Here is a short excerpt from Chapter 8:
Though there are thousands of types of human cancer, the bulk of cancer cases in humans are accounted for by just a few, under a dozen, types of cancer. The two most commonly occurring cancers of humans are basal cell carcinoma of skin and squamous cell carcinoma of skin. Together, these two tumors account for about 1.2 million new cancers each year in the U.S., nearly equal to the number of all the other types of cancers combined. These tumors are so common that, frequently, more than one basal cell carcinoma or squamous cell carcinoma will occur in the same individual. Fortunately for us, these two tumors seldom cause deaths; most cases are cured by simple excision. Cancer registries do not bother to collect records on these two cancers, and the published data on cancer incidence, compiled from registries and surveillance databases, typically ignores these two tumors. Nonetheless, we will see later in this chapter that basal cell carcinoma of skin and squamous cell carcinoma of skin tell us much about the biology of cancer in humans.I urge you to read more about this book. There's a good preview of the book at the Google Books site. If you like the book, please request your librarian to purchase a copy of this book for your library or reading room.
In Section 2.1, we discussed Pareto’s principle, wherein a few common items account for the majority of instances of any collection. Cancer obeys Pareto’s principle: a few cancers account for most cases of cancer occurring in humans. Collected U.S. data for the year 2008 indicate that, after excluding basal cell carcinomas and squamous cell carcinomas of skin, there were 1,437,180 new cancers. In the same year, there were 565,650 cancer deaths, of which 161,840 individuals died of lung cancer . The percentage of U.S. cancer deaths from lung cancer was 28.6% (161,840/565,650). Also in 2008, there were 49,960 deaths from colorectal cancer, accounting for 8.8% of U.S. cancer deaths (49,960/565,650). Just two cancers (lung and colorectal) accounted for 37.4% of deaths from cancer in the U.S. When age-adjusted data are examined, the top five cancer killers (lung, colon, breast, pancreas, and prostate) account for 57% of all cancer deaths  (see Glossary item, Age-adjusted).
Observing that a few types of cancers account for the bulk of human cancer deaths, funding agencies have concentrated their efforts on finding cures for the most common cancers. Just seven types of common cancer, out of about 6000 known cancers, account for over 36% of cancer funding . The justification for distributing cancer research funding toward research in the common cancers is simple. If cures can be found for the most common cancers, we could drastically reduce the number of cancer deaths in the U.S. and in the world. Curing a rare cancer that might affect a few hundred people worldwide would seem to be an ill-advised investment of our limited resources. Hence the rare cancers receive relatively little cancer funding compared with the common cancers.
The drawback to this straightforward approach is that it has failed. Despite decades of funding, we still do not know how to cure common cancers when they are diagnosed at an advanced disease stage. New discoveries in cancer genetics have highlighted the incredible complexity of the commonly occurring cancers. The complexity of the common cancers has been a seemingly insurmountable barrier blocking the development of simple and effective cures. Despite the long-term efforts of an army of cancer researchers, the age-adjusted death rate from cancers in the year 2000 was about the same as it was in 1975. A significant drop in the cancer death rate since the year 2000 is largely attributed to smoking cessation and other preventive measures; not due to effective new cures for the advanced stage common cancers.
- Jules J. Berman, Ph.D., M.D. tags: rare disease, common disease, orphan disease, orphan drugs, advanced stage cancer, ineffective cancer research, advanced stage cancers, cancer priorities, cancer funding, cancer research funding