Clinical Insights
Article
August 19, 2026
Cancer Screening Explained: Which Tests Are Available and When Should I Start
Cancer screening is designed to detect certain cancers before symptoms appear. By finding cancer early, screening can increase the chances of successful treatment and, in some cases, improve outcomes.
Today, routine screening programs focus on cancers where early detection has been shown to reduce cancer-related deaths. While recommendations vary slightly between healthcare systems, there is broad international agreement on which screening tests are most effective and the age groups most likely to benefit.
This guide explains the most common cancer screening tests, when screening typically begins, and what you can expect during each procedure.
Breast Cancer
Breast cancer is one of the most common cancers among women worldwide. Regular mammography has been shown to reduce breast cancer mortality by approximately 20% among women invited for screening. [1]
What Is a Mammogram?
A mammogram is a low-dose X-ray that produces detailed images of the breast and can detect cancers before they can be felt as a lump.
During the examination, each breast is briefly compressed between two plates to obtain clear images. While the compression may feel uncomfortable, it lasts only a few seconds, and the appointment is typically completed within 20 minutes.
If the mammogram identifies an area of concern, additional imaging such as ultrasound, diagnostic mammography, or occasionally MRI may be recommended to better understand the finding. [2]
When Should I Start Screening?
Most guidelines recommend that women at average risk begin mammography screening between 40 and 50 years of age, depending on local recommendations. Women with a strong family history of breast cancer or certain inherited genetic conditions may be advised to begin screening earlier or undergo additional imaging. [3]
Colorectal Cancer
Colorectal cancer screening is unique because it can both detect cancer early and reduce the risk of colorectal cancer by identifying precancerous polyps that can be removed before they become cancerous. [4] It has a few testing options.
What Is a FIT Test?
The Fecal Immunochemical Test (FIT) is one of the most common colorectal screening tests because it is simple, non-invasive, and can be completed at home.
FIT detects tiny amounts of blood in the stool that are invisible to the naked eye. It is more specific than the older Fecal Occult Blood Test (FOBT) and usually does not require dietary restrictions before testing. [5]
A positive stool test does not necessarily mean cancer is present. It simply indicates that further investigation is recommended.
What Happens During a Colonoscopy?
If a stool test is positive, or if someone is at increased risk, a colonoscopy may be recommended.
During the procedure, a doctor uses a thin, flexible camera to examine the inside of the colon while the patient is sedated. If polyps are found, they can often be removed during the same procedure, helping reduce the likelihood that some colorectal cancers will develop. [4]
When Should I Start Screening?
Most adults at average risk are encouraged to begin colorectal cancer screening between 45 and 50 years of age, although the exact age and screening method vary between healthcare systems. People with a strong family history, inflammatory bowel disease, or inherited conditions may be advised to begin screening earlier. [6]
Cervical Cancer
Cervical cancer is one of the few cancers that can often be prevented through routine screening. Persistent infection with certain high-risk types of human papillomavirus (HPV) causes almost all cervical cancers. [7,8]
Regular cervical cancer screening has been shown to reduce cervical cancer mortality by up to 80% when implemented as part of an organized screening program. [8]
What Is a Pap Test?
A Pap test (or Pap smear) collects a small sample of cells from the cervix during a routine pelvic examination. These cells are examined for abnormal changes that could develop into cancer if left untreated.
What Is HPV Testing?
Rather than looking for abnormal cells, HPV testing detects high-risk HPV types that are known to cause cervical cancer.
Many screening programs now use HPV testing on its own or together with a Pap test because it is more sensitive for identifying people at increased risk.
When Should I Start Screening?
Cervical cancer screening generally begins in the 20s, although the exact starting age and screening method vary according to local recommendations. Receiving the HPV vaccine remains one of the most effective ways to reduce cervical cancer risk, but vaccinated individuals should still participate in routine screening. [7,8]
Lung Cancer
Unlike other routine screening programs, lung cancer screening is recommended only for people at high risk, primarily because of a significant smoking history. [9]
What Is Low-Dose CT (LDCT)?
Low-dose computed tomography (LDCT) uses much less radiation than a standard CT scan while producing detailed images of the lungs. It can detect small lung cancers before symptoms develop.
Large clinical trials have shown that LDCT screening can reduce lung cancer mortality among high-risk individuals. [9]
When Should I Start Screening?
Lung cancer screening is generally recommended for adults aged 50 to 80 years with a significant smoking history. Eligibility depends on factors such as age, smoking history, and how long ago a person quit smoking. [9]
The Future of Cancer Screening
Routine screening programs have transformed the early detection of several common cancers. Even so, more than half of cancer deaths worldwide are caused by cancers that currently have no established routine screening program. [10]
Researchers are now evaluating different types of multi-cancer early detection (MCED) blood tests, including approaches that analyze DNA mutations, DNA methylation patterns, proteins, or combinations of biomarkers to detect signals associated with multiple cancers from a single blood sample. Rather than replacing mammograms, cervical screening, colorectal screening, or lung cancer screening, these tests are being studied as a way to complement existing screening programs, particularly for cancers that currently have no routine screening options.
As with any screening test, important questions remain. Who should be screened? How often should testing be performed? What follow-up is needed if a result is abnormal? Ongoing clinical studies are helping answer these questions and determine how MCED tests may be integrated into routine clinical care. [11]
While more research is needed, MCED represents one of the most promising developments in cancer screening and has the potential to expand access to early detection in the years ahead.
References
Myers ER, et al. JAMA. 2015;314(15):1615-1634. doi:10.1001/jama.2015.13183.
Mayo Clinic Staff. Mammogram. Mayo Clinic. Updated October 10, 2024. Accessed July 10, 2026. https://www.mayoclinic.org/tests-procedures/mammogram/about/pac-20384806
U.S. Preventive Services Task Force. JAMA. 2024;331(22):1918-1930. doi:10.1001/jama.2024.5534.
Mayo Clinic Staff. Colonoscopy. Mayo Clinic. Updated 2024. Accessed July 10, 2026.
American Cancer Society. Colorectal cancer screening tests. American Cancer Society. Updated May 27, 2026. Accessed July 10, 2026. https://www.cancer.org/cancer/types/colon-rectal-cancer/detection-diagnosis-staging/screening-tests-used.html
Lin JS, et al. JAMA. 2021;325(19):1978-1997. doi:10.1001/jama.2021.4417.
Centers for Disease Control and Prevention. Cervical cancer. Updated February 2024. Accessed July 10, 2026.
World Health Organization. Cervical cancer screening. Global Health Observatory Indicator Metadata Registry. Accessed July 10, 2026. https://www.who.int/data/gho/indicator-metadata-registry/imr-details/3240
U.S. Preventive Services Task Force. JAMA. 2021;325(10):962-970. doi:10.1001/jama.2021.1117.
Bray F, et al. CA Cancer J Clin. 2024;74(3):229-263. doi:10.3322/caac.21834.
Wade R, et al. Health Technol Assess. 2025;29(2):1-105. doi:10.3310/DLMT1294.