The CancerWeb Report, What's New In Cancer: August, 1996
Lung Cancer

• An antiasthmatic medication for cough due to lung cancer. - Most patients with lung cancer suffer from coughing, which can be an especially severe and distressing symptom for many. Such coughing is usually suppressed with opioid drugs, but these have a variety of side effects, including depression of respiration which can be dangerous in a patient whose lungs are already damaged. A recent report by researchers from Pavia, Italy, described the successful use by inhaler of sodium cromoglycate, an antiasthmatic medication commonly called cromolyn sodium or Intal, to reduce the severity of coughing in lung cancer patients. (Moroni, Br J Cancer 74:309, 1996, July)

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• Genetic predisposition to lung cancer, it can be a complex picture. - A genetic study done at the Saitama Cancer Center in Japan was described in the August 15, 1996 issue of Cancer Research. The study examined the specific forms of two genes, one called CYP1A1, which converts certain cancer-causing hydrocarbons like benzpyrene into active carcinogens, and if present in its B or C form predisposes to lung cancer, and a second gene, Mu-GSTM1, which if deficient or inactive leads to inadequate protection through lack of glutathione to neutralize these damaging substances. When the researchers looked at these two genes in 232 patients with lung cancer (non-small cell kind), they found that the longest survival among those who were smokers, about 100 months, occurred when the patients were positive for Mu-GSTM1 and with A-type CYP1A1, while the worst survival, 24 months, was for those negative for Mu-GSTM1 and positive for types B and C CYP1A1. (Goto, Cancer Res 56:3725, 1996)

  Editor's Comment: - This study tells us that merely looking at one predisposing genetic factor may not be adequate. Genetic susceptibility to cancer of any kind depends on a balance between those genetic factors which may favor formation of damaging chemicals or present some genetic target, and genetic control of the way in which cancer-producing chemicals are handled or neutralized in the body.

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• A new marker for the prognosis of lung cancer? - In a study from Kanazawa University in Japan, reported in the August, 1996 issue of Clinical Cancer Research, it was found that the level of a special factor for promoting the growth of blood vessel cells, called VEGF, was a good indicator of those lung cancer patients likely to do poorly. Patients with high expression of VEGF survived for a mean time of 8 months and only 16.7% survived for 5 years, compared with 151 months and 77.9% for those with low levels of VEGF expression. (Ohta, Clin Cancer Res 2:1411, 1996)

  Editor's Comment: - The differences reported were very striking, suggesting that VEGF may be a very useful indicator of prognosis. We have discussed the important role of formation of a new blood supply in growth of cancers in a number of earlier issue of the CancerWeb Report, and this result is a practical expression of that role. However, only 42 cases of lung cancer and 3 human lung cancer cell lines were examined, and from among these there were only 17 who actually underwent surgery and were evaluated for survival. This research should definitely be followed up with a larger study.

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• No increased risk of lung cancer from radon exposure. - A study of lung cancer cases (total of 1,973) in all those in Finland living in one-family houses over the period 1967 until the end of 1985 was reported in the July 17, 1996 issue of the Journal of the National Cancer Institute. Cases were diagnosed between 1985 and 1992, and 2,885 control subjects were used for this study to provide appropriate matching within the total group. Smoking (intensity, duration, age at starting) both active and passive, occupational exposure to asbestos, age, sex, time of residence, and 12-month radon levels were examined. The results failed to show any connection between indoor radon exposure and risk of lung cancer. (Auvinen, JNCI 88:966, 1996)

  Editor's Comment: - The issue of whether indoor exposure to radon is a significant cause of lung cancer is a highly visible one. Publicity surrounding the issue has already built a multimillion-dollar business in radon exposure measurement and control. However, although the role of radon in causing lung cancer in underground miners is very clear, the epidemiologic evidence of a similar role for residential radon is very shaky. One large Swedish study showed a significant association between indoor radon exposure and lung cancer, but at least six studies in Canada, China, Finland, Sweden, and the US, have failed to confirm this connection. This latest Finnish study is both negative and convincing. It was well carried out, used long-term radon measurements over 12 months, and took into account many of the complicating factors such as smoking and occupational exposures. Radon exposure might be expected to be a more serious problem in Finland because exposures tend to be higher there than elsewhere, because of the climate, natural uranium concentration, and type of house construction.