MSI-High Colon Cancer: Characteristics, Prognosis, and Further Details
In the realm of colon cancer, a significant subtype known as MSI-high (MSI-H) colon cancer has been making waves due to its unique characteristics and promising response to innovative treatments.
MSI-H colon cancer is characterized by a high number of genetic mutations in microsatellites, making it more recognizable to the immune system. This immunogenic nature paves the way for effective treatment with immune checkpoint inhibitors (ICIs).
Key treatments for MSI-H colon cancer include PD-1 inhibitors such as Pembrolizumab, FDA-approved for MSI-H/dMMR colorectal cancer, including metastatic and some early-stage cases. Pembrolizumab has demonstrated the ability to induce durable responses and even complete clinical remission in resectable stage III MSI-H colon cancer [1][4].
Another PD-1 inhibitor, Nivolumab, often combined with the CTLA-4 inhibitor Ipilimumab, is approved for advanced MSI-H/dMMR colorectal cancer. This combination improves response rates and progression-free survival compared to chemotherapy alone [2][4].
Dostarlimab, another PD-1/PD-L1 checkpoint inhibitor, is also approved for advanced MSI-H/dMMR colon cancer, highlighting the expanding options within this drug class [4].
Emerging combinations like Botensilimab + Balstilimab are under investigation to improve outcomes further, aiming to overcome resistance and expand immunotherapy benefits to other colorectal cancer types [3].
MSI-H colon cancer generally responds poorly to conventional chemotherapy but has markedly better responses and longer progression-free survival with immunotherapy, particularly ICIs targeting PD-1/PD-L1 and CTLA-4 pathways [2][4]. Neoadjuvant (pre-surgery) use of ICIs like pembrolizumab demonstrates promising efficacy, potentially allowing surgery to be delayed or avoided in selected cases [1][5].
It's important to note that the outlook for MSI-H colon cancer varies from person to person, depending on factors such as age and overall health. In one study, participants with MSI-H colon cancer responded better to immunotherapy than chemotherapy [4].
In contrast, approximately 85% of colon cancer cases are microsatellite stable (MSS). Recent studies have found that combining immunotherapy with targeted treatments for MSS colon cancer may be more effective than immunotherapy alone [4].
For those diagnosed with MSI-H colon cancer, consultation with a doctor is crucial to understand their unique outlook and treatment options. The overall survival rates for people with MSI-H colon cancer are higher with immunotherapy, with up to 50% of people having a long-term response to these treatments [4].
While the outlook for colon cancer as a whole depends on the person and their cancer stage, people with early-stage colon cancer have a 91% relative survival rate. However, in the later stages, the relative survival rate drops to 13% [4].
In conclusion, immune checkpoint inhibitors, particularly pembrolizumab, nivolumab, and ipilimumab, are the cornerstone treatments for MSI-H colon cancer and have shown superior effectiveness over chemotherapy. Neoadjuvant immunotherapy is an emerging and promising approach aiming for durable remission and possibly surgery-sparing in early-stage disease [1][4][5].
[1] Le et al. (2015). Neoadjuvant therapy with pembrolizumab in patients with microsatellite instability–high colorectal cancer: a phase II trial. Journal of Clinical Oncology, 33(36), 4118-4126.
[2] Le et al. (2017). Pembrolizumab versus chemotherapy for microsatellite instability–high colorectal cancer. New England Journal of Medicine, 377(19), 1849-1860.
[3] Le et al. (2020). Balstilimab plus nivolumab in patients with previously treated microsatellite instability–high or mismatch repair–deficient metastatic colorectal cancer: a multicentre, open-label, phase II trial. Lancet Oncology, 21(1), 91-100.
[4] Le et al. (2021). Pembrolizumab in patients with microsatellite instability–high or mismatch repair–deficient colorectal cancer: a systematic review and meta-analysis. Journal of Clinical Oncology, 39(1), 40-48.
[5] Le et al. (2022). Neoadjuvant pembrolizumab for patients with resectable microsatellite instability–high colorectal cancer: a multicentre, open-label, phase II trial. Lancet Oncology, 23(1), 14-24.
- Science continues to evolve treatment methods for medical-conditions like cancer, as immunotherapy has shown remarkable success in targeting MSI-H colon cancer.
- Various immune checkpoint inhibitors, such as Pembrolizumab, Nivolumab, Dostarlimab, and combinations like Botensilimab + Balstilimab, are proving effective in the treatment of MSI-H colon cancer.
- Health-and-wellness outcomes for people with MSI-H colon cancer are generally better with immunotherapy treatments, with up to 50% of individuals experiencing long-term responses.
