Pope lung nodule: Could it be cancer?

Pope Leo XIV was informed by his doctors that a lung nodule, a small spot on his lung, had been detected. At this point in time, the exact size of the nodule remains unknown. However, it is noted as being at an early stage and well localized, implying that it has not spread or metastasized. Despite this positive news, doctors advised the removal of the nodule.

The decision to remove the nodule is based on the dilemma faced by physicians when detecting incidental findings of lung nodules in asymptomatic individuals. This dilemma is particularly challenging due to the difficulty of performing biopsies on small nodules and the relatively low prevalence of malignancy in these cases. A 2019 study in the Annals of Thoracic Medicine highlights this concern.

It is essential to understand that most early-stage lung nodules are benign, which means they are not cancerous. However, there is a possibility of having multiple nodules, and they can all be benign. The pope will need a week to recover from the surgical procedure to remove the lung nodule. He is scheduled to travel to Uruguay, Argentina, and Peru between November 6-17.

Lung nodules are typically white spots or lesions on the lung, displaying a rounded or irregular shape. Radiologists identify them as opaque due to their density compared to the surrounding lung tissue. Lung nodules can originate from old lung infections, inhaled foreign particles, inflammation, scar tissue, or even cancer. Larger nodules, over 3 cm, pose a higher risk of obstructing the airway and impairing lung function.

Symptoms, such as chest pain, shortness of breath, wheezing, chronic cough, and coughing up blood, can develop if the nodule becomes malignant.

Determining when a lung nodule turns into life-threatening cancer is challenging, particularly concerning its size. A 2026 review article in the New England Journal of Medicine suggests that nodules smaller than 2 mm have a very low risk of cancer, which remains low up to a size of around 6-7 mm. The risk of cancer increases to about 9-10% at around 8-10 mm, and at larger than 1 cm, it becomes approximately 15%.

The density of the lung nodule is also a critical factor in assessing malignancy. Subsolid nodules, which are less prevalent than solid nodules, have a higher likelihood of being malignant.