October 20, 2005
HPV 16 is not common in the larynx, and therefore 1/200 patients getting larynx cancer when that person has HPV 16 may indicate a much higher risk with HPV 16 than with HPV 6 or HPV 11. However, we have had some other HPV 16 RRP patients, and they did not develop cancer. My point was simply that we cannot reliably predict clinical pattern solely on the basis of HPV type. Comparing the epidemiology of cervix to larynx is probably flawed, but the data for cervix is strong and larynx nearly completely lacking so reasonable to draw parallels (knowing the limitations) until we get data to show they are different. Certainly, all patients with active RRP should be followed regularly, regardless of type. If I had an HPV 16 infection, I would want an MD who would follow me carefully, but I would not panic and assume my RRP will convert to cancer.
As far as the process of conversion to malignancy is concerned, there are a number of changes that have to happen in a cell for it to become malignant. Some of those changes are induced by HPV, and yes, HPV 16 does seem to do this more efficiently than HPV 6 and 11. Other changes involve changes in cell genes, and happen at random independently of HPV. You need just the right combination of changes to get conversion to malignancy. The changes in cellular genes are more likely to happen if the cells are rapidly dividing. Larynx cells divide all the time, just like skin, but division increases with wound healing which could increase the random chances of the "wrong" changes happening.
Radiation therapy markedly increases the likelihood of random cellular changes, which is why radiation is not recommended for most RRP patients unless there is no choice.
Reducing trauma to the larynx is always a good idea, and some treatments may cause more trauma than others, but physician expertise is probably a critical factor. In fact, there are solid studies in the literature to show that the CO2 laser reduces frequency of papilloma regrowth (which may also be triggered by injury) when compared to cold knife excision, but we know that in unskilled hands the CO2 laser can cause a lot of trauma. My recommendation, chose a doctor who treats a lot of patients with RRP, and then follow his advice.
Bettie M. Steinberg, Ph.D.
Associate Director and Chief Scientific Officer
Institute for Medical Research at North Shore - LIJ
270-05 76th Avenue
New Hyde Park, NY 11040