Cardiorespiratory Fitness in Patients with Advanced Non-small Cell Lung Cancer: Why is this Feature Important to Evaluate? Can it be Improved?

Abstract

Patients suffering from non-small cell lung cancer (NSCLC) are frequently affected by a high level of symptom burden.1 Consequently, these patients also have a poor quality of life, insofar as symptom score is one of the five dimensions of quality of life (aside, functional, psychologic, social, and spiritual dimensions2). A high symptom score, by itself might require specific interventions, palliation or supportive therapies to achieve symptoms alleviation. Consequences of a high symptom score could be regarded from two major points of view. (i) some symptoms can indicate a severe patient disability and therefore might modify anticancer treatment program by limiting indication for some important treatment modalities such as surgery. (ii) high symptom score is reducing patient ability to achieve a normal familial and social activity. This interference between symptoms score and social life, referred to as global health status in quality of life scale, has been demonstrated as indicating a poor outcome.3 Among the most frequently observed symptoms in NSCLC, two could be regarded as directly involved in reducing patient daily activity living: dyspnoea and fatigue. Both symptoms have major impact in cardiopulmonary fitness on exercise. Studies that aim at measuring cardiopulmonary fitness in NSCLC might therefore be regarded as a global investigation exploring main host-tumor relationship features that could have major impact in both treatment decision and quality of life.4 Conversely, studies that aim at improving cardiopulmonary fitness on exercise might be considered as interesting approaches at improving quality of life. In this issue of the journal, Kasymjanova et al.5 presented a noninterventional study evaluating exercise capacity in patients with newly diagnosed advanced NSCLC and its relationship with survival. Temel et al.,6 also in this issue report an interventional study performed in an effort at improving functional outcome and symptoms in a similar advanced NSCLC population by mean of a structured exercise program. In this brief editorial we would like to summarize and comment on results of both studies by highlighting three different issues: (1) methodological aspects of the evaluation of cardiopulmonary fitness in oncologic patients; (2) multidimensional aspect of fatigue and dyspnoea in patients receiving treatment for advanced NSCLC; and (3) meaning of the evaluation and intervention on cardiopulmonary fitness for these patients in daily practice. Briefly, in the study by Kasymjanova et al., patients receiving chemotherapy for a NSCLC have underwent repeated evaluation by exercise tests (by means of the submaximum 6-minute walk test [6MW]): One before chemotherapy (preceded by a training test) and the second after the second cycle of chemotherapy. The main findings are as follows: a poor performance during the prestudy 6MW test (6MW 400 m) at presentation by itself, is an independent unfavorable prognostic factor; patients who did not achieve the complete program (but were only able to perform the prestudy test) were at higher risk of death. Among patients who completed both preand posttreatment 6MW tests, patients for whom performance on exercise had decreased, were at higher risk of disease progression