Immigration officials in th US were dumbfounded when a traveler's fingerprints had disappeared. This prompted them to hold the said person for four hors before they could solve the mystery - the traveler was a cancer patient and one of his cancer drugs had caused his fingerprints to disappear. His oncologist is now advising all cancer patients who are being treated with the commonly used drug, capecitabine, to carry a doctor's letter with them if they want to travel to the USA.

The incident is highlighted in a letter to the cancer journal, Annals of Oncology [1], published online today (Wednesday 27 May). According to the oncologist, several other cancer patients have reported loss of fingerprints on their blog sites, and some have also commented on similar problems entering the USA.

Dr Eng-Huat Tan, a senior consultant in the medical oncology department at the National Cancer Centre, Singapore, described how his patient, a 62-year-old man, had head and neck cancer that had spread (metastatic nasopharyngeal carcinoma), but which had responded well to chemotherapy. To help prevent a recurrence of the cancer the patient was put on a maintenance dose of capecitabine, an anti-metabolite drug.

Capecitabine is a common anti-cancer drug used in the treatment of a number of cancers such as head and neck cancers, breast, stomach and colorectal cancers. One of its adverse side-effects can be hand-foot syndrome; this is chronic inflammation of the palms or soles of the feet and the skin can peel, bleed and develop ulcers or blisters. "This can give rise to eradication of finger prints with time," said Dr Tan.