National Colorectal Cancer Awareness Month: Let's shine a light on colorectal cancer!
Published Mar 2, 2021 • By Clémence Arnaud
As March 1st marks the beginning of National Colorectal Cancer Awareness Month, we'd like to shine a light on colorectal cancer. It is a cancer whose incidence remains high despite the screening implemented in the US. New therapies continue to arrive on the market, like Keytruda®.
What is colorectal cancer? What therapeutic alternatives exist today? What is Keytruda® and how will it be used?
We explain it all in our article!
Colorectal cancer in a few figures
Colorectal cancer, sometimes also called colon cancer, includes cancers of the colon and rectum. Between 60 and 80% of colorectal cancers develop from benign tumors: polyps or adenomas. There are 4 stages of severity of these cancers, ranging from superficial damage to the gastrointestinal wall to metastasis, where the cancer spreads to other organs in the body. It is a cancer that is very prevalent throughout the world with risk factors such as excess weight/obesity, diet rich in red or processed meat and low in fiber, physical inactivity, alcohol or tobacco consumption.
In the US, the following trends have been observed:
- Mortality rates are in decline: Over the past twenty years, colorectal cancer mortality rates have decreased by almost 40%. It is the third leading cause of cancer-related deaths in both women and men in the United States.
- Incidence rates have declined by 35%: it is the third most common cancer diagnosed in the US for both men and women.
- Survival rate is improving and has more than doubled in the last 40 years: almost 9 in 10 people (84.6%) survive their colorectal cancer for one year or more and almost 7 in 10 (65.9%) survive for five years or more.
Screening is one of the factors that have made it possible to reduce the mortality rate of this cancer by detecting the disease at an early stage, thereby enabling patients to be treated more quickly. The Center for Disease Control and Prevention (CDC) and the U.S. Preventative Services Task Force (USPSTF) recommends screening to all men and women aged 50 to 75, which is conducted by testing for blood in the stool. This screening should be done every two years.
Treatments have also reduced patient mortality and increased life expectancy.
Colorectal cancer treatments
Treatment is adapted to each patient and care is multidisciplinary.
Surgery is very often used in the case of colorectal cancers. It consists of removing the part of the colon or rectum affected by the tumor. It can be done by making an incision in the abdominal wall to operate.
Another technique, laparoscopic surgery or minimally invasive surgery (MIS), is also possible and consists of introducing a miniature camera and surgical instruments through small incisions. As this technique is less invasive, it reduces hospitalization time, complications and improves patients' quality of life.
Chemotherapy can be prescribed alone or after surgery. Many compounds are on the market but fluorouracil (5-FU) remains the preferred option for colorectal cancer. To improve its efficacy, irinotecan (CAMPTO®) or oxaliplatin can be administered in parallel. Another drug exists, capecitabine (XELODA®), which is given in pill form. New drugs are still being developed to treat colorectal cancer.
For colorectal cancer that has metastasized, chemotherapy is systematically prescribed. It can be given before the first surgical operation in order to make the operation easier or instead of surgery when the latter is not possible.
Pembrolizumab, a new treatment for certain types of colorectal cancer
On June 29, 2020, the U.S. Food & Drug Administration (FDA) approved KEYTRUDA® (pembrolizumab) for certain types of colorectal cancer.
Keytruda® is a drug used to treat various cancers: melanoma, non-small cell lung cancer, kidney cancer and squamous cell carcinoma of the head and neck, for example. It is a monoclonal antibody that is administered by infusion.
Indications for using Keytruda® in cases of bowel cancer:
- It is a first-line monotherapy in microsatellite instable (MSI-H) metastatic bowel cancer or mismatch repair deficient (MMR deficient) metastatic bowel cancer in adults.
These two forms of cancer represent 5% of metastatic colorectal cancers.
A phase 3 study ( a study on a large number of patients) called Keynote-177 compared the efficacy of pembrolizumab with first-line chemotherapy. The study showed significant improvement of progression-free bowel cancer survival of 16.5 months in the pembrolizumab group, versus 8.2 months in the chemotherapy group. This represents a 40% reduction in progression risk with pembrolizumab.
The tolerability profile was also more favorable on pembrolizumab, with 22% of serious adverse events (grade 3 or 4) compared to 66% on chemotherapy.
The Keynote-177 study also studied the quality of life of patients on pembrolizumab compared with that of patients undergoing first-line chemotherapy. The assessment was carried out using two scales that measure quality of life. It was shown that the quality of life was improved and that the delay before quality of life deteriorated was longer.
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- Key statistics for Colorectal Cancer - American Cancer Society
- Cancer Stat Facts: Colorectal Cancer - NIH National Cancer Institute - Surveillance, Epidemiology, and End Results Program
- What Should I Know About Screening? - CDC
- Colorectal Cancer: Screening - U.S. Preventive Services Task Force
- FDA Approves First-Line Immunotherapy for Patients with MSI-H/dMMR Metastatic Colorectal Cancer - U.S. Food & Drugs Administration
- Study of Pembrolizumab (MK-3475) vs Standard Therapy in Participants With Microsatellite Instability-High (MSI-H) or Mismatch Repair Deficient (dMMR) Stage IV Colorectal Carcinoma (MK-3475-177/KEYNOTE-177) - ClinicalTrials.gov