Scanomed - Nukleráis medicina központok

Tumorous diseases of lungs

Lung cancer is classified into the group of malignant tumorous diseases. It is a pathological cell proliferation with uncontrolled cell-division, originating from pulmonary tissues.
If it is not treated, cancer cells may spread to neighboring tissues and to other parts of the body. This process is called metastasis. This is the most frequent tumorous disease which means 1,35 million new cases annually and it accounts for 1,18 million deaths worldwide. The most well-known symptoms of it are cough (coughing up blood), dyspnea and weight loss.

We can distinguish between small cell and non-small cell cancer types. Distinguishing is very important because this determines the future applied therapy. The non-small cell lung cancer (NSCLC) can be treated with surgical intervention but it responds not so well to chemo- and radiation therapy. For the small cell lung cancer (SCLC) just the opposite is characteristic: it is usually inoperable but more sensitive to chemotherapy and radiation therapy.

Among factors triggering lung cancer smoke takes the first place. Only 15% of patients suffering from lung cancer are non-smokers, in case of them genetic and other environmental factors (for example radon gas, contact with asbestos, air pollution and passive smoking) play a crucial role.


Round opacity in the lung (Solitary pulmonary nodule (SPN)

FDG PET-CT has an essential role in the diagnosis of round opacities (shadows) found in the lung. It is useful in determining whether the (more than 1 cm in size) round opacity is benign or malignant, especially if the histological sample taking was unsuccessful, controversial or contraindicated. Based on the seen PET-CT image we can distinguish between benign and malignant foci with high accuracy, but we can only report about the origin of the abnormality (primary or metastatic) after evaluation of clinical data, histological and other examinations. In case of inflammatory processes (for example in case of TB) we may get a false positive result. With proving or excluding distant metastases (adrenal gland, liver, bone) we can contribute to determining the oncological stage.


Non-small cell lung cancer (NSCLC)

From the group of lung cancers in case of the non-small cell lung cancer (NSCLC) has FDG PET-CT a well-defined role in the diagnostic process. The most important indication of PET-CT is in determining the stage after proving the presence of the disease with histological examination. Within this the aim is to detect thoracic lymph metastases and possible unnoticed distant metastases. In case of certain rare histological types of lung cancers, results of PET-CT examinations can be false negative.
PET-CT is also useful in follow-up of lung cancer patients to detect the recurrent/remaining viable tumor. In case of PET-CT examinations performed to follow the therapy it has to be taken into consideration that FDG accumulation of malignant tumors is also significantly reduced after chemo-and radiation therapy if the treatment is successful. According to this fact, if the aim of the examination is to detect the remaining viable cancer tissue after the treatment –based on international experience- one should wait with the control PET-CT for at least 3 weeks after chemotherapy and for at least 3 months after radiation therapy. The longer waiting period in case of radiation therapy is necessary because of arising of late or persistent inflammatory reactions at the radiation site.


PET-CT examination can be used to early assessment of therapeutic efficacy based on the tumor’s decreased FDG accumulation due to the treatment. This method has found to be reliable for distinguishing between diseases of bad and good therapeutic response.