Lampard is struggling to hold onto his job after a run of five defeats in the past eight league games.
The Blues' latest setback came against Leicester City, where they lost 2-0. And Cascarino believes results must change very soon or Lampard will get the sack.
"It never goes down well when you spend loads of money on signings who don't work out or are not playing well," the former Blues striker told talkSPORT.
"Upstairs will go, 'we'll give him more money and spend again', but they get a little bit nervous and edgy about doing that.
"He knows the job at Chelsea is full of criticism and it doesn't take a lot for that owner to make a change.
"Their performances have been really poor; take the win against Fulham, it was 1-0 and they struggled for long periods of the game.
"The highest team they've beaten this season is seventh – they've not beaten anybody above seventh.
"Their 3-0 win against West Ham at Stamford Bridge was their best result; they did enough to get over the line, but getting a performance plus a result is a huge problem.
"He's got three home games now back-to-back, one in the FA Cup against Luton and two league games.
"He has to win them. He might make the end of the season, but if he's going to make the end of the season he has to go on a run of winning games now.
"He can't go through getting knocked out of the cup or getting a horrendous result against Burnley or Wolves at Stamford Bridge.
"He won't survive that, and if the owner thinks, 'we aren't going to make the Champions League, we're way adrift of that position'... he knows he's walking on eggshells."