Many risk-modifying factors affect cancer incidence and mortality rates. We present an ecological study of incidence and/or mortality rates for cancers during 2007–2016 of 17 anatomical sites with respect to solar ultraviolet-B (UVB) doses and obesity prevalence. Solar UVB reduces cancer risk by producing vitamin D, which has many mechanisms to reduce risk of cancer incidence, progression, and metastasis. Obesity increases cancer risk through several mechanisms, including increased systemic inflammation. Data were averaged for 12 geographical regions. Solar UVB doses were significantly inversely correlated with mortality rates for five cancers for males and four for females. Obesity prevalence was directly correlated with mortality rates for three cancers for males and seven for females. The population attributable fraction of cancer mortality rates ascribed to low solar UVB dose was 0.03 for both males and females, whereas that for obesity prevalence was 0.05 for males and 0.08 for females. Thus, cancer mortality rates in France could be reduced through vitamin D supplementation and reducing the prevalence of obesity. Doing so also could reduce risk of other adverse health outcomes.