Walking the Tightrope tussen Tumor Dose Coverage and Meeting OAR Constraints

This case of ultracentral lung recurrence highlights the difficulty in maintaining a balance between adequate dose coverage to a radioresistant tumor and respecting Organs at Risk (OAR) constraints.1 For the first treatment, we recommend an oligometastatic curative approach with local therapy and no concurrent systemic therapy. Because of the radioresistance of colorectal adenocarcinoma, we recommend 60 Gy/8 fractions (fx) to achieve a biological effective dose (BED10) >100 Gy. We would keep proximal bronchial tree (PBT) maximum point dose to an organ (Dmax) <180 Gy BED3 because Dmax >180 Gy BED3 is a risk factor for treatment-related mortality.