Researchers in Australia made a warning that a tobacco filter is no more useful to reduce the risk of cancer.
According to the paper recently published by the researchers at Curtin University, filter ventilation does not reduce tar yield. Instead, it slows the speed of consuming. Therefore, smokers are to absorb more tar with filter ventilation.
The Sydney Morning Herald: Modern cigarette filters increase the risk of lung cancer, study finds
They also examined the relationship between the prevalence rate of lung adenocarcinoma and smoking; the former is still rising. As I understand, smoking is not responsible for the onset of adenocarcinoma. Thus, this relationship is not necessary to be investigated for proving the harm of filter.
On the other hand, a large cohort study is needed to clarify the benefit or harm of using a filter. It is not adequate to say the filter raises the risk of cancer with examining past literature because there are no studies to have suspected this possibility.
Anyway, it is no doubt that tobacco is harmful to the human body. We should know there are no ways to attenuate the health risk of smoking as far as you smoke.