Colorectal cancer is the 3rd most common cancer worldwide. Immunotherapy has been shown to be therapeutically effective in patients with colorectal cancer who have significant levels of microsatellite instability (regions of repeated DNA that change in length and therefore show instability). However, some microsatellite instability-high colorectal cancer patients have shown a poor response to immunotherapy in clinical trials. Therefore, researchers from the Harbin Medical University Cancer Hospital looked into the effectiveness of immunotherapy and its intrinsic resistance in patients with colorectal cancer who had significant levels of microsatellite instability.
This meta-analysis included 7 clinical trials involving 604 microsatellite instability-high colorectal cancer patients. Results indicated that 25% of cases of progressing illness had effectiveness following immunotherapy. Another discovery was that 31% of patients who received single-drug immunotherapy had intrinsic resistance, and subsequent investigation revealed that the rate of intrinsic resistance to dual-drug immunotherapy was 12%. This suggests that a lower incidence of intrinsic resistance can be observed with dual-drug immunotherapy. Furthermore, researchers found that, despite the fact that early immunotherapy can improve the objective response rate, it had no significant impact on the incidence of intrinsic resistance.
In conclusion, the choice of immunotherapy should be more cautious for patients with colorectal cancer who have high levels of microsatellite instability. Dual-drug immunotherapy significantly reduced the incidence of intrinsic resistance. Although it won’t reduce the incidence of intrinsic resistance, advancing immunotherapy can help these patients’ objective response rates.
結直腸癌是全球第三大常見癌症。免疫療法已被證明對具有顯著水平微衛星不穩定性（長度發生變化並因此顯示不穩定性的重複 DNA 區域）的結直腸癌患者俱有治療效果。然而，一些微衛星不穩定性高的結直腸癌患者在臨床試驗中表現出對免疫治療反應不佳。因此，哈爾濱醫科大學腫瘤醫院的研究人員研究了免疫療法的有效性及其對具有顯著微衛星不穩定性水平的結直腸癌患者的內在耐藥性。
該薈萃分析包括 7 項臨床試驗，涉及 604 名微衛星不穩定性高的結直腸癌患者。結果表明，25% 的疾病進展病例在免疫治療後有效。另一個發現是接受單藥免疫治療的患者中有31%存在內在耐藥，隨後的調查顯示雙藥免疫治療的內在耐藥率為12%。這表明使用雙藥免疫療法可以觀察到較低的內在耐藥發生率。此外，研究人員發現，儘管早期免疫療法可以提高客觀反應率，但它對內在耐藥性的發生率沒有顯著影響。
Reference: Wang R, Lian J, Wang X, Pang X, Xu B, Tang S, Shao J, Lu H. Intrinsic resistance and efficacy of immunotherapy in microsatellite instability-high colorectal cancer: A systematic review and meta-analysis. Bosn J of Basic Med Sci [Internet]. 2022Nov.19 [cited 2022Nov.27];. Available from: https://www.bjbms.org/ojs/index.php/bjbms/article/view/8286
Editor: Merima Bukva, MPharm