The Impact of Primary Tumor Sidedness on the Effect of Regorafenib in Refractory Metastatic Colorectal Cancer

Radiological complete response with regorafenib for multiple lung metastases of ascending colon cancer: a case report

BACKGROUND

Regorafenib is an oral diphenylurea multikinase inhibitor and currently approved for use following third-line therapy for metastatic colorectal cancer (CRC) patients. Only one case has previously been reported of metastatic CRC showing a complete response (CR) to regorafenib.

CASE PRESENTATION

A 68-year-old Japanese man underwent laparoscopy-assisted ileocecal resection and D3 lymphadenectomy due to his ascending colon cancer. Eighteen months after surgery, a laparoscopic hepatic left lateral segmentectomy was performed due to a liver tumor, and a pathological diagnosis of colorectal liver metastasis was made. Three months after the second surgery, contrast-enhanced computed tomography (CT) revealed multiple lung metastases. The patient had undergone 18 courses of the FOLFOX + bevacizumab chemotherapy regimen as their first-line therapy and 11 courses of the FOLFIRI + ramucirumab chemotherapy regimen as their second-line therapy. As their third-line therapy, the patient was administered the regorafenib chemotherapy regimen. We evaluated the chemotherapy treatment's effect on the lung tumors by CT after 3, 7, 11, and 17 courses of the regorafenib chemotherapy regimen, finding that the lung tumors had shrunk with time; thus, each tumor was considered a partial response (PR) based on the RECIST guidelines. After 21 courses of the regorafenib chemotherapy regimen, the chemotherapy was discontinued in response to the patient's wishes. Even at 1 and 3 months after the discontinuation of the chemotherapy, CT revealed that the lung tumors had shrunk, with each considered a PR. Furthermore, 9 months after the discontinuation of the chemotherapy, CT revealed scarring of the lung tumors. This was considered a CR, rather than a PR. The patient remains disease-free 18 months after the discontinuation of chemotherapy.

CONCLUSIONS

In this paper, we present the second case of radiological CR with regorafenib for multiple lung metastases of ascending colon cancer. Currently, there is no consensus on a treatment strategy for patients with radiological CR.

Poorer Survival in Patients with Cecum Cancer Compared with Sigmoid Colon Cancer

Background and Objectives: An increasing number of studies have shown the influence of primary tumor location of colon cancer on prognosis, but the prognostic difference between colon cancers at different locations remains controversial. After comparing the prognostic differences between left-sided and right-sided colon cancer, the study subdivided left-sided and right-sided colon cancer into three parts, respectively, and explored which parts had the most significant prognostic differences, with the aim to further analyze the prognostic significance of primary locations of colon cancer. Materials and Methods: Clinicopathological data of patients with colon cancer who underwent radical surgery from the Surveillance, Epidemiology, and End Results Program database were analyzed. The data was divided into two groups (2004−2009 and 2010−2015) based on time intervals. Two tumor locations with the most significant survival difference were explored by using Cox regression analyses. The prognostic difference of the two locations was further verified in survival analyses after propensity score matching. Results: Patients with right-sided colon cancer had worse cancer-specific and overall survival compared to left-sided colon cancer. Survival difference between cecum cancer and sigmoid colon cancer was found to be the most significant among six tumor locations in both 2004−2009 and 2010−2015 time periods. After propensity score matching, multivariate analyses showed that cecum cancer was an independent unfavorable factor for cancer specific survival (HR [95% CI]: 1.11 [1.04−1.17], p = 0.001 for 2004−2009; HR [95% CI]: 1.23 [1.13−1.33], p < 0.001 for 2010−2015) and overall survival (HR [95% CI]: 1.09 [1.04−1.14], p < 0.001 for 2004−2009; HR [95% CI]: 1.09 [1.04−1.14], p < 0.001 for 2010−2015) compared to sigmoid colon cancer. Conclusions: The study indicates the prognosis of cecum cancer is worse than that of sigmoid colon. The current dichotomy model (right-sided vs. left-sided colon) may be inappropriate for the study of colon cancer.

Evaluation of Factors Predicting the Effectiveness of Regorafenib in the Treatment of Metastatic Colorectal Cancer

OBJECTIVE

Regorafenib is a multikinase inhibitor, the effectiveness of which was demonstrated in metastatic colorectal cancer. This study aimed to investigate the factors that could predict the effectiveness of regorafenib.

MATERIALS AND METHODS

This study retrospectively reviewed the clinical characteristics, tumor characteristics, and previous therapies in 62 patients who presented to our center between 2016 and 2020 and used regorafenib for metastatic colorectal cancer. The effects of the investigated variables on the response obtained with regorafenib use were evaluated.

RESULTS

This study included a total of 62 patients diagnosed with metastatic colorectal cancer, of whom 30 (48.4%) were males and 32 (51.6%) were females. Patients' median age at diagnosis was 49 years (18- 68). Regorafenib therapy yielded a disease control rate of 64% [complete response=0, partial response= 14 (28%), and stable disease=18 (36%)]. Objective response was obtained in 28% of patients [complete response=0 and partial response=14 (28%)]. Progression-free survival was 4 months. The evaluation of the effects of patients' age, sex, performance status, previous treatments, metastatic sites, and RAS mutation status on the disease control rate and progression-free survival did not determine any positive or negative effects on progression-free survival. However, left-sided tumors had a positive effect on disease control rate (69.8% vs. 28.6%, P=.029). and previous use of cetuximab had a negative effect on disease control rate [76.5% vs. 37.5% (P=.007)].

CONCLUSION

In our study, tumor localization and previous cetuximab use were found to be correlated with the disease control rate in patients on regorafenib. However, the need for novel biomarkers that will predict the effectiveness of regorafenib in metastatic colorectal cancer treatment persists.

Complete response of MSI-high metastatic colon cancer following treatment with regorafenib: A case report

Regorafenib has been demonstrated to prolong survival in patients with metastatic colorectal cancer refractory to standard chemotherapy. However, overall survival is limited to 2.5 months. The present report describes a unique case of metastatic colon cancer, which showed a complete response to regorafenib. A 54-year-old woman was diagnosed with right colon cancer obstruction with peritoneal seeding. The patient underwent laparoscopic right hemicolectomy, and the pathology was T4aN2bM1, moderately differentiated adenocarcinoma with high microsatellite instability (MSI-H) and wild-type KRAS/NRAS. The first-line chemotherapy was fluorouracil, leucovorin and irinotecan with cetuximab. After 12 cycles, recurrence at the anastomotic site was identified. The patient underwent palliative colectomy, and superior mesenteric artery (SMA) lymph node metastases were evident. The patient received second-line chemotherapy of fluorouracil, leucovorin and oxaliplatin with bevacizumab. Progression of metastasis to the right common iliac lymph nodes was detected after only four cycles of therapy. Thereafter, the patient received regorafenib as third-line therapy, starting with 160 mg for two cycles and reducing the dose thereafter, for a total of 17 cycles. The previously confirmed SMA lymph node metastasis had disappeared after the seventh cycle, and the right common iliac lymph node metastasis was not visible on CT after the 16th cycle. The patient decided to terminate regorafenib and has not experienced recurrence 2 years since treatment cessation. This is the first report of refractory metastatic colon cancer with MSI-H showing a complete response to regorafenib. Further studies are required to investigate the efficacy of regorafenib in refractory metastatic colon cancer with MSI-H and to elucidate the mechanism of remission.

Primary Tumor Location as a Prognostic and Predictive Marker in Metastatic Colorectal Cancer (mCRC)

Clinico-pathological differences between adenocarcinoma in the right and left colo-rectum play a role in determining the prognosis and response to treatment. Studies suggest that primary tumor location is more relevant as the disease progresses and reflects a possible difference in biology and response to therapy. This review aims to explore the clinico-pathological features of right and left colo-rectum and the impact of primary tumor location on prognosis of CRC as well as discuss the available clinical data on tumor sidedness in metastatic colorectal cancer. In so far as the clinical data of tumor sidedness is concerned, very few reviews have discussed the clinical implications of sidedness in heavily pre-treated metastatic colorectal cancer (second and subsequent lines of therapy in metastatic disease). This review aims to fill the current gap in this setting.

BET inhibitor bromosporine enhances 5-FU effect in colorectal cancer cells

Treatment of colorectal cancer (CRC) remains a challenge because of the lack of effective early treatment strategies and high incidence of relapse. 5-Fluorouracil (5-FU) is a typical CRC treatment. Bromosporine is an innovative bromodomain and extraterminal domain (BET) inhibitor. We investigated if CRC could be targeted by the combination of 5-FU and bromosporine in a synergistic manner in vivo and in vitro. Our findings shown that the combination treatment inhibits cell viability, formation of colonies, increased apoptosis and cell cycle arrest at G0-G1. In addition, the expression level of BRD4 was high in HCT116 cells exposed to 5-FU that showed lower apoptosis against the parental cells. Moreover, the 5-FU-resistance was reversed significantly by BRD4 knockdown or inhibition. The drug combination showed increased activity against tumor than individual drug exposure in the xenograft model. In conclusion, this work serves as a basic clinical evaluation of 5-FU and bromosporine as an effective therapeutic approach for CRC.

Microarray Approach Combined with ddPCR: An Useful Pipeline for the Detection and Quantification of Circulating Tumour dna Mutations

It has now been established that in biological fluids such as blood, it is possible to detect cancer causing genomic alterations by analysing circulating tumour DNA (ctDNA). Information derived from ctDNA offers a unique opportunity to enrich our understanding of cancer biology, tumour evolution and therapeutic efficacy and resistance. Here, we propose a workflow to identify targeted mutations by a customized microarray-based assay for the simultaneous detection of single point mutations in different oncogenes (KRAS, NRAS and BRAF) followed by droplet digital PCR (ddPCR) to determine the fractional abundance of the mutated allele. Genetic variants were determined in the plasma of 20 metastatic colorectal cancer (mCRC) patients previously genotyped on tissue biopsy at the diagnosis for medication planning (T0) and following the tumour genetic evolution during treatment phase (T1 and T2) with the objective of allowing therapy response prediction and monitoring. Our preliminary results show that this combined approach is suitable for routine clinical practice. The microarray platform enables for a rapid, specific and sensitive detection of the most common mutations suitable for high-throughput analysis without costly instrumentation while, the ddPCR, consents an absolute quantification of the mutated allele in a longitudinal observational study on patients undergoing targeted therapy.