The FDA has approved a blood test for colorectal cancer (CRC) screening. The approved test is called Shield, manufactured by Guardant Health[1][2][4]. This approval marks a significant advancement in CRC screening, offering a less invasive alternative to traditional methods.
Key points about the FDA-approved Shield blood test:
1. Approved for adults aged 45 and older at average risk for CRC[1][2][4].
2. Detects CRC-derived alterations in cell-free DNA in the blood[5].
3. Showed 83.1% sensitivity for CRC detection in clinical trials[5].
4. Second FDA-approved blood-based CRC test, following Epi proColon in 2016[3][5].
Colorectal Cancer (CRC) Overview:
– Third most common cancer diagnosed in both men and women in the United States[2].
– Second leading cause of cancer-related deaths in the US[5].
– Estimated 106,590 new cases of colon cancer expected in 2024[2].
Importance of Screening:
– Regular screening can prevent up to 73% of CRC-related deaths[4].
– Current guidelines recommend screening starting at age 45[4].
– 25-50% of people who should be screened are not getting tested[4].
Screening Methods:
1. Colonoscopy: Considered the gold standard, but compliance is low due to its invasive nature[3].
2. Fecal tests: Less invasive but may be perceived as less convenient than blood tests[3].
3. Blood tests: Viewed as more user-friendly and may increase screening rates[3][4].
Shield Test Limitations:
– Poor at detecting precancerous growths (only 13% of advanced adenomas)[3].
– False positive rate of about 10%[1].
The approval of the Shield blood test is expected to improve CRC screening rates by offering a more convenient option. However, it’s important to note that colonoscopy remains the most accurate method for detecting both cancer and precancerous polyps[1][2]. The introduction of blood-based tests like Shield represents a significant step towards more accessible and patient-friendly cancer screening options, potentially leading to earlier detection and improved outcomes for CRC patients.
Best Prevention Strategies
Based on the search results, here are the best prevention strategies for colorectal cancer:
Regular Screening: The most effective way to reduce colorectal cancer risk is to get screened regularly, starting at age 45[14]. Screening can detect and remove precancerous polyps before they develop into cancer.
Physical Activity: Maintaining a regular exercise routine is linked to a decreased risk of colorectal cancer[14][16]. Aim for at least 30 minutes of moderate physical activity daily[12].
Healthy Diet: Focus on a diet rich in fruits, vegetables, and whole grains, while limiting red meat consumption to 18 ounces per week[12][13]. Avoid processed meats and limit fast food intake[12].
Weight Management: Maintain a healthy body weight, as excess belly fat is a risk factor for colorectal cancer[12][14].
Limit Alcohol Consumption: Restrict alcoholic drinks to one per day for women and two per day for men[12].
Avoid Tobacco: Don’t smoke, as tobacco use increases cancer risk[12][14].
Aspirin Use: Studies have shown that taking aspirin daily for at least two years can lower the risk of colorectal cancer, though this should be discussed with a healthcare provider due to potential side effects[16].
Polyp Removal: During colonoscopies, removing polyps larger than 1 centimeter may lower the risk of colorectal cancer[16].
Hormone Replacement Therapy: For postmenopausal women, combination hormone replacement therapy (estrogen and progestin) has been shown to lower the risk of invasive colorectal cancer, though it comes with other health considerations[16].
It’s important to note that while these strategies can help reduce risk, there’s no guaranteed way to prevent colorectal cancer entirely[12]. Individuals should consult with their healthcare providers to develop a personalized prevention plan based on their specific risk factors and overall health.
Treatment Options by Stage
Colon cancer treatment options vary significantly based on the cancer’s stage, location, and the patient’s overall health. Here’s an overview of the primary treatment modalities categorized by stage:
Stage 0 (Carcinoma in Situ)
– Surgery: Typically involves local excision or polypectomy, where the cancerous polyp is removed during a colonoscopy. If the tumor is too large, partial colectomy may be necessary[7][10].
Stage I
– Surgery: The main treatment is surgical resection to remove the tumor. If the cancer is found in a polyp and completely removed, no further treatment may be needed. However, if cancer cells are present at the margins, additional surgery may be required[7][10][11].
Stage II
– Surgery: Similar to Stage I, with wide surgical resection being the standard approach. Adjuvant chemotherapy may be considered, but it is often under clinical evaluation[7][8][10].
Stage III
– Surgery: Involves resection of the tumor along with nearby lymph nodes. Postoperative adjuvant chemotherapy is typically recommended to reduce the risk of recurrence. Common regimens include FOLFOX (5-FU, leucovorin, and oxaliplatin) or CapeOx (capecitabine and oxaliplatin) for about 3 to 6 months[7][10][11].
Stage IV and Recurrent Colon Cancer
– Surgery: Surgical resection may be an option if the cancer is localized to specific areas, such as the liver or lungs. However, if the cancer has spread widely, systemic therapies are emphasized.
– Systemic Therapy: This includes chemotherapy, targeted therapy, and immunotherapy. For advanced cases, clinical trials may also be an option to explore new treatment methodologies[7][8][9][10][11].
Additional Treatment Modalities
Chemotherapy: Often used post-surgery to eliminate remaining cancer cells, or pre-surgery to shrink tumors. It can also be used for symptomatic relief in advanced cases[8][9][10][11].
Radiation Therapy: Typically used in conjunction with surgery for rectal cancer but can also be applied in cases where surgery is not feasible to relieve symptoms[8][9][11].
Targeted Therapy and Immunotherapy: These are newer treatment options that may be available, particularly for advanced cancers. They are often explored in clinical trials[8][11].
Clinical Trials: Patients may consider enrolling in clinical trials to access cutting-edge treatments not widely available yet[7][8].
The choice of treatment is highly individualized and should be discussed thoroughly with a healthcare team, considering all factors including the cancer stage, potential side effects, and the patient’s preferences.
More Reading
[1] https://abcnews.go.com/Health/fda-approves-blood-test-detect-colon-cancer-average-risk/story?id=112364193
[2] https://www.cbsnews.com/news/fda-approves-blood-test-colon-cancer-detection/
[3] https://www.usnews.com/news/health-news/articles/2024-07-29/fda-approves-another-blood-test-for-colon-cancer-screening
[4] https://www.nytimes.com/2024/07/29/health/colon-cancer-blood-test-shield.html
[5] https://www.targetedonc.com/view/fda-approves-shield-blood-test-for-colorectal-cancer-screening
[6] https://timesofindia.indiatimes.com/world/us/fda-approves-blood-test-method-for-colon-cancer-screening/articleshow/112117596.cms
[7] https://www.cancer.gov/types/colorectal/hp/colon-treatment-pdq
[8] https://www.cancer.gov/types/colorectal/patient/colon-treatment-pdq
[9] https://www.hopkinsmedicine.org/health/conditions-and-diseases/colon-cancer/colon-cancer-treatment
[10] https://www.cancer.org/cancer/types/colon-rectal-cancer/treating/by-stage-colon.html
[11] https://www.mayoclinic.org/diseases-conditions/colon-cancer/diagnosis-treatment/drc-20353674
[12] https://www.hopkinsmedicine.org/health/conditions-and-diseases/colon-cancer/colon-cancer-prevention
[13] https://www.mdanderson.org/publications/focused-on-health/Colorectal-cancer-prevention-What-you-need-to-know.h24Z1591413.html
[14] https://www.cdc.gov/colorectal-cancer/prevention/index.html
[15] https://www.cedars-sinai.org/newsroom/6-expert-tips-to-prevent-colorectal-cancer/
[16] https://www.cancer.gov/types/colorectal/patient/colorectal-prevention-pdq
