Why We Really Can't "Cure" Cancer Yet?

Why can't we cure cancer? This science documentary explains the biology of cancer. How chemotherapy really works, why cancer treatment fails, and why a tumour is evolution running inside your own cells. Somewhere in the world tonight there is a cancer that is eleven thousand years old. It began in one dog before writing, before farming, before the wheel, and it is still alive, still spreading, walking around on four legs. How a tumour outlives its owner by eleven millennia is the key to why a single cure will never exist. We trace the real answer, from the day America gave itself a deadline to cure cancer by 1976 to the newest cancer research of 2026. Why penicillin works and no cancer drug ever can. The eyelid study that found tumour-driving mutations in a quarter of perfectly healthy skin cells. Bone cancer in a 76-million-year-old dinosaur. Why elephants carry twenty copies of the gene you have one of. The contagious cancers of dogs, Tasmanian devils and clams. And the cancers we genuinely have cured, and why nobody calls them cancer anymore. If a cancer cell is built from your own DNA, what is left to target? Why does a treatment that works make the next tumour immune? And if every cancer vanished tomorrow, why would life expectancy rise by just three years? Drop a comment: What part of this changed how you see the disease? ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ SOURCES ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ CANCER IS ALREADY IN YOU ▸ National Cancer Act of 1971. National Cancer Institute. cancer.gov ▸ Martincorena, I., et al. (2015). "High burden and pervasive positive selection of somatic mutations in normal human skin." Science, 348: 880–886. ▸ Bell, K. J. L., et al. (2015). "Prevalence of incidental prostate cancer: A systematic review of autopsy studies." Int. Journal of Cancer, 137(7): 1749–57. A TUMOUR IS A FOREST ▸ Gerlinger, M., et al. (2012). "Intratumor heterogeneity and branched evolution revealed by multiregion sequencing." NEJM, 366(10): 883–92. ▸ Greaves, M., & Maley, C. C. (2012). "Clonal evolution in cancer." Nature, 481: 306–313. CANCER IS OLDER THAN HUMANITY ▸ Ekhtiari, S., et al. (2020). "First case of osteosarcoma in a dinosaur: a multimodal diagnosis." Lancet Oncology, 21(8): 1021–22. ▸ Odes, E. J., et al. (2016). "Earliest hominin cancer: 1.7-million-year-old osteosarcoma from Swartkrans Cave." S. African Journal of Science, 112(7/8). PETO'S PARADOX ▸ Peto, R., et al. (1975). "Cancer and ageing in mice and men." British Journal of Cancer, 32(4): 411–26. ▸ Abegglen, L. M., et al. (2015). "Potential mechanisms for cancer resistance in elephants and comparative cellular response to DNA damage in humans." JAMA, 314(17). ▸ McBride, K. A., et al. (2014). "Li-Fraumeni syndrome: cancer risk assessment and clinical management." Nature Reviews Clin. Oncology, 11(5): 260–71. CONTAGIOUS CANCER ▸ Murgia, C., et al. (2006). "Clonal origin and evolution of a transmissible cancer." Cell, 126(3): 477–87. ▸ Baez-Ortega, A., et al. (2019). "Somatic evolution and global expansion of an ancient transmissible cancer lineage." Science, 365: eaau9923. ▸ Pye, R. J., et al. (2016). "A second transmissible cancer in Tasmanian devils." PNAS, 113(2): 374–79. ▸ Metzger, M. J., et al. (2015). "Horizontal transmission of clonal cancer cells causes leukemia in soft-shell clams." Cell, 161(2): 255–63. THE CANCERS WE DID CURE ▸ Siegel, R. L., et al. (2025). "Cancer statistics, 2025." CA: A Cancer Journal for Clinicians, 75(1): 10–45. ▸ Hunger, S. P., et al. (2012). "Improved survival for children and adolescents with acute lymphoblastic leukemia, 1990–2005." J. Clinical Oncology, 30(14): 1663–69. ▸ Einhorn, L. H. (2002). "Curing metastatic testicular cancer." PNAS, 99(7): 4592–4595. ▸ Wong, C. H., Siah, K. W., & Lo, A. W. (2019). "Estimation of clinical trial success rates and related parameters." Biostatistics, 20(2): 273–86. ▸ DiMasi, J. A., et al. (2013). "Clinical approval success rates for investigational cancer drugs." Clin. Pharmacology & Therapeutics, 94(3): 329–35. THE PRICE OF MULTICELLULARITY ▸ Greaves, M. (2015). "Evolutionary determinants of cancer." Cancer Discovery, 5(8): 806–20. ▸ Aktipis, C. A., et al. (2015). "Cancer across the tree of life: cooperation and cheating in multicellularity." Phil. Trans. Royal Society B, 370(1673). ▸ Olshansky, S. J., Carnes, B. A., & Cassel, C. (1990). "In search of Methuselah: estimating the upper limits to human longevity." Science, 250: 634–40. WHERE WE ARE NOW ▸ Tian, R., et al. (2026). "Biological aging and generational shifts in early-onset cancer risk." Nature Medicine. doi:10.1038/s41591-026-04448-w ▸ Merck & Moderna (19 August 2026). Phase 3 results: intismeran autogene plus pembrolizumab in adjuvant melanoma. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ For business inquiries: [email protected] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ #Cancer #CancerResearch #CancerTreatment #Chemotherapy #ScienceDocumentary #Biology #Oncology #CancerBiology