Next time the lead might change hands in the standings. Because there are matches like Roma - Napoli and Atalanta - Lazio. In case Atalanta win and Napoli lose, the new leader would be Atalanta. However it is really not easy to see this. Even though Roma are in a pretty impressive shape and they are playing home, Napoli are still a huge threat to them with their form. You must be remembering the Milan - Napoli match which Napoli defeated their opponent. Maybe they can do the same to Roma also unless Roma become very careful.
It isn't easy for Atalanta to win either. Lazio are one of the strongest teams of the recent weeks. I wouldn't be surprised if it ends in a draw.
Roma have shown an improvement in their performance. but to fight with Napoli won't be so good for them. Napoli are much more consistent and of course have better confidence in facing Roma. If Roma manages to end the match with a draw, it's good IMO.
Lazio vs Atalanta, have equal strength IMO. it will be a fierce match. However, the draw with Udinese experienced by Lazio is likely to affect their match slightly.
Lazio and Atalanta are the two teams to concede the fewest goals in Serie A. Their clash will be quite exciting. Lazio must win to close the 3-point gap between them. They will really try to win, but they will have to work hard to get past Atalanta's defense. A very good season is being played, all the big teams are in the championship race.