Updated: November 2004
1) Paget's Disease of the Nipple
The standard management of Paget's disease remains surgical excision. Since Paget's disease of the nipple is often associated with an underlying breast mass, the breast should be imaged with a mammogram and ultrasound, and if these investigations are non-diagnostic, an MRI of the breast should be considered. A partial mastectomy may be offered to selected patients if breast conservation will lead to an adequate cosmetic result. Such patients should be referred to a radiation oncologist for consideration of post operative radiotherapy. A sample of underlying breast tissue should be taken with the nipple to evaluate if an associated in-situ or invasive cancer is present. We encourage referral of patients to the B.C. Cancer Agency if partial mastectomy is to be considered.
2) Ductal Carcinoma in Situ (DCIS)
Appropriate management of DCIS requires detailed mammographic evaluation of the breast to obtain an assessment of the preoperative extent of the lesion. Close cooperation and communication between the radiologist, surgeon and pathologist is crucial to ensure adequate local therapy in women treated with breast conservation.
We are not presently recommending low axillary dissection for DCIS. However, the larger the focus of ductal carcinoma in situ, the higher the chance a focus of micro-invasive disease is present. Therefore, an axillary lymph node dissection, or sentinel node biopsy, may be appropriate in a patient with DCIS >5cm in diameter.
Although total mastectomy remains an option for women with DCIS, recent evidence has demonstrated that radiotherapy reduces the incidence of subsequent in situ and invasive breast recurrences. Currently, adjuvant radiotherapy is recommended for women with DCIS tumour >1 cm in diameter or comedo carcinoma who are interested in breast conservation, and in all patients with close margins (<5mm) of excision.
Women with well differentiated DCIS (cribriform, solid, papillary), <1cm in diameter with complete radiographic and pathologic excision (at least 5 mm of normal breast tissue between foci of DCIS and the inked margins) may be managed by wide excision alone.
Women with very diffuse areas of DCIS (e.g., >5 cm or greater than or equal to ¼ of the breast on mammogram) have a substantial risk of recurrence even after excision and radiotherapy and mastectomy is recommended. The Van Nuys prognostic index (which incorporates age, margin status, grade and size of the DCIS lesion can be useful at estimate the risk of relapse with breast conservation (Silverstein MJ Am J Surgery 186(2003); 337-343).
Tamoxifen has been shown in one randomized study (NSABP B24) to decrease the occurrence of both invasive and in situ disease in women with in situ disease when used in combination with radiation. The cumulative evidence of events at 5 years:
|
|
placebo |
tamoxifen |
|
|
all breast cancer events |
13.4% |
8.2% |
p= <0.1 |
|
contralateral breast cancer |
3.4% |
2.0% |
p= 0.01 |
The rate of endometrial cancer per 1000 women per year was 0.45 for placebo and 1.53 for tamoxifen.
However, a second smaller randomized trial did not demonstrate a statistically significant advantage to the addition of tamoxifen. This later trial did not include patients with margins and very few women over the age of 50, unlike the former trial. This emphasizes the importance of consideration of prognostic factors and the balance of risk and benefits in the consideration of tamoxifen in this setting. In addition, updated analysis of the NSABP B24 trial suggests that the benefit of tamoxifen in DCIS may be confined to those patients with ER positive tumours. Therefore, patients with DCIS who are considered appropriate candidates for tamoxifen should have ER receptors assessed.
The following guidelines should be used when considering tamoxifen in women with a diagnosis of in situ disease only:
– adjuvant tamoxifen should be offered to women with DCIS, after consideration of known risk factors in particular age and margin status, and after confirmation of ER positivity. It should not be considered for women with bilateral mastectomies, with an increased risk of endometrial cancer or thromboembolic events, or for women with a life expectancy of <10 years or who have recently been on tamoxifen for prevention. The tamoxifen dose should be 20 mg/day for 5 years.
3) Lobular Carcinoma In Situ
Use of this term is controversial. Most modern authors regard this as indicating a high risk for the development of infiltrating carcinoma in either or both breasts. Certainly the risk for subsequent carcinoma is not confined to the segment of the breast involved by the in situ change. The risk to each breast is approximately equal and approaches fifteen percent within ten to fifteen years. Patients can be given the option of either careful follow up or occasionally, bilateral mastectomy with or without immediate or delayed reconstruction. Recently tamoxifen was shown to decrease the risk of invasive cancer in women with lobular cancer in situ in the NSABP prevention trial using tamoxifen 20 mg daily for 5 years. Therefore these women are candidates for 5 years of tamoxifen prescription.