Three types of physical stress can affect your body—trauma (wear & tear), temperature, and pressure. Even everyday physical stress (minor trauma, being too cold or too hot, pressure changes) can aggravate established disease processes. For some people, extreme physical stress (severe trauma, severe hypothermia, severe hyperthermia, altitude sickness) can be the primary trigger for allowing disease processes to occur. In the eyes of ancient Chinese medicine cold is a major cause of disease with the kidneys being the most sensitive organ to cold in the body.
No matter how much you read on Google search that physical trauma cannot cause cancer, if you look hard enough and think arduously enough, one can find evidence that physical trauma can cause cancer. Researchers have in fact found that a causal link between physical trauma and cancer is plausible. “The most likely explanation of our findings is that physical trauma can cause breast cancer.”
Physical trauma resulting in cancer is relatively rare but it does happen. One accepted source is frequent, long-term application of hot objects to the body. It is possible that repeated burns on the same part of the body, such as those produced by kanger and kairo heaters (charcoal hand warmers), may produce skin cancer, especially if carcinogenic chemicals are also present. Frequently drinking scalding hot tea may produce esophageal cancer. Generally, it is believed that the cancer arises, or a pre-existing cancer is encouraged, during the process of repairing trauma. Repeated injuries to the same tissues might promote excessive cell proliferation, which could then increase the odds of cancer. 
Trauma is a serious injury or shock to the body. It is caused by a physical force, such as violence or an accident. The injury may be complicated by psychiatric, behavioral, and social factors. This can cause the injuries to be greater than just physical ones. Add the fact that X-rays and CAT scans are often used we should be able to understand that all of these factors together can be a trigger for the initialization of cancer.
During a traumatic event, the nervous system goes into survival mode (the sympathetic nervous system) and sometimes has difficulty reverting back into its normal, relaxed mode again (the parasympathetic nervous system). If the nervous system stays in survival mode, stress hormones such as cortisol are constantly released, causing an increase in blood pressure and blood sugar, which can in turn reduce the immune system's ability to heal. (Or prevent cancer.)
Russian doctor Natalya Alexandrovna Novikova MD writes that "there are numerous cases reported in the scientific medical literature of malignant tumors arising in places which many years prior had been damaged by a blow." Even some Western studies have pointed to a possible link between breast bruises and breast cancer that later developed. Cancer researcher Dr. Johanna Budwig quotes a child sarcoma case likely caused by repeated bruising.
 Eur J Cancer Prev. 2002 Jun;11(3):307-11. Can physical trauma cause breast cancer?
 in her book Russische Volksmedizin (the German translation of the Russian original)