SBRT may increase the risk of noncancer deaths in lung cancer patients
A recent study reports that treating early stage lung cancer patients with stereotactic body radiation therapy (SBRT) could increase their risk of death from noncancer causes.
These results were recently reported at the ESTRO 35 conference (29 April–3 May 2016, Turin, Italy) by Barbara Stam from the Netherlands Cancer Institute (Amsterdam, The Netherlands).
Stam and her team analyzed data from 565 patients diagnosed with early stage non-small-cell lung cancer who had been treated with SBRT. Utilizing a process termed deformable image registration they were able to create a ’template’ image of the heart onto which they mapped the anatomy of each patient.
Using this model, the team calculated the levels of radiation delivered to substructures of the heart and demonstrated that high doses of radiation to the superior vena cava and left atrium of the heart had the strongest association with an increased risk of noncancer death.
“Our results show that even within a few years a radiation dose to the heart is associated with an increased risk of noncancer death for early stage lung cancer patients, and they indicate which regions of the heart possibly play a role,” reported Stam.
The associations between higher radiation doses to the superior vena cava and the left atrium and deaths from noncancer causes were small but significant for the investigated patient group. In the left atrium, for every 1 Gy above the average dose of 7.9 Gy the risk increased by 1.5%, while for other structures the risk increased by between 1–2%.
The researcher’s believe that they can apply this knowledge to the development of techniques that spare these heart structures as much as possible.
“Validation and further investigations into the exact mechanisms and which heart structures are critical is warranted, but clinically, this could mean that patients might benefit from heart-sparing radiotherapy. For early stage lung cancer patients, treated with SBRT, we still need to investigate if heart sparing is possible, what compromises need to be made and whether it can increase survival,” continued Stam.
