Is it possible to get cancer from oral sex?

Not sex per se. Oral sex may transmit hpv infection that is implicated in oral cancer. It is not the sex per se, but the infection associated with the act that has cancer risk.
Cancer and oral sex. Cancer is not contagious. You will not contract cancer from oral sex. However, the risk for contracting hpv infection during oral sex is high-especially if your partner is known to be hpv +. There is a strong relationship between hpv infection with increased risk of developing certain cancer including oropharyngeal cancer and cervical cancer over period of time.