Comparison of the molecular profile of brain metastases from colorectal cancer and corresponding primary tumors

Unravelling the Complexity of Colorectal Cancer: Heterogeneity, Clonal Evolution, and Clinical Implications

Colorectal cancer (CRC) is a global health concern and a leading cause of death worldwide. The disease's course and response to treatment are significantly influenced by its heterogeneity, both within a single lesion and between primary and metastatic sites. Biomarkers, such as mutations in KRAS, NRAS, and BRAF, provide valuable guidance for treatment decisions in patients with metastatic CRC. While high concordance exists between mutational status in primary and metastatic lesions, some heterogeneity may be present. Circulating tumor DNA (ctDNA) analysis has proven invaluable in identifying genetic heterogeneity and predicting prognosis in RAS-mutated metastatic CRC patients. Tumor heterogeneity can arise from genetic and non-genetic factors, affecting tumor development and response to therapy. To comprehend and address clonal evolution and intratumoral heterogeneity, comprehensive genomic studies employing techniques such as next-generation sequencing and computational analysis are essential. Liquid biopsy, notably through analysis of ctDNA, enables real-time clonal evolution and treatment response monitoring. However, challenges remain in standardizing procedures and accurately characterizing tumor subpopulations. Various models elucidate the origin of CRC heterogeneity, highlighting the intricate molecular pathways involved. This review focuses on intrapatient cancer heterogeneity and genetic clonal evolution in metastatic CRC, with an emphasis on clinical applications.

Where Are We Now and Where Might We Be Headed in Understanding and Managing Brain Metastases in Colorectal Cancer Patients?

OPINION STATEMENT

Compared to liver and lung metastases, brain metastases (BMs) from colorectal cancer (CRC) are rare and remain poorly investigated despite the anticipated rise in their incidence. CRC patients bearing BM have a dismal prognosis with a median survival of 3-6 months, significantly lower than that of patients with BM from other primary tumors, and of those with metastatic CRC manifesting extracranially. While liver and lung metastases from CRC have more codified treatment strategies, there is no consensus regarding the treatment of BM in CRC, and their management follows the approaches of BM from other solid tumors. Therapeutic strategies are driven by the number and localisation of the lesion, consisting in local treatments such as surgery, stereotactic radiosurgery, or whole-brain radiotherapy. Novel treatment modalities are slowly finding their way into this shy unconsented armatorium including immunotherapy, monoclonal antibodies, tyrosine kinase inhibitors, or a combination of those, among others.This article reviews the pioneering strategies aiming at understanding, diagnosing, and managing this disease, and discusses future directions, challenges, and potential innovations in each of these domains.

HIGHLIGHTS

• With the increasing survival in CRC, brain and other rare/late-onset metastases are rising. • Distal colon/rectal primary location, long-standing progressive lung metastases, and longer survival are risk factors for BM development in CRC. • Late diagnosis and lack of consensus treatment strategies make BM-CRC diagnosis very dismal. • Liquid biopsies using circulating tumor cells might offer excellent opportunities in the early diagnosis of BM-CRC and the search for therapeutic options. • Multi-modality treatment including surgical metastatic resection, postoperative SRS with/without WBRT, and chemotherapy is the best current treatment option. • Recent mid-sized clinical trials, case reports, and preclinical models show the potential of unconventional therapeutic approaches as monoclonal antibodies, targeted therapies, and immunotherapy. Graphical abstract.

The impact of neurological performance and volumetrics on overall survival in brain metastasis in colorectal cancer: a retrospective single-center case series

Background

Brain metastasis (BM) of colorectal cancer is a disease with a poor prognosis of only a few months survival. However, it is difficult to estimate the individual prognosis of each patient due to the lack of definitive prognosis parameters. The number of metastases and the Karnofsky performance score are known predictors for survival. We investigated whether or not the neurological performance score and the tumor volumetrics are equally suitable predictors for survival.

Design

All patients with histologically diagnosed BM linked to colorectal cancer between 2012 and March 2020 were reviewed. The Medical Research Council Neurological Performance Score was used to quantify neurological performance. Univariate analysis with Kaplan-Meier estimate and log-rank test was performed. Survival prediction and multivariate analysis were performed employing Cox proportional hazard regression.

Results

Twenty-five patients were included in our analysis with an overall survival of 4.9 months after surgery of the BM. Survival decreased in the univariate analysis with increasing postoperative neurological performance score, low Karnofsky performance score, absence of radiation therapy and radiation therapy modality. The neurological performance score is a reliable scoring parameter for estimating the prognostic course analogous to the Karnofsky performance score. Neither preoperative nor post resection residual tumor volume had any impact on overall survival in our small cohort.

Conclusion

Our data suggest that the postoperative neurological performance is a valuable prognostic factor for colorectal cancer patients with BM. Tumor volumetrics show no correlation to survival. Further investigations with a larger number of cases are mandatory.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09435-1.

Expression and prognostic value of epithelial-to-mesenchymal transition and cancer stem cellmarkersin primary lesions and liver metastases of colorectal cancers

Cancer stem cells (CSCs) and epithelial mesenchymal transition (EMT) markers are considered useful indicators associated with metastasis and prognosis of colorectal cancers (CRCs). However, only a few studies have focused on the expression of these useful markers in metastases. Metastasectomy is widely used in advanced CRCs, and thus the postoperative prognostic factors are worth investigating. The present study investigated the consistency and differences of target proteins between primary and metastatic lesions of colorectal cancer, and discussed the prognostic indicators following resection of colorectal liver metastases. Clinical data of 56 patients with liver metastases from colorectal cancer were collected and the expression levels of target proteins (Ki-67, CD133, CD44, Snail, E-cadherin and β-catenin) were detected in primary tumor and matched liver metastases via immunohistochemistry analysis. Paired comparison between both tissue types was performed. The prognostic values of the target proteins for resectable colorectal cancer liver metastases were assessed. No significant differences were observed between the primary tissues and metastatic tissues. The consistency rates of these protein expression levels ranged from 51.8-78.6%. The maximum diameter of the liver metastases was <5 cm. Low Snail expression in metastases was associated with a longer overall survival (OS) time following resection of colorectal liver metastases. Furthermore, N0 stage and low carcinoembryonic antigen levels were associated with a longer progression-free survival time. Notably, no significant differences were observed in expression levels of the target proteins between the primary tumors and liver metastases. Taken together, the results of the present study suggest that Snail expression in liver metastases may be used as a novel independent prognostic factor for OS following resection of colorectal liver metastases.

Pathological and Molecular Characteristics of Colorectal Cancer with Brain Metastases

Background: Colorectal cancers (CRC) with brain metastases (BM) are scarcely described. The main objective of this study was to determine the molecular profile of CRC with BM. Methods: We included 82 CRC patients with BM. KRAS, NRAS, BRAF and mismatch repair (MMR) status were investigated on primary tumors (n = 82) and BM (n = 38). ALK, ROS1, cMET, HER-2, PD-1, PD-L1, CD3 and CD8 status were evaluated by immunohistochemistry, and when recommended, by fluorescence in situ hybridization. Results: In primary tumors, KRAS, NRAS and BRAF mutations were observed in 56%, 6%, and 6% of cases, respectively. No ROS1, ALK and cMET rearrangement was detected. Only one tumor presented HER-2 amplification. Molecular profiles were mostly concordant between BM and paired primary tumors, except for 9% of discordances for RAS mutation. CD3, CD8, PD-1 and PD-L1 expressions presented some discordance between primary tumors and BM. In multivariate analysis, multiple BM, lung metastases and PD-L1+ tumor were predictive of poor overall survival. Conclusions: CRCs with BM are associated with high frequency of RAS mutations and significant discordance for RAS mutational status between BM and paired primary tumors. Multiple BM, lung metastases and PD-L1+ have been identified as prognostic factors and can guide therapeutic decisions for CRC patients with BM.

Heterogeneity in Colorectal Cancer: A Challenge for Personalized Medicine?

High inter-patient variability and high spatial heterogeneity are features of colorectal cancer (CRC). This may influence the molecular characterization of tumor tissue, now mandatory for patients with metastatic CRC who are candidates for treatment with an anti-EGFR mAb, as false-negative results can occur, leading to non optimal therapy. Moreover, temporal molecular heterogeneity during treatment is known to influence the response to therapy and prognosis. We present a literature overview of advances made in characterizing molecular heterogeneity in CRC, underlining that the analysis of liquid biopsy could represent an efficient non-invasive tool to overcome the problem. We believe that understanding CRC heterogeneity is fundamental for a more accurate diagnosis, for selecting the best targets to ensure prolonged antitumor response, and for monitoring minimal residual disease and the onset of resistance to therapy, all essential components of successful personalized treatment.

Brain metastases in colorectal cancer: prognostic factors and survival analysis

PURPOSE

Colorectal cancer (CRC) brain metastases (BM) are an uncommon and late event. We aim to investigate the impact of clinical factors, treatment modalities and RAS/BRAF status on the outcomes of CRC patients with BM.

PATIENTS

We retrospectively analysed CRC patients who developed BM in our centre between January 1997 and June 2017. Clinical factors, treatment modalities, RAS/BRAF status and survival were evaluated.

RESULTS

Twenty-eight patients were recorded; 82% had left-sided (LS) CRC and 71% had lung metastases. Median time to BM diagnosis was 36 months (m) and 93% of patients received local treatment of BM (43% whole brain radiotherapy, 50% surgery). Right-sided (RS) CRC showed shorter time to BM, not previously described (9.3 vs 46.6 m for RS and LS CRC, respectively; HR = 4.7, p = 0.006). Median overall survival (mOS) from BM treatment was 9.5 m, better in patients who underwent surgery than those treated with radiotherapy alone (12.1 vs 4.6 m, respectively; HR = 0.3, p = 0.019) and in those without progressive metastatic extracranial disease (7.2 vs 20.9 m, for progressive and non-progressive, respectively; HR = 0.3, p = 0.056). Patients with two or more metastatic extracranial locations showed worse prognosis (5.9 vs 16.3 m, for > 2 vs 0-1, respectively; HR = 3.7, p = 0.015). RAS/BRAF status did not showed prognostic value.

CONCLUSIONS

Time to BM diagnosis is shorter in RS CRC. The presence of two or more metastatic extracranial locations and progressive metastatic extracranial disease at the time of BM diagnosis could be bad prognosis factors for CRC BM patients.

Phosphatidylinositol-3-Kinase Mutations Are Associated With Increased Local Failure in Brain Metastases Treated With Radiation

PURPOSE

To determine whether phosphatidylinositol-3-kinase (PI3K) mutations confer suboptimal local control after radiation therapy (RT) for brain metastases.

METHODS AND MATERIALS

We retrospectively reviewed 259 patients with brain metastases treated with RT during the period 2004 to 2017 for whom tumor genetic data (MSK-IMPACT) were available for primary or metastatic lesions. Associations between clinical factors, PI3K mutations status, and local failure (LF) were evaluated with univariate and multivariate competing risks regression.

RESULTS

A total of 112 patients received whole brain radiation therapy (WBRT) to a median dose of 30 Gy in 10 fractions, and 147 patients received stereotactic radiosurgery (SRS) to 338 lesions; 276 lesions were treated with single fraction SRS (median dose 21 Gy) and 76 lesions over 3 to 5 fractions SRS (median dose 30 Gy). PI3K mutations were present in 36 WBRT patients (32%) and 44 SRS patients (30%). For WBRT, patients with PI3K mutations (hazard ratio 2.67, P < .001) were found to be at higher risk for LF on multivariable analysis, and the 1-year cumulative incidence of LF was 50% (95% confidence interval [CI] 32%-65%) for patients with PI3K mutations versus 26% (95% CI 17%-37%) for patients without PI3K mutations. For SRS lesions, while PI3K mutations positivity was not statistically significantly associated with LF, higher rate of LF was observed: 1-year LF cumulative incidence of 11% (95% CI 6%-17%) for patients with PI3K mutations versus 5% (95% CI 3%-9%) for patients without PI3K mutations.

CONCLUSION

Patients with PI3K mutations are at higher risk for LF for brain metastases after RT. Novel therapeutic strategies to improve treatment outcomes in these patients should be considered.

Colorectal cancer and brain metastases: An aggressive disease with a different response to treatment

INTRODUCTION

Brain metastases (BM) are rare in colorectal cancer (CRC) and are associated with a dismal prognosis. This work aims to report the rate of BM in CRC patients treated in a single institution, along with survival and prognostic factors.

METHODS

Medical charts for patients with histologically proven CRC were retrospectively reviewed.

RESULTS

A total of 538 patients were identified, of whom 33% developed any metastatic disease and 4.4% presented BM. Lung was the most frequently associated metastatic site (in 68% of the cases). The only factor independently associated with BM development was the presence of metastatic disease at the time of initial presentation. The median duration from initial diagnosis to BM development was 38.6 months (SD 29.1 months). Median survival after BM development was 62 days (95% confidence interval [CI] 56-68). Patients diagnosed with BM within 1 year of cancer diagnosis responded significantly better to treatment than those who acquired BM later, with a median survival after BM diagnosis of 261 days versus 61 days, respectively (p = .002). Patients with BM who received antiangiogenic therapy had an improved median survival compared to those who did not (151 days vs 59 days, p = 0.02; hazard ratio for death 0.29 [95% CI 0.09-0.94]).

CONCLUSION

CRC with BM is an aggressive disease resistant to standard treatment and is associated with poor outcomes. Adding antiangiogenic therapy might be of value for those patients. Patients with BM developing early in the disease course might respond better to treatment.