LOS ANGELES (AdAge.com) -- CBS may soon decide to pull the plug on "Guiding Light," the longest-running daytime drama in TV history.

While no final decision has been made, the network's deal for the Procter & Gamble-produced drama -- the least-watched of the eight daytime serials currently on the air -- ends in September. But if CBS does drop "Guiding Light," it likely will lock in a decision within the next month, people familiar with the matter said. That would give writers a chance to tie up story lines.

CBS also would need to finalize new programming for the daytime hour that "Guiding Light" would be vacating.

In the most significant indication that the network is seriously pondering life without "Guiding Light," CBS has been talking to outside studios about potential replacement programming for the show, those close to the show said.

Possibilities under discussion include both game shows and talk shows. CBS could easily cut its programming costs for the hour in half by switching away from a scripted drama. Representatives for CBS and P&G declined comment.

In addition to contracting with an outside studio for programming to replace "Light," CBS daytime chief Barbara Bloom has been developing possible in-house candidates for the soap opera's slot.

CBS executives are taking their time deciding the fate of "Light," which has survived more than 70 years on radio and TV. P&G also produces the CBS soap "As the World Turns."

Nonetheless, a decision by CBS to end "Light's" run on the network wouldn't be a surprise.

The serial has been the subject of cancellation rumors for the better part of a decade. Those rumors became particularly intense within the past 18 months, but P&G threw something of a Hail Mary pass last year when it implemented a radical reworking of "Light's" production model.

On Feb. 29, 2008, the show ditched its traditional storytelling style in favor of a lower-cost model that also was intended to give the show a more realistic, less staged feel. Around the same time, CBS renewed "Light" for the current season, retaining an option for an additional season.

Ratings for the show haven't improved since the switch. "Light" is averaging a 0.9 rating among women 18 to 49 and a 1.6 household rating, according to Nielsen. So far this season, it's averaging 2.17 million viewers and a 0.9 rating in women 18 to 49; season-to-season, it's down 18% in viewers and down 25% in the demographic.

"Light" began life as a radio soap opera, moving to CBS TV.

It's possible P&G or CBS could attempt to keep the show alive in some form on the internet, though doing so likely would require another radical reinvention of its production model.

Much of the daytime-drama business is struggling, with ratings for most soaps down significantly in the past decade. NBC is down to one soap, "Days of Our Lives," following the decision to dump "Passions" in 2007 (the show survived one more season on DirecTV).

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Josef Adalian is a TV Week columnist and deputy editor.