Reevaluating Disease-Free Survival as an Endpoint vs Overall Survival in Stage III Adjuvant Colon Cancer Trials

Enhanced colon-targeted drug delivery through development of 5-fluorouracil-loaded cross-linked mastic gum nanoparticles

This study explored the development of a novel colon-specific drug delivery system for 5-fluorouracil (5-FU) using cross-linked mastic gum (MG) nanoparticles (NPs). The primary goal is to enhance the treatment efficacy of colon cancer while minimizing systemic side effects. We employed Fourier Transform Infrared Radiation (FTIR) and Scanning Electron Microscopy (SEM) for the detailed characterization of the samples. FTIR analysis confirmed the successful cross-linking of MG, whereas SEM images revealed the spherical and uniform morphology of the NPs. Additionally, analysis of drug encapsulation efficiency (83.53%), particle size (240 nm), and drug release kinetics (zero-order), and the drug release percentage (95.20% ) were analyzed. The results demonstrated that MG NPs effectively encapsulated and controlled the release of 5-FU in a colon-targeted manner. This study recommends the proposed drug delivery system because of its potential to improve the outcomes of colon cancer treatment.

Predicting disease-free survival following curative-intent resection of right-sided colon cancer using a pre- and post-operative nomogram: a prospective observational cohort study

INTRODUCTION

Disease prognostication can be achieved through the derivation of biologically and clinically integrated prediction models. The present study reports 1-, 3-, and 5-year disease-free survival (DFS) in patients undergoing right hemicolectomy for curative intent and both derives and validates a pre- and post-operative prediction tool for DFS for prognostication and risk stratification purposes.

METHOD

Consecutive patients undergoing right-sided curative-intent resection for colorectal cancer (2010-2020) in a tertiary care unit were followed-up prospectively for recurrence and survival outcomes. Survival analyses were used to derive pre- and post-operative models predicting 1-, 3-, and 5-year DFS. Calibration was reported and internal validation was performed using bootstrapping.

RESULTS

A total of 822 patients underwent resection and 528 had ≥5-year follow-up. The 1-, 3-, and 5-year DFS rates were 85.6%, 72.5% and 57.6%, respectively. Variables associated with death/recurrence included: increasing age (HR > 1.95, P = 0.037), male gender (HR 1.62, P < 0.001), ASA ≥3 (HR 1.79, P < 0.001), low albumin (HR 1.54, P < 0.001), T4 stage (HR 2.35, P = 0.023), R1 status (HR 1.63, P = 0.024), ≥4 positive lymph nodes (HR > 1.74, P < 0.001) and Clavien-Dindo ≥3 (HR 2.83, P < 0.001). The pre- and post-operative models contained 9 and 13 demographic, clinical, biochemical, operative and pathological variables, respectively (C-index 0.75 and 0.79, respectively). Excluding demographic, clinical and operative variables significantly reduced the C-index of the pre- (0.62) and post-operative models (0.70).

CONCLUSION

The presented prediction tools for DFS will help clinicians stratify risk, offer appropriate adjuvant treatment and predict long-term DFS following curative-intent right-sided colon cancer resection.

Proficient surgeons enhance conversion rates and sphincter preservation in robotic rectal cancer surgery with comparable long-term outcomes: a comparative study with laparoscopy in a large-volume center in China

BACKGROUND

Despite theoretical advantages, skepticism persists about robotic rectal cancer surgery due to the lack of evidence of benefit. This study aims to compare oncological and functional results of robotic-assisted surgery to laparoscopy, focusing on proficient surgeons with expertise in both techniques.

METHODS

This retrospective study reviewed and compared 1304 patients who underwent either robotic surgery (n = 295) or laparoscopic surgery (n = 1009) for rectal cancer. The surgical procedures were performed by a team of highly skilled surgeons who individually carry out more than 350 laparoscopic or robotic colorectal cancer surgeries over the course of their career. Perioperative outcomes, recurrence data, and intestinal function outcomes were compared between groups with a propensity score matching (PSM) method. The primary outcomes were sphincter preservation and conversion to open laparotomy. Secondary endpoints included 3-year disease-free survival (DFS), 3-year overall survival (OS), complications, and the occurrence of low anterior resection syndrome (LARS). Fisher's exact test and χ2 were used to compare discrete variables between groups, while parametric (t-test) and nonparametric (U test, Kruskal-Wallis) tests were used for continuous outcomes, as appropriate. The Kaplan-Meier and log-rank tests were employed to analyze and compare the DFS and OS outcomes.

RESULTS

The patients in the robotic group were younger, with a higher cN stage, positive EMVI and CRM, and a lower tumor location compared to the patients in the laparoscopic group. The robotic group also had more neoadjuvant chemoradiotherapy, causing an imbalance in (y)pT and (y)pN stage. Following PSM, all covariates were effectively balanced between the two groups. The robotic group had significantly higher sphincter preservation rates (94.0% vs. 84.4%, P < 0.001) and no conversions to open laparotomy, while the laparoscopic group had 7 cases (0 vs. 2.5%, P = 0.015). There were no significant differences observed in diverting ileostomy, operative time, estimated blood loss, complications, margin involvement, or duration of hospitalization. The median follow-up was 31 months. No significant differences were found between the robotic and laparoscopic groups in terms of 3-year OS (94.1% vs. 93.3%, P = 0.812) and DFS (85.9% vs. 84.7%, P = 0.797). The robotic group had similar rates of recurrence in various sites, including local, liver, lung, bone, and peritoneal metastases. Major LARS occurred in 11.3% of patients, while minor LARS occurred in 14.8% with no significant differences between the groups (P = 0.54).

CONCLUSION

Comparable complication rates, 3-year OS, and DFS were found between robotic and laparoscopic rectal cancer surgery. Furthermore, it shed light on supplementary benefits associated with this approach, such as decreased conversion rates and enhanced sphincter preservation, particularly when performed by skilled surgeons in specialized, high-volume medical facilities.

Results from the UNITED study: a multicenter study validating the prognostic effect of the tumor-stroma ratio in colon cancer

BACKGROUND

The TNM (tumor-node-metastasis) Evaluation Committee of Union for International Cancer Control (UICC) and College of American Pathologists (CAP) recommended to prospectively validate the cost-effective and robust tumor-stroma ratio (TSR) as an independent prognostic parameter, since high intratumor stromal percentages have previously predicted poor patient-related outcomes.

PATIENTS AND METHODS

The 'Uniform Noting for International application of Tumor-stroma ratio as Easy Diagnostic tool' (UNITED) study enrolled patients in 27 participating centers in 12 countries worldwide. The TSR, categorized as stroma-high (>50%) or stroma-low (≤50%), was scored through standardized microscopic assessment by certified pathologists, and effect on disease-free survival (DFS) was evaluated with 3-year median follow-up. Secondary endpoints were benefit assessment of adjuvant chemotherapy (ACT) and overall survival (OS).

RESULTS

A total of 1537 patients were included, with 1388 eligible stage II/III patients curatively operated between 2015 and 2021. DFS was significantly shorter in stroma-high (n = 428) than in stroma-low patients (n = 960) (3-year rates 70% versus 83%; P < 0.001). In multivariate analysis, TSR remained an independent prognosticator for DFS (P < 0.001, hazard ratio 1.49, 95% confidence interval 1.17-1.90). As secondary outcome, DFS was also worse in stage II and III stroma-high patients despite adjuvant treatment (3-year rates stage II 73% versus 92% and stage III 66% versus 80%; P = 0.008 and P = 0.011, respectively). In stage II patients not receiving ACT (n = 322), the TSR outperformed the American Society of Clinical Oncology (ASCO) criteria in identifying patients at risk of events (event rate 21% versus 9%), with a higher discriminatory 3-year DFS rate (stroma-high 80% versus ASCO high risk 91%). A trend toward worse 5-year OS in stroma-high was noticeable (74% versus 83% stroma-low; P = 0.102).

CONCLUSION

The multicenter UNITED study unequivocally validates the TSR as an independent prognosticator, confirming worse outcomes in stroma-high patients. The TSR improved current selection criteria for patients at risk of events, and stroma-high patients potentially experienced chemotherapy resistance. TSR implementation in pathology diagnostics and international guidelines is highly recommended as aid in personalized treatment.

The reliability and integrity of overall survival data based on follow-up records only and potential solutions to the challenges

Overall survival (OS) is considered the standard clinical endpoint to support effectiveness claims in new drug applications globally, particularly for lethal conditions such as cancer. However, the source and reliability of OS in the setting of clinical trials have seldom been doubted and discussed. This study first raised the common issue that data integrity and reliability are doubtful when we collect OS information or other time-to-event endpoints based solely on simple follow-up records by investigators without supporting material, especially since the 2019 COVID-19 pandemic. Then, two rounds of discussions with 30 Chinese experts were held and 12 potential source scenarios of three methods for obtaining the time of death of participants, including death certificate, death record and follow-up record, were sorted out and analysed. With a comprehensive assessment of the 12 scenarios by legitimacy, data reliability, data acquisition efficiency, difficulty of data acquisition, and coverage of participants, both short-term and long-term recommended sources, overall strategies and detailed measures for improving the integrity and reliability of death date are presented. In the short term, we suggest integrated sources such as public security systems made available to drug inspection centres appropriately as soon as possible to strengthen supervision. Death certificates provided by participants' family members and detailed standard follow-up records are recommended to investigators as the two channels of mutual compensation, and the acquisition of supporting materials is encouraged as long as it is not prohibited legally. Moreover, we expect that the sharing of electronic medical records and the legal disclosure of death records in established health registries can be realized with the joint efforts of the whole industry in the long-term. The above proposed solutions are mainly based on the context of China and can also provide reference for other countries in the world.

Prognostic Implications of Endoscopic Obstruction in Patients with Pathological Stage II Colon Cancers: a Single-Center Retrospective Cohort Study

BACKGROUND

The prognostic effect of endoscopic obstruction (eOB) on the survival of stage II colon cancer patients and the role of eOB in guiding postoperative adjuvant chemotherapy of stage II colon cancer are little known.

METHODS

In this retrospective, single-center cohort study, patients who had undergone curative surgery and preoperative colonoscope for stage II colon carcinoma were included. The eOB was defined as severe luminal colon obstruction that prevented the standard colonoscope from passing beyond the tumor. The association between eOB and stage II colon cancer survival and the predictive role of eOB for adjuvant chemotherapy were evaluated using multivariate Cox regression analysis.

RESULTS

Of 1102 included patients, 616 (55.9%) had eOB and 486 (44.1%) had no eOB. The median follow-up was 49 months (interquartile range, 38-68 months). Kaplan-Meier curves showed that patients with eOB had poor 5-year overall survival (OS; 85.3% vs. 95.3%, p < 0.001) compared to patients without eOB. Five-year disease-free survival (DFS; 78.5% vs. 87.6%, p = 0.004) was also poor in these patients. Multivariate analysis demonstrated eOB was a significant prognostic factor for poor OS (hazard ratio [HR] = 2.531, p < 0.001), but not for DFS (p = 0.081). Even when patients with clinical colonic obstruction were excluded from the population with eOB, the worse OS (HR = 2.262, p = 0.001) was observed. The OS and DFS of eOB patients improved slightly after adjuvant chemotherapy, but there was no statistical significance.

CONCLUSIONS

Stage II colon cancer patients with eOB have a poor prognosis. However, whether eOB can guide adjuvant chemotherapy still needs further study.

End of induction positron emission tomography complete response (PET-CR) as a surrogate for progression-free survival in previously untreated follicular lymphoma

Progression-free survival (PFS) has been the regulatory primary end-point for recent phase III trials in first-line follicular lymphoma (FL), but requires prolonged follow-up. Complete response (CR) at 30 months after initiation of induction treatment was validated as surrogate end-point for PFS. Our objective was to further evaluate surrogacy of CR measured by [¹⁸ F] fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging at the end of induction (EoI). Individual patient data were analysed from 1505 patients from five randomized trials. Trial-level surrogacy examining the association between treatment effects on EoI-PET-CR and PFS was evaluated using linear regression ( R WLS 2 $$ {R}_{\mathrm{WLS}}^2 $$ ) and bivariate Copula ( R Copula 2 $$ {R}_{\mathrm{Copula}}^2 $$ ) models. Although EoI-PET-CR strongly predicted PFS at a prognostic level, the trial-level assessment did not show strong correlation ( R WLS 2 = 0.56 $$ {R}_{\mathrm{WLS}}^2=0.56 $$ , confidence interval [CI]: 0.20-0.88; R Copula 2 = 0.35 $$ {R}_{\mathrm{Copula}}^2=0.35 $$ , CI: 0.0-0.82). The high uncertainty in estimation was possibly due to the small number of trials and the population of patients with available PET data. Maintenance therapy affecting PFS beyond induction treatment, but not EoI-PET-CR end-point, may have distorted the association between treatment effects. However, there will probably be a number of additional trials approaching completion with available PET response data. Refined evaluation of PET-CR based surrogate end-points is still warranted.