Revisiting the treatment strategy for rectal cancer through the pattern of local recurrence

Bioinformatics analysis of markers based on m6A related to prognosis combined with immune invasion of rectal adenocarcinoma

BACKGROUND

Colorectal cancer (CRC) is a common form of cancer, with rectal cancer accounting for approximately one-third of all cases. Among rectal cancers, 95% are classified as rectal adenocarcinoma (READ). Emerging evidence suggests that long noncoding RNAs (lncRNAs) play a significant role in the development and progression of various cancers. In our study, we aimed to identify differentially expressed lncRNAs potentially associated with m6A and establish a risk assessment model to predict clinical outcomes for READ patients.

METHODS

The READ dataset from the TCGA database was utilized in this study to synergistically and logically integrate m6A and lncRNA, while employing bioinformatics technology for the identification of suitable biomarkers. A risk prediction model comprising m6A-associated lncRNAs was constructed to investigate the prognostic, diagnostic, and biological functional relevance of these m6A-related lncRNAs.

RESULTS

Our research builds a composed of three related to m6A lncRNA rectal gland cancer prognosis model, and the model has been proved in the multi-dimensional can serve as the potential of the prognosis of rectal gland cancer biomarkers. Our study constructed a prognostic model of rectal adenocarcinoma consisting of three related m6A lncRNAs: linc00702, ac106900.1 and al583785.1.

CONCLUSION

The model has been validated as a potential prognostic biomarker for rectal cancer in multiple dimensions, aiming to provide clinicians with an indicator to assess the duration of straight adenocarcinoma. This enables early detection of rectal cancer and offers a promising target for immunotherapy.

MRI-based Radiomics Model for Preoperative Prediction of Lateral Pelvic Lymph Node Metastasis in Locally Advanced Rectal Cancer

RATIONALE AND OBJECTIVES

To develop a magnetic resonance imaging (MRI)-based radiomics model for preoperative prediction of lateral pelvic lymph node (LPLN) metastasis (LPLNM) in patients with locally advanced rectal cancer MATERIALS AND METHODS: We retrospectively enrolled 263 patients with rectal cancer who underwent total mesorectal excision and LPLN dissection. Radiomics features from the primary lesion and LPLNs on baseline MRI images were utilized to construct a radiomics model, and their radiomics scores were combined to develop a radiomics scoring system. A clinical prediction model was developed using logistic regression. A hybrid predicting model was created through multivariable logistic regression analysis, integrating the radiomics score with significant clinical risk factors (baseline Carcinoembryonic Antigen (CEA), clinical circumferential resection margin status, and the short axis diameter of LPLN). This hybrid model was presented with a hybrid clinical-radiomics nomogram, and its calibration, discrimination, and clinical usefulness were assessed.

RESULTS

A total of 148 patients were included in the analysis and randomly divided into a training cohort (n = 104) and an independent internal testing cohort (n = 44). The hybrid clinical-radiomics model exhibited the highest discrimination, with an area under the receiver operating characteristic (AUC) of 0.843 [95% confidence interval (CI), 0.706-0.968] in the testing cohort compared to the clinical model [AUC (95% CI) = 0.772 (0.589-0.856)] and radiomics model [AUC (95% CI) = 0.731 (0.613-0.849)]. The hybrid prediction model also demonstrated good calibration, and decision curve analysis confirmed its clinical usefulness.

CONCLUSION

This study developed a hybrid MRI-based radiomics model that incorporates a combination of radiomics score and significant clinical risk factors. The proposed model holds promise for individualized preoperative prediction of LPLNM in patients with locally advanced rectal cancer.

DATA AVAILABILITY STATEMENT

The data presented in this study are available on request from the corresponding author.

Identification of patient subgroups with low risk of postoperative local recurrence for whom total mesorectal excision surgery alone is sufficient: a multicenter retrospective analysis

PURPOSE

For rectal cancer, a multimodality approach is mandatory including neoadjuvant chemoradiotherapy, neoadjuvant chemotherapy, and lateral pelvic lymph node (LPLN) dissection, in addition to the total mesorectal excision (TME). However, these treatments are associated with adverse events. It is important to select patients who do or do not need these treatments.

METHODS

We retrospectively analyzed patients with cStage II and III rectal cancer who underwent curative resection at three hospitals. Recurrence patterns were classified into three types; pelvic cavity, LPLN, and distant recurrences, and the risk factors for each pattern of recurrence were compared. We then analyzed the risk of recurrence in the patients who underwent TME alone.

RESULTS

In total, 506 patients were enrolled in this study. Pelvic cavity recurrence was significantly associated with clinical assumption of circumferential resection margin involvement (cCRM) (p < 0.001), distant recurrence was associated with cN positivity (p < 0.001), and LPLN recurrence was associated with pretreatment LPLN swelling ≥ 5 mm (p < 0.001), lower tumor location (p = 0.016), and serum CEA level > 5 ng/mL (p = 0.008). In patients without cCRM and swollen LPLN, the local recurrence rate was extremely low even if they underwent TME alone; the 5-year recurrence rates of pelvic cavity and LPLN were 2.2% and 1.9%, respectively.

CONCLUSION

Additional treatments to TME for rectal cancer need to be performed based on the risk factors for each recurrence pattern.

Locally Recurrent Rectal Cancer According to a Standardized MRI Classification System: A Systematic Review of the Literature

(1) Background: The classification of locally recurrent rectal cancer (LRRC) is not currently standardized. The aim of this review was to evaluate pelvic LRRC according to the Beyond TME (BTME) classification system and to consider commonly associated primary tumour characteristics. (2) Methods: A systematic review of the literature prior to April 2020 was performed through electronic searches of the Science Citation Index Expanded, EMBASE, MEDLINE, and CENTRAL databases. The primary outcome was to assess the location and frequency of previously classified pelvic LRRC and translate this information into the BTME system. Secondary outcomes were assessing primary tumour characteristics. (3) Results: A total of 58 eligible studies classified 4558 sites of LRRC, most commonly found in the central compartment (18%), following anterior resection (44%), in patients with an 'advanced' primary tumour (63%) and following neoadjuvant radiotherapy (29%). Most patients also classified had a low rectal primary tumour. The lymph node status of the primary tumour leading to LRRC was comparable, with 52% node positive versus 48% node negative tumours. (4) Conclusions: This review evaluates the largest number of LRRCs to date using a single classification system. It has also highlighted the need for standardized reporting in order to optimise perioperative treatment planning.

Management of Clinically Involved Lateral Lymph Node Metastasis in Locally Advanced Rectal Cancer: A Radiation Dose Escalation Study

Background

Patients with lateral lymph nodes (LLNs) metastasis are not effectively treated with neoadjuvant chemoradiotherapy. This study aimed to compare the efficacy of three neoadjuvant therapeutic regimens, namely, chemotherapy, chemoradiotherapy, and chemoradiotherapy with a dose boost of LLNs, and to identify the optimal approach for treating LLNs metastasis of locally advanced rectal cancer.

Methods

A total of 202 patients with baseline LLNs metastasis (short axis ≥5 mm) and treated with neoadjuvant treatment, followed by radical surgery from 2011 to 2019, were enrolled. The short axis of the LLNs on baseline and restaging MRI were recorded. Survival outcomes were compared.

Results

In the booster subgroup, shrinkage of LLNs was significantly greater than in the neoadjuvant chemotherapy and chemoradiotherapy subgroups (P <0.001), without increasing radiation related side effects (P = 0.121). For patients with baseline LLNs of short axis ≥5 mm in the booster subgroup, the response rate (short axis <5 mm on restaging MRI) was 72.9%, significantly higher than patients in the neoadjuvant chemotherapy subgroup (48.9%, P = 0.007) and higher than for patients in the neoadjuvant chemoradiotherapy group (65.0%), but there was no statistical difference (P = 0.411). The 3-year local recurrence and lateral local recurrence rates were both 2.3% in the dose booster group, which were lower than those of the other two subgroups (local recurrence: P <0.001; lateral local recurrence: P <0.001). The short axis of lateral lymph nodes (≥5 and <5 mm) on restaging MRI was an independent risk factor for prognosis (P <0.05).

Conclusion

Radiation dose boost is an effective way of increasing the response rate and decreasing recurrence rates. The restaging LLNs with short axis ≥5 mm is a predictor of poor prognosis.

Systematic review of classification systems for locally recurrent rectal cancer

Background

Classification of pelvic local recurrence (LR) after surgery for primary rectal cancer is not currently standardized and optimal imaging is required to categorize anatomical site and plan treatment in patients with LR. The aim of this review was to evaluate the systems used to classify locally recurrent rectal cancer (LRRC) and the relevant published outcomes.

Methods

A systematic review of the literature prior to April 2020 was performed through electronic searches of the Science Citation Index Expanded, EMBASE, MEDLINE and CENTRAL databases. The primary outcome was to review the classifications currently in use; the secondary outcome was the extraction of relevant information provided by these classification systems including prognosis, anatomy and prediction of R0 after surgery.

Results

A total of 21 out of 58 eligible studies, classifying LR in 2086 patients, were reviewed. Studies used at least one of the following eight classification systems proposed by institutions or institutional groups (Mayo Clinic, Memorial Sloan-Kettering – original and modified, Royal Marsden and Leeds) or authors (Yamada, Hruby and Kusters). Negative survival outcomes were associated with increased pelvic fixity, associated symptoms of LR, lateral compared with central LR and involvement of three or more pelvic compartments. A total of seven studies used MRI with specifically defined anatomical compartments to classify LR.

Conclusion

This review highlights the various imaging systems in use to classify LRRC and some of the prognostic indicators for survival and oncological clearance based on these systems. Implementation of an agreed classification system to document pelvic LR consistently should provide more detailed information on anatomical site of recurrence, burden of disease and standards for comparative outcome assessment.

Adverse Oncologic Outcomes of Adenocarcinoma of the Anal Canal in Patients With Crohn's Disease

BACKGROUND

Anal lesions in cases of Crohn's disease can give rise to adenocarcinoma of the anal canal; however, the oncologic outcomes in these patients have not yet been thoroughly investigated.

OBJECTIVE

This study aimed to clarify the influence of Crohn's disease on the oncologic outcomes in patients with adenocarcinoma of the anal canal.

DESIGN

This was a retrospective observational study from a prospectively collected database.

SETTINGS

The study was conducted at a single institution.

PATIENTS

This study included 102 patients with adenocarcinoma of the anal canal, including 34 (33.3%) with Crohn's disease-associated lesions and 68 (66.7%) with non-Crohn's disease-associated lesions.

MAIN OUTCOME MEASURES

Prognostic factors were detected using a Cox regression analysis, and the oncologic outcomes were calculated using the Kaplan-Meier method.

RESULTS

Crohn's disease-associated patients were significantly younger (45 vs 62 y; p < 0.001), had a high incidence of external/anal gland-type disease (61.8% vs 5.9%, p < 0.001) and had large tumors (7.1 ± 3.0 vs 4.7 ± 2.3 cm; p = 0.03) in comparison with non-Crohn's disease-associated patients. A Cox regression analysis showed that an advanced clinical T stage (T3 or T4; tumor size ≥5 cm) was an independent risk factor for 5-year local recurrence-free survival (HR = 3.49; p = 0.04), disease-free survival (HR = 2.82; p = 0.008), and overall survival (HR = 2.92; p = 0.006), and Crohn's disease association was an independent prognostic factor for local recurrence-free survival (HR = 2.29; p = 0.04) and overall survival (HR = 2.86; p = 0.04). The oncologic outcomes of patients who had the 2 abovementioned negative factors (cT3,4 Crohn's disease-associated patients) were significantly poorer than those of T3,4 non-Crohn's disease-associated patients (5-year local recurrence-free survival: 32.5% vs 70.4%, p = 0.001; disease-free survival: 15.9% vs 40.7%, p = 0.04; overall survival: 25.8% vs 71.0%, p = 0.007).

LIMITATIONS

This was a single-arm, retrospective study.

CONCLUSIONS

Significantly poorer oncologic outcomes were confirmed in Crohn's disease-associated patients with large tumors. Thus, it is important to perform careful surveillance of anal lesions in patients with Crohn's disease while taking these facts into consideration. See Video Abstract at http://links.lww.com/DCR/B449.

RESULTADOS ONCOLGICOS ADVERSOS DEL ADENOCARCINOMA DEL CANAL ANAL EN PACIENTES CON ENFERMEDAD DE CROHN

ANTECEDENTES:Las lesiones anales en casos de enfermedad de Crohn pueden dar lugar a un adenocarcinoma del canal anal; sin embargo, los resultados oncológicos en estos pacientes aún no se han investigado a fondo.OBJETIVOS:Este estudio tuvo como objetivo aclarar la influencia de la enfermedad de Crohn en los resultados oncológicos en pacientes con adenocarcinoma del canal anal.DISEÑO:Estudio observacional retrospectivo de una base de datos recopilada prospectivamente.ENTORNO CLINICO:El estudio se realizó en una sola institución.PACIENTES:Este estudio incluyó 102 pacientes con adenocarcinoma del canal anal, incluidos 34 (33,3%) con lesiones asociadas a la enfermedad de Crohn y 68 (66,7%) con lesiones no asociadas a la enfermedad de Crohn.PRINCIPALES MEDIDAS DE VOLARACION:Los factores pronósticos se detectaron mediante un análisis de regresión de Cox y los resultados oncológicos se calcularon utilizando el método de Kaplan-Meier.RESULTADOS:Los pacientes asociados a la enfermedad de Crohn eran significativamente más jóvenes (45 versus a 62 años, p <0,001), tenían una alta incidencia de enfermedad de tipo glandular externo/ anal (61,8% versus a 5,9%, p <0,001) y tumores grandes (7,1 ± 3,0 cm versus a 4,7 ± 2,3 cm, p = 0,03) en comparación con los pacientes no asociados a la enfermedad de Crohn. Un análisis de regresión de Cox mostró que un estadío clínico T avanzado (T3,4; tamaño del tumor ≥5 cm) era un factor de riesgo independiente para la supervivencia sin recidiva local (SLF) a 5 años (índice de riesgo [HR]: 3,49, p = 0,04), supervivencia libre de enfermedad (SSE) (HR: 2,82, p = 0,008) y supervivencia general (SG) (HR: 2,92, p = 0,006), y la enfermedad de Crohn asociada fue un factor pronóstico independiente para la SLF (HR: 2,29, p = 0,04) y SG (HR: 2,86, p = 0,04). Los resultados oncológicos de los pacientes que tenían los dos factores negativos mencionados anteriormente (pacientes asociados con la enfermedad de Crohn cT3,4) fueron significativamente peores que los de los pacientes no asociados con la enfermedad de Crohn con T3,4 (LFS a 5 años: 32,5% versus a 70,4 %, p = 0,001; SSE: 15,9% versus a 40,7%, p = 0,04; SG: 25,8% versus a 71,0%, p = 0,007).LIMITACIONES:Un estudio retrospectivo de un solo brazo.CONCLUSIONES:Se confirmaron resultados oncológicos significativamente peores en pacientes asociados con la enfermedad de Crohn con tumores grandes. Por lo tanto, es importante realizar una vigilancia cuidadosa de las lesiones anales en pacientes con enfermedad de Crohn. Consulte Video Resumen en http://links.lww.com/DCR/B449.

Site-specific risk factors for local recurrence after rectal cancer surgery

BACKGROUND

Quite few studies examined risk factors for local recurrence after rectal cancer surgery with respect to local recurrence sites.

METHODS

Local recurrence sites were categorized into axial, anterior, posterior, and lateral (pelvic sidewall), and axial, anterior, and posterior type were combined as the "other" type of local recurrence. Among 76 patients enrolled into our prospective randomized controlled trial to determine the indication for pelvic autonomic nerve preservation (PANP) in patients with advanced lower rectal cancer (UMIN000021353), multivariate analyses were conducted to elucidate risk factors for either lateral or the "other" type of local recurrence.

RESULTS

Univariate analyses showed that tumor distance from the anal verge was significantly (p = 0.017), and type of operation (sphincter preserving operation (SPO) vs. abdominoperineal resection (APR)) was marginally (p = 0.065) associated with pelvic sidewall recurrence. Multivariate analysis using these two parameters showed that tumor distance from the anal verge was significantly and independently correlated with pelvic sidewall recurrence (p = 0.017). As for the "other" type of local recurrence, univariate analyses showed that depth of tumor invasion (p = 0.011), radial margin status (p < 0.001), and adjuvant chemotherapy (p = 0.037) were significantly associated, and multivariate analysis using these three parameters revealed that depth of tumor invasion (p = 0.004) and radial margin status (p < 0.001) were significantly and independently correlated with the "other" type of local recurrence.

CONCLUSION

Risk factors for local recurrence after rectal cancer surgery were totally different with respect to the intra-pelvic recurrent sites. Site-specific probability of local recurrence can be inferred using these risk factors.

TRIAL REGISTRATION NUMBER

UMIN000021353.

A Ten-N6-Methyladenosine (m6A)-Modified Gene Signature Based on a Risk Score System Predicts Patient Prognosis in Rectum Adenocarcinoma

OBJECTIVES

The study aims to analyze the expression of N6-methyladenosine (m6A)-modified genes in rectum adenocarcinoma (READ) and identify reliable prognostic biomarkers to predict the prognosis of READ.

MATERIALS AND METHODS

RNA sequence data of READ and corresponding clinical survival data were obtained from The Cancer Genome Atlas (TCGA) database. N6-methyladenosine (m6A)-modified genes in READ were downloaded from the "m6Avar" database. Differentially expressed m6A-modified genes in READ stratified by different clinicopathological characteristics were identified using the "limma" package in R. Protein-protein interaction (PPI) network and co-expression analysis of differentially expressed genes (DEGs) were performed using "STRING" and Cytoscape, respectively. Principal component analysis (PCA) was done using R. In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were used to functionally annotate the differentially expressed genes in different subgroups. Univariate Cox regression analyses were conducted to identify the powerful independent prognostic factors in READ associated with overall survival (OS). A robust likelihood-based survival model was built using the "rbsurv" package to screen for survival-associated signature genes. The Support Vector Machine (SVM) was used to predict the prognosis of READ through the risk score of survival-associated signature genes. Correlation analysis were carried out using GraphPad prism 8.

RESULTS

We screened 974 differentially expressed m6A-modified genes among four types of READ samples. Two READ subgroups (group 1 and group 2) were identified by K means clustering according to the expression of DEGs. The two subgroups were significantly different in overall survival and pathological stages. Next, 118 differentially expressed genes between the two subgroups were screened and the expression of 112 genes was found to be related to the prognosis of READ. Next, a panel of 10 survival-associated signature genes including adamtsl1, csmd2, fam13c, fam184a, klhl4, olfml2b, pdzd4, sec14l5, setbp1, tmem132b was constructed. The signature performed very well for prognosis prediction, time-dependent receiver-operating characteristic (ROC) analysis displaying an area under the curve (AUC) of 0.863, 0.8721, and 0.8752 for 3-year survival rate, prognostic status, and pathological stage prediction, respectively. Correlation analysis showed that the expression levels of the 10 m6A-modified genes were positively correlated with that of m6A demethylase FTO and ALKBH5.

CONCLUSION

This study identified potential m6A-modified genes that may be involved in the pathophysiology of READ and constructed a novel gene expression panel for READ risk stratification and prognosis prediction.

Histological grades of rectal cancer: whole-volume histogram analysis of apparent diffusion coefficient based on reduced field-of-view diffusion-weighted imaging

Background

To explore the role of whole-lesion histogram analysis of apparent diffusion coefficient (ADC) derived from reduced field-of-view (rFOV) diffusion-weighted imaging (DWI) technique in discriminating histological grades of rectal carcinoma.

Methods

Altogether, 49 patients with rectal cancer were enrolled in this retrospective study. All patients received preoperative 3.0 T MR scan. Histogram parameters from rFOV DWI were calculated and correlated with histological differentiation of rectal cancer. The parameters were compared between different histological grades of rectal cancer by independent Student's t-test or Man-Whitney U-test. The Spearman correlation test analyzed correlations between histological grade and histogram parameters. The diagnostic performance of individual parameters for distinguishing poorly from well-/moderately differentiated tumors was assessed by receiver operating characteristic curve (ROC) analysis.

Results

There were significant differences for ADCmean, 25^th, 50^th, 75^th, 90^th, 95^th percentiles, skewness, and kurtosis of rFOV DWI sequence between well-, moderately, and poorly differentiated rectal cancers (P<0.05). Significant correlations were noted between histological grades and the above histogram parameters (r=0.679, 0.540, 0.701, 0.730, 0.669, 0.574, -0.730, and -0.760 respectively, P<0.001). Among the individual histogram parameter, kurtosis achieved the highest AUC of 0.882 with an optimal cutoff value of 1.934 in distinguishing poorly from well-/moderately differentiated rectal cancers. The combination of ADCmean, 75^th percentile, and kurtosis yielded the highest AUC of 0.927 with a sensitivity of 88.00% and a sensitivity of 91.7% using logistic regression.

Conclusions

Quantitative whole-lesion ADC histogram analysis based on the rFOV DWI technique could help differentiate histological grades of rectal cancer. The combination of ADCmean, 75^th percentile, and kurtosis may be the best choice.

Significance of lymph node involvement in local recurrence of colorectal cancer

BACKGROUND

There are few data on lymphatic spread concomitant to local recurrence (LR) of colorectal cancer (CRC). The objectives of this study were to determine variables associated with lymphatic spread, to analyze the distribution of LN+, and understand the underlying mechanisms.

METHODS

A total of 76 patients underwent resection of LR of CRC between January 2007 and December 2018 at Institut cancérologique de l'Ouest and were retrospectively reviewed.

RESULTS

Twenty-five (32.9%) patients had lymph node (LN) involvement with LR. Lymphatics from the mesocolon-rectum and aorto-iliac compartments were involved in 21%, 20.3% and 18.1%, 20.3% for pelvic and retroperitoneal LRs, respectively. In multivariate analysis, the only predictive factor for LN invasion (LN+) was a primary positive LN status (odds ratio, 5.3; P = .007). Despite a trend toward a worse median overall survival in the LN+ group, the difference was not significant in comparison with the LN- group (46 vs. 57 months; P = 0.31) or with the LN- plus LN not assessed groups (46 months vs not reached; P = .07).

CONCLUSIONS

LN invasion with LR from CRC is a frequent occurrence without significant impact on survival. The only predictive factor is a primary positive nodal status.

Optimal treatment strategy for rectal cancer based on the risk factors for recurrence patterns

BACKGROUND

For rectal cancer, multimodality therapeutic approach is necessary to prevent local recurrence and distant metastasis. However, the efficacy of additional treatments, such as neoadjuvant chemoradiotherapy (nCRT), neoadjuvant chemotherapy (NAC), and lateral pelvic lymph node dissection (LPLND), has not been scrutinized.

METHODS

Recurrence patterns were categorized into local recurrence and distant metastasis. Local recurrence was classified into two types: (1) pelvic cavity recurrence and (2) LPLN recurrence. First, we analyzed the risk factors for each recurrence pattern. Second, based on the status of clinically suspected involvement of circumferential resection margin (cCRM), the efficacy of additional treatments was investigated.

RESULTS

A total of 240 patients was enrolled. nCRT was performed for 25 (10%), NAC was for 46 (19%), and LPLND was for 35 patients (15%). As the recurrence patterns, pelvic cavity recurrence occurred in 15 (6%), LPLN recurrence in 8 (3%), and distant metastasis in 42 patients (18%). Five-year overall survival and relapse-free survival were 87% and 70%, respectively. Multivariate analysis indicated that pelvic cavity recurrence was associated with cCRM status and tumor histology, that LPLN recurrence was with serum carcinoembryonic antigen level and LPLN swelling, and that distant metastasis was with clinical N category. In the cCRM-positive subgroup (n = 66), cumulative rate of pelvic cavity recurrence was lower in the nCRT group than in the NAC or non-NAC/nCRT group (P = 0.02 and 0.09, respectively).

CONCLUSION

cCRM status was associated with pelvic cavity recurrence, and LPLN swelling was with LPLN recurrence. nCRT could reduce pelvic cavity recurrence in cCRM-positive subgroup.

Feasibility of Extended Dissection of Lateral Pelvic Lymph Nodes During Laparoscopic Total Mesorectal Excision in Patients with Locally Advanced Lower Rectal Cancer: A Single-Center Pilot Study After Neoadjuvant Chemotherapy

BACKGROUND The feasibility of additional dissection of the lateral pelvic lymph nodes (LPLNs) in patients undergoing total mesorectal excision (TME) combined with neoadjuvant chemotherapy (NAC) for locally advanced rectal cancer (LARC) is controversial. The use of laparoscopic surgery is also debated. In the present study, we evaluated the utility of laparoscopic dissection of LPLNs during TME for patients with LARC and metastatic LPLNs after NAC, based on our experience with 19 cases. MATERIAL AND METHODS Twenty-five patients with LARC with swollen LPLNs who underwent laparoscopic TME and LPLN dissection were enrolled in this pilot study. The patients were divided into 2 groups: those patients with NAC (n=19) and without NAC (n=6). Our NAC regimen involved 4 to 6 courses of FOLFOX plus panitumumab, cetuximab, or bevacizumab. RESULTS The operative duration was significantly longer in the NAC group than in the non-NAC group (648 vs. 558 minutes, respectively; P=0.022). The rate of major complications, defined as grade ≥3 according to the Clavien-Dindo classification, was similar between the 2 groups (15.8% vs. 33.3%, respectively; P=0.4016). No conversion to conventional laparotomy occurred in either group. In the NAC group, a histopathological complete response was obtained in 2 patients (10.5%), and a nearly complete response (Tis N0 M0) was observed in one patient (5.3%). Although the operation time was prolonged in the NAC group, the other perioperative factors showed no differences between the 2 groups. CONCLUSIONS Laparoscopic LPLN dissection is feasible in patients with LARC and clinically swollen LPLNs, even after NAC.

Prediction of lateral pelvic lymph node metastasis from lower rectal cancer using magnetic resonance imaging and risk factors for metastasis: Multicenter study of the Lymph Node Committee of the Japanese Society for Cancer of the Colon and Rectum

PURPOSE

The goal of the study was to examine prediction of lateral pelvic lymph node (LPLN) metastasis from lower rectal cancer using a logistic model including risk factors for LPLN metastasis and magnetic resonance imaging (MRI) clinical LPLN (cLPLN) status, compared to prediction based on MRI alone.

METHODS

The subjects were 272 patients with lower rectal cancer who underwent MRI prior to mesorectal excision combined with LPLN dissection (LPLD) at six institutes. No patients received neoadjuvant therapy. Prediction models for right and left pathological LPLN (pLPLN) metastasis were developed using cLPLN status, histopathological grade, and perirectal lymph node (PRLN) status. For evaluation, data for patients with left LPLD were substituted into the right-side equation and vice versa.

RESULTS

Left LPLN metastasis was predicted using the right-side model with accuracy of 86.5%, sensitivity 56.4%, specificity 92.7%, positive predictive value (PPV) 61.1%, and negative predictive value (NPV) 91.2%, while these data using MRI cLPLN status alone were 80.4, 76.9, 81.2, 45.5, and 94.5%, respectively. Similarly, right LPLN metastasis was predicted using the left-side equation with accuracy of 83.8%, sensitivity 57.8%, specificity 90.4%, PPV 60.5%, and NPV 89.4%, and the equivalent data using MRI alone were 78.4, 68.9, 80.8, 47.7, and 91.1%, respectively. The AUCs for the right- and left-side equations were significantly higher than the equivalent AUCs for MRI cLPLN status alone.

CONCLUSIONS

A logistic model including risk factors for LPLN metastasis and MRI findings had significantly better performance for prediction of LPLN metastasis compared with a model based on MRI findings alone.

A Multicenter Phase 2 Study on the Feasibility and Efficacy of Neoadjuvant Chemotherapy Without Radiotherapy for Locally Advanced Rectal Cancer

BACKGROUND

This prospective multicenter phase 2 study aimed to evaluate the feasibility and efficacy of neoadjuvant chemotherapy (NAC) without radiotherapy for locally advanced rectal cancer (LARC).

METHODS

Patients with LARC (cStage II and III) were included in the study. Those with cT4b tumor were excluded. Six cycles of modified FOLFOX6 (mFOLFOX6) plus either bevacizumab or cetuximab, depending on KRAS status, were administered before surgery. The primary end point of the study was the R0 resection rate. The secondary end points were adverse effect, rate of NAC completion, postoperative complications, and pathologic complete response (pCR) rate.

RESULTS

The study enrolled 60 patients from eight institutions. For the study, mFOLFOX6 was administered with cetuximab to 40 patients who had wild-type KRAS and with bevacizumab to 20 patients who had KRAS mutations. The completion rate for NAC was 88.4%. Sphincter-preserving surgery was performed for 43 patients and abdominoperineal resection for 17 patients. The median operation time was 335 min, and the median blood loss was 40 g. The R0 resection rate was 98.3%, and the pCR rate was 16.7%. The overall postoperative complication rate (≥grade 2) was 21.7%. The complications included anastomotic leakage (11.6%), surgical-site infection (6.7%), and urinary dysfunction (3.3%). The patients with wild-type KRAS did not differ significantly from those with KRAS mutations in terms of response rate, postoperative complication rate, and pCR rate.

CONCLUSION

The findings show that NAC is a feasible and promising treatment option for LARC (This study is registered with UMIN-CTR, UMIN000005654).