The increasing human lifespan is a cause for optimism, yet it is essential to recognize that aging presents significant challenges, particularly in industrialized societies. The issue extends beyond the fact that elderly individuals are often less economically productive; they also experience a higher burden of chronic illnesses, necessitating substantial healthcare expenditures. Therefore, it is crucial to distinguish between lifespan in general and healthy lifespan (healthspan). From a public health and biomedical research perspective, the primary objective should not merely be to extend life expectancy but to ensure that extended years are spent in good health.

One of the most pressing concerns associated with aging is the exponential increase in cancer risk. Aging is one of the strongest risk factors for cancer, likely due to the accumulation of genetic mutations, epigenetic alterations, and immune system decline over time.

In a previous commentary on female scientists in my country, I explored how some scholars failed to provide insights into fundamental biological questions, while a group of dedicated female scientists endeavored to address an important evolutionary puzzle: why humans have been adapted to different UV radiation levels across various regions on Earth through variations in melanin levels in their skin, or have been adapted to high levels of external and internal exposures to ionizing radiation in areas such as the high-background radiation areas (HBRAs) of Ramsar. However, humans have not developed robust cancer suppression mechanisms.

This paradox highlights the fundamental link between aging and cancer—a connection that underscores the necessity for further research into biological adaptations, DNA repair mechanisms, and evolutionary constraints. Understanding why humans have evolved to tolerate certain environmental stressors but remain vulnerable to cancer with age could provide valuable insights for developing new cancer prevention and treatment strategies.

References:

Faraz M, Nematollahi S, Tahmasebi S, Welsh JS, Bevelacqua JJ, Mortazavi SMJ, Mortazavi SA. The Association between Breast Cup Size and Breast Cancer Incidence: Insights from a Global Dataset. J Biomed Phys Eng. 2025 Feb 1;15(1):93-100. doi: 10.31661/jbpe.v0i0.2412-1869. PMID: 39975528; PMCID: PMC11833153. https://pubmed.ncbi.nlm.nih.gov/39975528/

Mortazavi SMJ, Zare O, Ghasemi L, Taghizadeh P, Faghani P, Arshadi M, Mortazavi SAR, Sihver L. A Reexamination of Peto's Paradox: Insights Gained from Human Adaptation to Varied Levels of Ionizing and Non-ionizing Radiation. J Biomed Phys Eng. 2024 Jun 1;14(3):309-314. doi: 10.31661/jbpe.v0i0.2402-1729. PMID: 39027707; PMCID: PMC11252545. https://pubmed.ncbi.nlm.nih.gov/39027707/

New research shows bigger animals get more cancer, defying decades-old belief, Published: March 6, 2025 8.32pm GMThttps://theconversation.com/new-research-shows-bigger-animals-get-more-cancer-defying-decades-old-belief-251287

Welsh, MD, "Sharks Get Cancer, Mole Rats Don't: How Animals Could Hold the Key to Unlocking Cancer Immunity in Humans," published by Prometheus Books and distributed by Penguin Random House. https://www.sciencedaily.com/releases/2016/05/160506132525.htm