Washington, Nov 11 (IANS): A large study has found that cigarette smoking prior to the first diagnosis of lung (stage I), bladder, kidney or head and neck cancer increases the risk of developing a second smoking-associated cancer.

"As survival improves for a number of smoking-related cancers, patients are living longer; however, smoking may increase the risk of developing a second smoking-related cancer among these survivors," said Meredith S. Shiels, lead study author and research fellow with the National Cancer Institute's Division of Cancer Epidemiology and Genetics.

Researchers examined data from five cohorts which included 2,552 patients with stage I lung, 6,386 with bladder, 3,179 with kidney and 2,967 with head and neck cancer.

They found that the association between smoking and developing a second primary smoking-associated cancer was similar to the association between smoking and developing a first primary smoking-associated cancer.

Patients who smoked more than 20 cigarettes per day had a 5.41-fold higher risk of developing cancer than individuals who have never smoked.

Notably, current smoking at any level increased the risk of overall mortality across all cancer disease sites.

"Our study demonstrates that health care providers should emphasise the importance of smoking cessation to all their patients, including cancer survivors," Shiels concluded.

The study was published in the Journal of Clinical Oncology.