Blacks' Surgery Rate, Cancer Deaths Linked
A big reason lung cancer is deadlier for blacks than for whites is that blacks are less likely to have the cancer surgically removed while they have a chance of survival, according to a study in today's issue of the New England Journal of Medicine. The researchers, from Memorial Sloan-Kettering Cancer Center in New York, said they don't know exactly why this is so.
Early lung cancer has few symptoms, so many patients do not learn they have it until it is too late to operate. Even with surgery, the chances are poor. About 34,000 Americans a year are diagnosed with non-small-cell lung cancer--the most common kind--early enough for surgery to make a difference.
The study looked at 10,984 such patients in a National Cancer Institute database of people in five states and five cities outside of those states. It found that the overall five-year survival rate among elderly whites was 34.1 percent, compared with 26.4 percent among elderly blacks.
Black patients were almost 13 percent less likely to have surgery than whites. Among those who did, about 39 percent of blacks and 43 percent of whites lived at least five years after the diagnosis. Without the operation, only 4 percent of blacks and 5 percent of whites made it that long.
"Obviously, the opening question left by this study is what is going on in that doctor-patient relationship or interaction" that leads to the black-white difference, said Peter B. Bach, who led the study.
Cancer Resistance Developed in Mice
Scientists have created cancer-resistant mice by deleting certain genes that govern the formation of blood vessels--a breakthrough that could lead to new drugs for wiping out tumors in people.
Each of the 57 specially bred mice was injected with 100 million tumor cells. Many didn't develop cancer; others grew tumors, but they eventually shrank or didn't spread. Deleting most copies of the genes appeared to have no harmful side effects on the mice.
The finding, reported in today's issue of the journal Nature by researchers at Memorial Sloan-Kettering, is the latest advance in one of the most promising areas of cancer research: angiogenesis, or blood vessel formation. Scientists are trying to find ways to kill cancer by stopping the growth of the blood vessels that nourish tumors.
Last year, in one of the most celebrated developments in angiogenesis research, Judah Folkman of Harvard University reported that two proteins, angiostatin and endostatin, caused tumors in rats to shrink or disappear by cutting off their blood supply. Tests on people are about to get underway.
The mice study involved two genes called Id1 and Id3 that were found to play a vital role in the little-understood process of angiogenesis.
TB Can Strike Survivors Again
Recovering from one bout of tuberculosis is no protection from contracting another strain of the lung ailment, an international team reports in today's New England Journal of Medicine. The researchers tested 16 people who suffered a second bout of TB, and found that 12 of the cases involved bacteria with a different DNA fingerprint. In other words, after recovering from one TB infection, they acquired a new one rather than suffering a relapse.
That suggests that an elderly person who develops a second case of TB may have been struck by a resistant strain, not one of the older strains still responsive to antibiotics. It also means that people who recover once from TB are not immune to future infections.
"If natural infection does not confer protective immunity, the development of improved vaccines against tuberculosis will be especially challenging," experts noted in an accompanying editorial.