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 exp...