# Radiotherapy-Related Clinical and Functional Sequelae in Lung Cancer Survivors
## 2 Materials and Methods
### Outcomes  
At admission, we collected patients' anthropometric data, comorbidities, tumor location, and radiotherapy characteristics from their medical history [19]. Comorbidities were evaluated with the Charlson Index, which has been validated for several disorders [20]. Data collection was performed at the laboratories of the University of Granada.  
The main study outcomes included respiratory symptoms (i.e., dyspnea, cough, and fatigue), functionality, and the quality of life of lung cancer survivors.  
Dyspnea was evaluated with the Modified Borg Scale, which has been validated in respiratory and cancer patients [21]. Patients rated their respiratory distress on a total scale of 0-10 (0 = no distress and 10 = breathing was very difficult).  
Cough was assessed with the Cough Assessment Test (COAT) [22]. This scale is composed of five subscales that measure the severity of cough and cough frequency, limitations on activities of daily life, sleep disturbance, fatigue, and hypersensitivity to some irritants. Each item is scored from 0 to 4, with a total score of 0-20. Higher scores indicate a more severe cough.  
Fatigue was measured with the Piper Fatigue Scale-Revised (PFS-R) [23]. This scale includes 22 items that assess self-reported fatigue using numerical rating scales (0-10). It contains 4 subscales that reflect the subjective experience of fatigue: behavioral/severity, affective meaning, sensory, and cognitive/mood. The overall score is obtained by adding up the total scores and dividing the result by the total number of items. Higher scores indicate higher levels of fatigue.  
Functional status was evaluated by assessing physical activity levels and muscle strength. The International Physical Activity Questionnaire-Short Form (IPAQ-SF) was used to assess physical activity levels [24]. Time spent performing physical activity is classified as vigorous exercise, moderate activities, or walking. An MET score is calculated based on the performed physical activity according to the classification by [PERSON] et al. [25]. Total METs/hour per week for each physical activity subtype were calculated and then added together to calculate the total METs per week. Sedentary behavior was measured with the recorded sitting time (minutes per day) [26].  
Additionally, an evaluation of the perceived barriers to perform physical activity was included. This measure was assessed with the Physical Activity Barriers After Cancer (PABAC) instrument [27]. This tool includes 12 barrier items scored on a 4-point Likert scale (1 = strongly disagree to 4 = strongly agree). The total score was obtained by adding up the items, with possible scores ranging from 12 to 48. Higher scores indicate more barriers to physical activity.  
Muscle strength was explored by measuring the cross-sectional area of the rectus femoris [28]. A B-mode ultrasonography with an 8 MHz 5.6 cm linear transducer (ECO 3 Expert Doppler, Chison, Wuxi, China) was used, similarly to the method of [PERSON] et al. [29]. The transducer was positioned perpendicular to the long axis of the thigh on its superior aspect, at three-fifths of the distance from the anterior superior iliac spine to the superior patellar border. The evaluation was conducted in a supine position with the extended leg relaxed. Rectus femoris cross-sectional area (RFCSA) was calculated using a planimetric technique, tracing the inner echogenic line of the rectus femoris with a movable cursor on a frozen image. RFCSA was calculated as the average of three consecutive measurements within 10%.  
Finally, self-perceived health-related quality of life was evaluated with the EuroQol-5 Dimensions 5 Levels (EQ-5D-5L) (Rotterdam, The Netherlands) [30]. This tool is composed of five items that assess five dimensions (i.e., mobility; self-care; usual activities; pain; anxiety/depression) and a 0-100 visual analog scale (VAS) where patients report their self-perceived status. The Spanish version of this questionnaire has shown good validity and high reliability [30].