Second to prostate cancer, lung cancer is the most common cancer among South African men, and over 44  000 South Africans die each year from tobacco-related diseases.

Researchers based these new recommendations on a review of past studies which compared long-term health in smokers who underwent low-dose computed tomography (CT) screening for lung cancer, and those who received another cancer test or “usual care” instead.

The National Lung Screening Trial performed in the United States provided most of the evidence in favour of screening. The study found a 20% lower risk of lung cancer death among more than 26 000 people screened with low-dose CT annually for three years, compared to those who were tested with so-called chest radiographs instead.

But the combined prior research also suggested that in any round of CT screening, about one in five people will have positive results that require further testing, sometimes with invasive procedures – although only 1% will actually have lung cancer.

Assessing risk

According to the new recommendations from the American College of Chest Physicians and the American Society of Clinical Oncology, annual screening should be offered to current and former smokers, age 55 to 74, who have smoked at least a pack of cigarettes a day for 30 years.

The screening recommendations don’t apply to former smokers who quit more than 15 years ago, the researchers reported in the Journal of the American Medical Association.

Possible harms of lung cancer screening, they said, include the radiation associated with CT scans – which over long periods of time may increase the risk of cancer itself – as well as the unnecessary extra procedures and anxiety that come with a positive test that turns out to be a benign nodule.

Currently, most lung cancers aren’t caught until stage III or IV, and less than one in five people with a new diagnosis survives five years.

“Some people potentially will be harmed, and there’s even the chance some people will die (because of complications from screening). But that’s also the case of flu shots… and driving to the doctor’s office,” said Dr James Mulshine, a lung cancer researcher at Rush Medical College in Chicago (United States) who wasn’€™t involved in the study. He also suggested CT scans and other procedures are becoming safer over time, lowering the chance of screening-related harm.

Sources: Reuters Health, CANSA


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