Hypoxia Induced by Vascular Damage at High Doses Could Compromise the Outcome of Radiotherapy

• Background/Aim: This study investigated the impact of temporary vascular collapse on tumour control probability (TCP) in stereotactic body radiotherapy (SBRT), taking into account different radiosensitivities of chronically and acutely hypoxic cells. Materials and Methods: Three-dimensional tumours with heterogeneous oxygenation were simulated assuming different fractions of collapsed vessels at every treatment fraction. The modelled tumours contained a chronically hypoxic subvolume of 30-60% of the tumour diameter, and a hypoxic fraction ≤5 mm Hg of 30-50%. The rest of the tumours were well-oxygenated at the start of the simulated treatment. Results: For all simulated cases, the largest reduction in TCP from 97% to 2% was found in a tumour with a small chronically hypoxic core treated with 60 Gy in eight fractions and assuming a treatment-induced vascular collapse of 35% in the well-oxygenated region. Conclusion: The timing of SBRT fractions should be considered together with the tumour oxygenation to avoid loss of TCP in SBRT.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Cancer och onkologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cancer and Oncology (hsv//eng)

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Keyword

Hypoxia

vascular damage

stereotactic body radiotherapy

SBRT

tumour control probability

TCP

tumour oxygenation

Publication and Content Type

ref (subject category)

art (subject category)