Guidelines for time-to-event end-point definitions in adjuvant randomised trials for patients with localised colon cancer: Results of the DATECAN initiative

Survival Outcomes in Patients with Monobloc-Resected Stage IIC (pT4bN0) Colon Cancer: A Retrospective Observational Cohort Study

BACKGROUND

Stage II colon cancer (CC) exhibits considerable prognostic heterogeneous. Our objective was to assess survival but also the prognosis impact of microsatellite instability (MSI) in patients with stage IIC (T4bN0M0) CC.

PATIENTS AND METHODS

We conducted a retrospective observational study including all patients who had primary stage IIC CC resection between 2010 and 2020 in 2 expert centers. The primary endpoint was overall survival (OS) and disease-free survival (DFS) and time-to-relapse (TTR) were secondary endpoints.

RESULTS

Sixty-six patients, median age of 74 years [30-95], were included, with 37.9% presenting MSI (n = 25). Organ invasion involved the last ileal loop (n = 17), another colonic segment (n = 15), omentum (n = 13), visceral peritoneum (n = 13), and the bladder (n = 4). Surgical quality criteria showed complete monobloc resection in all patients and 93.9% R0 resection. After a median follow-up of 5 years [3.5-6.6], the entire population showed a 5-year OS of 65.2% [53.0-80.3] and 5-year DFS of 53.5% [41.1-69.6], with 18.9% [6.8-29.4] experiencing relapses at 5 years. The MSI phenotype correlated with improved 5-year OS (75.5% [56.5-100] vs. 59.5% [44.9-79.0], HR 0.41 [0.17-0.99]; P = .04), but DFS and TTR did not differ. Adjuvant chemotherapy was administered to 34.9% of patients. Univariate analysis identified age > 65 years, MSI status, and the number of nodes as factors associated with OS.

CONCLUSION

These data underline, in relation to a low rate of relapse, the lack of consensus regarding the appropriate indication for adjuvant chemotherapy in this high-risk stage II population.

Progression-free survival, disease-free survival and other composite end points in oncology: improved reporting is needed

Composite outcome measures such as progression-free survival and disease-free survival are increasingly used as surrogate end points in oncology research, frequently serving as the primary end point of pivotal trials that form the basis for FDA and EMA approvals. Such outcome measures combine two or more distinct events (for example, tumour (re)growth, new lesions and/or death) into a single, time-to-event end point. The use of a composite end point can increase the statistical power of a clinical trial and decrease the follow-up period required to demonstrate efficacy, thus lowering costs; however, these end points have a number of limitations. Composite outcomes are often vaguely defined, with definitions that vary greatly between studies, complicating comparisons of results across trials. Altering the makeup of events included in a composite outcome can alter study conclusions, including whether treatment effects are statistically significant. Moreover, the events included in a composite outcome often vary in clinical significance, reflect distinct biological pathways and/or are affected differently by treatment. Therefore, knowing the precise breakdown of the component events is essential to accurately interpret trial results and gauge the true benefit of an intervention. In oncology clinical trials, however, such information is rarely provided. In this Perspective, we emphasize this deficiency through a review of 50 studies with progression-free survival as an outcome published in five top oncology journals, discuss the advantages and challenges of using composite end points, and highlight the need for transparent reporting of the component events.

Time to recurrence and its relation to survival after recurrence in patients resected for stage III colon cancer

BACKGROUND

It is intuitively thought that early relapse is associated with poor survival after recurrence (SAR) in resected colon cancer (CC) patients, but this has never been formally studied.

METHODS

We pooled data from stage III patients treated with oxaliplatin-based adjuvant therapy in two phase III trials, to analyse time to recurrence (TTR) and its relationship with SAR. TTR and SAR were also studied according to molecular status (mismatch repair (MMR), RAS, and BRAFV600E). Early relapsing patients were defined as patients having a TTR event within 12 months after starting adjuvant chemotherapy.

RESULTS

4548 stage III CC patients were included in the present analysis. Deficient MMR (dMMR) CC patients experienced fewer recurrences than proficient (p)MMR CC patients (18.8% versus 27.6%) but had a significantly shorter median TTR (mTTR; 0.74 versus 1.40 years, p < 0.0001). In pMMR patients, BRAF and RAS mutations were also associated with earlier mTTR as compared to double wild-type (WT) patients (0.99 versus 1.38 versus 1.54 years, respectively, p < 0.0001). Early recurrence occurred in 397 patients and was associated with a median SAR (2.2 versus 3.3 years, p = 0.0007). However, this association was mainly due to pMMR/RAS and BRAFV600E mutated tumours and was not confirmed in dMMR and pMMR/double WT subgroups.

CONCLUSION

In resected stage III CC treated with standard oxaliplatin-based adjuvant therapy, TTR varies between dMMR, pMMR/RAS, or BRAFV600E mutated and pMMR/double WT tumours. In addition, early relapse is associated with poor survival, mainly due to patients resected for a pMMR/RAS or BRAFV600E mutated tumour.

Treatment patterns and survival outcomes of early-onset colorectal cancer patients in Alberta, Canada: a population-based study

BACKGROUND

The incidence of early-onset (<50) colorectal cancer (eoCRC) has been increasing in Canada. Little is known about treatment patterns and outcomes among this patient population in Canada.

PATIENTS AND METHODS

We conducted a retrospective population-based cohort study of CRC patients in Alberta (2010-2018) using electronic medical records and administrative claims data. Treatment patterns and CRC-specific mortality were compared between early-onset age groups (<40 and 40-49) and average age-at-onset (60-70) (aoCRC) patients with multivariable logistic regression and cox proportional hazard models.

RESULTS

There were 334 and 935 patients in the early-onset groups and 4606 in the aoCRC group. Compared with aoCRC, patients <40 were more likely to receive chemotherapy in stage II colon (OR 3.41, CI 1.75-6.47) and stage III rectal (OR 3.01, CI 1.18-10.21), and to receive systemic therapy (OR 2.40, CI 1.46-4.12) and radiation in stage IV CRC (OR 2.70, CI 1.48-4.92). The 40-49 age group was more likely to receive chemotherapy in stage II colon (OR 2.13, CI 1.25-3.56), and chemoradiation in stage II rectal (OR 2.16, CI 1.25-3.80) and stage III rectal (OR 1.63, CI 1.13-2.40), as well as systemic therapy in stage IV CRC (OR 2.46, CI 1.75-3.52). Survival did not differ between <40 and 60-70 age groups. Survival was significantly higher for the 40-49 age group, but only in stage IV (HR 0.79, CI 0.67-0.94).

CONCLUSIONS

EoCRC patients tended to receive more therapy than average age CRC patients with minimal survival gains. Additional research to identify optimal treatment strategies for eoCRC patients is required.

Utility and safety of the self-expandable metallic colonic stent in Japanese patients who received systemic chemotherapy or palliative treatment for obstructive primary advanced colorectal cancer: A retrospective single-center medical chart evaluation

Background and Aim

The present study aimed to compare the utility and safety of the colonic self-expandable metallic stent between patients with obstructive primary colorectal cancer who underwent chemotherapy or palliative treatment care and patients bridging for surgery.

Methods

The cases of 71 patients with colonic obstructive stenosis and in-dwelling stents who were hospitalized between May 2012 and April 2020 at Karatsu Red Cross Hospital were retrospectively analyzed. The patients were classified into three groups: bridging for curative surgery (group I), receiving systemic chemotherapy (group II-A), and receiving only palliative treatment (group II-B). Technical and clinical success rates and complication rates after stenting were evaluated.

Results

No significant differences were observed in the technical (procedure) success rates (group I: 100%; group II, 97.6% [II-A: 100%; II-B: 95.8%]). The total clinical success rate was 85.9% (61/71) and did not vary significantly among the groups (group I: 82.8%; group II 88.0% [II-A: 83.3%; II-B: 91.6%]). No significant differences were observed in the early complication rates between groups I and II and in the late complication rates between groups II-A and II-B. Nutrition status, general condition, tumor staging, and 1-year survival were poorer in group II than in group I.

Conclusion

The findings show that colonic stenting for malignant obstruction was performed successfully and safely both in patients who received systemic chemotherapy or palliative therapy and in patients bridging for curative surgery, regardless of risk status for malnutrition, poor general condition, cancer stage progression, and short survival.

Accurate population-based model for individual prediction of colon cancer recurrence

BACKGROUND

Prediction models are useful tools in the clinical management of colon cancer patients, particularly when estimating the recurrence rate and, thus, the need for adjuvant treatment. However, the most used models (MSKCC, ACCENT) are based on several decades-old patient series from clinical trials, likely overestimating the current risk of recurrence, especially in low-risk groups, as outcomes have improved over time. The aim was to develop and validate an updated model for the prediction of recurrence within 5 years after surgery using routinely collected clinicopathologic variables.

MATERIAL AND METHODS

A population-based cohort from the Swedish Colorectal Cancer Registry of 16,134 stage I-III colon cancer cases was used. A multivariable model was constructed using Cox proportional hazards regression. Three-quarters of the cases were used for model development and one quarter for internal validation. External validation was performed using 12,769 stage II-III patients from the Norwegian Colorectal Cancer Registry. The model was compared to previous nomograms.

RESULTS

The nomogram consisted of eight variables: sex, sidedness, pT-substages, number of positive and found lymph nodes, emergency surgery, lymphovascular and perineural invasion. The area under the curve (AUC) was 0.78 in the model, 0.76 in internal validation, and 0.70 in external validation. The model calibrated well, especially in low-risk patients, and performed better than existing nomograms in the Swedish registry data. The new nomogram's AUC was equal to that of the MSKCC but the calibration was better.

CONCLUSION

The nomogram based on recently operated patients from a population registry predicts recurrence risk more accurately than previous nomograms. It performs best in the low-risk groups where the risk-benefit ratio of adjuvant treatment is debatable and the need for an accurate prediction model is the largest.

Does neoadjuvant FOLFOX chemotherapy improve the prognosis of high-risk Stage II and III colon cancers? Three years' follow-up results of the PRODIGE 22 phase II randomized multicentre trial

AIM

Neoadjuvant chemotherapy has proven valuable in locally advanced resectable colon cancer (CC) but its effect on oncological outcomes is uncertain. The aim of the present paper was to report 3-year oncological outcomes, representing the secondary endpoints of the PRODIGE 22 trial.

METHOD

PRODIGE 22 was a randomized multicentre phase II trial in high-risk T3, T4 and/or N2 CC patients on CT scan. Patients were randomized between 6 months of adjuvant FOLFOX (upfront surgery) or perioperative FOLFOX (four cycles before surgery and eight cycles after; FOLFOX perioperative). In wild-type RAS patients, a third arm testing perioperative FOLFOX-cetuximab was added. The primary endpoint was the tumour regression grade. Secondary endpoints were 3-year overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS) and time to recurrence (TTR).

RESULTS

Overall, 120 patients were enrolled. At interim analysis, the FOLFOX-cetuximab arm was stopped for futility. The remaining 104 patients represented our intention-to-treat population. In the perioperative group, 96% received the scheduled four neoadjuvant cycles and all but one had adjuvant FOLFOX for eight cycles. In the control arm, 38 (73%) patients received adjuvant FOLFOX. The median follow-up was 54.3 months. Three-year OS was 90.4% in both arms [hazard ratio (HR) = 0.85], 3-year DFS, RFS and TTR were, respectively, 76.8% and 69.2% (HR=0.94), 73% and 69.2% (HR = 0.86) and 82% and 72% (HR = 0.67) in the perioperative and control arms, respectively. Forest plots did not show any subgroup with significant difference for survival outcomes. No benefit from adding cetuximab was observed.

CONCLUSION

Perioperative FOLFOX has no detrimental effect on long-term oncological outcomes and may be an option for some patients with locally advanced CC.

Recurrence Risk after Radical Colorectal Cancer Surgery-Less Than before, But How High Is It?

Simple Summary

Evidence indicates that recurrence risk after colon cancer today is less than it was when trials performed decades ago showed that adjuvant chemotherapy reduces the risk and prolong disease-free and overall survival. After rectal cancer surgery, local recurrence rates have decreased but it is unclear if systemic recurrences have. After a systematic review of available literature reporting recurrence risks after curative colorectal cancer surgery we report that the risks are lower today than they were in the past and that this risk reduction is not solely ascribed to the use of adjuvant therapy. Adjuvant therapy always means overtreatment of many patients, already cured by the surgery. Fewer recurrences mean that progress in the care of these patients has happened but also that the present guidelines giving recommendations based upon old data must be adjusted. The relative gains from adding chemotherapy are not altered, but the absolute number of patients gaining is less.

Abstract

Adjuvant chemotherapy aims at eradicating tumour cells sometimes present after radical surgery for a colorectal cancer (CRC) and thereby diminish the recurrence rate and prolong time to recurrence (TTR). Remaining tumour cells will lead to recurrent disease that is usually fatal. Adjuvant therapy is administered based upon the estimated recurrence risk, which in turn defines the need for this treatment. This systematic overview aims at describing whether the need has decreased since trials showing that adjuvant chemotherapy provides benefits in colon cancer were performed decades ago. Thanks to other improvements than the administration of adjuvant chemotherapy, such as better staging, improved surgery, the use of radiotherapy and more careful pathology, recurrence risks have decreased. Methodological difficulties including intertrial comparisons decades apart and the present selective use of adjuvant therapy prevent an accurate estimate of the magnitude of the decreased need. Furthermore, most trials do not report recurrence rates or TTR, only disease-free and overall survival (DFS/OS). Fewer colon cancer patients, particularly in stage II but also in stage III, today display a sufficient need for adjuvant treatment considering the burden of treatment, especially when oxaliplatin is added. In rectal cancer, neo-adjuvant treatment will be increasingly used, diminishing the need for adjuvant treatment.

The future of colorectal cancer research: an interview with Hans Schmoll

Hans Schmoll speaks to Rachel Jenkins, Managing Commissioning Editor. Over four decades of professional activity, Hans has become one of the most highly esteemed and influential medical oncologists in Germany. As Editor of the German standard reference book for medical and multidisciplinary oncology (6000 pages) [1], he has defined treatment standards and education in medical oncology in the German speaking countries. His work as a research scientist has covered numerous fields in medical oncology, in particular, genitourinary and gastrointestinal cancers, where he has defined worldwide standards for the management of germ-cell cancer and early and late stages of colon cancer. Within the European Society of Medical Oncology, he served on the Executive Board as founding chair of the Multidisciplinary Oncology Committee and as scientific chair of the Istanbul European Society of Medical Oncology Congress 2006.

Adjuvant Chemotherapy in Elderly Colorectal Cancer Patients

The value of adjuvant chemotherapy in elderly patients has been the subject of many overviews, with opinions varying from “not effective”, since randomized trials have not been performed, to “as effective as in young individuals”, based upon many retrospective analyses of randomized trials that have included patients of all ages. In the absence of randomized trials performed specifically with elderly patients, retrospective analyses demonstrate that the influence on the time to tumour recurrence (TTR) may be the same as in young individuals, but that endpoints that include death for any reason, such as recurrence-free survival (RFS), disease-free survival (DFS), and overall survival (OS), are poorer in the elderly. This is particularly true if oxaliplatin has been part of the treatment. The need for adjuvant chemotherapy after colorectal cancer surgery in elderly patients is basically the same as that in younger patients. The reduction in recurrence risks may be similar, provided the chosen treatment is tolerated but survival gains are less. Adding oxaliplatin to a fluoropyrimidine is probably not beneficial in individuals above a biological age of approximately 70 years. If an oxaliplatin combination is administered to elderly patients, three months of therapy is in all probability the most realistic goal.

Immunotherapy for Early Stage Colorectal Cancer: A Glance into the Future

Immune checkpoint inhibitors (ICI) have reshaped therapeutic strategies for cancer patients. The development of ICI for early stage colorectal cancer is accompanied by specific challenges: (i) the selection of patients who are likely to benefit from these treatments, i.e., patients with tumors harboring predictive factors of efficacy of ICI, such as microsatellite instability and/or mismatch repair deficiency (MSI/dMMR), or other potential parameters (increased T cell infiltration using Immunoscore® or others, high tumor mutational burden, POLE mutation), (ii) the selection of patients at risk of disease recurrence (poor prognostic features), and (iii) the choice of an accurate clinical trial methodological framework. In this review, we will discuss the ins and outs of clinical research of ICI for early stage MSI/dMMR CC patients in adjuvant and neoadjuvant settings. We will then summarize data that might support the development of ICI in localized colorectal cancer beyond MSI/dMMR.