Clinical Update: Contraceptive Pearl
(May 2002)

The Mystery of Declining Cervical Cancer

Question: Incidence rates for cervical cancer (which occurs primarily in the developing world) have successively dropped by almost 40 percent between 1975 and 2000. (This translates to over 280,000 fewer cases worldwide.) What factors appear to be responsible for this mysterious drop?

1. Safer sexual behavior--resulting in less risk of infection with human papillomavirus, the causative agent of cervical cancer
2. Less smoking among women
3. Better screening and treatment for cervical cancer
4. Better ability to estimate cervical cancer
5. Reduction in the number of births to women in the developing world
6. Other

Answer: It seems likely that the most significant factor is answer: e) the reduced number of births, though other factors may have been at work. The total fertility rate in the developing world has fallen from about 7 in the 1950s and 60s to about 3.2 today.

Comments about the other suggested answers

1. It seems unlikely that there has been any large aggregate safer sexual behavior that would result in markedly reduced HPV infection.
2. Smoking has if anything probably increased.
3. Screening/treatment programs in the developing world are far too small to have had a substantial effect on overall incidence.
4. It is also possible that estimates have improved, but the case estimates were made by the same expert at the International Agency for Research on Cancer (DM Parkin) and changing methodology seems unlikely to account for the consistent downward trend.
5. It is also possible that other factors (nutrition, hygiene) could be involved, but seem unlikely to have that much impact.

---

These "Pearls" were prepared by Dr. James D. Shelton, Senior Medical Scientist, Office of Population, United States Agency for International Development (USAID).

Jim Shelton's Pearls online

Go to JHPIEGO TrainerNews