Cancer statistics: pluses and minuses.

Cancer statistics: Pluses and minuses

while scientists and the medical health profession continue to improve cancer treatments and prolong patients' lives, the number of new cancer cases keeps rising by about 1 percent each year, according to a report released last week by the National Cancer Institute in Bethesda, Md. Summarizing the latest (1985) data on cancer incidence and mortality, the annual report, unlike its predecessors, also includes a look at long-term cancer trends, starting in 1950.

Edward Sondik from the institute's Division of Cancer Prevention and Control said last week that the increases have been largely due to increases in lung cancer, still the leading cause of cancer deaths. But figures also indicate that new cases of lung cancer and deaths from the disease are decreasing or leveling off for many groups. Despite the good news regarding lung cancer, data based on all cancer sites combined show increases in both incidence (the number of new cases each year per 100,000 of a population) and mortality. During the 36-year period studied, incidence of all cancers increased 36 percent, while mortality increased 6.7 percent. Overall survival, based on 5-year survival beyond initial diagnosis, increased from 39 to 50 percent.

Most dramatic of the changing trends are those for cervical cancer, stomach cancer, melanoma and non-Hodgkin's lymphoma, says Sondik, who presented the report at the regular meeting of the National Cancer Advisory Board. Incidence of cervical cancer fell 77 percent, with mortality also dropping 73 percent - a sign of improved early detection methods, says Sondik. Stomach cancer's incidence and mortality also decreased by about 70 percent. On the other side, melanoma showed the greatest increase, with incidence more than doubling. Fortunately, says Sondik, mortality has not risen nearly so fast, because of better diagnosis. But for non-Hodgkin's lymphoma, both mortality and incidence rose about 120 percent.