No, nothing triggers the disease known as cancer. Cancer is a pathogenic disease which means it is an infection and nothing more. Your fear of cancer would more of a trigger than a scar.
On the other hand a person diagnosed with TB could have just as easily been diagnosed as cancer. The diagnose is based on what you tell them in the objective and subjective interview and whatever disease they are trying to promote at the time. "THEY" are trying to make TB a new profitable industry which is why people get diagnosed with TB instead of cancer.
The medical industry recognized the folly of curing TB in the past and now they are trying to undo the cure.