What we know about Pope Leo XIV's lung cancer operation

Pope Leo XIV had a cancerous tumor surgically removed from his right lung on Tuesday in a 90-minute operation described as "successful" by the Vatican.

Here are what several medical experts told AFP about the surgery and diagnosis.

What is pulmonary adenocarcinoma?

Pulmonary adenocarcinoma, the type of tumor removed from the Pope, generally comes from "a primary cancer," said Dr. Juanita Mora, a medical spokesperson for the American Lung Association.

She told AFP that "is a good thing" because it means the tumor is from lung cancer instead of generating from the spread of another cancer.

There are two main types of lung cancer: "small cell" cancers, which spread aggressively and make up about 10 to 15% of diagnoses, and "non-small cell" cancers, which make up the vast majority.

"Adenocarcinoma is the most common kind of what's called non-small cell lung cancer," David Spigel, a medical oncologist specializing in lung cancer research at Nashville's Sarah Cannon Research Institute, told AFP.

Read morePope Leo diagnosed with lung cancer after doctors successfully remove nodule

Promising outlook

David Carbone, director of the Oncology Center at Ohio State University, noted that while smoking is the most well-known risk factor for a lung cancer diagnosis, "most lung cancers that we diagnose today are in people who haven't smoked, or (stopped) many years ago."

Lung cancer is the top cause of cancer death worldwide, according to the World Health Organization (WHO), but the prognosis can vary significantly depending on the type of lung cancer and how advanced it is when first detected.

"When we look at five-year survival rate from lung adenocarcinoma, and it's nicely localized, the rate is approximately 63 to 67 percent," Mora said.

"But if we catch it early, it becomes 80 to 98%, especially after surgical removal."

In such a case, the patient "will achieve a cure and never have their life threatened by cancer," Spigel added.

A standard procedure

Pope Leo XIV announced the presence of the lung nodule on Sunday, saying it had been "detected at a very early stage" and was localized.

Read morePope Leo says will undergo surgery for early-stage lung nodule

The Vatican said "the lower lobe of the right lung was removed" during Tuesday's operation to remove the mass.

"He had part of his right lung taken out, which is the standard procedure," Carbone told AFP.

"There's a lot of reserve in the lung, and people can have an entire lung removed and live a normal life," he added.

"I would expect that he'd be back to completely full level of activity very soon."

What now?

The question now is whether Pope Leo XIV will need additional treatment such as chemotherapy or radiation.

According to the experts consulted by AFP, the answer will depend on several factors, such as the size of the cancerous mass removed, how aggressive it was, its genetic characteristics, and whether or not it has spread.

A Vatican source indicated that additional testing is underway.

For Carbone, the fact that the Pope has already undergone surgery is encouraging.

"Because if it had spread to, for example, the lymph nodes in the center of the chest, he would have had some treatment before surgery, which he didn't have," he explained.

"They really do go straight to surgery only for the earliest stage tumors, which makes me think this was a very early stage tumor, and has a quite good prognosis."

He stressed that treatment for lung cancer has improved considerably over the past few decades, "and the prognosis is better than ever. So I would be hopeful for a full recovery."