QUALITY OF LIFE IN LUNG CANCER PATIENTS

Luka Tehovnik is a student finishing his pharmacy degree in Slovenia.  During his final year he completed a study exploring the Quality of Life in Lung Cancer Patients.  This is his description of the study.  You may contact Luka through LinkedIn or Twitter.


Lung cancer is a disease that affects lungs. It is characterized by the worst prognosis. Its incidence and mortality rates are the highest in the world, taking the lead among all newly discovered cancers. Chemotherapy is the cornerstone of treatment of advanced lung cancer. Since treatment is palliative, the Quality of Life (QoL) is at least as important as the length of survival. QoL in lung cancer patients is affected by several factors related to the patients, stage of disease and treatment characteristics. Therefore, the effect of treatment on QoL has become progressively more relevant.


Lung cancer is the leading cause of cancer death in the United States. It may primarily form in lung cells or it can spread from the other body parts as metastases. It is divided into two major types as small cell (SCLC) and non-small cell lung cancer (NSCLC). Those types differentiate from each other by their biology, therapy and prognosis. SCLC is more aggressive compared to NSCLC. Prognosis is bad for both types of cancer; however, odds for being cured are improved with early-stage disease at diagnosis. Smoking is the primary risk factor, which accounts for more than 85-90 % of all lung-cancer related deaths.


Common symptoms of lung cancer include cough, shortness of breath (dyspnea), weight loss and chest pain; patients, presenting with those symptoms are more likely to have chronic obstructive pulmonary disease (COPD). Most patients are diagnosed with advanced, metastatic disease. Those patients are treated with chemotherapy for palliation. The term palliation implies improvement in either the duration or QoL remaining.


The treatment of lung cancer depends on the type of lung cancer, how spread it is (stage of the disease), molecular-biological characteristics of tumor, patient’s fitness for treatment (performance status) and other diseases (comorbidities). Lung cancer can be treated by surgery, irradiation and systemic treatment. Those approaches can be used differently depending on the disease and patient characteristics as described above. Disease stage remains the most powerful prognostic factor. Treatment can be aimed to cure (in early-stages of the disease) or just to put the disease into remission, which is defined as a state of absence of the disease. Most patients are diagnosed with advanced disease and the goal is to put them into remission for as long as possible. Since the treatment goal is extending their survival and easing the disease symptoms, improving patient’s QoL is also very important.


In the past, clinical trials had focused only on endpoints like physical or laboratory measures of response in form of disease progression and survival. More recently, endpoints that reflect the patient’s perception of their well-being and satisfaction with therapy have been included. Changes in biomedical outcomes may reflect as improvement in patient’s QoL but not always.


The World Health Organization (WHO) defines health as a “state of complete physical, mental and social well-being and not merely the absence of infirmity and disease.” This definition reflects the focus on a broader picture of health that includes health-related quality of life (HRQoL). Even though there is no exact definition, a general agreement says that it is a multidimensional concept that focuses on the impact of disease and its treatment on the well-being of an individual. Sometimes other aspects like economic and existential well-being are also included. It depends on the nature of a study which aspects of QoL will be included and studied. Those aspects or dimensions can include general health, physical functioning, physical symptoms and toxicity, emotional functioning, cognitive functioning, role functioning, social wellbeing and functioning, sexual functioning and existential issues. There are different instruments for measuring QoL which differ in aspects of QoL and diseases they cover.


QoL is a subjective multidimensional construct. Consequently, it must be assessed by patients alone using validated multidimensional instruments - questionnaires. Those questionnaires include different aspects of QoL, which are needed to obtain all the relevant data to track all the changes and for a complete evaluation of overall QoL. It is important that patients complete QoL questionnaires by themselves since their physician, nurse or relatives are unable to appropriately evaluate it.


There are a lot of different tools to evaluate QoL. It is important to choose the correct one when designing a clinical trial. Probably the most known questionnaire, developed specifically for cancer patients include EORTC QLQ-C30. There is also another one, which supplement the core questionnaire and was developed specifically for lung cancer patients – EORTC-LC13. It was found that those instruments respond to changes in clinical state and are strongly predictive of survival.


Cancer diagnosis may have a major psychological, disease and treatment related impact on a patient’s health-related QoL. Majority of lung cancer patients are diagnosed with metastatic disease. Since prolonging their life is generally unsuccessful, improving QoL is a more realistic goal. QoL is important aspect and should become implemented in a common clinical practice and considered when making treatment decisions. However, further research is necessary to build upon our existing findings on QoL.

Literature:
  1. Fairclough DL. Design and Analysis of Quality of Life Studies in Clinical Trials, 2. Ed. Boca Raton: CRC Press, 2010.
  2. Michael M, Tannock IF. Measuring health-related quality of life in clinical trials that evaluate the role of chemotherapy in cancer treatment. CMAJ 1998; 158(13): p. 1727-34.
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