Clinicopathological factors influencing outcome in metastatic colorectal cancer patients treated with fluoropyrimidine and bevacizumab maintenance treatment vs observation: an individual patient data meta-analysis of two phase 3 trials

Chemotherapy Duration for Various Indications in Colorectal Cancer: a Review

PURPOSE OF REVIEW

The treatment of colorectal cancer (CRC) has evolved and become more personalized during the past several years. For example, depotentiation/reduced duration of systemic therapies has proven to be beneficial in both advanced and early stages of the disease.

RECENT FINDINGS

In particular, recent randomized studies of stage III and high-risk stage II CRC showed that a shorter duration (3 months), when compared to the historical 6-month comparator, provides nearly similar overall survival (OS) and disease-free survival (DFS). In the setting of advanced, inoperable CRC, a relatively short induction phase (six to eight cycles) followed by biological agents is the current standard of care in RAS wild-type (wt). versus RAS mutated cases. With regard to potentially operable stage IV disease (with the aim of converting liver metastases to operability), a relatively short number of cycles (four to six cycles) should be offered with re-staging and re-evaluation for surgery as soon as possible in most cases. For inoperable liver metastases, a relatively intensive triplet or doublet plus targeted therapy may attain conversion in some cases and may even result in cure. Rectal cancer treatment continues to be a complex disease in terms of treatment and oncological results. Recent data seem to showcase the benefits of more prolonged sequential strategies (total neoadjuvant therapy, all treatment delivered before surgery, to reduce the risk of distant metastases and local control). In recent years, different strategies regarding treatment intensity have been employed in CRC in adjuvant and metastatic setting. Introduction of triplets as first-line therapy for colon cancer and as induction phase for rectal cancer are now therapeutic options. Conversely in stage II disease or low-risk stage III resected CRC, a reduced chemotherapy length is a new standard of care.

Treatment breaks in first line treatment of advanced colorectal cancer: An individual patient data meta-analysis

BACKGROUND

Intermittent systemic anti-cancer therapy in patients with advanced colorectal cancer (aCRC) may improve quality of life without compromising overall survival (OS). We aimed to use individual patient data meta-analysis (IPDMA) from multiple randomised controlled trials evaluating intermittent strategies to inform clinical practice. We also aimed to validate whether thrombocytosis as a predictive biomarker identified patients with significantly reduced OS receiving a complete treatment break.

PATIENTS AND METHODS

An IPDMA of intermittent strategy impact on survival was undertaken, including all relevant trials in which data were available. Intermittent strategies were classified into two groups: a planned stopping of all therapy ("treatment break strategy"; 6 trials; 2,907 patients) or to the same treatment omitting oxaliplatin ("maintenance strategy"; 3 trials; 1,271 patients). The primary analysis sample was of patients successfully completing induction therapy. Additionally, a pre-planned analysis of the predictive value of thrombocytosis on survival under a continuous versus an intermittent strategy was undertaken.

RESULTS

All trials had comparable inclusion criteria. The overall IPDMA of intermittent therapy versus continuous therapy demonstrated no detriment in OS (HR = 1.03 [95% CI 0.93-1.14]), whether from complete break (HR 1.04 [95% CI 0.87-1.26]) or maintenance strategies (HR 0.99 [95% CI 0.87-1.13]). Thrombocytosis was confirmed as a marker of poor prognosis in aCRC, but did not predict for OS detriment from treatment break strategies (interaction HR = 0.97 [95% CI 0.66-1.40] compared to continuous therapy).

CONCLUSION

The highest levels of evidence from this IPDMA indicate no detriment in survival for patients receiving an intermittent therapy strategy, either for maintenance or complete break strategies. Although, thrombocytosis is confirmed as a marker of poor prognosis, it is not predictive of poor outcome for patients treated with intermittent therapy. An intermittent chemotherapy strategy can therefore be applied irrespective of baseline platelet count and does not result in inferior OS compared to continuous chemotherapy.

Predictive factors for early progression during induction chemotherapy and chemotherapy-free interval: analysis from PRODIGE 9 trial

Background

Identifying patients with metastatic colorectal cancer who will have an early disease progression during induction chemotherapy (IC) and identifying patients who may have a chemotherapy-free interval (CFI) after IC are two major challenges.

Methods

A logistic model was used to identify factors associated with early progression during IC and with short duration of the first CFI in 488 patients enrolled in the PRODIGE 9 trial. Independent factors were defined with a threshold 0.10.

Results

In multivariate analysis, baseline leukocytes >10 × 10⁹/L (OR = 1.98 [1.02–3.8], p = 0.04), and stable or increasing CEA at 2 months (OR = 3.61 [1.68–7.75], p = 0.01) were independent factors associated with progression during IC. Male gender (OR = 1.725 [0.92–3.325], p = 0.09) and no tumour response at first evaluation (OR = 1.90 [0.96–3.76], p = 0.07) were significantly associated with a short CFI. The presence of BRAF V600E mutation was also associated with short CFI (OR = 4.59 [0.95; 22.3], p = 0.058).

Conclusion

High baseline leukocyte count and the lack of CEA decrease level at first evaluation were associated with early progression, and could be in favour of early chemotherapy intensification. Male gender, no tumour response at first evaluation and BRAF mutation are associated with a short CFI, and may be considered for maintenance chemotherapy after IC.

Clinical trial number

NCT00952029.

Maintenance Versus Intermittent Strategies in the Treatment of Metastatic Colorectal Cancer: A Meta-Analysis from Another Angle

INTRODUCTION

Considering the differences in overall survival (OS) and progression-free survival (PFS), treatment options for metastatic colorectal cancer (mCRC) are still inconclusive. We carried out a meta-analysis of maintenance and intermittent strategies for the treatment of mCRC aiming at providing an accurate estimation of different treatments in increasing the chance and duration of survival.

METHODS

PubMed, Embase and CNKI were systematically searched. The pooled hazard ratio (HR) and 95% confidence interval (CI) were counted. We used STATA 12.0 and RevMan 5.2 for statistical analyses.

RESULTS

A total of six publications with a population of 1975 mCRC patients were included in our meta-analysis. Analysis of OS revealed a statistically significant benefit associated with maintenance therapy (HR: 0.86, 95% CI 0.75-0.98, P = 0.02). Comparing maintenance therapy with an intermittent strategy, the first progression-free survival (PFS1) showed no significant difference (HR, 0.77; 95% CI 0.48-1.24, P = 0.29), but maintenance therapy improved the second progression-free survival (PFS2) significantly (HR, 0.66; 95% CI 0.54-0.81, P < 0.001). Sensitivity analysis was carried out to assess the stability of results. No publication bias was detected during analysis.

CONCLUSION

Compared with the maintenance strategy, first-line chemotherapy that was completely stopped until disease progression did not benefit mCRC patients in terms of OS and PFS2. Therefore, a maintenance strategy is a good option for individualized mCRC patients.

Targeting Angiogenesis in Colorectal Carcinoma

Neo-angiogenesis plays a key role in colorectal cancer, with the vascular endothelial growth factor family proteins and their receptors in particular triggering multiple signaling networks that result in endothelial cell survival, migration, mitogenesis, differentiation, and vascular permeability. Anti-angiogenic therapies have improved colorectal cancer prognosis within the past 15 years. Bevacizumab demonstrated efficacy in combination with chemotherapy under different conditions, including as first- and second-line therapies, and also as a maintenance treatment strategy. Other drugs targeting angiogenesis effectors (e.g., ramucirumab and aflibercept) were approved after bevacizumab failure, confirming the concept of "continuous anti-angiogenic blocking". Recently, a number of new orally available multiple receptor tyrosine kinase inhibitors have been tested in late-stage clinical trials, with modest efficacy. Due to the availability of several anti-angiogenic agents, we need well-designed prospective randomized trials to optimize therapeutic sequencing. The place of biosimilars in the therapeutic armamentarium remains unclear at the moment. Further research is warranted to identify robust predictive biomarkers of efficacy and innovative clinically meaningful anti-angiogenic drugs that are cost-efficient.

Prognostic value of the combination of microsatellite instability and BRAF mutation in colorectal cancer

Purpose

The aim of this study was to investigate the prognostic value of the combination of microsatellite instability (MSI) and BRAF V600E mutation in colorectal cancer (CRC).

Materials and methods

We compare the prognosis difference among CRC patients with four subtypes according to MSI and BRAF mutation, ie, microsatellite stable/BRAF wild type (MSS/BRAFwt), MSS/BRAF mutation (MSS/BRAFmut), MSI/BRAFwt, and MSI/BRAFmut, by pooling the previous related reports and public available data sets till December 2017 for the first time.

Results

Twenty-seven independent studies comprising 24,067 CRC patients were included. Meta-analysis suggested that, compared with MSS/BRAFwt subtype, MSS/BRAFmut was associated with shorter overall survival (OS) (N=25, HR = 2.018, 95% CI = 1.706-2.388, P=2.220E-16), while there was a trend of association of MSI/BRAFmut with OS (N=13, HR = 1.324, 95% CI = 0.938-1.868, P=1.096E-01) and no association of MSI/BRAFwt with OS (N=17, HR = 0.996, 95% CI = 0.801-1.240, P=9.761E-01). Compared with MSI/ BRAFwt subtype, MSI/BRAFmut was a poor factor for OS (N=22, HR = 1.470, 95% CI = 1.243-1.740, P=7.122E-06). Compared with MSS/BRAFmut subtype, both MSI/BRAFwt (N=11, HR = 0.560, 95% CI = 0.433-0.725, P=1.034E-05) and MSI/BRAFmut (N=16, HR = 0.741, 95% CI = 0.567-0.968, P=2.781E-02) were favorable for OS. Subgroup analysis revealed similar results in all subgroups except the subgroup of stage IV cancer, in which MSI showed poor effects on OS in BRAF wild-type patients (N=6, HR = 1.493, 95% CI = 1.187-1.879, P=6.262E-04) but not in BRAF-mutated patients (N=5, HR = 1.143, 95% CI = 0.789-1.655, P=4.839E-01). Meta-analysis regression and test of interaction revealed no interaction of MSI with BRAF mutation when evaluating the associations of MSI/BRAF mutation subtypes with OS in CRC.

Conclusion

Among the four subtypes according to MSI and BRAF mutation, MSS/BRAFmut was a poor prognostic factor, while MSS/BRAFwt and MSI/BRAFwt were comparable and favorable and MSI/BRAFmut was moderate in CRC. The combination of MSI/BRAF mutations could facilitate the planning of individualized treatment strategies and prognosis improvement in CRC.

Duration of first-line treatment for metastatic colorectal cancer: Translating the available evidence into general recommendations for routine practice

Over the last two decades the number of front-line regimens for metastatic colorectal cancer has progressively increased. Nevertheless, there is still no consensus on the optimal duration of treatment or the role of de-escalated/maintenance strategies after induction chemotherapy. In this article we provide an overview of the studies that addressed the duration of first-line systemic treatment with cytotoxic agents plus or minus targeted therapies highlighting caveats and limitations of the same. Also, we try to translate the available evidence into practical recommendations that can be used in everyday practice to inform treatment decisions. The main conclusion of our review article is that continuing induction treatment until progression may improve disease control but there is no evidence to suggest that adopting this practice can prolong survival. On the other hand, de-escalated treatment strategies offer an opportunity to reduce the burden of toxicity while maintaining satisfactory oncological outcomes.