Wednesday, July 9, 2008

Neoplasms: 2

This is the second blog in a series of blogs on neoplasia.

Let us admit that we are not winning the war on cancer.

Here are the facts, published by the U.S. National Cancer Institute's SEER (Surveillance, Epidemiology and End Results) project, and available at:

Table I-2
All Races, Males and Females

Age Group 1950 1978 2005

0-4 11.1 4.6 2.2
5-14 6.7 4.1 2.5
15-24 8.6 6.1 4.1
25-34 20.4 14.2 9.1
35-44 63.6 50.7 32.8
45-54 174.2 179.6 118.3
55-64 391.3 428.9 329.7
65-74 710.0 803.4 748.8
75-84 1167.2 1204.1 1265.1
85+ 1450.7 1535.3 1643.7
All Ages 195.4 204.4 184.0

The numbers are deaths per 100,000 population. These numbers are age-adjusted. We'll talks about age adjustment of incidence rates in a future blog, but for the moment, it suffices to note that age-adjustments compensates for incidence biases that would apply if there were large age-shifts in the populations (1950, 1978, 2005).

For all ages, the death rate from cancer rose from 195.4 in 1950 to 204.4 in 1975 and then dropped a little to 184.0 in 2005. Much has been made of the drop in death rate between 1975 and 2005. Actually, the drop takes us to a number that is very similar to the death rate back in 1950.

If you look at the different age groups, the biggest drops occur in the pediatric ages. This confirms what we already know, that we have made remarkable gains in treating childhood cancer. However, childhood cancer is rare. The large drop in the incidence of childhood cancer is just a drop in the bucket of the large number of cancer deaths occurring in adults.

With few exceptions, adults are dying from the same types of cancers today that were killing adults in 1950, and at about the same rates.

How can this be true when we are told by experts that cancer survival is improving?

Here is an excerpt from the MedicineNet site:

The title of the report is, "Better and Longer Survival for Cancer Patients"

The lead-off text is, "Statistics (released in 1997) show that cancer patients are living longer and even "beating" the disease. Information released at an AMA sponsored conference for science writers, showed that the death rate from the dreaded disease has decreased by 3 percent in the last few years. In the 1940's only one patient in four survived on the average. By the 1960's, that figure was up to one in three, and now has reached 50% survival."

When we look at death rates, it seems that our risk of dying from cancer is about the same today as it was in 1950. Contrariwise, when we talk about cancer survival, it looks as though we've made remarkable progress.

What's going on?

In the next few blogs, I'll discuss the kinds of lessons we learn from looking at cancer death rates and the kinds of information we get when we study cancer survival.

-Copyright (C) 2008 Jules J. Berman

key words: cancer, tumor, tumour, carcinogen, neoplasia, neoplastic development, classification, biomedical informatics, tumor development, precancer, benign tumor, ontology, classification, developmental lineage classification and taxonomy of neoplasms

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