As a result of mammographic detection, ductal carcinoma in situ (DCIS) is an increasing problem in breast clinics. Both histopathology and molecular profiling can identify subtypes likely to progress to invasive disease, but there is no subgroup with a zero likelihood of subsequent invasion. In patients with low/intermediate grade DCIS, if breast irradiation is not being carried out after free margins have been achieved the patient should be aware of the risks of withholding and the benefits and morbidity of adjuvant radiotherapy. Either tamoxifen or an aromatase inhibitor may be of value in those with low/intermediate ER+ve disease if radiotherapy is being withheld. For those patients with extensive or multicentric DCIS, mastectomy is the appropriate treatment. This is best combined with sentinel node biopsy and all such cases should be offered immediate reconstruction.
IntroductionIn the not so distant past, no real distinction was made between invasive breast cancer and ductal carcinoma in situ (DCIS), both being treated by mastectomy, often including an axillary clearance. Such radical surgery for DCIS became questioned as results emerged from randomised trials indicating that breast conservation was a safe and effective alternative to mastectomy for invasive breast cancer. 1, 2,3,4,5 At the same time, as a by-product of national mammographic screening programmes, the incidence of DCIS was increasing, representing up to a quarter of screen-detected malignancy. In the US in 1975 the incidence of DCIS was 2 per 100,000 and by 1985 was 10, rising to 22 in 1995 and 30 by 2005. 6 Was it reasonable to offer a mastectomy for a non-life threatening condition? We know now that the answer is "yes and no". For some women, as a result of incomplete excision of DCIS, progression to invasive disease will reduce life expectancy. But are we yet in a position to individualise treatment for women diagnosed with DCIS? The aim of treatment is to eradicate the DCIS thereby reducing the risk of recurrence of DCIS or progression to invasive disease. DCIS is a miscellany of conditions with a spectrum of risk of malignancy and it is essential that it is not universally downgraded to being regarded as a benign precursor of with an attendant laissez faire attitude towards the management of high grade disease.
HistopathologyRandomised trials of treatment for DCIS have not only yielded evidence of relative efficacy of treatments tested but have also led to central pathological review by pathologists with a special interest in breast cancer. This has enabled the delineation of groups with differing risks of subsequent relapse or progression to invasive disease.Pinder et al conducted a full pathological review of 1222/1694 (72 %) of specimens from women participating in the UKCCCR/ANZ DCIS trial. 7 Those pathological features associated with ipsilateral recurrence in univariate analysis included high cytonuclear grade, larger lesions, growth pattern, presence of necrosis or chronic inflammation, margin involvement or uncertain...