Can frequent cavities or s.mutans cause mouth or oral cancer even if i am non smoker? does cavities alone contribute? i am getting frequent cavities even though i brush vigorously and have a diet which is very very low in sugar. what to do?

Carious lesions do not result in cancer but if left untreated will result in loss of the affected teeth.

Oral cancer does not occur from cavities. Since you are a non smoker and have a good diet, than no concern of oral cancer. Your oral hygiene techniques should be discussed with your dentist. You may be under a lot of stress and or anxiety, have a low amount of saliva in mouth, and not brushing with a soft brush. All can contribute to cavities.