1.Psychological distress
Anxiety and depression related to diagnosis of cancer is very common and overall QOL and survival is very much related to it. In a study by Zabora et al, it was seen that among all types of cancers, lung cancer patients show highest intensity of stress. Depression affects up to 40% patients and anxiety up to 25% of lung cancer patients. The level of anxiety increases during treatment which is related to decline in QOL whereas depression is associated with loss of possibility for proper functioning.
- Symptoms related
On the basis of Lung Cancer Symptom Scale, Iyer et al reported that the most common symptoms are fatigue (98%), loss of appetite (98%), respiratory problems (94%), cough (93%), pain (90%) and blood in sputum (70%). There is a strong correlation with the severity of symptoms and QOL, moreover fatigue was recognized as the most severe factor in detrimental emotional, physical functioning and overall QOL.
- Treatment related
Results of many studies indicate improvement in functioning with time after receiving treatment.
3.1 Surgery
Early stage lung cancer can be surgically resected and there are studies comparing the extent of surgical resection to QOL. Patients who had pneumonectomy had significantly worse postoperative QOL as compared to those who had lobectomy only. This was reported in a study where statistically significant differences were seen in physical functioning at 3 months, social functioning at 3-6 months, role functioning at 3-6-12 months and general health at 3-6 months time period. However, physical functioning partly recovers after one year. Age was also found to be inversely related to physical functioning and directly related to fatigue and dyspnea score.
3.2 Chemotherapy
Studies have found a negative correlation between chemotherapy given and overall QOL in lung cancer. The functional scores are directly related to the number of chemotherapy cycles given and older age of patients. Along with the global QOL scores, there is a decline in social and emotional functioning as well, however these changes are temporary and return to baseline after nine months.
3.3 Radiation
Radiation can also affect QOL in lung cancer and its related mainly to the radiation dose given. In a randomized study by RTOG 0617, a clinically meaningful decline in QOL (45%vs 30%, p value of 0.02) was seen in the high dose radiation arm (74Gy) at 3 months as compared to standard doses of radiation (60Gy). Also the study revealed a very important fact that baseline QOL was significantly associated with survival in lung cancer on multivariate analysis. With the increasing use of stereotactic body radiotherapy (SBRT) in early stage lung cancer, STRIPE trial was conducted by Adebahr et al to see the effect of SBRT on QOL. The results showed no clinically relevant changes in global health status and function scores in patients receiving SBRT indicating that SBRT causes less or no severe treatment related complications.
Conclusions
Although lung cancer is one of the commonest cancers, yet health related QOl is not studied uniformly in many studies. One recent study provides a comprehensive overview of relevant RCTs evaluating the impact of systemic therapies on HRQoL in advanced NSCLC.The study shows that a vast variety in HRQoL measurements, data collection at different time points and varied spectrum of treatment modalities make reporting and analyzing of HRQoL data comparisons difficult. Quality of reporting HRQoL outcomes remains poor with certain aspects being systematically underreported. Nevertheless, adequate and complete reporting is critical for clinical decision-making to improve HRQoL in this critical patient population.
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