After a contentious debate, the General Assembly in 2008 approved a plan that eventually would allow a $150 million cancer treatment center in the metro Atlanta area.

The controversial bill created a loophole in the state’s certificate-of-need law that regulates the construction of health care facilities. The legislation had been opposed by, among others, the Georgia Chamber of Commerce and local hospitals.

But the bill eventually passed. Cancer Treatment Centers of America, an Illinois-based company, was given a pathway to state certificate-of-need approval after it promised that most of its patients would come from outside Georgia.

Now, three years later, CTCA says it expects to start construction in June of a 50-bed facility in Newnan. The hospital is expected to open in September 2012, said company spokeswoman Kristin Schaner.

The privately held company received its certificate of need from the state in December 2009.

“We want to provide another choice for quality cancer treatment for patients and their families in the Southeast,’’ Schaner said Monday.

It will be CTCA’s fifth hospital. Its other hospitals are in Tulsa, Philadelphia, Goodyear, Ariz., and Zion, Ill.

The company has estimated that the facility would create 500 jobs and $500 million in economic activity in the first five years of operation. Political leaders such as former Gov. Sonny Perdue supported the cancer project.

“We provide individualized, personalized cancer treatment,’’ Schaner said.

Using a holistic approach, Cancer Treatment Centers of America says it combines traditional treatment and state-of-the-art technology with complementary therapies that boost the immune system, manage side effects and improve quality of life for patients.

Some critics have said that CTCA marketing targets emotionally vulnerable patients with advanced-stage cancer.

Atlanta doctors testified before a Georgia House committee in 2007 – when a CTCA bill failed to pass — that there was no proof that some of the company techniques work. But several cancer patients told the House panel that their cancers had been arrested by CTCA physicians and treatments, the Atlanta Journal-Constitution reported.

The next year, the Georgia Chamber argued hospitals in the state already provided “first-class” cancer care, and that CTCA didn’t need an exception in certificate-of-need rules.

Supporters such as Sen. Tommie Williams (R-Lyons) said the CTCA facility would be good for competition. Patients said CTCA offered services not provided by other hospitals, in areas such as spiritual support.

In 2008, the legislation allowing a CTCA loophole cleared the General Assembly.

Next year, the quest by Cancer Treatment Centers to enter Georgia will become complete.