Longkanker: 80% van alle longkanker in risciogroepen zou kunnen worden voorkomen en tijdig genezen als er op tijd een CT scan zou worden gemaakt.

Actuele ontwikkelingen over therapeutische behandelingen van longkanker zijn te lezen onder kankersoorten-longkanker

28 oktober 2006: Bron: N Engl J Med. 2006;355:1763-1771, 1822-1824 en Medscape

80% van alle longkanker in risiciogroepen (bv. rokers) zou kunnen worden voorkomen en tijdig genezen van hun longkanker als er op tijd een CT scan zou worden gemaakt. Dit zijn de zeer opmerkelijke en hoopvolle uitkomsten uit een grote studie onder ruim 31.000 personen uitgevoerd gedurende 12 jaar. Ter vergelijking: 88% van de mensen waar vroegtijdig longkanker werd ontdekt door vroegtijdige screening d.m.v. een CT-scan was na tien jaar nog in leven. Van de longkankerpatiënten die longkanker stadium 4 ontwikkelden voordat het ontdekt werd leeft nog slechts 5% na vijf jaar. Een zeer groot verschil dus. Onderstaand artikel uit Medscape spreekt voor zich lijkt ons.

October 26, 2006 — Some 80% of deaths from lung cancer could be prevented by spiral computed tomography (CT) scanning in high-risk populations, say researchers reporting on a large collaborative study in the October 26 issue of The New England Journal of Medicine. Such screening detects lung cancer at its earliest stage, when it is curable, whereas usually with lung cancer, the diagnosis is made at an advanced stage of the disease, when the prospect is much bleaker.

Of the lung cancer cases detected by CT screening in the study, 85% were in clinical stage I, and these patients had an estimated 10-year survival rate of 88%, the group reports. In contrast, the 5-year survival rate for patients with stage IV lung cancer is about 5%, an accompanying editorial points out.

"We believe this study provides compelling evidence that CT screening for lung cancer offers new hope for millions of people at risk for this disease, and could dramatically reverse lung cancer death rates," says principal investigator Claudia Henschke MD, PhD, New York–Presbyterian/Weill Cornell Medical Center, in a press statement.

Rates of Detection Similar to Mammograms
Conducted by the International Early Lung Action Program Investigators, the study spanned the United States, Europe, Israel, China, and Japan. The group screened 31,567 asymptomatic persons at high risk for lung cancer from 1993 to 2005, followed by repeat screenings in 27,456 of these individuals. All of the participants were 40 years or older and were current or former smokers, had been exposed to second-hand smoke, or had occupational exposure to asbestos, beryllium, uranium, or radon.

Scanning revealed lung cancer in 484 participants, of whom 412 (85%) had clinical stage I lung cancer, the group reports.

The rates of detection were 1.3% on baseline CT screening and 0.3% on annual screening. These values are slightly higher than those for the detection of breast cancer on baseline screening (0.6% - 1.0%) and similar to those for annual screening (0.2% - 0.4%) among women aged 40 years or older, the researchers note.

Estimates for the cost-effectiveness of CT screening for lung cancer are similar or better than those for mammography screening for breast cancer, Dr. Henschke comments in the press statement. The charge for a low-dose CT scan, such as those used in the study, varies from about $200 to $300. However, the cost of treating lung cancer when caught in stage I is less than half that for treatment of late-stage disease.

However, the editorial says "the question of cost-effectiveness remains unanswered." But it praises the study as a "provocative, welcome salvo in the long struggle to reduce the tremendous burden of lung cancer on society."

Best Survival Rates Ever Reported
This study contributes "a substantial amount of new important information regarding the management of clinical stage 1 lung cancer that is detected on CT screening," writes editorialist Michel Unger, MD, from the Pulmonary Cancer Detection and Prevention Program at Fox Chase Cancer Center in Philadelphia, Pennsylvania.

"The 88% survival rate is the best that has ever been seen in lung cancer, as far as I am aware," Dr. Unger told Medscape in an interview. "This is a very positive finding," he commented, "as lung cancer is the biggest killer among all the cancers — in the United States, lung cancer kills more people that breast, colon, prostate and cervical cancer combined." The lower mortality among patients with these other cancers is due, at least in part, to widespread use of screening methods to detect these cancers, Dr. Unger writes in the editorial.

There is not as yet any screening for lung cancer. The US Preventive Services Task Force last considered the issue in 2004 and concluded that there was insufficient evidence. Until recently, there was little "vigorous research" on this issue, Dr. Unger notes. The situation was not helped by studies in the 1970s that showed that chest x-rays in smokers were ineffective in detecting early lung cancer. Also, there is still a stigma associated with the condition — "unfortunately, we have not left behind the idea that lung cancer is a punishment, not a disease," Dr. Unger comments.

Single Study Should Not Change Policy
Dr. Unger commented to Medscape that the current study of CT screening is "very impressive," but he pointed out that it was a case-controlled study, not a randomized clinical trial. "A single study should not change policy," he said. It should be considered as a factor, but there are many other issues that policy makers need to take into account.

Dr. Unger pointed out that the success of the current study must be attributed to the whole process that involved — not just the CT screening, but also the whole management algorithm that was in place, including prompt treatment with surgical resection and/or chemotherapy and/or radiation. Of the 412 patients with stage I lung cancer, 302 underwent surgical resection within 1 month of diagnosis, and within this group, the survival rate was 92%. A further 8 patients in this subgroup of stage I disease opted not to receive any treatment; all 8 untreated patients died within 5 years of diagnosis.

It is the whole process that is important, not just the screening, Dr. Unger emphasized, and this is essential to bear in mind when policies about screening are being considered. The other point is the question of whom to screen, as this influences how cost-effective the screening turns out to be. "At the moment, we don't have a good definition of a high-risk population," he said. "We know that smoking is a risk factor, but not all smokers develop lung cancer, and we may need to wait until we have better pointers, such as biomarkers or genetic protein patterns that identify those individuals who will go on to develop lung cancer."

N Engl J Med. 2006;355:1763-1771, 1822-1824.

preventie, longkanker, CT-scan