GRIPPED by a horrifying cancer nightmare, BARBRA STREISAND is fighting against any threat from the deadly disease after under­going secret colon surgery, The ENQUIRER has learned exclusively.

The ENQUIRER reported in 2004 that the 69-year-old superstar had part of her colon removed after a routine screening revealed the presence of polyps. Now she’s terrified the polyps will return, and doctors will hand her a death sentence, insiders say.

While she gets regular checkups and fol­lowed doctors’ orders to change her lifestyle, Barbra’s concern over cancer threatens to throw a dark shadow over her happiness with husband James Brolin, sources say.

“Barbra believes she’s in a battle for her life, but it’s heartbreaking to see a woman who was given a second chance waste it with worry,” divulged a family friend.

“All this obsessive drama is unnecessary, and now Barbra’s close friends and family are worrying about her.

“She’s done everything that the doctors asked her to do to stay cancer-free. She’s changed her diet, lost weight, started exercis­ing and scheduled more precautionary tests than anyone I know.

“But every time the doctor gives her a clean bill of health, Barbra is sure that the next test will show she has cancer.

“It’s like she’s playing Russian roulette with her checkups. If she got lucky this time, she’s sure that she’ll get the bullet next time and be told she has malignant polyps.”

Barbra’s husband, actor James Brolin, pushed her to have surgery in 2004 after a routine screening revealed the presence of polyps in her colon.

Polyps can be one of the earliest signs of cancer, and doctors recommend that they be removed as soon as possible.

Her surgery was doneat Cedars-Sinai Medical Center in Los Angeles, and took a couple of hours. Due to the highly special­ized technique used by Barbra’s surgeon, the “Little Fockers” star was able to leave the hospital about 24 hours after the operation.

After polyps are removed, a colonoscopy generally should be repeated in three to five years, according to Dr. Herman Kattlove, a Los Angeles-based oncologist and former spokesperson for the Ameri­can Cancer Society.

“If the colonoscopy reveals cancerous growths that need to be removed and the colon resected surgi­cally, the American Cancer Society recommends re­screening at one year, followed by three- and five-year intervals afterward,” Dr. Kattlove – who has not treated Barbra – told The ENQUIRER.

“If there is a strong fam­ily history of colon cancer, these intervals should be reduced.”

Barbra has no family history of colon can­cer, but she insists on having a colonoscopy every two years, the insider revealed.

“While the excessive testing is unnecessary, it seems to be the only thing that gives Barbra peace of mind,” said the source.

“When she goes more than three months without having a colonoscopy, and feels the slightest ‘pinch’ of pain, she begins to imag­ine the worst.

“I think Barbra almost convinces herself she probably has polyps spreading in her co­lon at that moment – just waiting to kill her.

“When Barbra had surgery in 2004, I re­member that she was terrified she’d have a

Colostomy, but now she fears something even worse – death.”

According to the American Cancer Society, one in 20 Americans will develop colorectal cancer during their lifetimes. In 2011, a total of 141,210 new cases were diag­nosed, and the disease is expected to kill 49,380 people this year.

“It’s heartbreaking to watch Barbra battle to keep the cancer at bay,” the insider added.

 “While Barbra appears to be going overboard with her doctor’s visits and colonoscopies, it is as if she just won’t stop. It’s her health that’s at stake, and she’ll do what­ever it takes to stay healthy.”