"Delays" in diagnosis: a misleading concept, yet providing opportunities for advancing clinical care.

Delay in diagnosis is a pejorative term for an interval better described as lag time, a period of considerable concern to health care administrators, providers, and consumers, receiving attention in numerous countries over many years. The general assumption that the longer the lag time the poorer the prospect for survival is not supported by the evidence that points to a more complex relationship. In some instances shorter lag times are associated with longer survival and in others correlate with shorter survival; in many instances there is no clear relationship. The associations between numerous demographic variables, such as the patient's age and the nature of the first health care contact, and lag time account for no more than 20% of the variance in this interval. It appears that more important determinants are the biology of the tumor and its related clinical behavior. Nevertheless, to minimize anxiety in patients and families, every effort should be made to reach a timely diagnosis. With the exceptions of retinoblastoma and malignant melanoma, campaigns to enhance public awareness have met with limited success with regard to reducing lag times in children and adolescents with cancer, indicating a challenge worthy of international attention.