Is that the equivalent of 6.5 years of normal aging-related cancer risk (spread over ~1.35 actual years), or does risk scale non-linearly? If it's a normal +5

Is that the equivalent of 6.5 years of normal aging-related cancer risk (spread over ~1.35 actual years), or does risk scale non-linearly? If it's a normal +5 bonus years of risk, it seems like something that would be acceptable for such a voyage. But you'd be a bit hard-pressed to find something worth it on Earth, it would have to be something truly spectacular.