Immunotherapy prior to surgery may improve outcomes for some patients with colorectal cancer
June 2024
A phase II study presented at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting aimed to investigate whether the immunotherapy agent pembrolizumab given before surgery may improve outcomes in certain patients with stage II or III dMMR/MSI-H colorectal cancer (CRC).
Immunotherapy: a class of drugs that stimulate the body’s own immune system to more effectively target cancer cells.
dMMR/MSI-H : this stands for MisMatch Repair deficient, Microsatellite Instability High. This is an important biomarker in colorectal cancer which suggests that the tumour is more likely to respond to immunotherapy treatment. About 10-15% of patients with stage II or III CRC have dMMR/MSI-H disease.
The study
32 patients with stage II or III dMMR/SMI-H CRC were assigned to receive 9 weeks of pembrolizumab (Keytruda) immunotherapy before they received surgery, instead of the standard approach of chemotherapy followed by surgery.
59% of the patients who received pembrolizumab before surgery showed no signs of cancer following the nine weeks of treatment. The remaining 41% of patients who had lingering tumours after nine weeks of pembrolizumab had them removed during surgery.
Importantly, 100% of the 32 patients involved in the trial were cancer-free after treatment and did not experience disease recurrence for a median of 9.7 months following surgery. Compared to the standard of care approach of chemotherapy following by surgery among CRC patients that are dMMR/MSI-H, less than 5% are cancer-free following surgery.
In the experimental approach using pembrolizumab following by surgery, the patients did not require additional adjuvant or post-surgical chemotherapy, therefore avoiding additional side effects.
Conclusions
The researchers note that initial findings suggest that pembrolizumab is a safe and effective treatment that improves outcomes in patients with stage II/III CRC expressing dMMR/MSI-H, improving the chances of a cure at these earlier stages. More extensive follow-up is needed in the study to assess whether the patients remain cancer-free for a longer period of time.
