The role of PET/CT as a prognosticator and outcome predictor in lung cancer

ABSTRACT

Positron emission tomography/computed tomography (PET/CT) is an important imaging tool for management of lung cancer and can be utilized in diagnosis, staging, restaging, treatment planning and evaluating treatment response. In the past decade PET/CT has proven to be beneficial for the prediction of prognosis and outcome. PET findings before and after treatment, the quantitative PET parameters such as standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) as well as delayed PET/CT imaging can be used to determine patient prognosis and outcome. Other tracers such as hypoxia and proliferation marker tracers may be used for prognostication. The prognostic factors derived from PET/CT imaging help early development of risk-adapted treatment strategies, which provides cost-effective treatment and leads to improved patient management. Here, we discuss findings of studies related to application of PET/CT in lung cancer as well as some technical updates on quantitative PET/CT in lung cancer.

KEYWORDS:

• Lung cancer
• FDG-PET/CT
• delayed time point imaging
• PET/MRI
• metabolic tumor volume
• total lesion glycolysis

Financial and competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Key issues

• Lung cancer is the most common cause of cancer-related deaths in the United State and worldwide.

• Positron emission tomography/computed tomography (PET/CT) can provide morphological and functional information, which is very useful in cancer management.

• PET/CT has important role for diagnosis and staging, treatment planning, and detection of recurrent disease in lung cancers as well as differentiate benign and malignant pulmonary nodule, provides mediastinal staging and reduce number of futile thoracotomies and mediastinoscopies.

• Clinical staging, prediction of treatment outcome, treatment response and prognosis are most important prognostic value of PET/CT in lung cancer patients.

• Patients with complete metabolic response have a significantly longer survival than patients with non-complete metabolic response after radical radiotherapy or chemoradiotherapy.

• PET/CT findings before and after treatment, and delayed PET imaging as well as quantitative PET parameters such as SUV, MTV and TLG have widely been investigated as a predictor of clinical outcome.

• The higher accuracy of PET/CT compared to conventional method for staging of lung cancer, results in prevention of ineffective and unnecessary costly diagnostic procedures and also helps clinicians to classify patients who require more or less aggressive treatment that will improve outcome.