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

• Ability to repair DNA, a critical factor in lung cancer development? - It is obvious that factors other than exposure to carcinogens are involved in lung cancer, since only 10-15% of smokers develop the disease. The most likely candidate is some genetic-based factor. A report in the September 15, 1996 issue of Cancer Research looked at the ability of lymphocytes isolated from the blood of lung cancer patients and matched controls to repair DNA, a genetic based capability. The researchers found that the mean level of repair in cancer cases was lower than in controls (3.3% versus 5.1%). Factoring in age, sex, ethnic, and smoking status, cases were calculated to be 5-times more likely to have reduced DNA repair capacity. Among subgroups examined, reduced repair capacity was more likely in cancer cases aged below 65 years and smokers. The data suggested that lowered ability to repair damaged DNA is a factor in developing lung cancer. (Wei, Cancer Res 56:4103, 1996)

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• Pleural effusions without an apparent primary cancer - Malignant pleural effusions, fluid containing cancer cells in the chest, accounts for about 12% of all cancers in patients presenting without clear evidence of a primary cancer. Between 6% and 15% of these effusions turn out to be from unknown primary tumors after the patients are worked up. An article from the Royal Marsden Hospital in the UK, appearing in the September, 1996 issue of the British Journal of Cancer, described 42 patients with such effusions and no obvious evidence of primary disease. A primary tumor, lung cancer, was found in 15 patients (36%) and a thoracic CT scan was compatible with lung cancer in 11 patients. Fiber optic bronchoscopy did not reveal any cases not also seen with CT. Symptom relief was achieved in 78%, and 86% of patients showed an objective response, after chemotherapy (MVP, MCF, or ECF). These patients had a poor overall median survival of only 12 months. (Bonnefoi, Br J Cancer 74:832, 1996)

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• CYFRA 21-1, further evidence of its value as a prognostic indicator for lung cancer - Cytokeratins are structural proteins that form part of what can best be described as the cell's skeleton. Normally they are not found in the serum, but cell destruction and death of tumor cells may release fragments of them. A test for such fragments, the CYFRA 21-1 assay test, was applied by an international group of researchers in Poland, Italy, and the US to 91 patients who were to undergo surgery for squamous cell lung cancer. Their study, reported September, 1996 in the British Journal of Cancer, described elevated preoperative levels of CYFRA 21-1 in 55% of the patients. There was a clear association between increasing CYFRA 21-1 levels and advancing stage of the disease (TNM stage), and poor overall and disease-free survival. (Niklinski, Br J Cancer 74:956, 1996)

  Editor's Comment: - CYFRA 21-1 has already achieved some recognition as a diagnostic factor (e.g., Stieber, Cancer 72:707, 1993) and the authors of the article presented here have shown previously that it is associated with positive lymph nodes (Niklinski, Eur J Cancer Prev 3:227, 1994), as well as with tumor recurrence when measured postoperatively (Niklinski, Eur Respir J 8:291, 1995). The present report represents a logical extension of the use of this marker to obtain preoperative prognostic information on likely treatment failure.

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• Effects of cigarette smoking on lung function in boys and girls - Although not strictly addressing lung cancer, an article in the September 26, 1996 issue of the New England Journal of Medicine is nevertheless highly relevant. Doctors at the Brigham and Women's Hospital and Harvard University in Boston claimed that cigarette smoking (5 or more per day) in adolescents 10-18 years of age is associated with some degree of airway obstruction and a lowered rate of growth of lung function. The most notable finding in this study of 5,158 boys and 4,902 girls was that the effect was significantly greater in girls than in boys. The growth of two measures of lung function, called FEV1 and FEF25-75, were 1.09% and 1.25% per year slower in smokers than non-smokers in girls, versus 0.2% and 0.93% per year slower in boys who were smokers compared with non-smokers. (Gold, New Engl J Med 335:931, 1996)

  Editor's Comment: - Assuming that effects on growth in lung function are likely to reflect damage to lung structure and function, which might also affect the risk of developing cancer, the greater susceptibility of females in this study could translate into a greater sensitivity to the carcinogenic action of smoking.