Highlights
- Colorectal cancer treatments are advancing quickly beyond traditional chemotherapy and surgery.
- Immunotherapy, including immune checkpoint therapy, and personalized immunotherapy are showing promise for giving patients longer and better quality of life and for putting cancer in remission.
- Some of these treatments are not yet widely available, and the larger impact is still being studied.
Colorectal cancer treatments have advanced rapidly over the last few decades. In particular, immunotherapy is showing promise as a tool for fighting these cancers. Here’s what you should know about colon cancer treatment, immunotherapy, and immune checkpoint therapy.
How Is Colorectal Cancer Treated?
If you’re at risk for colorectal cancer, it’s worth knowing how it’s treated and what treatments are used at every stage of the disease.
Colonoscopic surgery
Advances in technology have made surgery through colonoscopy much more common. During this procedure, which is done under general sedation, a colonoscope with surgical attachments is fed into the colon to remove polyps and cancerous growths.
This procedure is most commonly done with early-stage colorectal cancer. It’s also used to remove benign polyps in the colon.
Other forms of surgery
More advanced cancers may be treated with other techniques, including laparoscopic surgery, where instruments are introduced through a small incision in the stomach, or, in advanced cases, a partial colectomy.
During a colectomy, the cancerous portion of the colon is removed and either reconnected surgically or replaced with an ostomy. Colectomy will usually involve the removal of lymph nodes to test for the spread of cancer cells.
Chemotherapy
In chemotherapy, drugs that are toxic to certain cells are used to kill the tumor. Chemotherapy can be utilized to diminish the size of the tumor in order to avoid colectomy or to make other surgical options more viable. Chemo may also be used to prevent the spread of cancer to other parts of the body or as a follow-up treatment for colectomy.
The downside of chemotherapy is that since the colon has rapidly dividing cells and a collection of microbiota, side effects can be unpleasant.
Radiation therapy
Similar to chemotherapy, radiation is used to diminish the size of a tumor before it can be removed completely or to fight cancer in a targeted way. Radiation therapy and chemotherapy may be combined. Also like chemotherapy, radiation therapy has side effects that may be difficult to live with.
For years, these were the only tools doctors had to treat cancer, and they are used often to this day. However, immunotherapy is becoming an increasingly popular cancer treatment that can make older approaches more effective or unnecessary.
What Is Immunotherapy?
In immunotherapy, diseases are fought either by activating or suppressing the immune system in specific ways. If you’ve ever received a vaccine, you’ve experienced a form of immunotherapy. The inactivated or disabled viral particles trigger the immune response, training your body to fight off that virus if you encounter it again.
In the case of cancer, immuno-oncology takes away cancer’s methods of hiding from the immune system. The body is generally efficient at finding and destroying precancerous cells, so cancer cells develop methods of concealing signals that would otherwise attract the immune system. Immunotherapy shuts down those methods and helps the immune system do its work.
However, there’s only so much the immune system can do on its own. While it can attack cancer in the general sense, it needs certain tools to be more effective at targeting specific cells. Immunotherapy can also be combined with other treatments, such as chemotherapy, to create a two-pronged approach to shrink the tumor and reduce its spread.
What Is Immune Checkpoint Therapy?
The immune system needs to strike a delicate balance with cancer, killing the unhealthy cells without affecting the healthy ones. To protect the body, immune cells have “checkpoint” proteins that bond to immune cells and turn them off.
Cancer cells exploit this mechanism to coat themselves with checkpoints that shut off the immune system. Knowing this, researchers have been working to disable the specific checkpoints cancer cells use.
Several drugs on the market, including nivolumab (Opdivo) and pembrolizumab (Keytruda) use this approach to reduce the size of tumors and give patients more time with their loved ones. There’s also promise in combining several checkpoint drugs, although that work is still ongoing.
The potential trade-off for patients is that these checkpoints exist for a reason. Although rare, it is possible for an immune overreaction to occur with these medications. People living with autoimmune disorders, in particular, will need to be extremely careful with these drugs.
As of this writing, immune checkpoint therapy is generally reserved for patients who have more advanced forms of colorectal cancer. Opdivo was only approved for colon cancer in 2017, with Keytruda approved in 2020, so doctors are still learning best practices with these drugs.
Currently, researchers are working on a refinement of immune checkpoint therapy that would allow the immune system to find a specific tumor.
What Is Personalized Immunotherapy?
Every tumor is genetically unique, as cancer uses specific mutations to our DNA to protect itself and spread in the body. Individualized immunotherapy (also called individualized immuno-oncology), is an approach that uses the uniqueness of each tumor to fight it.
In personalized immunotherapy, the tumor is sequenced and a custom vaccine designed to target that specific tumor, stripping away its ability to hide from the immune system and enter other parts of the body. Instead of fighting cancer in general, this vaccine targets the cancer specific to the person.
Immune checkpoint therapy helps by shutting off the defenses, so this tumor-specific vaccine can go to work, reducing the size of the tumor and opening the door to other treatments. While personalized cancer treatment is currently under study for safety, it should be available in the near future.
Colorectal Cancer Treatment Starts With Testing
If you’re at risk for colorectal cancer, the best step to take is to stay informed about your options. Regular testing helps you monitor your condition and act before cancer becomes too severe or spreads to other areas of your body.
Use at-home colorectal cancer screening tests, and follow the eDrugstore blog for evidence-based information on colorectal cancer and immunotherapy.
Dan is a long-time freelance writer focusing on technology, science, health, and medicine, with a lifelong interest in physics, biology, and medicine. His work has taken a particular focus on scientific studies “beyond the headlines,” reading the study to more closely examine the results.
