New Advances in Rectal Cancer Treatment

A small trial for a new drug found 100% remission in patients with rectal cancer (Cercek et al., 2022). The researchers used an anti-PD1 monoclonal antibody named dostarlimab, which essentially means that an antibody was made to bind to the PD-1 receptor to prevent its normal action. PD-1 is normally expressed on the outer surface of immune cells. It usually binds to its counterpart on cancer cells called PD-L1. Once these two bind together, they essentially form a protective barrier that prevents the body from producing a normal response to a cancer cell to destroy it (Potter, 2017).

In this study, patients who had stage 2 or 3 rectal cancer were administered dostarlimab every three weeks for a period of 6 months. These patients were evaluated by researchers once the regimen was completed to assess the cancer’s progression. If an individual showed absence of cancer on multiple tests, they were described as “clinically complete.” Patients were given the option of proceeding with chemotherapy or surgery after completing the drug.

The results of this study showed a fast, positive response to the drug. Symptoms of cancer were found to resolve 9 weeks after dostarlimab was started in a significant portion of the patients. Researchers also found that patients who completed all 6 months of the drug dosage were all clinically complete, meaning signs of cancer were not present. Amazingly, after another year of follow-up, researchers found that none of the patients needed chemotherapy or surgery.

This study shows that rectal cancer can potentially be treated with drugs rather than the more traditional methods. This is great news because traditional methods of treating rectal cancer often involve surgery, which could leave a patient with permanent adverse effects. However, to truly assess the impact of this drug, more research needs to be done. This study had a very small sample size with mostly women participants (62%) that were of older age and white. It would be interesting to see if these results could be generalizable to a larger, more diverse population. As of right now though, this study is an excellent start to showing that cancer can be stopped with less invasive treatments.

Citations:

Cercek, A., Lumish, M., Sinopoli, J., Weiss, J., Shia, J., Lamendola-Essel, M., El Dika, I. H., Segal, N., Shcherba, M., Sugarman, R., Stadler, Z., Yaeger, R., Smith, J. J., Rousseau, B., Argiles, G., Patel, M., Desai, A., Saltz, L. B., Widmar, M., … Diaz, L. A. (2022). PD-1 blockade in mismatch repair–deficient, locally advanced rectal cancer. New England Journal of Medicine. https://doi.org/10.1056/nejmoa2201445

Potter, M. (2017, July 18). Anti-PD-1: A novel immunotherapy. Johns Hopkins Kimmel Cancer Center. Retrieved from https://www.hopkinsmedicine.org/kimmel_cancer_center/cancers_we_treat/melanoma/_archive_me/anti_pd_1.html