CANADA: Clinical practice guidelines for the care and treatment of breast cancer: The management of ductal carcinoma in situ [10/03/2001; Canadian Medical Association Journal] This article provides a summary of changes made by Health Canada's Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer to the article "Clinical practice guidelines for the care and treatment of breast cancer: 5. The management of ductal carcinoma in situ (DCIS)," originally published in 19981 (the 2001 update can be found online). Although there are not many changes to the guideline, new studies have provided more evidence to support the original recommendations. DCIS of the breast is a proliferation of malignant-appearing cells of the ducts and terminal lobular units of the breast that have not breached the ductal basement membrane. Since more women are having screening mammography, DCIS is being diagnosed more frequently. In 1996, over 200000 Canadian women aged 50-69 participated in 7 provincial screening programs. Of the 991 cancers detected, 171 were DCIS (17%, or 0.8 cases per 1000 women screened). DCIS can be considered a precursor of invasive breast cancer and, if left untreated, can develop into invasive disease in up to 35% of cases within 10 years. Again the steering committee emphasizes the importance of careful surgical removal of the area of DCIS and attention to meticulous pathological processing and reporting. The most clinically useful factors in terms of predicting local recurrence of the DCIS and progression to invasive cancer are nuclear grade, presence of necrosis, involvement of surgical margins and lesion size. The original guideline recommended mastectomy, breast-conserving surgery (BCS) plus radiotherapy or BCS alone as treatment options for DCIS, and this recommendation has not changed substantially. The use of breast irradiation after BCS was supported by the results of 1 randomized trial in the 1998 guideline. A report has since been published of a second randomized trial, in which the European Organisation for Research and Treatment of Cancer randomly assigned 1010 women with DCIS to either BCS or BCS plus breast irradiation. At a median follow-up of 4 years, the rate of local recurrence was significantly lower in the group treated by BCS plus radiotherapy than in the group treated by BCS alone (9% v. 16%, p = 0.005). The survival rate was 99% in both groups. A large retrospective study has emphasized the importance of ensuring that there is a wide rim of normal tissue around the excised tumour if there is consideration that a woman treated with BCS might not have radiotherapy. The steering committee feels that it is difficult to identify patients at such a low risk of breast cancer recurrence that radiotherapy could be omitted after BCS even though in such women the risk reduction in absolute terms associated with radiotherapy may be small. The 1998 guideline stated that "omission of radiotherapy may be considered when lesions are small and low grade, and when pathological assessment shows clear margins." The updated recommendation states that "BCS should usually be followed by radiotherapy. Patients with a sufficiently low risk of local recurrence with BCS alone are difficult to identify. However, BCS alone may be considered after a careful discussion with the patient, if detailed pathological assessment confirms that the lesion is small and does not have high-grade nuclei or comedo-type necrosis and the surgical margins are clear of disease. In addition, in such circumstances the surgical excision should be cosmetically acceptable." In 1998 the steering committee concluded that evidence was not available to support the use of tamoxifen in the treatment of women with DCIS. Since then, the results were published of the National Surgical Adjuvant Breast Project B-24 trial, in which 1804 women with DCIS who received BCS plus radiotherapy were randomly assigned to receive tamoxifen or placebo. At 5 years the incidence of invasive breast cancer was significantly lower in the tamoxifen group than in the placebo group (4.1% v. 7.2%, p = 0.004); the corresponding incidence rates of recurrent DCIS were 4.2% and 6.2% (p = 0.08). Tamoxifen can be associated with side effects. The updated recommendation for DCIS states that "the role of tamoxifen in the management of patients with DCIS continues to evolve. The potential benefits and risks should be discussed with patients." Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.