Provincial Health Services Authority (PHSA) improves the health of British Columbians by seeking province-wide solutions to specialized health care needs in collaboration with BC health authorities and other partners.
Updated February 2016
Updated 28 September 2011
Updated August 2015
Updated August 2016
Updated July 2009
Updated January 2017
Updated October 2015
Pathological TNM Stage: see below.
Updated February 2016
Revised November 2017
A diagnosis of breast cancer requires patients and their caregivers to make a number of important decisions during the course of the disease. Surgery, systemic therapy, and radiotherapy are important treatments that optimize local, regional, and systemic control of the disease and optimize quality of life for patients with breast cancer. Multi-disciplinary care is an important resource that can aid in making these difficult decisions.
The mainstay of definitive treatment among patients with non-metastatic invasive and insitu breast cancer is surgical resection of the breast cancer, with consideration of neoadjuvant or adjuvant therapy. Those patients with inoperable, non-metastatic breast cancer may potentially be cured by neoadjuvant therapy, possibly followed by surgery. Patients with either recurrent or metastatic breast cancer may benefit significantly from treatment, with the primary goal of optimizing quality of life for those patients.
Updated April 2021
Appropriate management of pure 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, pathologist and oncologist is crucial to ensure adequate local therapy in patients treated with breast conservation. Treatment for patients with concomitant microinvasive and invasive disease should be based on the presence of the invasive disease, as discussed in separate sections.
Axillary staging is not routinely recommended for patients with pure DCIS because the risk of axillary nodal involvement is <1%. Sentinel lymph node biopsy is advised for patients undergoing mastectomy for DCIS due to the possibility of an invasive component in the final surgical specimen.1
DCIS is a non-obligate precursor of invasive disease. At present, all patients with pure DCIS are offered treatment. Patients with pure DCIS may be treated with breast conserving therapy or mastectomy. Both management strategies are associated with survival exceeding 98%. Patients undergoing breast conserving surgery (including partial mastectomy, lumpectomy, wide excision, or excisional biopsy) with a positive margin (defined by ink on DCIS) after surgery should undergo wider local excision. A 2-mm margin is associated with a decreased risk of in-breast tumor recurrence compared to narrower margins. Margin widths greater than 2 mm do not confer a significant benefit in local control compared to a 2 mm margin and thus re-excision for margins wider than 2-mm should not be routinely carried out2. Clinical judgment should be utilized for determination of the need for re-excision in patients with a smaller negative margin width (0.1-1.9 mm).2
Radiotherapy reduces the incidence of in situ and invasive breast recurrences after breast conserving surgery by half.3,4,5,6 Currently, adjuvant radiotherapy is recommended after breast conserving surgery for women with DCIS with higher risk features, e.g. younger age, high nuclear grade, larger tumour, comedo carcinoma, or close margins (<5mm) of excision. Women with well differentiated DCIS (cribriform, solid, papillary) that are <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 considered for management by wide excision alone. All patients should be referred to BC Cancer after breast-conserving surgery for an individualized discussion of the risks and benefits of adjuvant radiotherapy.
Radiotherapy should optimally start once healing from the partial mastectomy is complete, generally within 10 weeks of partial mastectomy. If post-operative problems occur, including hematoma, large seroma, infection, breast edema with erythema, or wound dehiscence occur, the start of radiotherapy may be delayed to allow resolution. There is no randomised trial evidence showing detriment to delay the start of radiotherapy however, retrospective data from British Columbia shows that there is no detriment to delay up to 20 weeks after BCS for patients with invasive disease7, which likely also applies to DCIS. Radiotherapy planning and prescription is similar to those with invasive disease and are described separately.
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 partial mastectomy and radiotherapy, and mastectomy is recommended.8
There are a number of prognostic models (VNPI, MSKCC)9,10 that can be used to estimate the risk of local recurrence considering factors such as age, margin status, nuclear grade, size of the DCIS lesion, but the performance of these models has been variable.11,12 In the future, tests using a combination of biomarkers, e.g. tumour gene profiling, may be useful for prognostication.
The use of adjuvant hormonal therapy is somewhat controversial. Adjuvant tamoxifen has been shown to decrease the occurrence of ipsilateral and contralateral breast cancers in women with in situ disease.4 This benefit is limited to those patients with ER positive tumours. No randomized trial has shown an improvement in survival with tamoxifen.4,5,6 The benefit must be weighed against the increased risk of thromboembolic events and uterine cancer. Adjuvant tamoxifen should not be considered for women with bilateral mastectomies, those with an increased risk of endometrial cancer or thromboembolic events, those with a life expectancy of <10 years or those who have taken tamoxifen for prevention. If used, the recommended tamoxifen dose is 20 mg/day for 5 years. Contraindications to tamoxifen are discussed more thoroughly below.
The role of adjuvant aromatase inhibitors is not clearly established. A randomized study of adjuvant tamoxifen versus anastrozole in women with DCIS treated with lumpectomy showed that anastrozole offers a similar degree of benefit and similar number of side effects as tamoxifen, although the side effect profile differed.13
Invasive breast cancer requires multimodality management that is specific to the stage of the disease. The majority of patients with invasive breast cancer have ductal breast cancer and, less commonly, lobular breast cancer. While there is a slight difference in the natural history of lobular and ductal breast cancer, patients with these two different pathologies are treated in the same way. The management sections that follow, aside from the section about less common histologies, refer in particular to those with invasive ductal or lobular breast cancer.
The indications for different adjuvant radiotherapy options are discussed below. It is important to note that not all patients will be eligible for all radiotherapy techniques and dose and fractionation regimens. Radiotherapy treatment options will be presented and discussed with the patient by their radiation oncologist to determine the most effective, safe, and efficient treatment based on the individual patient and disease factors.
Radiation Therapy following Breast Conserving Surgery (pT1T2;N0)
Patients treated with breast conserving surgery (BCS; lumpectomy, partial or segmental mastectomy) for stage I or II breast cancer should have a consultation with a Radiation Oncologist regarding the role of radiation therapy (RT).
RT to the breast following BCS reduces the risk of breast recurrence and may lower the risk of systemic recurrence and breast cancer death.1,2,3,4,5 In a meta-analysis of 17 older breast cancer trials, at 10 years after diagnosis, a 20% absolute reduction in the risk of breast recurrence (from 30% to 10%) translated into a 4-5% reduction in the chance of dying from breast cancer.1 However, in newer breast cancer radiotherapy trials, in lower-risk patients, in-breast local recurrences were closer to 1-3% after radiotherapy with no difference in survival.6,7 RT should be considered following BCS but patients with multiple comorbidities, limited life expectancy, who desire to avoid RT, or who have a low risk of recurrence may be considered to omit RT (see below section). In addition to breast RT, regional nodal RT may be indicated in select node-negative patients, such as those with a number of high-risk features including large tumour, high grade, lymphovascular involvement, central/inner quadrant location, or those with triple-negative (i.e. ER/PR negative, her-2-neu negative) disease.5
Timing of Adjuvant Radiotherapy
Randomized trials have shown improved local control with a boost of RT to the surgical bed following tangential RT for selected patients. Boost RT can increase radiation induced breast fibrosis and decrease cosmetic outcome. 9,10,11
Indications for supplemental boost dose of RT:
Patients who might be spared radiation therapy after breast conserving surgery
Radiation therapy consistently reduces the relative risk of local recurrence by 60-70%. Patients with a < 5% risk of local recurrence at 10 years are challenging to identify but might reasonably be considered for treatment with BCS alone. Women with the following factors likely have a 10 year risk of breast recurrence of 5% or less, if also prescribed adjuvant hormonal therapy: age >60 years, pN0, ER strongly positive, Grade 1 ductal carcinoma without lymphatic or vascular invasion and clear margins. Such women should be informed that RT will further decrease the risk of breast recurrence, but that the absolute benefit of RT on long-term survival is small.12,13,14,15
Partial breast radiotherapy following breast conserving surgery
Multiple randomized trials have tested the efficacy, safety and convenience of partial-breast irradiation (PBI) as an alternative to conventional whole-breast irradiation (WBI) for early-stage, favorable breast cancer. The rationale for this approach is that most recurrences occur at, or near, the primary tumor bed. PBI refers to the use of focused radiation to only the part of the breast where the tumor was removed. Accelerated partial breast irradiation (APBI) describes PBI treatment over a short period of time. There are three common modalities for PBI: 1) external beam radiotherapy (short tangents, 3D conformal radiotherapy and IMRT), 2) brachytherapy, and 3) intraoperative radiotherapy
Trials have shown similar outcomes with a low rate of ipsilateral-breast tumor recurrence (IBTR) for women who received WBI or PBI (accelerated and conventionally fractionated).6,7,16,17,18 Long-term data from two large randomized studies, the RAPID trial and the NSABP B-39/RTOG 0413, comparing WBI with APBI were recently published. In the RAPID trial, which used external-beam radiotherapy in both arms(6) there was no difference in the rate of IBTR between APBI and WBI (3.0% versus 2.8% respectively). Compared to the WBI arm, in which only 21% were treated with boost radiotherapy, the twice daily regimen was associated with an increase in moderate late toxicity and adverse cosmesis. In the NSABP B-39 trial Ref), the 10-year IBTR was 3.9% for WBI and 4.6%for APBI. The trial did not meet its goal of establishing equivalence, but the small absolute difference in recurrence-free interval (0.7%) is not likely to be clinically significant. In addition, the 10-year IBTR outcomes were nearly identical for patients treated with external beam radiotherapy: 3.8% for WBI and 3.7% for APBI. Compared to the WBI arm, in which 80% were treated with the addition of boost radiotherapy, the twice daily regimen was not associated with an increase in moderate late toxicity and adverse cosmesis. Other previously reported randomized trials evaluating different PBI methods have demonstrated equivalent early and late toxicity to that of whole-breast irradiation.
The American Society of Therapeutic Radiation and Oncology (ASTRO)19, the American Brachytherapy Society (ABS) 20, and the Groupe Européen de Curiethérapie- European Society for Therapeutic Radiation and Oncology (GEC-ESTRO)21 have all published evidence-based guidelines on the appropriate selection of patients for APBI following breast-conserving surgery and surgical lymph node evaluation. The BC Cancer Breast Tumor Group has reviewed the published guidelines and concluded that PBI is a reasonable alternative standard of care treatment in appropriately selected patients who meet the following criteria:
Patients with minimal lymphovascular invasion may be suitable for PBI if their other breast cancer risk factors are favorable. Microscopic multifocality may be suitable for PBI, provided the total lesion size (including foci of multifocality and intervening normal breast parenchyma) is < 3 cm. Patients with (1) anterior (at skin) and/or posterior (at pectoralis fascia) positive margins that cannot be rendered negative with further surgery (2) mixed invasive and DCIS component with clear invasive margins but close DCIS margins (≤ 2 mm) and (3) pure DCIS and a single close non-anterior, non-posterior margin can have PBI with a boost. Patients over 70 with low-risk disease who are clinically node negative and did not have SLNB or ALND may have PBI as per the discretion of the treating oncologist.
Patients with lobular breast cancer and patients treated with neoadjuvant chemotherapy are not suitable for PBI.
PBI can be delivered using external beam radiation treatment (short tangents, 3D conformal radiotherapy or IMRT) or permanent seed brachytherapy.22,23 Due to concerns of adverse late cosmetic outcomes, the use of 38.5 Gy / 10 APBI twice daily fractionation over 5 days (ie accelerated partial breast RT) is not recommended.6,18 Based on the results of the FAST-Forward trial, comparing whole breast irradiation with 40 Gy / 15 versus 27 Gy / 5 and 26 Gy / 5, it is recommended to use 26 Gy / 5 PBI for patients whose dosimetry meets the planning constraints of the FAST-Forward trial and 40 Gy / 15 for patients whose breast separation is too large to meet the planning constraints of the FAST-Forward trial.24 If a boost is indicated when using 26Gy/ 5 PBI, the recommend boost dose is 10 Gy / 5 or 16 Gy / 8, as was used in the FAST-Forward trial.24
Short-course adjuvant radiotherapy
Five-fraction breast radiotherapy can be offered to patients undergoing tangent, breast-only, adjuvant treatment. It is a 5-fraction regimen delivered over 5 consecutive working days as used in the FAST-Forward Phase III trial.24 Five-year follow-up data demonstrated that local control with 26 Gy in 5 daily fractions was not inferior for local control with 40 Gy in 15 daily fractions. Cosmetic outcomes were also equivalent at 5 years. Greater than 5-year follow-up data has not yet been published. Although a wide range of patients were included in the trial, some patient, disease, and treatment characteristics were uncommon and therefore the overall conclusions may be less applicable to these sub-groups. Patients should only be treated with one-week breast radiotherapy if their plans meet the dosimetric constraints used in the trial. Patients with DCIS and with very low risk invasive breast cancer were not included in the FAST-Forward trial because they had a very low likelihood of outcome events occurring. The results of the FAST-Forward could be extrapolated to include these groups of patients. It is recommended that patients undergoing nodal radiotherapy and patients with breast reconstruction should not be treated with short-course at this time unless participating in a clinical trial.
Radiation therapy following mastectomy (pT1,T2;N0)
The majority of patients with pT1-T2 pN0 disease will not derive a benefit from adjuvant RT.25 Some patients may have a higher risk of locoregional recurrence and may benefit from adjuvant radiotherapy for local control but an overall survival benefit has not been demonstrated. This group would include: patients with close or positive margins with pT2 tumour plus other high risk features, such as grade 3 histology, high volume lymphatic or vascular invasion, age<50 years, and central or inner quadrant tumours26 and patients with clear margins post-mastectomy with central/inner quadrant tumours, or those with T2 tumour size with other high risk features, e.g. high grade, lymphovascular involvement, or triple-negative (i.e. ER/PR negative, her-2-neu negative) disease.27 Patients with these high-risk features should be referred after mastectomy for discussion of adjuvant RT with a radiation oncologist.
Radiation therapy following mastectomy or breast conserving surgery (pT1,T2;N1, and T3;N0)
Locoregional RT improves outcomes following mastectomy or breast conserving surgery for patients with node-positive breast cancer or node-negative T3 breast cancer. 25,27,28,29,30,31 A reduction in loco-regional recurrence and reduced breast cancer mortality is seen even for patients with only a moderate risk (e.g. 1-3 nodes positive) of loco-regional recurrence.25,28,29,32 The breast cancer specific-outcomes improvement may not translate to an overall survival benefit.5,32 Patients with lymph node positive disease and increased risk of internal mammary chain involvement may derive proportionally more benefit from adjuvant loco-regional radiotherapy. 33 Patients with pT1-T2 pN1 and T3N0 should be referred for discussion of adjuvant RT with a radiation oncologist.
Radiation therapy following mastectomy or breast conserving surgery (pT1-T3;N2-3, and T4;N0-3)
Locoregional RT is recommended for patients with locally advanced breast cancer following mastectomy or breast conserving surgery. Adjuvant RT has been shown to decrease locoregional recurrence and reduce breast cancer mortality even in patients treated with adjuvant chemotherapy.25,28,29,30
Timing of adjuvant radiotherapy following mastectomy or in lymph node positive patients: Timing is as described above in the post-BCS for node-negative patients.
**Details of radiotherapy planning and prescription in the post-breast conserving surgery and post-mastectomy setting are described separately (Section 6.10).
Table 2. Contraindications to starting or continuing Tamoxifen
DVT=deep venous thrombosis; PE=pulmonary embolis
Table 3. Contraindications to Aromatase Inhibitors
Table 4. Minimum eligibility criteria for BC funded Oncotype Dx Assay®
Revised November 2017
Side effects of curative intent, adjuvant radiation therapy are directly proportional to the volume of the irradiated tissues. Since radiation therapy (except whole body radiation) is essentially a localized treatment, the side effects depend also on the anatomic location irradiated. The severity of side effects is directly related to the dose of radiation delivered and the time over which it is delivered.
Updated October 2015
Revised 9 March 2011
Food Sources of Calcium
Adapted from the Manual of Clinical Dietetics, 6th Edition (p.746-747), by American Dietetic Association et al, 2000.
Calcium intake from all sources should not exceed 2000 mg per day.
Food Sources of Vitamin D
Adapted from the Manual of Clinical Dietetics, 6th Edition (p.746-747), by American Dietetic Association et al, 2000.
Vitamin D intake from all sources should not exceed 4000 IU per day.
Updated 5 March 2007
BC Cancer. All Rights Reserved.