overall DFS (APR; HR 2.088, 95% CI: 1.082-4.031, P = 0.028, mrEMVI; HR: 2.729, 95% CI: 1.230-6.058, P = 0.014). mrEMVI was only independent prognostic factor for systemic recurrence with statistical significance (HR: 3.321, 95% CI: 1.185-9.309, P = 0.022).

CONCLUSION

Even in rectal cancer patients with a good response to chemoradiotherapy followed by curative surgery, extramural vascular invasion and APR may predict poor disease-free survival outcomes. Intensified treatment strategy should be considered.

Oncological outcome after MRI-based selection for neoadjuvant chemoradiotherapy in the OCUM Rectal Cancer Trial

BACKGROUND

It is not clear whether all patients with rectal cancer need chemoradiotherapy. A restrictive use of neoadjuvant chemoradiotherapy (nCRT) based on MRI findings for rectal cancer was investigated in this study.

METHODS

This prospective multicentre observational study included patients with stage cT2-4 rectal cancer, with any cN and cM0 status. Carcinomas in the middle and lower third that were 1 mm or less from the mesorectal fascia, all cT4 tumours, and all cT3 tumours of the lower third were classified as high risk, and these patients received nCRT followed by total mesorectal excision (TME). All other carcinomas with a minimum distance of more than 1 mm from the mesorectal fascia and those in the upper third were classified as low risk; these patients underwent TME alone (no nCRT). Patients were followed for at least 3 years. Outcomes were the rates of local recurrence, distant metastasis and survival.

RESULTS

Among 545 patients included, 428 were treated according to the study protocol: 254 (59·3 per cent) had TME alone and 174 (40·7 per cent) received nCRT and TME. Median follow-up was 60 months. The 3- and 5-year local recurrence rates were 1·3 and 2·7 per cent respectively, with no differences between the two treatment protocols. Patients with disease requiring nCRT had higher 3- and 5-year rates of distant metastasis (17·3 and 24·9 per cent respectively versus 8·9 and 14·4 per cent in patients who had TME alone; P = 0·005) and worse disease-free survival compared with that in patients who did not need nCRT (3- and 5-year rates 76·7 and 66·7 per cent, versus 84·9 and 76·0 per cent in the TME-alone group; P = 0·016).

CONCLUSION

Restriction of nCRT to high-risk patients achieved good results.

ACR Appropriateness Criteria® Pretreatment Staging of Colorectal Cancer

Colorectal cancers are common tumors in the United States and appropriate imaging is essential to direct appropriate care. Staging and treatment differs between tumors arising in the colon versus the rectum. Local staging for colon cancer is less integral to directing therapy given radical resection is often standard. Surgical options for rectal carcinoma are more varied and rely on accurate assessment of the sphincter, circumferential resection margins, and peritoneal reflection. These important anatomic landmarks are best appreciated on high-resolution imaging with transrectal ultrasound or MRI. When metastatic disease is suspected, imaging modalities that provide a global view of the body, such as CT with contrast or PET/CT may be indicated. Rectal cancer often metastasizes to the liver and so MRI of the liver with and without contrast provides accurate staging for liver metastases. This article focuses on local and distant staging and reviews the appropriateness of different imaging for both variants. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

KRAS and BRAF mutations in circulating tumour DNA from locally advanced rectal cancer

There are limited data on circulating, cell-free, tumour (ct)DNA analysis in locally advanced rectal cancer (LARC). Digital droplet (dd)PCR was used to investigate KRAS/BRAF mutations in ctDNA from baseline blood samples of 97 LARC patients who were treated with CAPOX followed by chemoradiotherapy, surgery and adjuvant CAPOX ± cetuximab in a randomised phase II trial. KRAS mutation in G12D, G12V or G13D was detected in the ctDNA of 43% and 35% of patients with tumours that were mutant and wild-type for these hotspot mutations, respectively, according to standard PCR-based analyses on tissue. The detection rate in the ctDNA of 10 patients with less common mutations was 50%. In 26 cases ctDNA analysis revealed KRAS mutations that were not previously found in tissue. Twenty-two of these (84.6%) were detected following repeat tissue testing by ddPCR. Overall, the ctDNA detection rate in the KRAS mutant population was 66%. Detection of KRAS mutation in ctDNA failed to predict prognosis or refine patient selection for cetuximab. While this study confirms the feasibility of ctDNA analysis in LARC and the high sensitivity of ddPCR, larger series are needed to better address the role of ctDNA as a prognostic or predictive tool in this setting.

The Perfect Total Mesorectal Excision Obviates the Need for Anything Else in the Management of Most Rectal Cancers

This article discusses the local control of primary rectal cancer and its locoregional spread in the light of modern advances. In recent years, the use of neoadjuvant chemoradiation has spread widely. However, its true benefit is not always balanced with its morbidities. Often total mesorectal excision (TME) is the best option. We will discuss the indications for immediate surgery for chemoradiation in advance and the importance of a delay in the management plan. To understand this selection, it is mandatory to know the true extent of tissue at risk for tumor dissemination and spread. Considering that TME may be enough for many patients and that most local recurrences are failures of surgical technique we introduce a new concept of total mesorectal irradiation. This exploits the new reality that precise, focused neoadjuvant therapy can offer a better response with fewer complications. Together these important changes in cancer board (multidisciplinary team) planning can also offer selected patients complete control of their cancer with no need for surgery.

Current issues of preoperative radio(chemo)therapy and its future evolution in locally advanced rectal cancer

Neoadjuvant therapies are effective for local control and tumor downstaging. Up to date, preoperative long-course chemoradiotherapy and short-course radiotherapy are the two primary guideline-recommended neoadjuvant therapies for locally advanced rectal cancer patients. However, clinicians throughout the world are trying their best to further optimize the regimens and concepts of neoadjuvants. Hence, there is an urgent need to summarize evidence regarding indications of neaoadjuvant therapies and relative merits of current standard regimens. In addition, we also reviewed the optimized regimens mainly based on short-course radiotherapy with delayed surgery, consolidation chemotherapy, induction chemotherapy, chemotherapy alone without radiation and concepts in terms of organ preservation and personalized treatments to further explore the future evolution of neoadjuvant therapies in rectal cancer.

What has preoperative radio(chemo)therapy brought to localized rectal cancer patients in terms of perioperative and long-term outcomes over the past decades? A systematic review and meta-analysis based on 41,121 patients

We asked what preoperative radiotherapy/chemoradiotherapy (PRT/PCRT) has brought to patients in terms of perioperative and long-term outcomes over the past decades. A systematic review and meta-analysis was conducted using PubMed, Embase and Web of Science databases. All original comparative studies published in English that were related to PRT/PCRT and surgical resection and which analyzed survival, postoperative and quality of life outcomes were included. Data synthesis and statistical analysis were carried out using Stata software. Data from 106 comparative studies based on 80 different trials enrolling 41,121 patients were included in our study. Based on our overall analyses, PRT/PCRT significantly improved patients' local recurrence-free survival (LRFS), but neither overall survival (OS) nor metastasis-free survival (MFS) showed improvement. In addition, PRT significantly increased the postoperative morbidity and mortality but PCRT did not have a significant effect. Furthermore, PRT/PCRT significantly increased the risk of postoperative wound complications but not anastomotic leakage and bowel obstruction. Our comprehensive subgroup analyses further supported the aforementioned results. Meanwhile, long-term anorectal symptoms (impaired squeeze pressures, use of pads, incontinence and urgency) and erectile dysfunction were also significantly increased in patients after PRT/PCRT. The benefits of PRT/PCRT as applied over the last several decades have not been sufficient to improve OS. Metastases of primary tumor and postoperative adverse effects were the two primary obstacles for an improved OS. In fact, the greatest advantage of PRT/PCRT is still local tumor control and a significantly improved LRFS.

A Dose-finding and Biomarker Evaluation Phase Ib Study of Everolimus in Association With 5-Fluorouracil and Pelvic Radiotherapy as Neoadjuvant Treatment of Locally Advanced Rectal Cancer (E-LARC Study)

BACKGROUND

During the past 20 years, considerable improvement has occurred in the treatment of patients with locally advanced rectal cancer (LARC). With the introduction of multimodal treatment, refinements in preclinical staging and improvements in surgical skills, local relapse is no longer the major problem for patients with LARC. However, many patients die of metastatic disease. The present phase Ib study aimed to establish the maximum tolerated dose of everolimus combined with 5-fluorouracil and radiotherapy in patients with LARC.

PATIENTS AND METHODS

Patients were sequentially assigned to 4 cohorts with an increasing dose of everolimus, starting from 14 days before 5-fluorouracil and radiotherapy and continuing throughout concomitant treatment. The secondary endpoints were the Dworak tumor regression grade, pathologic complete response rate, neoadjuvant rectal score, biomarker assessment (phosphorylated mTOR [mammalian target of rapamycin] protein and phosphorylated-p70S6K protein).

RESULTS

At the time of this report, 12 patients had been treated, and no dose-limiting toxicity was recorded. The most frequently reported acute toxicities were rectal tenesmus, skin rash, diarrhea, and dysuria. All 12 patients underwent curative R0 resection. Two patients had Dworak tumor regression grade 4 (pathologic complete response). No everolimus-related postoperative complications were observed. No relationship was found between biomarker expression and the clinicopathologic outcomes.

CONCLUSION

Although the addition of everolimus did not appear to worsen the toxicity of chemoradiation in patients with LARC, evaluation of its activity deserves further investigation in larger clinical trials.

Tumor deposits: markers of poor prognosis in patients with locally advanced rectal cancer following neoadjuvant chemoradiotherapy

Background

Tumor deposits (TDs) were reported to be poor prognoses in colorectal carcinoma, but the significance in locally advanced rectal cancer (LARC) (T3-4/N+) following neoadjuvant chemoradiotherapy (neo-CRT) and surgery is unclear. Since adjuvant chemotherapy showed no benefit for LARC following neo-CRT, it is of great value to investigate whether TDs can identify the subgroup of patients who may benefit from adjuvant chemotherapy.

Methods

Between 2004 and 2012, 310 LARC patients following neo-CRT and surgery were retrospectively reviewed. Overall survival (OS), disease-free survival (DFS), distant metastasis free survival (DMFS) and local recurrence free survival (LRFS) were evaluated by Kaplan-Meier method, log-rank test and Cox models.

Results

TDs-positive patients showed adverse OS, DFS and DMFS (all P≤0.001), but not LRFS (P = 0.273). In multivariate analysis, TDs continued to be associated with poor OS (HR = 2.44, 95% CI 1.32-4.4, P = 0.004) and DFS (HR = 1.99, 95% CI 1.21-3.27, P = 0.007), but not DMFS (HR = 1.77, 95% CI 0.97-3.20, P = 0.061) or LRFS (HR = 1.85, 95% CI 0.58-5.85, P = 0.298). Among TDs-positive patients, adjuvant chemotherapy significantly improved OS (P = 0.045) and DMFS (P = 0.026), but not DFS (P = 0.127) or LRFS (P = 0.862).

Conclusions

TDs are predictive of poor survival in LARC after neo-CRT. Fortunately, TDs-positive patients appear to benefit from adjuvant chemotherapy.

Essential Items for Structured Reporting of Rectal Cancer MRI: 2016 Consensus Recommendation from the Korean Society of Abdominal Radiology

High-resolution rectal MRI plays a crucial role in evaluating rectal cancer by providing multiple prognostic findings and imaging features that guide proper patient management. Quality reporting is critical for accurate effective communication of the information among multiple disciplines, for which a systematic structured approach is beneficial. Existing guides on reporting of rectal MRI are divergent on some issues, largely reflecting the differences in overall management of rectal cancer patients between the United States and Europe. The Korean Society of Abdominal Radiology (KSAR) study group for rectal cancer has developed an expert consensus recommendation regarding essential items for structured reporting of rectal cancer MRI using a modified Delphi method. This recommendation aims at presenting an up-to-date, evidence-based, practical, structured reporting template that can be readily adopted in daily clinical practice. In addition, a thorough explanation of the clinical and scientific rationale underlying the reporting items and their formats is provided. This KSAR recommendation may serve as a useful tool to help achieve more standardized optimal care for rectal cancer patients using rectal MRI.

Validation of a rectal cancer outcome prediction model with a cohort of Chinese patients

The risk of local recurrence (LR), distant metastases (DM) and overall survival (OS) of locally advanced rectal cancer after preoperative chemoradiation can be estimated by prediction models and visualized using nomograms, which have been trained and validated in European clinical trial populations. Data of 277 consecutive locally advanced rectal adenocarcinoma patients treated with preoperative chemoradiation and surgery from Shanghai Cancer Center, were retrospectively collected and used for external validation. Concordance index (C-index) and calibration curves were used to assess the performance of the previously developed prediction models in this routine clinical validation population. The C-index for the published prediction models was 0.72 ± 0.079, 0.75 ± 0.043 and 0.72 ± 0.089 in predicting 2-year LR, DM and OS in the Chinese population, respectively. Kaplan-Meier curves indicated good discriminating performance regarding LR, but could not convincingly discriminate a low-risk and medium-risk group for distant control and OS. Calibration curves showed a trend of underestimation of local and distant control, as well as OS in the observed data compared with the estimates predicted by the model.

In conclusion, we externally validated three models for predicting 2-year LR, DM and OS of locally advanced rectal cancer patients who underwent preoperative chemoradiation and curative surgery with good discrimination in a single Chinese cohort. However, the model overestimated the local control rate compared to observations in the clinical cohort. Validation in other clinical cohorts and optimization of the prediction model, perhaps by including additional prognostic factors, may enhance model validity and its applicability for personalized treatment of locally advanced rectal cancer.

Prognostic aspects of dynamic contrast-enhanced magnetic resonance imaging in synchronous distant metastatic rectal cancer

OBJECTIVES

To explore the correlations between DCE-MRI quantitative parameters and synchronous distant metastasis and the clinicopathological factors in rectal cancers.

METHODS

Sixty-three patients with rectal cancer (synchronous distant metastasis, n = 31; non-metastasis, n = 32) were enrolled in this study. Student's t test and ANOVA were used to compare DCE-MRI parameters (K ^trans , K _ep and V _e ). The receiver operating characteristic (ROC) analysis was used to find the reasonable threshold of DCE-MRI parameters to differentiate lesions with synchronous distant metastasis from those without metastasis.

RESULTS

The K ^trans , K _ep , and V _e value were significantly higher in the lesions with distant metastasis than in the lesions without distant metastasis (0.536 ± 0.242 vs. 0.299 ± 0.118 min^-1, p < 0.001; 1.598 ± 0.477 vs. 1.341 ± 0.390 min^-1, p = 0.022; and 0.324 ± 0.173 vs. 0.249 ± 0.091, p = 0.034; respectively). The K ^trans showed the highest AUCs of 0.788 (p < 0.001), with sensitivity of 61.29 % and specificity of 87.5 %, respectively.

CONCLUSIONS

DCE-MRI parameters may represent a prognostic indicator for synchronous distant metastases in patients with rectal cancer.

KEY POINTS

• The K ^trans , K _ep and V _e values correlated with synchronous distant metastasis. • Higher K ^trans , K _ep and V _e values were noted among patients with metastasis. • DCE-MRI parameters might represent a prognostic indicator for synchronous distant metastases.

Beyond Histologic Staging: Emerging Imaging Strategies in Colorectal Cancer with Special Focus on Magnetic Resonance Imaging

Imaging plays an increasingly important role in the staging and management of colorectal cancer. In recent years, magnetic resonance imaging (MRI) has supplanted transrectal ultrasound as the preferred modality for the locoregional staging of rectal cancer. Furthermore, the advent of both diffusion-weighted imaging and hepatobiliary contrast agents has significantly enhanced the ability of MRI to detect colorectal liver metastases. In clinical practice, MRI routinely provides prognostic information, helps to guide surgical strategy, and determines the need for neoadjuvant therapies related to both the primary tumor and metastatic disease. Expanding on these roles for MRI, positron emission tomography (PET)/MRI is the newest clinical hybrid imaging modality and combines the metabolic information of PET with the high soft tissue contrast of MRI. The addition of PET/MRI to the clinical staging armamentarium has the potential to provide comprehensive state-of-the-art colorectal cancer staging in a single examination.