The survival benefit of adjuvant radiotherapy for pathological T4N2M0 colon cancer in the Modern Chemotherapy Era: evidence from the SEER database 2004-2015

Study protocol of short-course radiotherapy combined with CAPOX and PD-1 inhibitor for locally advanced colon cancer: a randomised, prospective, multicentre, phase II trial (TORCH-C)

INTRODUCTION

The preliminary result of the TORCH trial has shown a promising complete response (CR) for managing locally advanced rectal cancer with neoadjuvant short-course radiotherapy (SCRT) combined with chemotherapy and PD-1 inhibitor. For locally advanced colon cancer (LACC) with bulky nodal disease and/or clinically T4, neoadjuvant chemotherapy followed by colectomy with en bloc removal of regional lymph nodes is the suggested treatment. However, the CR rate is less than 5%. TORCH-C will aim to investigate neoadjuvant SCRT combined with chemotherapy and PD-1 inhibitor in LACC.

METHODS AND ANALYSIS

TORCH-C is a randomised, prospective, multicentre, double-arm, open, phase II trial of SCRT combined with chemotherapy and immunotherapy in LACC with microsatellite stable (MSS) patients and cT4 or bulky nodes. Eligible patients will be identified by the multidisciplinary team. 120 patients will be randomised 1:1 to the intervention or control arm. The patients in the control arm will receive four cycles of capecitabine plus oxaliplatin (CAPOX). The patients in the intervention arm will receive SCRT, followed by four cycles of CAPOX and PD-1 inhibitor (serplulimab). Both arms will receive curative surgery, followed by four cycles of CAPOX. The primary endpoint is pathological complete regression.TORCH-C (TORCH-colon) trial aims to investigate whether the combination of immunotherapy and chemoradiotherapy improves the treatment effect in LACC with MSS. TORCH-C will establish the TORCH platform, a key part of our long-term strategy to develop neoadjuvant treatment for colorectal cancer.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee of Fudan University Shanghai Cancer Center (approval number: 2211265-12).

TRIAL REGISTRATION NUMBER

NCT05732493.

Optimal treatment strategy and prognostic analysis for patients with non-metastatic pT4 colon adenocarcinoma

Objective

This study endeavored to explore the optimal treatment strategy and conduct a prognostic analysis for patients diagnosed with pT4M0 (pathologic stage T4) colon adenocarcinoma (COAD).

Methods and materials

A total of 8,843 patients diagnosed with pT4M0 COAD between January 2010 and December 2015 were included in this study from the Surveillance, Epidemiology, and End Results (SEER) database. These patients were randomly divided into a training set and an internal validation set using a 7:3 ratio. Variables that demonstrated statistical significance (P<0.05) in univariate COX regression analysis or held clinical significance were incorporated into the multivariate COX regression model. Subsequently, this model was utilized to formulate a nomogram. The predictive accuracy and discriminability of the nomogram were assessed using the C-index, area under the curve (AUC), and calibration curves. Decision curve analysis (DCA) was conducted to confirm the clinical validity of the model.

Results

In the entire SEER cohort, the 3-year overall survival (OS) rate (74.22% vs. 63.20%, P<0.001) and the 3-year cancer-specific survival (CSS) rate (76.25% vs. 66.98%, P<0.001) in the surgery combined with postoperative adjuvant therapy (S+ADT) group surpassed those in the surgery (S) group. Multivariate COX regression analysis of the training set unveiled correlations between age, race, N stage, serum CEA (carcinoembryonic antigen), differentiation, number of resected lymph nodes, and treatment modalities with OS and CSS. Nomograms for OS and CSS were meticulously crafted based on these variables, achieving C-indexes of 0.692 and 0.690 in the training set, respectively. The robust predictive ability of the nomogram was further affirmed through receiver operating characteristic (ROC) and calibration curves in both the training and validation sets.

Conclusion

In individuals diagnosed with pT4M0 COAD, the integration of surgery with adjuvant chemoradiotherapy demonstrated a substantial extension of long-term survival. The nomogram, which incorporated key factors such as age, race, differentiation, N stage, serum CEA level, tumor size, and the number of resected lymph nodes, stood as a dependable tool for predicting OS and CSS rates. This predictive model held promise in aiding clinicians by identifying high-risk patients and facilitating the development of personalized treatment plans.

Pretreatment Carcinoembryonic Antigen Level Serves as a Potential Biomarker to Guide Adjuvant Radiotherapy in pT4N+ Colon Cancer Patients

The survival benefit of adjuvant radiotherapy in T4 colon cancer (CC) remains controversial, with conflicting results reported in the literature. This study aimed to explore the relationship between pretreatment carcinoembryonic antigen (CEA) level and overall survival (OS) of pT4N+ CC patients treated with adjuvant radiotherapy. Data of pT4N+ CC patients who received curative surgery between 2004 and 2015 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. The primary outcome was OS, and subgroup analysis was conducted according to pretreatment CEA level. A total of 8763 patients were eligible for our study. In the CEA-normal group, 151 patients received adjuvant radiotherapy, while 3932 patients did not. In the CEA-elevated group, 212 patients received adjuvant radiotherapy, while 4468 patients did not. In general, adjuvant radiotherapy was associated with better OS in pT4N+ CC patients (HR = 0.846, 95% CI = 0.733-0.976, P = 0.022). Intriguingly, only patients with an elevated pretreatment CEA level gained a survival benefit from adjuvant radiotherapy (HR = 0.782; 95% CI = 0.651-0.939; P = 0.008) while those with a normal pretreatment CEA level did not (HR = 0.907; 95% CI = 0.721-1.141; P = 0.403). Multivariable Cox regression analysis demonstrated that adjuvant radiotherapy was an independent protective factor in pT4N+ CC patients with an elevated pretreatment CEA level. Pretreatment CEA levels could serve as a potential biomarker to screen pT4N+ CC patients who would benefit from adjuvant radiotherapy.

Identifying the long-term survival beneficiary of chemotherapy for stage N1c sigmoid colon cancer

Sigmoid colon cancer often has an unsatisfactory prognosis. This study explored the effect of tumor deposits (TDs) on survival, and whether their presence/absence influence individualized treatment. Data of postoperative patients with sigmoid colon cancer were extracted from the Surveillance, Epidemiology, and End Results database. Overall survival (OS) was calculated using the Kaplan-Meier method and prognostic factors were identified using Cox regression analysis and random forest (RF). The nomogram's discrimination performance was evaluated using a concordance index (C-index), integrated discrimination improvement (IDI), calibration curves, and decision-curve analysis. The N1c group showed a worse prognosis than the N0 group. For N1c patients, a combination of surgery and chemotherapy prolonged survival, compared to surgery alone; however, the chemotherapy-surgery combination did not affect the OS of patients younger than 70 years, in stage T1-2, and/or of black race. Multivariable analysis and RF presented Age, T stage, and N stage were the most important predictors for OS. The novel nomogram had superiority to the TNM staging system with improved C-index and IDI, as well as good consistency and higher clinical benefit. TDs are associated with poor survival from sigmoid colon cancer, and considering TDs can inform the formulation of individual treatment regimens. The nomogram shows satisfactory prediction ability for OS.

Postoperative locoregional recurrence pattern and treatment management of stage pT4 sigmoid colon cancer: a retrospective cohort study

BACKGROUND

This study aimed to explore the pattern of locoregional recurrence after surgery in patients with non-metastatic stage pT4 sigmoid colon cancer and the role of adjuvant radiotherapy on survival.

METHODS

We retrospectively analyzed data from 208 patients who underwent surgery in our hospital. The patients were randomly divided into training and validation groups at a 1:1 ratio. Patients at high risk for locoregional recurrence were screened using Cox regression analysis. Based on the data of 2,886 patients in the Surveillance, Epidemiology, and End Results (SEER) database, the effect of adjuvant radiotherapy on overall survival (OS) and cancer-specific survival (CSS) was evaluated by Kaplan-Meier curves.

RESULTS

Of the 208 patients, 57 (27.4%) presented with locoregional recurrences (14 anastomotic and 43 abdominal or pelvic lymph node recurrences). Multivariate analysis showed that serum CEA, differentiation, lymph node dissection number, and N stage were independent predictors of locoregional recurrence-free survival (all p < 0.05). A risk-stratification model was constructed, and a total score of ≥ 6.5 points was considered the high-risk group for locoregional recurrence. Both the training and validation sets presented that the model had a good predictive ability (area under the curve = 0.828 and 0.724, respectively). Analysis of SEER data revealed that adjuvant radiotherapy significantly prolonged OS and CSS in the high-risk population (all p < 0.05, vs. no radiotherapy).

CONCLUSIONS

Patients with a total risk score of 6.5 or more had a high likelihood of locoregional recurrence, and perhaps adjuvant radiotherapy could improve their survival.

DUOX2, a New Biomarker for Disseminated Gastric Cancer's Response to Low Dose Radiation in Mice

Treatment options are rather limited for gastrointestinal cancer patients whose disease has disseminated into the intra-abdominal cavity. Here, we designed pre-clinical studies to evaluate the potential application of chemopotentiation by Low Dose Fractionated Radiation Therapy (LDFRT) for disseminated gastric cancer and evaluate the role of a likely biomarker, Dual Oxidase 2 (DUOX2). Nude mice were injected orthotopically with human gastric cancer cells expressing endogenous or reduced levels of DUOX2 and randomly assigned to four treatment groups: 1; vehicle alone, 2; modified regimen of docetaxel, cisplatin and 5'-fluorouracil (mDCF) for three consecutive days, 3; Low Dose- Whole Abdomen Radiation Therapy (LD-WART) (5 fractions of 0.15 Gy in three days), 4; mDCF and LD-WART. The combined regimen increased the odds of preventing cancer dissemination (mDCF + LD-WART OR = 4.16; 80% CI = 1.0, 17.29) in the DUOX2 positive tumors, while tumors expressing lower DUOX2 levels were more responsive to mDCF alone with no added benefit from LD-WART. The molecular mechanisms underlying DUOX2 effects in response to the combined regimen include NF-κB upregulation. These data are particularly important since our study indicates that about 33% of human stomach adenocarcinoma do not express DUOX2. DUOX2 thus seems a likely biomarker for potential clinical application of chemopotentiation by LD-WART.

Prognostic analysis and beneficiary identification of adjuvant external beam radiotherapy for stage pT4b sigmoid colon cancer

The clinical efficacy of adjuvant radiotherapy in sigmoid colon cancer remains questioned. To evaluate the clinical efficacy of adjuvant external beam radiotherapy (EBRT) for patients with pathologic stage T4b sigmoid colon cancer. Patients with stage pT4b sigmoid colon cancer receiving adjuvant EBRT or not followed by surgery between 2004 and 2016 were extracted from the Surveillance, Epidemiology, and End Results database. Analysis of overall survival (OS) was performed using Kaplan-Meier curves and prognostic factors were identified using Cox proportional hazards regression models with 95% confidence intervals within the entire cohort. A risk-stratification system was then developed based on the β regression coefficient. Among 2073 patients, 284 (13.7%) underwent adjuvant EBRT. The median OS in the group receiving adjuvant EBRT was significantly longer than that in the non-radiotherapy group (p < 0.001). Age, serum carcinoembryonic antigen (CEA) level, perineural invasion, lymph node dissection (LND) number, and adjuvant EBRT were independent factors associated with OS. A risk-stratification system was generated, which showed that low-risk patients had a higher 5-year survival rate than high-risk patients (75.6% vs. 42.3%, p < 0.001). Adjuvant EBRT significantly prolonged the 5-year survival rate of high-risk patients (62.6% vs. 38.3%, p = 0.009) but showed no survival benefit among low-risk patients (87.7% vs. 73.2%, p = 0.100). Our risk-stratification model comprising age, serum CEA, perineural invasion, and LND number predicted the outcomes of patients with stage pT4b sigmoid colon cancer based on which subgroup of high-risk patients should receive adjuvant EBRT.