Mongoose.findOne doesn't return anything, why?

I need to return the search results from Mongoose.findOne to variable

results = Lang.findOne({page: params.page,lang: params.lang, param: params.param}, function(err, lang) {
  if( err || !lang) {
    console.log("No translation!");
  } else {           
    return lang.trans;
  };
}

Is there a way to do this? I tried several hours to find a solution with async. functions and nothing ... I also found articles where it was said that this is impossible, but is there any alternative for realize this?

It's really important to me because I need this to my multilingual project, I need to get the translation:

 res.render('index',{titleGen : req.__({page:'home', lang:req.locale, param:'hello'})});