Many types of cancer can be detected at an early stage, when they have just started to form and have yet to spread to other parts of the body. Early detection can be critical, because cancer can often be more successfully treated in its initial stages than when it has grown and metastasized.
Self exams and screening
Cancer is often detected when an individual notices a change in his or her health — excessive fatigue, for example, or unusual bleeding, a lump that doesn’t go away, unexplained weight loss, night sweats, or a persistent change in bowel or bladder habits. Diagnostic tests can help determine whether these problems are caused by cancer or some other disorder.
In people at average risk for cancer, formal self-exams for breast cancer and testicular cancer are of limited use and are not recommended. However, it is important to be aware of changes in one’s body and report them to one’s physician.
Everyone should check themselves regularly for signs of skin cancer, such as a mole that’s new or changing in size, shape, or color, a new growth or bump, or a sore that bleeds and doesn’t heal after a few weeks.
Screening tests for the general public
Screening tests are used to detect certain kinds of cancers when they’re small and easier to treat successfully. In some cases they can detect abnormal growths before they become cancerous. Removing such growths can help prevent cancer.
The American Cancer Society and U.S. Preventive Services Task Force set screening guidelines for a variety of common cancers, specifying the age at which screening should begin and the frequency with which it should be done.
Screening procedures include:
- Mammography for breast cancer.
- Colonoscopy for colorectal cancer.
- Pap tests for cervical cancer. Women whose Pap tests show abnormal cells may have a follow-up DNA test to detect the human papillomavirus (HPV), which can contribute to the development of cervical cancer.
- Digital rectal exams and PSA tests for prostate cancer.
Screening for high-risk groups
For people who have had cancer or have a strong family history of cancer, additional or more frequent screenings may be recommended.
“While most cancers are sporadic — meaning they arise from factors that aren’t inherited ‚ about 15% of cancers do have an underlying inherited component,” says Huma Q. Rana, MD, clinical director of Cancer Genetics and Prevention at Dana-Farber. “People with a first- or second-degree relative — a parent, sibling, child, grandparent, aunt, uncle, nephew, or niece — who had cancer, especially at a young age, should consider being tested for inherited genetic mutations that raise their risk for specific types of cancer.”
Even when people with a family cluster of cancer don’t test positive for a cancer-related mutation, family members may share other genetic factors that put them at heightened risk for the disease, Rana says. Anyone with a strong family history of cancer should talk with their physician about a screening plan tailored to their needs.
Such a plan might include starting screening at an earlier age than people in the general population, being screened more often, or screening with additional technologies. People with an increased risk of breast cancer, for example, might be advised to have breast MRI scans as well as mammography. People from families with a high risk of pancreatic cancer are increasingly counseled to be tested for the disease using endoscopic ultrasound or MRI.
As scientists learn more about the inherited roots of some cancers, screening recommendations are adjusted to reflect the new findings.
“It’s increasingly recognized that some gene mutations associated with increased breast and ovarian cancer risk can also lead to aggressive prostate cancer and, potentially, prostate cancer at an earlier age,” Rana relates. “In some populations, earlier prostate cancer surveillance is recommended, beginning, for some, at age 40.”
Research is also beginning to show that in families where increased cancer risk isn’t linked to an abnormality in a single gene, it may result from variations in several genes that cumulatively put someone in a higher risk category, Rana continues. Studies have validated these “polygenic risk scores” in certain cancer types including breast and prostate cancer, but their use in clinical care continues to be evaluated. In the WISDOM study, for example, investigators are exploring whether polygenic risk factors can be used to personalize women’s mammography schedules.
As a general rule, “if you see something suspicious, say something to your doctor,” Rana counsels. Even with the outbreak of COVID-19, people should not delay seeing their doctor or health care practitioner about concerning symptoms. “For people who are at high risk for cancer, if you’ve fallen behind in your screening, it’s important to get back on schedule.”