Her diagnosis was disclosed as she backed a £3.4m bid to improve care for cancer patients in Manchester, where she has been undergoing treatment.
"I've had cancer and my brother's had cancer and we know how it affects people," Caroline, 50, said in a statement ahead of the launch of the Macmillan Cancer Improvement Partnership next month.
Actress Caroline Aherne has revealed that she is battling lung cancer
"It's brilliant that all these big institutions want to make cancer care better for Manchester people, but even the best doctors, nurses and managers on earth aren't going to be able to understand what needs improving unless people affected by cancer in Manchester get involved and tell them what needs to change."
Both Caroline and her brother Patrick were born with a rare cancer of the retina, which left the award-winning actress almost blind in one eye.
Caroline Aherne is best known for her role in the TV series The Royle Family
She has also been treated for bladder cancer in the past, and lost her father to the disease.
Patrick told Macmillan Cancer Research that his sister was diagnosed "late last year" and that "the form of lung cancer that she is suffering from is genetic and linked to the retinoblastoma she had as a baby."
He added: "Her bladder cancer was also genetic and linked to the retinoblastoma."
Macmillan Cancer Support have confirmed that Caroline will speak at an appeal to improve cancer care in Manchester on 26 June.
"Caroline's one of Manchester's own — she's loved here and people identify with her," said Nicola Cook, from the charity.
"We hope that if people see that Caroline is sitting down and talking to us then maybe they'll know that they can too."