Prognostic value of KRAS mutation status in colorectal cancer patients: a population-based competing risk analysis

KRAS, NRAS, and BRAF Hot-Spot Mutations in Relation to Sidedness of Primary Colorectal Cancer: A Retrospective Cohort Study

Background/Objective: Studies have shown an association between colorectal cancer (CRC) sidedness and gene mutations that may affect CRC clinical behavior. This study examined the association between specific KRAS, NRAS, and BRAF hot-spot mutations and primary CRC sidedness. Methods: We performed a retrospective cohort analysis of 722 patients diagnosed with primary CRC and tested for KRAS, NRAS, and BRAF hot-spot mutations at the University of Texas Medical Branch (UTMB) from January 2016 through July 2023. Multivariable logistic regressions analyses were conducted. Results:KRAS, NRAS, and BRAF hot-spot mutations rates were 37.8%, 4.6%, and 6.1%, respectively. Right-sided primary CRC had the highest prevalence of mutated tumors (64%). KRAS and BRAF hot-spot mutations were significantly different according to tumor sidedness. KRAS p.Gly12Asp, p.Gly12Val, and p.Gly13Asp showed a significantly increased likelihood of right-sided primary CRC compared to KRAS wildtype, 128%, 134%, and 221% higher, respectively. Conversely, KRAS p.Gly12Val and p.Gly13Asp mutations were associated with decreased likelihood of rectal cancer (53% lower) and left-sided tumors (56% lower), respectively. BRAF p.Val600Glu mutation, as opposed to BRAF wildtype, was associated with a 278% higher likelihood of right-sided CRC. No significant associations were observed between NRAS mutations and primary CRC sidedness. Conclusions: In primary CRC, specific mutations in KRAS (p.Gly12Asp, p.Gly12Val, and p.Gly13Asp) and BRAF p.Val600Glu were associated with increased likelihood of right-sided tumors. KRAS p.Gly12Val and p.Gly13Asp mutations were associated with decreased likelihood of rectal cancer and left-sided tumors, respectively. These findings suggest that tumorigenesis and mutational processes differ based on tumor sidedness. Further studies are needed to substantiate these findings.

A novel platform for mutation detection in colorectal cancer using a PNA-LNA molecular switch

Detection of KRAS mutation in colorectal cancer (CRC) is important in the prediction of response to target therapy. The study aims to develop a novel mutation detection platform called the "PNA-LNA molecular switch" for the detection of KRAS mutation in CRC. We employed the enhanced binding specificity of peptide nucleic acid (PNA) and locked nucleic acid (LNA) in conjunction with a loop-mediated isothermal amplification (LAMP) approach to identify the mutation status of KRAS oncogene codon 12 (c.35G>T/G12V and c.35G>A/G12D) using synthetic oligonucleotides and colon cancer cell lines (Caco-2 and SW480). This method specifically blocked the amplification of the wild-type sequences while substantially amplifying the mutated ones, which was visualized by both colorimetric and fluorescence assays. We then checked the mutation profile of KRAS codon 12 in the DNA derived from tumor tissue samples (number of samples, n = 30) and circulating tumor cells (n = 24) from CRC patients. Finally, we validated the results by comparing them with the data obtained from DNA sequencing of colon tumors (n = 21) of the same CRC patients. This method showed excellent sensitivity (1 DNA copy/μl), reproducibility [relative standard deviation (%RSD) < 5%, for n = 3], and linear dynamic range (1 ag/μl-10 pg/μl, R2 = 0.94). This platform is significantly faster, relatively cheaper, has superior sensitivity and specificity, and does not require any high-end equipment. To conclude, this method has the potential to be translated into clinical settings for the detection of mutations in diverse diseases and conditions.

MRI T2WI-based radiomics combined with KRAS gene mutation constructed models for predicting liver metastasis in rectal cancer

BACKGROUND

The study aimed to identify the optimal model for predicting rectal cancer liver metastasis (RCLM). This involved constructing various prediction models to aid clinicians in early diagnosis and precise decision-making.

METHODS

A retrospective analysis was conducted on 193 patients diagnosed with rectal adenocarcinoma were randomly divided into training set (n = 136) and validation set (n = 57) at a ratio of 7:3. The predictive performance of three models was internally validated by 10-fold cross-validation in the training set. Delineation of the tumor region of interest (ROI) was performed, followed by the extraction of radiomics features from the ROI. The least absolute shrinkage and selection operator (LASSO) regression algorithm and multivariate Cox analysis were employed to reduce the dimensionality of radiomics features and identify significant features. Logistic regression was employed to construct three prediction models: clinical, radiomics, and combined models (radiomics + clinical). The predictive performance of each model was assessed and compared.

RESULTS

KRAS mutation emerged as an independent predictor of liver metastasis, yielding an odds ratio (OR) of 8.296 (95%CI: 3.471-19.830; p < 0.001). 5 radiomics features will be used to construct radiomics model. The combined model was built by integrating radiomics model with clinical model. In both the training set (AUC:0.842, 95%CI: 0.778-0.907) and the validation set (AUC: 0.805; 95%CI: 0.692-0.918), the AUCs for the combined model surpassed those of the radiomics and clinical models.

CONCLUSIONS

Our study reveals that KRAS mutation stands as an independent predictor of RCLM. The radiomics features based on MR play a crucial role in the evaluation of RCLM. The combined model exhibits superior performance in the prediction of liver metastasis.

CLINICAL TRIAL NUMBER

Not applicable.

Serum Uric Acid Level May Be a Predictive Factor for BRAF V600E Mutation in Older Patients with Metastatic Colorectal Cancer: An Exploratory Analysis

INTRODUCTION

This study aimed to show the relationship between the serum uric acid level measured at diagnosis and the BRAF mutation status in the primary tumor tissue in patients with metastatic colorectal cancer.

METHODS

In this retrospective cross-sectional study, 264 patients (64% male) whose serum uric acid level was measured at the time of diagnosis and whose BRAF mutation status in the primary tumor was determined were included.

RESULTS

The BRAF mutation rate was 14% (n = 37). The median serum uric acid levels of all patients were 6.9 mg/dL (25%, 75% percentile range 3.7, 8.2). The serum uric acid level cut-off value was 6.6 mg/dL. Sensitivity and specificity for BRAF mutated patients were 84% and 27%, respectively. These rates were calculated as 85% and 70% in BRAF-mutated patients aged 65 and over. There was a significant correlation between BRAF mutation and high serum uric acid level, female gender, tumor located in the ascending colon, and multiple metastatic sites. The independent factors affecting BRAF mutation were age 65 and over, tumor in the ascending colon, and high serum uric acid level.

CONCLUSION

As a result, we concluded that high serum uric acid level measured during diagnosis in metastatic colorectal cancer is an accessible and economical biomarker that can predict BRAF mutation in patients aged 65 and over.

The effects of KRAS Mutations on the Prognosis of Rectal Cancer Following Neoadjuvant Chemoradiotherapy and Surgery

BACKGROUND

Rectal cancers with mutations in the KRAS gene have worse prognoses than wild-type malignancies. Variants at codon 12 of KRAS have particularly detrimental effects on prognosis. We aimed to analyze whether KRAS mutations act as adverse prognostic factors following neoadjuvant concurrent chemoradiotherapy (CRT) and surgery for rectal cancer treatment.

METHODS

We analyzed the effects of KRAS mutations on disease-free survival (DFS) and locoregional recurrence-free survival (LRFS) in 125 patients with cT2-4N0-2M0 rectal cancer who underwent surgery following CRT between June 2014 and March 2023 Inje University Busan Paik Hospital.

RESULTS

The median follow-up period was 39.7 (range, 7.5-98.2) months. There were 25 patients (20.0%) who harbored KRAS mutations. Among them, 22 patients (17.6%) had codon 12 variants. Overall, 43 patients (34.4%) showed recurrence, of which 10 (8.0%) had locoregional recurrence and 35 (28.0%) had distant metastases (two occurred simultaneously). DFS was significantly reduced in the patients with KRAS mutations (p = 0.005). LRFS was also reduced in patients with KRAS mutations (p = 0.039). DFS and LRFS were also relatively low in the subgroup with KRAS mutations at codon 12 (n = 22) (p = 0.003 and p = 0.017, respectively). However, pathologic complete response rate following CRT was not affected by KRAS mutations (p = 0.197). Overall survival was also not associated with KRAS mutations (p = 0.486).

CONCLUSION

KRAS mutation is related to decreased DFS and LRFS, when surgery is performed following neoadjuvant CRT to treat rectal cancer. These effects are particularly pronounced for KRAS mutations at codon 12.

KRAS status predicted by pretreatment MRI radiomics was associated with lung metastasis in locally advanced rectal cancer patients

BACKGROUND

Mutated KRAS may indicate an invasive nature and predict prognosis in locally advanced rectal cancer (LARC). We aimed to establish a radiomic model using pretreatment T2W MRIs to predict KRAS status and explore the association between the KRAS status or model predictions and lung metastasis.

METHODS

In this retrospective multicentre study, LARC patients from two institutions between January 2012 and January 2019 were randomly divided into training and testing cohorts. Least absolute shrinkage and selection operator (LASSO) regression and the support vector machine (SVM) classifier were utilized to select significant radiomic features and establish a prediction model, which was validated by radiomic score distribution and decision curve analysis. The association between the model stratification and lung metastasis was investigated by Cox regression and Kaplan‒Meier survival analysis; the results were compared by the log-rank test.

RESULTS

Overall, 103 patients were enrolled (73 and 30 in the training and testing cohorts, respectively). The median follow-up was 38.1 months (interquartile range: 26.9, 49.4). The radiomic model had an area under the curve (AUC) of 0.983 in the training cohort and 0.814 in the testing cohort. Using a cut-off of 0.679 defined by the receiver operating characteristic (ROC) curve, patients with a high radiomic score (RS) had a higher risk for lung metastasis (HR 3.565, 95% CI 1.337, 9.505, p = 0.011), showing similar predictive performances for the mutant and wild-type KRAS groups (HR 3.225, 95% CI 1.249, 8.323, p = 0.016, IDI: 1.08%, p = 0.687; NRI 2.23%, p = 0.766).

CONCLUSIONS

We established and validated a radiomic model for predicting KRAS status in LARC. Patients with high RS experienced more lung metastases. The model could noninvasively detect KRAS status and may help individualize clinical decision-making.

Current advances in detecting genetic and epigenetic biomarkers of colorectal cancer

Colorectal carcinoma (CRC) is the third most common cancer in terms of diagnosis and the second in terms of mortality. Recent studies have shown that various proteins, extracellular vesicles (i.e., exosomes), specific genetic variants, gene transcripts, cell-free DNA (cfDNA), circulating tumor DNA (ctDNA), microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and altered epigenetic patterns, can be used to detect, and assess the prognosis of CRC. Over the last decade, a plethora of conventional methodologies (e.g., polymerase chain reaction [PCR], direct sequencing, enzyme-linked immunosorbent assay [ELISA], microarray, in situ hybridization) as well as advanced analytical methodologies (e.g., microfluidics, electrochemical biosensors, surface-enhanced Raman spectroscopy [SERS]) have been developed for analyzing genetic and epigenetic biomarkers using both optical and non-optical tools. Despite these methodologies, no gold standard detection method has yet been implemented that can analyze CRC with high specificity and sensitivity in an inexpensive, simple, and time-efficient manner. Moreover, until now, no study has critically reviewed the advantages and limitations of these methodologies. Here, an overview of the most used genetic and epigenetic biomarkers for CRC and their detection methods are discussed. Furthermore, a summary of the major biological, technical, and clinical challenges and advantages/limitations of existing techniques is also presented.

Is the combination of immunotherapy with conventional chemotherapy the key to increase the efficacy of colorectal cancer treatment?

Colorectal cancer (CRC) is among the most prevalent and deadly neoplasms worldwide. According to GLOBOCAN predictions, its incidence will increase from 1.15 million CRC cases in 2020 to 1.92 million cases in 2040. Therefore, a better understanding of the mechanisms involved in CRC development is necessary to improve strategies focused on reducing the incidence, prevalence, and mortality of this oncological pathology. Surgery, chemotherapy, and radiotherapy are the main strategies for treating CRC. The conventional chemotherapeutic agent utilized throughout the last four decades is 5-fluorouracil, notwithstanding its low efficiency as a single therapy. In contrast, combining 5-fluorouracil therapy with leucovorin and oxaliplatin or irinotecan increases its efficiency. However, these treatments have limited and temporary solutions and aggressive side effects. Additionally, most patients treated with these regimens develop drug resistance, which leads to disease progression. The immune response is considered a hallmark of cancer; thus, the use of new strategies and methodologies involving immune molecules, cells, and transcription factors has been suggested for CRC patients diagnosed in stages III and IV. Despite the critical advances in immunotherapy, the development and impact of immune checkpoint inhibitors on CRC is still under investigation because less than 25% of CRC patients display an increased 5-year survival. The causes of CRC are diverse and include modifiable environmental factors (smoking, diet, obesity, and alcoholism), individual genetic mutations, and inflammation-associated bowel diseases. Due to these diverse causes, the solutions likely cannot be generalized. Interestingly, new strategies, such as single-cell multiomics, proteomics, genomics, flow cytometry, and massive sequencing for tumor microenvironment analysis, are beginning to clarify the way forward. Thus, the individual mechanisms involved in developing the CRC microenvironment, their causes, and their consequences need to be understood from a genetic and immunological perspective. This review highlighted the importance of altering the immune response in CRC. It focused on drugs that may modulate the immune response and show specific efficacy and contrasted with evidence that immunosuppression or the promotion of the immune response is the answer to generating effective treatments with combined chemotherapeutic drugs.

Mutant KRAS Drives Immune Evasion by Sensitizing Cytotoxic T-Cells to Activation-Induced Cell Death in Colorectal Cancer

The roles of oncogenic KRAS in tumor immune evasion remain poorly understood. Here, mutant KRAS is identified as a key driver of tumor immune evasion in colorectal cancer (CRC). In human CRC specimens, a significant reduction in cytotoxic CD8+ T-cell tumor infiltration is found in patients with mutant versus wild type KRAS. This phenomenon is confirmed by preclinical models of CRC, and further study showed KRAS mutant tumors exhibited poor response to anti-PD-1 and adoptive T-cell therapies. Mechanistic analysis revealed lactic acid derived from mutant KRAS-expressing tumor cells sensitized tumor-specific cytotoxic CD8+ T-cells to activation-induced cell death via NF-κB inactivation; this may underlie the inverse association between intratumoral cytotoxic CD8+ T-cells and KRAS mutation. Importantly, KRAS mutated tumor resistance to immunotherapies can be overcome by inhibiting KRAS or blocking lactic acid production. Together, this work suggests the KRAS-mediated immune program is an exploitable therapeutic approach for the treatment of patients with KRAS mutant CRC.

The impact of RAS mutation on the treatment strategy of colorectal cancer

Kirsten rat sarcoma (KRAS) is the most frequently mutated oncogene in colorectal cancer, being present in 30% of patients with localized disease and in almost half of the patients that develop metastatic disease. While the development of chemotherapy doublets and targeted therapy have improved survival in recent years, KRAS mutation still has a controversial role regarding its prognostic and predictive value both in the adjuvant and in the metastatic setting. The impact of KRAS mutation on treatment strategy remains to be better defined. The development of new KRAS inhibitors promising new treatment options is on the horizon.

Impact of KRAS Mutation on Survival Outcome of Patients With Metastatic Colorectal Cancer in Jordan

Background Colorectal cancer (CRC) is the most prevalent cancer in males, with an incidence rate (IR) of 13.1%, and the second most prevalent cancer in females, with an IR of 8.4%, coming after breast cancer in Jordan. The present study was motivated by conflicting clinical data regarding the prognostic impact of Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation in patients with metastatic colorectal cancer (mCRC). Our study aimed to investigate if KRAS mutation conferred a negative prognostic value in Jordanian patients with mCRC. Materials and methods The current study is a retrospective study that collected data from a cohort of 135 mCRC patients diagnosed between 1 January 2017 and 1 January 2022 at our Oncology Department at the Jordanian Military Cancer Center (MCAC) using our patients' electronic medical records. The last follow-up date was 1 September 2022. From the cohort, we obtained data regarding age, sex, date of diagnosis, metastatic spread, KRAS status, either mutated KRAS or wild-type KRAS, and location of the primary tumor. All patients underwent tumor tissue biopsies to determine KRAS mutational status based on quantitative polymerase chain reaction and reverse hybridization from an accredited diagnostic laboratory at Jordan University Hospital. Statistical analysis was carried out to address the associations between KRAS mutation and the patients-tumor characteristics and their prognosis on survival. Results KRAS mutation was found in 40.3% of the participants in the study, and 56.7% had the wild type. There was a predilection of KRAS mutation, with 67% on the right side versus 33% on the left side (p = 0.018). Kaplan-Meier survival analysis showed worse survival outcomes in KRAS mutant patients (p = 0.002). The median overall survival in the KRAS mutant patients was 17 months (95% confidence interval (CI): 13.762-19.273) compared to 21 months (95% CI: 20.507-27.648) in patients with wild-type KRAS. Additionally, the Cox regression model identified that KRAS mutation carries a poorer prognosis on survival outcome hazard ratio (HR: 2.045, 95% CI: 1.291-3.237, p = 0.002). The test also showed statistical significance in the metastatic site (lung only). But this time, it was associated with a better survival outcome (HR: 0.383, 95% CI: 0.186-0.788, p = 0.009). Conclusion The present study shows that the presence of KRAS mutation has been found to negatively impact the prognosis and survival outcome of Jordanian patients with mCRC.

Comparative Analysis of First-Line FOLFOX Treatment With and Without Anti-VEGF Therapy in Metastatic Colorectal Carcinoma: A Real-World Data Study

BACKGROUND

FOLFOX (leucovorin calcium [folinic acid], fluorouracil, and oxaliplatin) combined with or without anti-VEGF therapy represents one of the primary first-line treatment options for metastatic colorectal carcinoma (mCRC). However, there is limited comparative data on the impact of anti-VEGF therapy on treatment effectiveness, survival outcomes, and tumor location.

METHODS

This retrospective, comparative study utilized data from the AIM Cancer Care Quality Program and commercially insured patients treated at medical oncology clinics in the US. We analyzed 1652 mCRC patients who received FOLFOX, of which 1015 (61.4%) were also treated with anti-VEGF therapy (VEGF cohort).

RESULTS

Patients in the VEGF cohort exhibited a higher frequency of lung (33% vs 23%; P < .001) and liver metastases (74% vs 62%; P < .001), underwent fewer liver surgeries prior to treatment (1.2% vs 3.6%; P = .002), and had a higher proportion of right-sided tumors (27% vs 18%; P = .001). Adjusted analysis revealed no significant difference in overall survival (OS) between patients treated with and without anti-VEGF (median survival: 25.4 vs 26.0 months; P = .4). FOLFOX-only treated patients experienced higher rates of post-treatment hospitalizations (22% vs 15%; P < .001). Notably, left-sided tumors treated with anti-VEGF showed a trend toward decreased OS (median survival: 26.8 vs 33 months; P = .09).

CONCLUSION

Our real-world data analysis suggests that the addition of anti-VEGF to FOLFOX offers limited and short-lived benefits in the context of mCRC and may provide differential survival benefit based on tumor sidedness.

Prognostic Value of KRAS Mutations in Colorectal Cancer Patients

Colorectal cancer (CRC) remains a major public health issue. The detection of parameters that affect CRC prognosis is of great significance. KRAS mutations, play a crucial role in tumorigenesis with a strong predictive value. KRAS-mutated stage-IV CRC patients gain no benefit of the anti-EGFR therapy. The KRAS G12C mutation subtype is under investigation for treatment regimens. The present study aimed to detect various RAS mutations in a cohort of 578 RAS-mutated CRC patients; 49% of them had de novo metastatic disease; 60% were male; 71.4% had left-sided tumors; and 94.6% had a good performance status. KRAS mutations were detected in 93.2% of patients, with KRAS G12D being the most common subtype (30.1%). KRAS mutations presented shorter progression-free (PFS) and overall survival (OS), compared with NRAS mutations, although not significantly (PFS: 13.8 vs. 18.5 months; p = 0.552; OS: 53.1 vs. 60.9 months; p = 0.249). KRAS G12D mutations presented better OS rates (p = 0.04). KRAS G12C mutation, even though not significantly, presented worse PFS and OS rates. KRAS exon 3 and 4 mutations presented different PFS and OS rates, although these were not significant. Concluding, KRAS G12D and G12C mutations lead to better and worst prognosis, respectively. Further studies are warranted to validate such findings and their possible therapeutic implication.

9-ING-41, a Small Molecule Inhibitor of GSK-3β, Potentiates the Effects of Chemotherapy on Colorectal Cancer Cells

Colorectal cancer (CRC) is one of the most common and lethal types of cancer. Although researchers have made significant efforts to study the mechanisms underlying CRC drug resistance, our knowledge of this disease is still limited, and novel therapies are in high demand. It is urgent to find new targeted therapy considering limited chemotherapy options. KRAS mutations are the most frequent molecular alterations in CRC. However, there are no approved K-Ras targeted therapies for these tumors yet. GSK-3β is demonstrated to be a critically important kinase for the survival and proliferation of K-Ras–dependent pancreatic cancer cells. In this study, we tested combinations of standard-of-care therapy and 9-ING-41, a small molecule inhibitor of GSK-3β, in CRC cell lines and patient-derived tumor organoid models of CRC. We demonstrate that 9-ING-41 inhibits the growth of CRC cells via a distinct from chemotherapy mechanism of action. Although molecular biomarkers of 9-ING-41 efficacy are yet to be identified, the addition of 9-ING-41 to the standard-of-care drugs 5-FU and oxaliplatin could significantly enhance growth inhibition in certain CRC cells. The results of the transcriptomic analysis support our findings of cell cycle arrest and DNA repair deficiency in 9-ING-41–treated CRC cells. Notably, we find substantial similarity in the changes of the transcriptomic profile after inhibition of GSK-3β and suppression of STK33, another critically important kinase for K-Ras–dependent cells, which could be an interesting point for future research. Overall, the results of this study provide a rationale for the further investigation of GSK-3 inhibitors in combination with standard-of-care treatment of CRC.

Role of MRI‑based radiomics in locally advanced rectal cancer (Review)

Colorectal cancer is the third most common type of cancer, with high morbidity and mortality rates. In particular, locally advanced rectal cancer (LARC) is difficult to treat and has a high recurrence rate. Neoadjuvant chemoradiotherapy (NCRT) is one of the standard treatment programs of LARC. If the response to treatment and prognosis in patients with LARC can be predicted, it will guide clinical decision‑making. Radiomics is characterized by the extraction of high‑dimensional quantitative features from medical imaging data, followed by data analysis and model construction, which can be used for tumor diagnosis, staging, prediction of treatment response and prognosis. In recent years, a number of studies have assessed the role of radiomics in NCRT for LARC. MRI‑based radiomics provides valuable data and is expected to become an imaging biomarker for predicting treatment response and prognosis. The potential of radiomics to guide personalized medicine is widely recognized; however, current limitations and challenges prevent its application to clinical decision‑making. The present review summarizes the applications, limitations and prospects of MRI‑based radiomics in LARC.

Mutations in the KRAS gene as a predictive biomarker of therapeutic response in patients with colorectal cancer

Introduction: Despite the important role of general KRAS mutational status in the selection of an adequate therapeutic protocol in patients with colorectal cancer (CRC), studies that focus on its specific mutations and their significance on progression of disease are scarce. This study aimed to determine the significance of specific KRAS mutations in response to standard chemotherapy protocols with oxaliplatin-based (FOLFOX 4, OXFL) in the first-line and irinotecan-based chemotherapy (FOLFIRI, IFL) in the second-line therapy, and to evaluate the correlation between these mutations and clinicopathological characteristics of CRC patients.

Methods: Genomic DNA was extracted from the FFPE tumour tissue sections while the KRAS mutation test was performed by using PCR methods.

Results: Prevalence of KRAS gene mutations in CRC patients was 45%. Mutated KRAS was more frequent in later stages of tumor infiltrations (P =0.0017), on the right side of the colon (P= 0.0044), and in patients who developed metastases in the first 6 months after CRC diagnosis than in patients who developed metastases after 24 months (P=0.0083). In a group of patients with a poor therapeutic response to standard chemotherapy the most frequent mutations in KRAS gene were G12D and G12V (63.88%), while in a group of patients with a good response to therapeutic protocols the most prevalent mutation was G12A (66.66%).

Conclusion: Our results indicate that there was a significant difference in biological behaviour between tumours harboring different mutations in KRAS gene. Overall, mutation G12A could be a novel prognostic biomarker for CRC patients treated with standard chemotherapy.

MRI Radiomics Signature as a Potential Biomarker for Predicting KRAS Status in Locally Advanced Rectal Cancer Patients

Background and Purpose

Locally advanced rectal cancer (LARC) is a heterogeneous disease with little information about KRAS status and image features. The purpose of this study was to analyze the association between T2 magnetic resonance imaging (MRI) radiomics features and KRAS status in LARC patients.

Material and Methods

Eighty-three patients with KRAS status information and T2 MRI images between 2012.05 and 2019.09 were included. Least absolute shrinkage and selection operator (LASSO) regression was performed to assess the associations between features and gene status. The patients were divided 7:3 into training and validation sets. The C-index and the average area under the receiver operator characteristic curve (AUC) were used for performance evaluation.

Results

The clinical characteristics of 83 patients in the KRAS mutant and wild-type cohorts were balanced. Forty-two (50.6%) patients had KRAS mutations, and 41 (49.4%) patients had wild-type KRAS. A total of 253 radiomics features were extracted from the T2-MRI images of LARC patients. One radiomic feature named X.LL_scaled_std, a standard deviation value of scaled wavelet-transformed low-pass channel filter, was selected from 253 features (P=0.019). The radiomics-based C-index values were 0.801 (95% CI: 0.772-0.830) and 0.703 (95% CI: 0.620-0.786) in the training and validation sets, respectively.

Conclusion

Radiomics features could differentiate KRAS status in LARC patients based on T2-MRI images. Further validation in a larger dataset is necessary in the future.