Single-center randomized trial of Streptococcus salivarius K12 for radiotherapy-induced oral mucositis in patients with head and neck tumors

Oral mucositis is a common debilitating toxicity associated with radiotherapy (RT) for head and neck tumors. A prospective, randomized, double-blind, placebo-controlled trial at Sichuan University (Chengdu, China) evaluated efficacy and safety of Streptococcus salivarius K12 (SsK12) for reducing incidence and duration of RT-induced severe oral mucositis (SOM) in head and neck tumor patients. Patients sucked SsK12 or placebo lozenges thrice daily from the initiation to the end of RT. SOM was evaluated twice a week during RT and once a week thereafter up to 8 weeks. The figure shows that the incidence of SOM was significantly lower in the SsK12 group as compared with the placebo group (36.6% versus 54.2%; p=0.0351). The duration (mean 8.9 days versus 18.3 days; p=0.0084) and time to develop SOM (median NE versus 42.0 days; HR 0.55; p=0.0123) were also improved in the SsK12 group as compared with the placebo group. Adverse events were similar between groups. High-throughput sequencing results indicated that SsK12 inhibited opportunistic pathogens and enriched oral commensals during RT. The authors conclude that SsK12 probiotic significantly reduced the incidence, onset, and duration of SOM, with a good safety profile.