It’s Not a Coincidence That Multiple Family Members Develop Can.cer: These Are 6 Can.cers With Clear Hereditary Links
So which types of cancer show the strongest hereditary tendencies? If parents have had cancer, what should their children do to reduce the risk?
Cancer does not always stem from lifestyle or daily habits. In clinical practice, many patients are assessed as having an “inborn risk” from birth due to genetic factors within the family. Some cancers do not occur in just one individual but repeat across multiple generations.
So which cancers are most clearly hereditary? And if parents are affected, how can their children lower their risk?
1. Thyroid cancer – children face a threefold higher risk if a parent is affected
Thyroid cancer is one of the cancers with a relatively clear genetic association. Studies show that about 4% of thyroid cancer cases involve hereditary factors, and the risk for children increases by roughly three times if either parent has had the disease.
Medullary thyroid cancer has the strongest hereditary component. About 25–30% of cases are linked to gene mutations and often run in families. For non-medullary types, the hereditary rate is lower but still accounts for around 5%.
For people with a first-degree relative who had thyroid cancer, doctors recommend regular thyroid ultrasounds combined with thyroid-stimulating hormone (TSH) tests. If results are normal, screening can be repeated every 2–3 years.
2. Colorectal cancer – children may face up to a 50% risk
Colorectal cancer shows a very strong familial pattern. Around 20% of patients have a family history, and if a parent is affected, the child’s risk may be 2–3 times higher than average.
Particularly dangerous is familial adenomatous polyposis (FAP), a genetic disorder that causes hundreds or even thousands of polyps to develop in the colon at a young age. Without intervention, nearly 100% of FAP patients will develop colorectal cancer before age 40. If a parent has this condition, the hereditary risk for children can be as high as 50%.
For high-risk individuals, early colonoscopy is critical. While the general population is advised to begin screening at age 40, those with a family history should start earlier—around ages 30–35—and repeat every 3–5 years.
3. Stomach cancer – risk increases 2–3 times
About 10–15% of stomach cancer cases are linked to family history, often appearing at a younger age and affecting multiple members within the same family line. The most notable form is hereditary diffuse gastric cancer, associated with mutations in the CDH1 gene.
Carriers of this mutation face a lifetime stomach cancer risk of 60–80%. In addition, women with CDH1 mutations also have a higher risk of breast cancer.
For families with a history of stomach cancer, experts recommend regular gastroscopy starting at age 40 or earlier, repeated every 1–2 years, along with imaging tests when necessary.
4. Lung cancer – about 50% of patients have a family history
Smoking remains the leading cause of lung cancer, but genetic factors also play a significant role. Many studies show a high proportion of lung cancer patients have relatives who were also affected.
Specifically, about 35.8% of patients with squamous cell lung cancer have a family history, while among women with lung adenocarcinoma, the figure reaches 58.3%. If one or two first-degree relatives are affected, the risk increases about 2.5 times; if three or more relatives are affected, the risk rises more than fourfold.
For high-risk groups, low-dose CT (LDCT) scans are considered an effective screening method and are recommended starting at age 45, or earlier if multiple risk factors are present.
5. Breast cancer – daughters face a threefold higher risk if their mother is affected
Breast cancer is the most thoroughly studied cancer in terms of heredity. If a mother develops breast cancer—especially before age 50—or if there are two or more first-degree relatives with breast or ovarian cancer, a daughter’s risk may be 2–3 times higher.
This is often linked to mutations in the BRCA1 and BRCA2 genes, which can be inherited from either parent. Women carrying these mutations have a much higher risk of breast and ovarian cancer than the general population.
Women with a family history are advised to have annual breast ultrasounds starting at age 35 and mammograms from age 40. For BRCA mutation carriers, screening should begin as early as age 25.
6. Prostate cancer – risk rises sharply with affected relatives
About 5–15% of prostate cancer cases are associated with hereditary factors. If a family member has had the disease, a man’s risk may increase by around 60%.
Having one first-degree relative with prostate cancer can double the risk; having two or more can increase the risk by 5–11 times. In these cases, the disease also tends to appear 6–7 years earlier than in men without a family history.
Therefore, men with a family history are advised to begin prostate cancer screening at age 40 and undergo annual checkups for early detection.
Genetic predisposition does not mean a certain cancer diagnosis, but it does make the body more vulnerable to carcinogenic factors. When combined with smoking, unhealthy diets, physical inactivity, or exposure to toxic chemicals, the risk increases significantly.
Understanding your family medical history, proactively undergoing early screening, and maintaining a healthy lifestyle are the most effective ways to reduce risk and protect long-term health.
