Impact of the 12-gene recurrence score assay on deciding adjuvant chemotherapy for stage II and IIIA/B colon cancer: the SUNRISE-DI study

Treatments and clinical outcomes in stage II colon cancer patients with 12-gene Oncotype DX Colon Recurrence Score® assay-guided therapy: real-world data

BACKGROUND

The 12-gene Oncotype DX Colon Recurrence Score® result quantifies the recurrence risk in stage II/III colon cancer (CC). This real-world study investigated stage II CC patients whose treatment decisions incorporated the Recurrence Score® (RS) result.

MATERIALS AND METHODS

This retrospective analysis of a prospectively designed cohort included all stage II, mismatch repair-proficient CC patients who underwent 12-gene testing through Clalit between January 2011 and December 2016 and had available data with a minimum 3-year follow-up.

RESULTS

The analysis included 938 patients {median age 68 [interquartile range (IQR) 60-76] years; 96% T3 tumors}. The median RS was 26 (IQR 19-33) and the three RS categories (0-29, 30-40, 41-100) included 65%, 24%, and 11% of patients, respectively. Chemotherapy (CT) use differed significantly between the three RS categories (14%, 36%, and 60%, respectively; P < 0.001). The CT and observation-only groups were imbalanced with worse clinicopathologic characteristics in the former. Among observation-only patients, Kaplan-Meier (KM) estimates for recurrence-free interval (RFI) and CC-specific survival (CCSS) differed significantly between the three RS categories (P < 0.001). Clinical outcomes by treatment (CT versus observation) within each RS category revealed no differences in RFI and CCSS in the RS 0-29 and 30-40 categories. In contrast, in the RS 41-100 category, the difference in RFI trended toward significance (P = 0.066), and for CCSS, a statistically significant difference was observed, with better outcomes among CT-treated patients (P = 0.035).

CONCLUSIONS

RS results are prognostic in stage II CC. Among RS 41-100 patients, outcomes were better in CT-treated versus observation-only patients despite worse clinicopathologic characteristics, suggesting that CT confers clinical benefit in high-risk patients.

[Molecular pathology of colorectal cancer]

In recent years, the treatment of colorectal carcinoma has experienced increasing individualization. In addition to RAS and BRAF mutational status that is firmly established in routine diagnostics, new therapeutic options evolved based on MSI and HER2 status as well as primary tumour localization. Offering the best targeted options in therapy requires new evidence-based decision-making algorithms regarding timing and scope of molecular pathological diagnostics in order for patients to receive an optimized therapy according to current treatment guidelines. New targeted therapies, some of which are about to be approved and for which pathology has to provide new molecular pathological biomarkers, will also play an increasingly important role in the future.

Impact of the 12-gene recurrence score in influencing adjuvant chemotherapy prescription in mismatch repair proficient stage II/III colonic carcinoma-a systematic review and meta-analysis

INTRODUCTION

The 12-gene recurrence score (RS) is a clinically validated assay which predicts recurrence risk in patients with stage II/III colon cancer. Decisions regarding adjuvant chemotherapy may be guided using this assay or based on the judgement of tumour board.

AIMS

To assess the concordance between the RS and MDT decisions regarding adjuvant chemotherapy in colon cancer.

METHODS

A systematic review was performed in accordance with PRISMA guidelines. Meta-analyses were performed using the Mantel-Haenszel method using the Review Manager version 5.4 software.

RESULTS

Four studies including 855 patients with a mean age of 68 years (range: 25-90 years) met inclusion criteria. Overall, 79.2% had stage II disease (677/855) and 20.8% had stage III disease (178/855). For the entire cohort, concordant results between the 12-gene assay and MDT were more likely than discordant (odds ratio (OR): 0.38, 95% confidence interval (CI): 0.25-0.56, P < 0.001). Patients were more likely to have chemotherapy omitted than escalated when using the RS (OR: 9.76, 95% CI: 6.72-14.18, P < 0.001). For those with stage II disease, concordant results between the 12-gene assay and MDT were more likely than discordant (OR: 0.30, 95% CI: 0.17-0.53, P < 0.001). In stage II disease, patients were more likely to have chemotherapy omitted than escalated when using the RS (OR: 7.39, 95% CI: 4.85-11.26, P < 0.001).

CONCLUSIONS

The use of the 12-gene signature refutes the decision of tumour board in 25% of cases, with 75% of discordant decisions resulting in omission of adjuvant chemotherapy. Therefore, it is possible that a proportion of such patients are being overtreated when relying on tumour board decisions alone.

Cost-effectiveness of precision molecular diagnostic tests for stage II colorectal cancer

Background

In colorectal cancer, inappropriate use of adjuvant chemotherapies may lead to significant increases in healthcare costs and harms to patients. Genome-based interventions are being increasingly used in the stratification of patients according to their risk profiles. However, earlier cost-effectiveness analyses of precision molecular diagnostics have indicated a paucity of data on comparative health economic outcomes. Our aim was to compare the cost-effectiveness of marketed genomic tests used in the prognosis of stage II colorectal cancer patients.

Methods

A Markov model was developed to compare the cost-effectiveness of treatment guided by any one of the following genomic tests: 12-gene assay or the 18-gene expression assay or the 482-gene signature or the Immunoscore assay in a hypothetical cohort of patients (n=1,000) with stage II colorectal cancer. Our study investigated outcomes in three health states: no recurrence, recurrence and death. This study was conducted from a societal perspective, and a 3% discount was applied to the costs and health outcomes. Sensitivity analyses were performed to assess the uncertainty of model parameters on the results.

Results

The cost of the Immunoscore assay strategy in stage II colorectal cancer patients was estimated to be US $23,564 with a gain of 3.903 quality-adjusted life years (QALYs) as compared with the 12-gene assay strategy at US $24,545 and 3.903 QALYs; the 18-gene assay strategy at US $28,374 and 3.623 QALYs; and the 482-gene signature treatment strategy at US $33,315 with 3.704 QALYs. Sensitivity analyses indicated that incremental cost-effectiveness ratio (ICER) values were sensitive to costs of genomic tests and adjuvant chemotherapies; and utilities related to patients in the no-recurrence health state.

Conclusions

Overall, the Immunoscore assay seems to be a dominant strategy at a threshold willingness-to-pay of $50,000 per QALY, but in the US other tests have been used for longer. Thus, the 12-gene assay may generate cost savings compared to the 18-gene expression assay. The findings of our study may provide useful information to policymakers regarding selection of the most appropriate genomic test, and resource allocation decisions.