TURKISH JOURNAL OF ONCOLOGY 2025 , Vol 40 , Num 3
Investigation of Effects of Radiotherapy Methods Applied with Different Fractions and Doses on Carbon Footprint in Patients with Rectal Cancer
Sultan ZORTUL1,Abdulsamet ZORTUL2,Yasemin ÖRS2
1Department of Family Medicine, Erzurum Tortum District State Hospital, Erzurum-Türkiye
2Department of Radiation Oncology, Erzurum City Hospital, Erzurum-Türkiye
DOI : 10.5505/tjo.2025.4565 OBJECTIVE
This study aimed to compare the greenhouse gas emissions resulting from two different radiotherapy (RT) methods used in the treatment of rectal cancer and to investigate their impact on the carbon footprint.

METHODS
Variables contributing to carbon emissions were identified and quantified. The carbon footprint was evaluated based on the total emissions produced during two RT regimens: 50 Gy in 25 fractions (longcourse radiotherapy, LCRT) and 25 Gy in 5 fractions (short-course radiotherapy, SCRT).

RESULTS
A total of 12 patients participated in the study, with a mean age of 68.5±13.83 years. Among them, 83.3% (n=10) were male. The overall carbon footprint from all procedures was calculated as 168.6±85.4 kg CO?e (carbon dioxide equivalent) per patient. The mean emission for SCRT was 105±9.4 kg CO?e, while for LCRT it was 231.4±80.6 kg CO?e per patient?a statistically significant difference (p=0.004). Inpatient treatment resulted in lower carbon emissions than outpatient treatment. The highest contributors to carbon emissions in both groups were radiotherapy and imaging procedures, followed by transportation, electricity use, and heating systems.

CONCLUSION
The study concluded that SCRT, inpatient treatment, proximity of patients" residences to the hospital, and the use of public transportation were associated with reduced carbon footprint values. Keywords : Carbon footprint; greenhouse gases; radiotherapy; rectum cancer