Which action most directly contributes to primary cancer prevention by addressing the leading cause of cancer deaths in North America?

• A. Getting regular colonoscopies
• B. Wearing sunscreen
• C. Self-breast exams
• D. Quitting smoking

Answer: (D)

Quitting smoking directly reduces exposure to tobacco carcinogens and lowers the risk of multiple cancers, especially lung cancer, which is the leading cause of cancer deaths in North America. Primary prevention aims to stop cancer from developing in the first place, and addressing the most powerful, modifiable risk factor does that best. The other options focus on screening or prevention for specific cancers—colonoscopies help reduce colorectal cancer risk, sunscreen lowers skin cancer risk, and self-breast exams are screening for breast cancer. While valuable, they don't tackle the main driver of cancer mortality as directly as quitting smoking.