Controversial cancer test gains support

August 14, 2005

Some cancer specialists have stepped up calls for smokers and ex-smokers to undergo advanced screening for lung cancer. They reacted to the recent deaths of Peter Jennings and Barbara Bel Geddes and the disclosure that Dana Reeve has lung cancer by urging people to have their lungs screened with special helical CT chest scans.

Because health insurance plans do not cover such screening, anxious patients who can afford it are paying about $300 for the test out of pocket. The American Cancer Society discourages using the advanced CT scan technique for screening because doctors do not yet know how to interpret findings of small lesions. A helical scan can show lumps as small as 2 millimetres in diameter, but doctors do not know what to make of such lesions. The tumors may not actually be cancerous, and even small cancers may spontaneously remit or may grow so slowly that surgery, radiation or chemotherapy would do far more harm than good. Preliminary results of a large ongoing study, expected within a year, may provide tentative guidelines on when to perform a biopsy and when CT screening would be worthwhile.

Smoking one pack of cigarettes daily for 20 years or more brings a 50 percent chance of dying from lung cancer. For any smoker, 10 years of abstinence cuts the risk in half. Women are more vulnerable than men even if they don't smoke. Environmental pollutants work with smoking to increase risk. People with affected parents or siblings are 2–3 times more likely to fall ill with lung cancer. A malignant tumor can grow silently for years. In the United States by the time it is recognized a lung cancer has spread in 3 out of 4 patients. Routine chest X-ray screening does not improve survival rate. Although patients treated after their lung cancer has shown up in a highly sensitive helical (also called "spiral") CT scan are much more likely to survive, this may only be because small cancers grow very slowly or would cause no trouble even without treatment.

On the other hand, some cancer experts already strongly support performing the screening. They point out that prompt treatment of lung cancer clearly improves prognosis and that an equivocal scan can be repeated after some months to see if a lesion has enlarged. Furthermore, a decision not to wait for conclusive science but to undergo a helical scan would be supported by consideration of a patient's age, family history, history of smoking and other risk factors. Annual scanning has been recommended for people over age 50 who have smoked 1 pack daily for 30 years or 2 packs for 15 and who also have a known lung condition.