After Selena Gomez revealed her big secret of lupus diagnosis and undergoing chemotherapy, doctors have spoken up as to why the ‘Good For You’ singer had to make use of the cancer-killing treatment to get rid of the condition.

“Treatment for lupus varies from patient to patient,” Dr. Bonnie Bermas, M.D., the director of theBrigham and Women’s Hospital Lupus Center told HollywoodLife in an exclusive interview. “Some patients, depending on their manifestations, can be treated with chemotherapy either by pill form or intravenously.”

Lupus can be recognized as an inflammatory disease that targets the body’s organs, and, chemotherapy can significantly change the “abnormal behavior of [affected] cells and slows down the reproduction of these cells.”

Moreover, such treatment can be utilized if the lupus is becoming a concern for the kidneys and/or the central nervous system.

Assuring the public, Dr. Bermas added that the dose of chemotherapy that Gomez used to keep the disease under control is much lower than those used for the treatment of cancer. The duration of the treatment is also shorter.

The former Disney star made a major decision to look after herself and prioritize her treatment by taking a break last year. According to her interview with Billboard Magazine in its October issue, she could have experienced a stroke if her condition was left unchecked.

"I wanted so badly to say, 'You guys have no idea. I'm in chemotherapy. You're assholes.' I locked myself away until I was confident and comfortable again," she recalled, referring to the time she went out of the spotlight, sparking rumors as to what was holding her off from the cameras.

Now, Gomez is hitting back with her highly-anticipated album titled “Revival,’ and her breakout single ‘Good For You’ along with the recent hit ‘Same Old Love’ has greatly appealed to fans.

The 23-year-old explained that she has been taking out her frustrations and anger by focusing on her music. .

The singer-turned-fashion designer also announced that she is set to go on a a Revival tour! In a video shared on Instagram, Gomez said that such tour will start in May, and will cover the United States and Canada. Later in the year, the show will also go global; specific tour dates will be scheduled soon.