The Vatican, on Tuesday, announced that Pope Leo XIV had been diagnosed with lung cancer following a successful surgery that lasted about “90 minutes.”

The Pontiff’s “An intraoperative histological examination confirmed the diagnosis of lung adenocarcinoma, as suspected from the preoperative examinations,” the Vatican said in a statement.

The Pope’s diagnosis of lung adenocarcinoma followed an earlier announcement that he would undergo surgery to remove a small nodule from his lung. The Pontiff had a family history of cancer. Both his parents died of cancer.

What studies say about lung adenocarcinoma

A study published by Harvard Health on February 5, 2026, defined lung adenocarcinoma as a type of non-small cell lung cancer. It occurs when abnormal lung cells multiply uncontrollably and form a tumour.

“Eventually, tumor cells can spread (metastasize) to other parts of the body including the lymph nodes around and between, the lungs, liver, bones, adrenal glands and brain,” the study said. “Adenocarcinoma is the most common form of lung cancer.”

Although adenocarcinoma is generally associated with smokers, it is the most common type of lung cancer among non-smokers. It is also the most common form of lung cancer in women and people younger than 45. Compared with other types of lung cancer, adenocarcinoma is more likely to remain confined to one area.

Categories of lung adenocarcinoma

The Vatican did not specify the stage of the Pope’s lung cancer or mention its type. However, the National Cancer Institute categorised lung adenocarcinoma into “three distinct subtypes based on gene expression data: Proximal proliferative, proximal inflammatory, and terminal respiratory unit.”

Causes and risk factors

According to the American Cancer Society (ACS), smoking is by far the leading risk factor for lung cancer. About 80 per cent of lung cancer deaths are thought to result from smoking, and this figure is probably even higher for small cell lung cancer (SCLC).

“Cigar smoking, pipe smoking, and menthol cigarette smoking are almost as likely to cause lung cancer as cigarette smoking. Smoking low-tar or “light” cigarettes increases lung cancer risk as much as regular cigarettes,” a study by the American Cancer Society said.

It added, “If you don’t smoke, breathing in the smoke of others (called secondhand smoke or environmental tobacco smoke) can increase your risk of developing lung cancer.

Other risk factors include exposure to asbestos, radon and other cancer-causing agents, including uranium, arsenic, vinyl chloride, nickel chromates, coal products, mustard gas, chloromethyl ethers and diesel exhaust.

Symptoms

Studies show that adenocarcinoma and other lung cancers can cause symptoms such as coughing, coughing up blood or mucus, wheezing, shortness of breath, difficulty breathing, chest pain, weight loss and poor appetite, among others.

Treatment

“Treatment depends on the cancer’s stage as well as the patient’s condition, lung function, and other factors. (Some patients may have other lung conditions, such as emphysema or COPD – chronic obstructive pulmonary disease.),” a Harvard Health study said.

It added, “If the cancer has not spread, surgery is usually the treatment of choice. There are three types of surgery: Wedge resection removes only a small part of the lung. Lobectomy removes one lobe of the lung. Pneumonectomy removes an entire lung.”