One in five cancer patients wait more than three months before visiting a doctor about their symptoms, a new study suggests.
Twenty one percent of patients who took part in the study waited for at least three months before raising the issue with a medical professional.
Researchers found that patients with prostate cancer and rectal cancer were most likely to delay while breast cancer patients were the least likely, according to the research, published in the British Journal of Cancer.
The researchers surveyed 2,371 patients with 15 different cancers about the symptoms that had led to diagnosis.
Almost half of prostate cancer patients and 37% of rectal cancer patients reported a delay of three months or more between first noticing the symptoms to going to see a doctor while only 8% of breast cancer patients waited this long.
Embarrassment, worrying about wasting a doctor's time and not realising their symptoms were serious were among the most common reasons for delay.
"This research highlights that we must do more to make sure the public recognises key symptoms of cancer like unexplained pain, unusual bleeding or weight loss, as well as a lump and make sure they get these checked out as soon as possible," said lead author Dr Lindsay Forbes, co-director of the King's College London's Early Presentation Group.
"Although a worrying number of patients across society are waiting too long to go to their doctor, it is those in the most deprived areas that are most likely to delay."
Sara Hiom, director of early diagnosis at Cancer Reserach UK which part funded the study, said: "This research highlights how incredibly important it is that everyone is aware of the wide range of cancer symptoms, and has the confidence to tell their doctor.
"The earlier cancer is diagnosed, the higher the chance of survival and it's essential that people report any symptoms promptly to their GP. No one should be waiting three months before booking an appointment.
"It's important that we continue investing in our work with both the National Health Service and Public Health England on the Be Clear on Cancer campaigns which are successfully raising awareness of these cancer symptoms and encouraging people to see their doctors."