Breast cancer growth rates favour abolition of rule

Potter et al highlight the failure of the two week wait initiative to discriminate between patients with breast cancer and those with benign disease.¹

However, what is more important is whether earlier diagnosis provided by a fast track system improves outcomes for patients. Evidence for this is lacking. This is likely to be due to the underlying biology and kinetics of tumour growth. Most breast cancers are relatively slow growing, with an average tumour volume doubling time of 280 days. Assuming that each cancer develops from a single cell and assuming a constant doubling time of 280 days, a tumour of 2 mm (the lowest mammographically detectable level) will have been present for more than 18 years.² A clinically detectable tumour will have been present for even longer.

Moreover, the development of metastases, which ultimately affects the potential for curative treatment, is likely to have occurred even before the primary tumour is clinically detectable.³ Therefore, the importance of whether a patient is seen by a breast specialist within two weeks of referral is largely down to psychosocial issues such as patients' anxiety.

Despite evidence that most referred breast lumps will be benign, most patients who find a lump will fear that they have cancer. A patient referred routinely with a lump may well have the same degree of anxiety as a patient referred urgently, but will have longer to endure the uncertainty of knowing whether she has cancer or not.

By abolishing the two week wait, resources could be directed towards reducing waiting times for all patients and help ensure timely diagnosis and reduction of anxiety for all.