Integration of stereotactic radiotherapy in the treatment of metastatic colorectal cancer patients: a real practice study with long-term outcome and prognostic factors

Optimizing Treatment Strategy for Oligometastases/Oligo-Recurrence of Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer, and nearly half of CRC patients experience metastases. Oligometastatic CRC represents a distinct clinical state characterized by limited metastatic involvement, demonstrating a less aggressive nature and potentially improved survival with multidisciplinary treatment. However, the varied clinical scenarios giving rise to oligometastases necessitate a precise definition, considering primary tumor status and oncological factors, to optimize treatment strategies. This review delineates the concepts of oligometastatic CRC, encompassing oligo-recurrence, where the primary tumor is under control, resulting in a more favorable prognosis. A comprehensive examination of multidisciplinary treatment with local treatments and systemic therapy is provided. The overarching objective in managing oligometastatic CRC is the complete eradication of metastases, offering prospects of a cure. Essential to this management approach are local treatments, with surgical resection serving as the standard of care. Percutaneous ablation and stereotactic body radiotherapy present less invasive alternatives for lesions unsuitable for surgery, demonstrating efficacy in select cases. Perioperative systemic therapy, aiming to control micrometastatic disease and enhance local treatment effectiveness, has shown improvements in progression-free survival through clinical trials. However, the extension of overall survival remains variable. The review emphasizes the need for further prospective trials to establish a cohesive definition and an optimized treatment strategy for oligometastatic CRC.

Oligo-metastatic neoPlasms from the gastro-intestinal tract: iDentIfiCaTIon of cliNical and molecular drivers: the PREDICTION study

BACKGROUND

Metastatic disease in tumors originating from the gastrointestinal tract can exhibit varying degrees of tumor burden at presentation. Some patients follow a less aggressive disease course, characterized by a limited number of metastatic sites, referred to as "oligo-metastatic disease" (OMD). The precise biological characteristics that define the oligometastatic behavior remain uncertain. In this study, we present a protocol designed to prospectively identify OMD, with the aim of proposing novel therapeutic approaches and monitoring strategies.

METHODS

The PREDICTION study is a monocentric, prospective, observational investigation. Enrolled patients will receive standard treatment, while translational activities will involve analysis of the tumor microenvironment and genomic profiling using immunohistochemistry and next-generation sequencing, respectively. The first primary objective (descriptive) is to determine the prevalence of biological characteristics in OMD derived from gastrointestinal tract neoplasms, including high genetic concordance between primary tumors and metastases, a significant infiltration of T lymphocytes, and the absence of clonal evolution favoring specific driver genes (KRAS and PIK3CA). The second co-primary objective (analytic) is to identify a prognostic score for true OMD, with a primary focus on metastatic colorectal cancer. The score will comprise genetic concordance (> 80%), high T-lymphocyte infiltration, and the absence of clonal evolution favoring driver genes. It is hypothesized that patients with true OMD (score 3+) will have a lower rate of progression/recurrence within one year (20%) compared to those with false OMD (80%). The endpoint of the co-primary objective is the rate of recurrence/progression at one year. Considering a reasonable probability (60%) of the three factors occurring simultaneously in true OMD (score 3+), using a significance level of α = 0.05 and a test power of 90%, the study requires a minimum enrollment of 32 patients.

DISCUSSION

Few studies have explored the precise genetic and biological features of OMD thus far. In clinical settings, the diagnosis of OMD is typically made retrospectively, as some patients who undergo intensive treatment for oligometastases develop polymetastatic diseases within a year, while others do not experience disease progression (true OMD). In the coming years, the identification of true OMD will allow us to employ more personalized and comprehensive strategies in cancer treatment.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT05806151.

Oligo-Metastatic Cancers: Putative Biomarkers, Emerging Challenges and New Perspectives

Some cancer patients display a less aggressive form of metastatic disease, characterized by a low tumor burden and involving a smaller number of sites, which is referred to as "oligometastatic disease" (OMD). This review discusses new biomarkers, as well as methodological challenges and perspectives characterizing OMD. Recent studies have revealed that specific microRNA profiles, chromosome patterns, driver gene mutations (ERBB2, PBRM1, SETD2, KRAS, PIK3CA, SMAD4), polymorphisms (TCF7L2), and levels of immune cell infiltration into metastases, depending on the tumor type, are associated with an oligometastatic behavior. This suggests that OMD could be a distinct disease with specific biological and molecular characteristics. Therefore, the heterogeneity of initial tumor burden and inclusion of OMD patients in clinical trials pose a crucial methodological question that requires responses in the near future. Additionally, a solid understanding of the molecular and biological features of OMD will be necessary to support and complete the clinical staging systems, enabling a better distinction of metastatic behavior and tailored treatments.

Tumour Burden Reporting in Phase III Clinical Trials of Metastatic Lung, Breast, and Colorectal Cancers: A Systematic Review

Simple Summary

The initial tumour burden is a strong and well-known prognostic factor in oncology. A systematic review was performed to examine if and how the initial tumour burden is reported in phase III clinical trials in the most frequent and deadly cancers. Seventy trials were selected, which mostly included biologic agents. The identification of low-burden metastatic disease was performed in 28.6% of studies; it was a stratification factor for randomisation in only 25.7% of studies. In two studies, a significant imbalance between arms in patients with low-burden disease was revealed. Our findings emphasise the need for the better assessment of tumour burden in clinical trials.

Abstract

Background: Randomised phase III clinical trials represent a methodological milestone to select effective drugs against metastatic cancers. In this context, and particularly in the efficacy assessment of biologic drugs, the initial metastatic tumour burden is a strong prognostic factor. Methods: A systematic literature review of randomised, phase III, first-line, clinical trials in metastatic breast, colorectal, and lung cancers, published from 2016 to 2021, was performed. Three groups of variables were collected: identity-, method- (including tumour burden assessment) and outcome-related. Results: Seventy trials were selected. A large portion of studies (41.4%) focused on the effects of biologic agents (signal inhibitors and immuno-therapies). A definition of low-burden disease based predominantly on the number of involved organs was reported in 28.6% of studies. No explicit reference to oligo-metastatic disease was found either in inclusion/exclusion criteria or in final descriptive data analyses. Disease extent, heterogeneously defined, was a stratification factor for randomisation in only 25.7% of studies. In two studies, a significant imbalance between arms in patients with low-burden disease was revealed. Conclusions: Attention to initial tumour burden in designing future clinical trials (including the harmonisation of definitions and the reporting of eventual oligo-metastatic disease, complete estimates of tumour volume, and its consideration as a stratification factor) should be increased.

Knowing When to Use Stereotactic Ablative Radiation Therapy in Oligometastatic Cancer

Oligometastatic patients are a heterogeneous and yet not well-defined population. The actual definition identifies as oligometastatic, patients with 1-5 metastases in 1-3 different organs. However, only a proportion of these patients are "true" oligometastatic and therefore derive some kinds of benefit from local ablative approaches like stereotactic ablative radiation therapy (SABR). Since SABR is an easily accessible, effective and well-tolerated treatment, it is widely employed in the oligometastatic scenarios, without a particular focus on selection criteria. However, it should be crucial to identify predictive and prognostic features that could be clinically implemented. Therefore, we conducted this narrative review of the available literature to summarize all clinical, radiomic, genetic and epigenetic features found to be predictive of overall survival, progression-free survival or local control of oligometastatic patients treated with SABR.

A meta-analysis of stereotactic radiotherapy for pulmonary oligometastases from colorectal cancer

BACKGROUND

For patients with colon cancer with lung metastasis, conventional radiotherapy is commonly used, which mainly acts on the double-stranded DNA inside the tumor cells. However, many foreign studies have found that increasing the dose of radiotherapy cannot improve the prognosis of patients, and because of its side effects on normal tissues, the commonly used dose of radiotherapy is usually between 60 and 70 Gy. However, the local control of lung tumors using this dose is not good. With the rapid development of science and technology, stereotactic body radiotherapy (SBRT) technology has been widely used in patients with non-small cell lung cancer, and SBRT is also used in patients with colon cancer and lung metastasis. However, some studies have found that because there are more hypoxic cells in colon cancer tissues than in other tissues, and hypoxic cells are relatively insensitive to radiation, the efficacy of SBRT in patients with lung metastasis from colon cancer is worse than that in patients with lung metastasis from other sites. However, this conclusion is controversial. There is no definite conclusion about the optimal dose of radiotherapy. Some studies have found that increasing the dose of radiotherapy can improve the prognosis of patients with colon cancer and lung metastasis. However, this conclusion is controversial. On the basis of many studies both in China and other countries, this study made a meta-analysis on the efficacy of SBRT in the treatment of colon cancer with lung metastasis and non-colon cancer with lung metastasis, as well as a comparison of the efficacy of different radiation doses in the treatment of colon cancer with lung metastasis, in order to provide evidence-based medicine-related evidence.

AIM

To compare the efficacy of stereotactic radiotherapy for colon cancer with lung metastasis and non-colon cancer with lung metastasis (Study 1), and to compare the efficacy of different doses of radiotherapy for colon cancer with lung metastasis (Study 2).

Methods

The controlled trials including cases with pulmonary oligometastases from colon cancer published from January 2008 to December 2018 were searched according to the method of the Cochrane Collaboration, and meta-analysis was carried out by using RevMan5.3 software.

Results

Fourteen studies were included, of which nine were included in Study 1, involving 486 patients with colon cancer and 938 with non-colon cancer, and five were included in Study 2, involving 157 patients treated with high doses and 185 treated with low doses. Meta-analysis indicated that the clinical efficacy of stereotactic radiotherapy for pulmonary oligometastases from colorectal was significantly lower than that for pulmonary oligometastases from other cancers, and that the efficacy of high doses was significantly better than that of low doses (P < 0.05).

Conclusion

SBRT has worse efficacy for pulmonary oligometastases from colorectal than for those from other cancer, and better efficacy for pulmonary oligometastases from colon cancer can be achieved by dose escalation.