“There’s almost an unspoken scientific consensus that it’s always environmental,” said Simon Strong, whose child passed away from acute myeloid leukemia in June 2015 at the age of 12 (1).

In recent years, cases of pediatric cancer in the United States surged by almost 50% according to alarming but under-reported statistics by the National Cancer Institute (2). And in 2018, from birth to age 19, up to 16,000 children will have a new diagnosis (3).

According to the World Health Organization (WHO), cancer is the second leading cause of death globally, accounting for nearly 10 million deaths in 2020 (4). The rising in pediatric cancer has evidently brought up debates on whether or not lifestyle and environmental factors are the dominant causes relating to cancer.

Understanding Cancer

Cancer is a complex disease that occurs when cells in the body grow and divide uncontrollably, forming lumps of tissue called tumors. These tumors can either be benign or malignant. The former does not spread to other parts of the body and usually does not grow back after they are removed. The latter, on the other hand, can invade nearby tissues and organs, and sometimes break off and travel to other parts of the body through a process called metastasis.

Cancer can occur almost anywhere in the body, and it can start from almost any type of cell. Normally, cells in the body grow and divide in an orderly manner to replace old or damaged cells. However, sometimes this process goes awry, and cells start to grow and divide uncontrollably (5).

The Extrinsic Factors to Increase the Risk of Cancer

A study published in the Nature journal discovered that many cancers, such as lung, colorectal, bladder, and thyroid cancers, have a significant number of mutations that were probably caused by external factors. Moreover, the researchers found convincing epidemiological evidence supporting the significant role of external factors in cancer development.

An examination of immigrants who migrated from countries with low cancer rates to those with high cancer rates showed that these individuals developed a higher likelihood of cancer. This implies that external factors are responsible (6).

Many well-known extrinsic factors contribute to cancer, to name a few (7):

• Cigarette Smoking and Tobacco Use
• Infections
• Radiation
• Immunosuppressive Medicines After Organ Transplant
• Diet
• Alcohol
• Physical Activity
• Obesity
• Diabetes
• Environmental Risk Factors

Genetic Factors

A new study by researchers from the Johns Hopkins Kimmel Cancer Center in Baltimore, MD found that random DNA mutations during cell division may account for around 65% of cancer incidence, while the remaining 35% may be explained by hereditary or environmental factors.

Tissue-specific stem cells make random mutations — caused by DNA errors during cell division replication — that are drivers of cancer; the more these mutations expand, the higher the cancer risk (8).

DNA changes, whether caused by a random mistake or by a carcinogen, can happen throughout our lives and even in the womb (9).

Is cancer hereditary?

Cancer cannot be inherited from parents, nor can genetic changes in tumor cells. However, a genetic mutation that increases the risk of developing cancer can be inherited if it is present in a parent’s egg or sperm cells.

Inherited mutations in the BRCA1 and BRCA2 genes, for example, are known to increase the risk of breast and ovarian cancer (10). Other genetic conditions, such as Lynch syndrome, can increase the risk of colorectal and other types of cancer (11).

A family cancer syndrome (12), also known as hereditary cancer syndrome, is a rare condition in which family members have a higher risk of developing certain types of cancer. These syndromes are caused by inherited genetic variants in certain cancer-related genes.

In some cases, people with family cancer syndromes tend to develop cancer at an early age or have other non-cancer-related health conditions.

Genetic Testing for Cancer Risk

Certain genetic tests can detect whether you’ve inherited a genetic change that could increase your risk of cancer. Typically, this testing is done with a small blood sample, but it may also be done with saliva, cells from inside the cheek, or skin cells.

For those with a family history of breast and ovarian cancer, genetic tests can aid in screening and treatment decisions.

The doctor or health care provider will determine if you should be tested for genetic changes that increase cancer risk. They will likely inquire about certain patterns in your personal or family medical history, such as cancer at an unusually young age or several relatives with the same type of cancer.

References:

1. Families seek answers for us rise in childhood cancers (2019) The Guardian. Guardian News and Media. Available at: https://www.theguardian.com/us-news/2019/jul/30/toxic-america-families-seek-answers-childhood-cancers (Accessed: March 9, 2023).
2. Seer Cancer Statistics Review 1975–2015 (no date). Available at: https://seer.cancer.gov/archive/csr/1975_2015/results_merged/sect_29_childhood_cancer_iccc.pdf (Accessed: March 9, 2023).
3. Cancer in children and adolescents (no date) National Cancer Institute. Available at: https://www.cancer.gov/types/childhood-cancers/child-adolescent-cancers-fact-sheet#q1 (Accessed: March 9, 2023).
4. Cancer (no date) World Health Organization. World Health Organization. Available at: https://www.who.int/news-room/fact-sheets/detail/cancer(Accessed: March 9, 2023).
5. What is cancer? (no date) National Cancer Institute. Available at: https://www.cancer.gov/about-cancer/understanding/what-is-cancer(Accessed: March 9, 2023).
6. Most cancer cases ‘caused by lifestyle, environment — not bad luck’ (no date) Medical News Today. MediLexicon International. Available at: https://www.medicalnewstoday.com/articles/304230 (Accessed: March 9, 2023).
7. Cancer prevention overview (PDQ®)–patient version (no date) National Cancer Institute. Available at: https://www.cancer.gov/about-cancer/causes-prevention/patient-prevention-overview-pdq (Accessed: March 9, 2023).
8. Two thirds of cancer cases down to ‘bad luck,’ new study claims (no date) Medical News Today. MediLexicon International. Available at: https://www.medicalnewstoday.com/articles/287542 (Accessed: March 9, 2023).
9. January 12, 2023, December 22, 2022 and December 2, 2022 (no date) Mosaic mutations in embryos can cause cancer later in life, National Cancer Institute. Available at: https://www.cancer.gov/news-events/cancer-currents-blog/2022/cancer-mosaic-mutations-embryo (Accessed: March 9, 2023).
10. BRCA gene mutations: Cancer risk and Genetic Testing Fact Sheet (no date) National Cancer Institute. Available at: https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet (Accessed: March 9, 2023).
11. Lynch syndrome (2022) Mayo Clinic. Mayo Foundation for Medical Education and Research. Available at: https://www.mayoclinic.org/diseases-conditions/lynch-syndrome/symptoms-causes/syc-20374714#:~:text=Lynch%20syndrome%20is%20a%20condition,and%20other%20types%20of%20cancer. (Accessed: March 9, 2023).
12. NCI Dictionary of Cancer terms (no date) National Cancer Institute. Available at: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/family-cancer-syndrome (Accessed: March 9, 2023).
13. It’s in your genes: New breakthrough in genetics now helps families with a history of cancer predict and prevent the world’s most dreaded disease (2013) India Today. India Today. Available at: https://www.indiatoday.in/magazine/health/story/20130617-cancer-genes-carried-in-families-hereditary-breast-prostate-764013-1999-11-29(Accessed: March 9, 2023).