The study will be conducted on patients requiring radiotherapy to thoracic region (including lung, esophagus, and breast cancers) reporting to the department. Once the consent has been obtained, initial assessment of the patient will be done after a brief explanation of the study.

Before RT, patients will undergo tests to evaluate their baseline physical parameters: including heart rate (HR), Blood pressure (BP), Oxygen Saturation (SpO2), and dyspnea status will be recorded. For assessment of effort tolerance, 6-Minute Walk Test (6MWT) in meters and Peak Expiratory Flow Rate (PEFR) in mL/sec will be used. QLQ-C30 questionnaire will be administered the patients as a part of subjective assessment of effort tolerance and quality of life. Patients’ demographic factors (age, gender, smoking history, comorbidities, etc.) will be recorded from their medical records.Patient will receive treatment as per the standard practice specific to the cancer site. Prior to starting RT, the patients will be requested to fill-in the QoL questionnaire, and perform the 6 minute walk test, which involves them walking at regular pace in-loop around a designated flat surface for a duration of six minutes, and the distance covered during this duration will be recorded. They will also be asked to perform the PEFR test, which involves them blowing forcibly into a PEFR meter in order to determine the PEFR. The dosimetric data of the approved radiation plan will be recorded (multiple parameters) from the Treatment Planning System. The patients will receive their treatment as per the standard practice.

Patient will receive treatment as per the standard practice specific to the cancer site. Prior to starting RT, the patients will be requested to fill-in the QoL questionnaire, and perform the 6 minute walk test, which involves them walking at regular pace in-loop around a designated flat surface for a duration of six minutes, and the distance covered during this duration will be recorded. They will also be asked to perform the PEFR test, which involves them blowing forcibly into a PEFR meter in order to determine the PEFR. The dosimetric data of the approved radiation plan will be recorded (multiple parameters) from the Treatment Planning System. The patients will receive their treatment as per the standard practice.

 At 4 months following completion of treatment, at their routine scheduled follow-up, patients will be enquired about their subjective perception and will be requested to again fill-in the QoL questionnaire. General examination including recording of vitals will be done. The patients will then be requested to again perform 6MWT and PEFR as a part of reassessment

The current Study will help in better understanding of the radiation effects on the heart and the lung on eventual functional outcomes in physical effort tolerance of the patients. It will also help in recognizing the patients who might be more vulnerable to development of manifest cardiopulmonary toxicity.