What dose-fractionation would you use to treat a single large melanoma lung metastasis?

Given the radioresistant nature of melanoma, for a 4 cm lung oligometastasis, I would carry the dose to 50 Gy in 5 fractions. Even if the tumor is abutting the lateral parietal pleura, I do not reduce the prescribed dose. I understand that one may be concerned about rib fractures. However, in my experience, the fracture will heal with time. An attempt to spare the chest wall will result in undercoverage of the PTV. If the tumor is located centrally and abutting OARs, I would use the technique de...