Changing trends

Authors

  • Dr. David S. Rosenthal MD

    1. Rosenthal is President of the American Cancer Society and Director, University Health Services; Henry K. Oliver Professor of Hygiene; and Professor of Medicine, Harvard Medical School, Cambridge, MA
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The data in “Cancer Statistics, 1998” are both unique and encouraging.1 For the first time, the American Cancer Society's Department of Epidemiology and Surveillance reports a favorable change in direction, with a reduction in the total number of new cancer cases and declining cancer death rates in the United States. In addition, 5-year survival rates continue to improve for most cancers (except those of the lung and bronchus).

This good news in cancer statistics comes at a most opportune time. The ACS Board of Directors is formulating its direction for the next decade, adopting programs that will dramatically reduce both the incidence of and deaths from cancer. In February 1997, the Board of Directors resolved to achieve a 50% decrease in cancer mortality by the year 2015. At its February meeting this year, the Board will develop a goal for decreasing the incidence of cancer by the year 2015.

“Cancer Statistics, 1997” included a projection of 1,382,400 new cases of cancer for the calendar year 1997.2 A midyear review published in the July/August issue of CA adjusted the estimate to 1,257,800 (a 9.0% decrease).3 The current article by Landis and colleagues puts the 1998 estimate at 1,228,600 (a further decrease of 2%).1 In summary, the current estimate of new cases for 1998 is more than 11% lower than the original estimate of January 1997.

The major reason for readjustment of the 1997 estimate was the correction in the expected number of new prostate cancer cases. As Wingo and colleagues3 note, the incidence of prostate cancer increased dramatically in the late 1980s and early 1990s partly because of new techniques of early detection, such as prostate-specific antigen screening.

In January 1997, the estimate for new cases of prostate cancer was 334,500.2 The correction in July 1997 reduced the projection to 209,900,3 and the 1998 estimate is 184,500.1 The current figure better represents the expected number of new prostate cancer cases now that adjustment has been made for the significant increase in incidence attributable to early detection techniques.

Although these estimates should not be used to track true incidence (which is better done with data from the Surveillance, Epidemiology, and End Results [SEER] program and state cancer registries), this is the first time that the trend in estimation of figures has changed direction.

This year, the number of deaths from cancer is estimated at 564,800.1 Last year's estimate was very much the same at 560,000.2 Within these numbers, significant downward trends were seen in many cancers: in lung and bronchus cancer and in prostate cancer among men, in breast cancer among women, and in colon and rectal cancer among both men and women.

SEER data confirm a decrease in mortality for each year from 1991 through 1995. The nation's cancer death rate fell 2.6% in this period, the first sustained decline since recordkeeping first began in the 1930s.4

Specifically, between 1990 and 1994, deaths decreased 1.4% per year for lung cancer among men, 0.5% per year for prostate cancer, and 1.9% and 1.5% per year among men and women, respectively, for colon and rectal cancer.1 In addition, breast cancer deaths among women decreased 1.8%, but, unfortunately, deaths caused by lung cancer continue to increase among women.1 The decreased death rates have been seen in both white and African American populations.

Finally, 5-year relative survival rates also continue to improve. In whites, the 5-year survival rate for all sites was 50% in 1974 to 1976; the rate rose to 52% in 1980 to 1982 and to 60% in 1986 to 1993 (Table 11, p. 23).1

Survival rates in African Americans also have increased, but at a slower rate, creating a larger gap. African Americans had a 5-year relative survival rate for all sites of 39% in 1974 to 1976, which rose only slightly to 40% in 1980 to 1982 and to 44% in 1986 to 1993.1

Specific cancer sites have had striking changes in survival rates. Included among such sites is breast cancer, the survival rate of which is now up to 86% in white women but only 70% in African American women. Similar differences can be seen in survival rates for colon and rectal cancer, endometrial cancer, and prostate cancer. Thus, not all of the news is good news. African Americans have survival rates that are 10% to 15% lower than those of whites for the most frequent cancers other than lung cancer.

Although many difficulties are inherent in the estimation of new cases, sufficient data exist to prove that both incidence and mortality rates are decreasing. The factors leading to these changing trends may be debated, that is, whether they are caused by prevention, early detection, or aggressive therapy. Whatever the primary cause for these favorable trends, we should accept the challenge to enhance our efforts in all areas.

“Cancer Statistics, 1998” alerts us to areas that need further attention, particularly the differences in survival statistics between African Americans and whites. The other major discrepancy in mortality has been a more favorable decline in mortality among men (almost 4.3%) than among women (1.1%). The disparity is probably the result of the continued increase in lung cancer deaths among women.

Although we should be pleased with the changing trends in cancer mortality, incidence, and survival, we must still be aware that cancer is the leading cause of death in some age groups. We must remember that more than half a million people will die of cancer this coming year. We must make a New Year's resolution to work together collaboratively with all health care organizations to develop and implement programs to hasten the decline in the incidence of and mortality from cancer.

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