Thanks to research, treatment options are increasing in number and efficacy across multiple types of cancer and for diverse populations of patients, even as side effects are minimized and better managed to maximize patients’ quality of life. Preventing cancer, however, remains a high priority to improve public health.

Cancer prevention encompasses many strategies, including lifestyle changes that can minimize cancer risk, better screening tools to diagnose cancer sooner, and approaches that can prevent cancer by preventing infection from cancer-causing organisms. To advance cancer prevention, however, means not only figuring out which new approaches will work but also implementing those approaches proven to be effective in relevant populations.

Carolyn Taylor

"In my travels around the world, I’ve met so many inspiring patients, clinicians, and advocates who motivate me. They are a constant reminder that cancer does not discriminate, but in a way unites us and reinforces just how alike we are and how small the world is."
—Carolyn Taylor

Carolyn is a photographer and president and founder of Global Focus on Cancer, a non-profit organization developed to create, implement, and assist with cancer awareness programs and cancer support groups in the US and in countries where access to information about cancer is critically lacking. Read more in this ASCO Connection blog post.

Longer Real-World Follow-Up Validates That HPV Vaccines Reduce Cervical Cancer Risk

Vaccines against several forms of human papillomavirus (HPV) were developed and licensed for adolescents and young adults to prevent HPV infection, which can lead to cervical cancer and anogenital warts later in life.15 Since the first vaccine was licensed in 2006, nearly 100 countries have instituted HPV vaccination programs. Currently in the United States, the vaccine is approved for females and males age 9-45 years.16 Clinical trials that led to vaccine approvals showed nearly 100% protection against persistent cervical infections with HPV types 16 and 18, which account for 70% of cervical cancers and 86%-95% of all other HPV-associated cancers.17

In a 2019 analysis of data from 40 trials in 14 high-income countries, researchers reported that the prevalence of HPV 16 and 18 dropped by 83% among females age 13-19 years and by 66% in young women age 20-24 years in the 5-8 years after the introduction of HPV vaccination.18 The prevalence also decreased for women age 25-29 years (most of whom are unvaccinated in the general population) in the same period. Decreases in prevalence were also seen for HPV 31, 33, and 45 for females age 13-24 years.

The researchers also looked at the population-level impact of vaccination on rates of precancerous cervical lesions (cervical intraepithelial neoplasia grade 2+, or CIN2+). Among those screened for CIN2+, researchers found a decrease of 51% in incidence in females age 15-19 and 31% among women age 20-24 years. The study results not only provide strong evidence that HPV vaccines prevent cervical cancer in real-world settings but also bolster the importance of vaccination programs worldwide.

Large Study Finds No Cancer Protection Benefit From Vitamin D Supplements

By helping the body absorb calcium, vitamin D is important to bone health. This fat-soluble vitamin is also important to the function of muscles, nerves, and the immune system. It is found in a relatively small number of foods, and through sun exposure the body produces some vitamin D for itself.

In recent years, some small observational studies have suggested that low levels of vitamin D in the blood may be associated with greater risks of cancer. Larger studies were needed, however, to determine if the link could hold up to a more rigorous analysis

In a large federally funded, randomized, double-blind, placebo-controlled trial published in 2019, the Vitamin D and Omega-3 Trial (VITAL; ClinicalTrials.gov identifier: NCT01169259),19 researchers could not reproduce the links between low vitamin D and increased risk of cancer. More than 25,000 healthy people were randomly assigned to receive either 2,000 IU per day of vitamin D3 (along with omega-3 fatty acid supplementation) or placebo. Men enrolled in the trial had to be at least 50 years of age, and women had to be at least 55 years.

After a median follow-up of more than 5 years, there were no differences between those who received vitamin D/omega-3 supplements and those who did not in terms of death from cancer, invasive cancer of any type, breast cancer, prostate cancer, or colorectal cancer. These study results mean that otherwise healthy people do not benefit from vitamin D supplementation to prevent cancer. This study was funded in part by the NIH.

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