NEW YORK, Aug 2: A Brooklyn physician is raising awareness about a subtle but potentially serious sign of lung cancer—changes in the shape and texture of fingernails.

Dr. Davood Johari, a pulmonary and critical care specialist at NYC Health + Hospitals/Kings County, told the New York Post that between 5% and 15% of lung cancer patients develop a condition known as nail clubbing, which typically emerges in the later stages of the disease—often too late for effective treatment.

“Fingertips appear wider and rounder than normal, with the nails curving downward, resembling an upside-down spoon,” Johari explained, as World Lung Cancer Day was observed on August 1. “The nail bed—the area under the nail—feels spongy and softer. The fingertip might also appear red or feel warmer than usual.”

While the exact cause of nail clubbing and its link to lung cancer remains unclear, experts believe it may be related to hormone-like substances produced by tumors. These substances can cause blood vessels in the fingers to widen, increasing blood flow and fluid buildup beneath the nails.

Lung cancer continues to be the leading cause of cancer-related deaths worldwide. In the United States alone, approximately 226,650 new cases are expected this year, with an estimated 125,000 deaths, according to health officials.

Dr. Johari emphasized the importance of being vigilant. He urged anyone who notices persistent changes in nail color, shape, or thickness lasting more than two weeks—even in the absence of other symptoms—to seek medical evaluation.

He also noted other potential warning signs of lung cancer, such as a persistent cough, changes in voice, unexplained weight loss or fatigue, ongoing shoulder pain that worsens at night, and visual disturbances or drooping eyelids.

Lung cancer diagnoses typically begin with a review of medical history, a physical examination, and imaging studies. A biopsy is required to confirm the presence of cancer.

Dr. Johari added that nail clubbing can also signal other serious health conditions, including chronic lung infections, congenital heart defects, gastrointestinal disorders, and autoimmune diseases. He further cautioned that other nail abnormalities—such as dark streaks, bruising that doesn’t heal, nail separation, or bleeding—may also indicate various types of cancer and should not be ignored.

“Many nail changes are harmless and may be due to aging, injury, or everyday activities like applying nail polish,” Johari said. “However, persistent changes in nail color, shape, or thickness should always be evaluated by a physician.”

While smoking remains the most well-known cause of lung cancer, Dr. Johari noted that other risk factors also play a significant role. One of the most serious is radon exposure—a naturally occurring, colorless, odorless, and tasteless gas that is the second leading cause of lung cancer in the U.S., particularly among non-smokers, according to the Ohio State University Comprehensive Cancer Center.

Radon is commonly found in rock, soil, and groundwater. Health experts recommend testing homes for radon and following local safety guidelines, as high levels can often be reduced through proper mitigation systems.

Other risk factors include age, with two-thirds of lung cancer cases diagnosed in individuals over 65, and most in those over 45. A family or personal history of the disease also increases the likelihood of developing it.

In addition, environmental and occupational exposures—such as to arsenic, asbestos, cadmium, chromium, uranium, and certain petroleum products—can contribute to lung cancer risk. Other contributing factors include air pollution, previous radiation therapy to the chest or breasts, and a history of lung diseases such as tuberculosis.