The role of neoadjuvant chemotherapy in patients with locally advanced colon cancer: A systematic review and meta-analysis

Overcoming common emerging barriers to effective neoadjuvant immunotherapies

INTRODUCTION

Neoadjuvant immunotherapy has rapidly evolved as a novel approach in oncology, reshaping the standard treatment for several malignancies, including melanoma, lung, bladder, colorectal, and breast cancer. While it has an acceptable safety profile, challenges persist due to the complexity of the tumor microenvironment (TME), immune evasion, T-cell exhaustion, and identification of biomarkers. Addressing these issues is critical for optimizing treatment regimens, minimizing immune-related adverse events, and ensuring successful clinical integration.

AREAS COVERED

This review explores current research on neoadjuvant immunotherapy, emphasizing its impact on standard of care treatment, efficacy, safety, and clinical challenges. A literature search was conducted using PubMed and ClinicalTrials.gov for studies published in the last 5 years. Ongoing research aims to enhance the efficacy of neoadjuvant immunotherapy, identify resistance mechanisms, and broaden indications. Current clinical trials focus on biomarker-driven patient selection, refining immune response modulation through combination strategies, and developing evidence-based protocols for implementation into routine oncology practice.

EXPERT OPINION

Neoadjuvant immunotherapeutic options have rapidly changed the oncological treatment landscape in only a few years, and this treatment paradigm has quickly become a new standard of care in multiple solid tumors. With continued clinical investigation, neoadjuvant immunotherapy has the dramatic potential to further advance cancer care.

High-performance CT features supporting accurate pre-operative tumor staging in colon cancer

Background and aims

Accurate pre-treatment tumor staging is essential for treatment decision-making. Multi-slice spiral computed tomography (CT) is currently the standard method for pre-operative clinical tumor staging, but accurately applying the CT findings in tumor staging remains a challenge due to the poor pathological understanding of the CT signs. We aimed to pathologically interpret the key CT findings in order to identify reliable markers for pre-treatment staging of colon cancer.

Patients and methods

The following CT features from 136 colon adenocarcinomas were analyzed: colon wall pliability, outline contour, pericolic fat attenuations and vascularity, tumor fusion with adjacent organs, ascites, tumor size, and relevance between tumor and retroperitoneal fascia. These CT features were corroborated with histopathological findings. The diagnostic performance of these was further analyzed.

Results

Based on the postoperative pathological tumor staging (pT), 136 colon adenocarcinomas were classified into four stages: pT1 (n = 5), pT2 (n = 7), pT3 (n = 96), and pT4 (n = 28). Key findings include the following: (1) soft colon wall is a characteristic of the pT1 tumors, whereas stiff colon wall is a characteristic of the pT2~pT4 tumors; pathologically, stiff colon wall reflects the infiltration of tumor cells with desmoplastic reaction (DR) in muscularis propria; (2) small protuberances may help exclude the pT2 tumors. Histopathologically, small protuberances in pT2 cancer represent the pure DR on the surface of lamina propria, whereas the small protuberances in pT3~pT4 cancers represent the sub-serosal or extra-serosal cancer cell foci enwrapped by DR; (3) the presence of large protuberances, extensive reticulonodular fat stranding, and fusion with surrounding organs and ascites are diagnostic of pT4 tumors; and (4) the presence of extra-fascial nodules/streaks on CT scan could accurately diagnose the ascending/descending colon cancer of pT4 stage. Histologically, the presence of the above five CT features (large protuberances, extensive reticulonodular fat stranding, fusion with surrounding organs, ascites, and extra-fascial nodules/streaks) reflect the farther and deeper infiltration of tumor cells in serosa or retroperitoneal fascia involvement.

Conclusion

Our studies have identified multiple CT features that are practically useful in identifying and differentiating different stages of colon cancer prior to surgical procedures. These high-performance markers will provide valuable insights to the clinicians in making appropriate decisions in the management of patients with colon cancer.

Novel regimens and treatment strategies in neoadjuvant therapy for colorectal cancer: A systematic review

Objective

The objective of this systematic review was to describe novel regimens and treatment strategies in neoadjuvant therapy for colorectal cancer (CRC). The aim was to summarize the current advancements in neoadjuvant chemotherapy (NACT) for CRC, including the use of cytotoxic drugs, targeted treatments, and immunotherapy. The analysis aimed to provide insights into the potential benefits and drawbacks of these novel approaches and highlight the need for further research to optimize NACT use in CRC and improve patient outcomes.

Methods

From October 20, 2023, to December 10, 2023, a comprehensive literature search was conducted across multiple databases, including PubMed, Ovid, Web of Science, the Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Embase, and Scopus. Studies addressing the use of and treatment strategies for CRC and neoadjuvant therapies were included. Screening was conducted in two steps, initially by title and abstract and then by full-text articles. English-language articles were considered, while preprints, non-English publications, and articles published as grey literature were excluded from the study. A total of 85 studies were selected for further analysis after screening and filtering.

Results

After filtering out duplicates and items that were irrelevant to our research query from the initial database search's 510 results, 397 unique articles were found. Eighty-five studies were chosen for additional analysis after the articles underwent two rounds of screening.

Conclusion

The review concluded that neoadjuvant therapy for CRC has evolved beyond conventional approaches and holds promise for improving patient outcomes. Future prospects for advancing neoadjuvant approaches are promising, with ongoing clinical trials investigating the refinement of strategies, identification of predictive biomarkers, and optimization of patient selection. The adoption of novel regimens, precision medicine, and immunotherapy offers opportunities to redefine treatment paradigms and enhance patient care in CRC.

Neoadjuvant Chemotherapy in Colon Cancer: More Than Just an Optical Illusion

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.

Neoadjuvant Chemotherapy With Oxaliplatin and Fluoropyrimidine Versus Upfront Surgery for Locally Advanced Colon Cancer: The Randomized, Phase III OPTICAL Trial

PURPOSE

The role of neoadjuvant chemotherapy (NAC) in colon cancer remains unclear. This trial investigated whether 3 months of modified infusional fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) or capecitabine and oxaliplatin (CAPOX) as NAC could improve outcomes in patients with locally advanced colon cancer versus upfront surgery.

PATIENTS AND METHODS

OPTICAL was a randomized, phase III trial in patients with clinically staged locally advanced colon cancer (T3 with extramural spread into the mesocolic fat ≥5 mm or T4). Patients were randomly assigned 1:1 to receive six preoperative cycles of mFOLFOX6 or four cycles of CAPOX, followed by surgery and adjuvant chemotherapy (NAC group), or immediate surgery and the physician's choice of adjuvant chemotherapy (upfront surgery group). The primary end point was 3-year disease-free survival (DFS) assessed in the modified intention-to-treat (mITT) population.

RESULTS

Between January 2016 and April 2021, of the 752 patients enrolled, 744 patients were included in the mITT analysis (371 in the NAC group; 373 in the upfront surgery group). At a median follow-up of 48.0 months (IQR, 46.0-50.1), 3-year DFS rates were 82.1% in the NAC group and 77.5% in the upfront surgery group (stratified hazard ratio [HR], 0.74 [95% CI, 0.54 to 1.03]). The R0 resection was achieved in 98% of patients who underwent surgery in both groups. Compared with upfront surgery, NAC resulted in a 7% pathologic complete response rate (pCR), significantly lower rates of advanced tumor staging (pT3-4: 77% v 94%), lymph node metastasis (pN1-2: 31% v 46%), and potentially improved overall survival (stratified HR, 0.44 [95% CI, 0.25 to 0.77]).

CONCLUSION

NAC with mFOLFOX6 or CAPOX did not show a significant DFS benefit. However, this neoadjuvant approach was safe, resulted in substantial pathologic downstaging, and appears to be a viable therapeutic option for locally advanced colon cancer.

Laparoscopic versus open surgery in obstructive colorectal cancer patients following stents placement: a comprehensive meta-analysis of cohort studies

BACKGROUND

Over the past decade, the use of stent placement as a bridge to surgery (BTS) has emerged as an alternative to emergency surgery for patients with (OCRC). However, the optimal surgical approach remains indeterminate. This study seeks to evaluate the safety and feasibility of a combined treatment modality involving stent placement and laparoscopic surgery for OCRC presenting with malignant obstruction.

METHODS

A comprehensive search of PubMed, Cochrane Library, EMBASE, Web of Science, and ClinicalTrials.gov was conducted until June 2023 to identify studies that compared laparoscopic to open surgery in patients with OCBC following stent insertion.

RESULTS

The meta-analysis incorporated 12 cohort studies, encompassing 933 patients. There was no statistically significant difference in the 30-day mortality rates between the two groups (relative risk [RR], 1.09; 95% confidence interval [CI] 0.26 to 4.48; P = 0.95). Compared to the laparoscopic approach group, the open approach group had a higher rate of overall postoperative complications (POCs) (RR 0.52; 95% CI 0.37 to 0.72, P < 0.0001). There was no significant variance in lymph node (LN) dissection number between the groups (mean differences [MD], 1.64; 95% CI - 1.51 to 4.78; P = 0.31). Notably, laparoscopic surgery resulted in less intraoperative blood loss (MD, - 25.84 ml; 95% CI - 52.16 to 0.49; P = 0.05) and a longer operation time (MD, 20.99 mins; 95% CI 2.31 to 39.44; P = 0.03). The laparoscopic approach was associated with a shorter length of hospital stay (LOS) (MD - 3.29 days; 95% CI - 5.27 to 1.31; P = 0.001). Conversely, the open approach group had a higher rate of postoperative surgical site infection (SSI) (RR 0.47; 95% CI 0.23 to 0.96, P = 0.04). Although the number of included studies was insufficient to conduct a meta-analysis, several of them imply that laparoscopic surgery may yield more favorable outcomes in terms of the 3-year overall survival rate (OS), 3-year disease-free survival rate (DFS), 5-year OS, and 5-year DFS when compared to open surgery. It is worth noting that these differences lack statistical significance.

CONCLUSION

In patients with OCRC subjected to stent insertion, laparoscopic surgery arguably presents a modest superiority over open surgery by diminishing the overall postoperative risk and potentially reducing the LOS.