According to the study, presented at the ESTRO 37 conference, even small differences in how the patient lies during radiotherapy of lung or esophageal cancer, can affect survival.
Differences of a few millimeters lead to the fact that radiation therapy designed to target tumor may move closer to the heart and reduce the chances of survival. Research suggests that survival can be improved after the introduction of more stringent treatment recommendations to ensure the exact position of the patient.
Radiation therapy plays an important role in the treatment of cancer, but previous studies show that it has a negative long-term effects on the heart, increasing the risk of heart disease.
When planning radiation therapy, doctors create a CT image of the patient. It shows the exact position and size of the tumor in the body. Each time the treatment is created and used another image to check that the patient and the tumor is in the same position within a certain threshold.
A new study presented Corinne Johnson, of Cancer Research Center at the University of Manchester in the UK. She and colleagues studied a group of 780 patients with non-small cell lung cancer who are receiving radiation therapy. Before the procedure makes the image to confirm that the patients are in the range of 5 mm from its original position. They used the data of these images to assess how exactly the dose of radiation therapy delivered during the course of treatment, and whether it has been moved a little closer or a little farther from the patient's heart.
Scientists have found that patients with a slight shift in the direction of the heart risk of death increased by 30%. When they repeated the study with a group of 177 patients with esophageal cancer, we found another big difference - about 50%.
"The study examined how small differences in position of the patient may affect survival, even when the imaging protocol is used. This suggests that even small errors can have a serious impact on the survival chances of patients, especially when the tumor is located close to vital organs ", - explained Johnson.