The chart for Mars entering Cancer tells the story without resorting to any other methods. Mars tends to be at it's worst in Taurus, Libra, and Cancer- where it's considered fallen, as the red planet is exalted in Capricorn, the sign opposite Cancer.
|From Mundane Charts|
This Mars->Cancer ingress shows Mars culminating over London, and forming an angular grand cross with the rising Moon, setting Uranus, and Pluto on the Nadir. A more volatile picture would be hard to find.