Fast track — ArticlesInfluence of delay on survival in patients with breast cancer: a systematic review
Introduction
Detection and treatment of cancer at an early stage improves the prospects for long-term survival. In many types of cancer, the outlook for patients with small, localised tumours is much better than that of patients with advanced or metastatic disease. If cancers are diagnosed early, microscopic spread of disease may not have occurred. Excision of the primary tumour may therefore be curative. For some cancers, evidence shows that diagnosis and treatment before symptoms appear is associated with improved survival rates. The influence on survival of delays in diagnosis and treatment after onset of symptoms has, however, been much less clear.
Whether longer delays in patients who have symptoms are associated with worse outcomes cannot be studied in randomised controlled trials. Detailed analysis of observational data is therefore necessary, taking into account, wherever possible, potential confounding factors. Among patients with breast cancer, uncertainty persists about the possible impact of delays on survival, despite many different reports.1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86 The question, however, remains important. Breast cancer is a common disease with more than 30 000 new cases per year in the UK.87, 88 Most (>75%) patients present after symptoms occur, rather than through the National Health Service breast-screening programme. In about a third of these patients, the time between the first symptom and start of treatment is more than 3 months89 and, in about a quarter of patients, more than 6 months.25, 43, 48, 51 Although age-standardised mortality ratios have fallen in the past decade90, 91, 92 breast cancer remains a major cause of death for women in the UK.
Our primary hypothesis was that longer delays between onset of symptoms and diagnosis or treatment are associated with worse survival rates in patients with breast cancer and that this association is not simply attributable to lead-time bias. We tested also a secondary hypothesis that patients with longer duration of symptoms would generally present with more advanced disease and that this relation between delay and stage would account for the poorer survival anticipated in patients with longer delays. These hypotheses were based on the findings from a study of patients attending the Guy's Hospital Breast Unit, London, UK,89 which we consequently excluded from this review.
This study forms part of a larger report commissioned by the National Health Service Cancer Research and Development Programme.93 A review of factors that influence delays by patients or providers is published in this issue of The Lancet (see page 1127).94
Section snippets
Data search
We did the review according to principles laid down to protect against bias.95, 96 Details of the methods are reported elsewhere, including the full search strategy and lists of all duplicate and excluded reports.93 We started the review in June, 1996, and completed it in March, 1998. We attempted to identify all observational studies (worldwide) related to women presenting with symptoms of breast cancer, with direct data linking duration of symptoms and survival. We did not limit the year of
Results
We identified 87 original studies that included information directly linking duration of symptoms (delay) and survival. The studies involved a total of 101 954 patients and were published between 1907 and 1996 (table 1). One report related to two separate studies of different cohorts.
Discussion
The combined results from each of the three categories support our primary hypothesis that longer delays are associated with worse survival rates. In category I the association between longer delay and worse survival was significant among studies with unrestricted samples and among those confined to patients with operable disease. In category II, 13 of 14 studies with unrestricted samples showed a significant adverse relation between longer delays and survival. Four of five studies confined to
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