Patients diagnosed by chance with lung cancer in cat scans have considerable better prognostics that patients diagnosed due to symptoms like chest pains, cough or pneumonia. These results are presented in a new scientific article by a research team at Landspítali University Hospital and the University of Iceland published recently in the European Respiratory Journal Open Research. The article describes the frequency of lung cancer diagnosed by chance, i.e. during patients' scans who bear no symptoms of the disease. It appears that around a third of those who undergo surgery for lung cancer are diagnosed incidentally. The results show the importance of diagnosing lung cancer early even though the best preventive measures against this type of cancer is the prohibition and eradication of smoking.
Lung cancer is the second most common cancer in Iceland in both genders with the highest mortality rate. Smoking is considered the cause of 90 percent of all lung cancers in Iceland, and around 160 cases are diagnosed annually. The symptoms for lung cancer are subtle which can delay diagnosis. However, lung cancer can sometimes be diagnosed without there being any symptoms, but the prognostics of those patients have not been previously studied in Iceland.
The research extended to all patients that underwent surgery for lung cancer during a 20 year period, 1990 - 2010. The cases were 508 in total and thereof 174 that were diagnosed incidentally; i.e. without symptoms or 34% of the group. In that group, most diagnoses were made in a traditional X-ray (75%) or in a cat scan of the chest (24%). Chest imaging in patients whose tumours were detected incidentally was undertaken for miscellaneous indications, most often at work-up for cardiovascular diseases (30%), preoperative evaluation (14%), unrelated cancer workup (13%) or after chest trauma (10%).
The proportion of incidentally detected tumours did not differ significantly during these 20 years even though access to imaging has increased considerably during this period. However, the proportion of tumours that were incidentally detected at CT rose steadily to 15% during the research period. The tumours that were diagnosed detected incidentally proved almost 2cm smaller than in patients with symptoms and had rarely spread to other organs. Five-year cancer-specific survival for those who were diagnosed incidentally was best if diagnosed by CT or 68%, compared to 57% in patients diagnosed with cancer by chest radiography, versus 41% in symptomatic patients.
The first author is Andri Wilberg Orrason at the Department of Cardiothoracic Surgery at Landspitali University Hospital, but Tómas Guðbjartsson, Professor at the University of Iceland's Faculty of Medicine and Chief Physician at the Department of Cardiothoracic Surgery at Landspitali University Hospital, led the study. Other authors are the doctors Kristján Baldvinsson, Húnbogi Þorsteinsson, Martin Ingi Sigurðsson and Steinn Jónsson, Professor at the UI Faculty of Medicine.