Discussion
colorectal cancer, tumor, melanoma, CRC, lung cancer
COLORECTAL CANCER, RECURRENCE, METASTASIS, TUMOR, MELANOMA, ADVERSE EVENTS, LUNG CANCER, MALIGNANCIES, LIVER METASTASIS
This clinical trial was a single-arm, single-center study, which included six MSS–CRC patients with postoperative recurrence or metastasis. After the personalized neoantigen vaccination, four of six patients exhibited a positive immune response to the neoantigen vaccine and had significantly longer PFS time than the other two patients with negative neoantigen response (19 vs 11 months). No significant adverse events were observed in the six enrolled patients during the neoantigen vaccine administration. All patients reported that the quality of life had improved during the vaccine treatment. According to the analysis of the above results, even MSS–CRC patients with postoperative recurrence or metastasis are expected to benefit from this immunotherapy. The most surprising thing was the performance of patient W02. The patient received chemotherapy again when liver metastasis occurred after colorectal cancer surgery during which time there was no significant decrease in carcinoembryonic antigen (CEA). The patient started the single-drug treatment of vaccine after stopping the chemotherapy treatment. After four injections, the patient's CEA dropped from an initial 126.7 to 82.73 ng/mL (Fig. Case report of advanced colorectal cancer patient W02. In China, the incidence rate of CRC is fifth among all malignancies [Previous studies had proved the safety and effectiveness of personalized tumor vaccines based on neoantigens in the treatment of melanoma and advanced lung cancer [In summary, our results preliminarily prove that personalized neoantigen vaccine therapy is a safe, feasible and immunological effective strategy for MSS–CRC patients with postoperative recurrence or metastasis and may provide clinical benefit. Patients who exhibit stronger positive immune responses to the neoantigen vaccines tend to have better clinical outcomes. However, this study still has the following shortcomings: Firstly, we failed to detect the intensity of the immune response quantitatively and accurately determine the duration of the immune response; secondly, due to limited sample size enrolled in this study, the corresponding findings will still need to be validated in large-scale clinical trials.