From the Guidelines
Breast cancer treatment with radiotherapy should involve whole breast irradiation with or without a boost to the tumor bed, especially for node-positive disease, as it significantly reduces the 10-year risk of recurrence and 15-year risk of breast cancer death. This approach is supported by the results of a meta-analysis by the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG), as reported in the 2016 NCCN clinical practice guidelines in oncology 1.
Key Considerations for Radiotherapy in Breast Cancer
- The standard treatment duration is typically 3-6 weeks, with daily sessions of external beam radiation therapy to the affected breast or chest wall.
- Modern techniques such as 3D conformal radiation therapy, intensity-modulated radiation therapy (IMRT), and hypofractionated radiation are used to minimize damage to healthy tissue.
- For some patients, partial breast irradiation may be an option, targeting only the tumor bed rather than the entire breast.
- Side effects of radiotherapy include skin redness, fatigue, and breast swelling, which are usually temporary.
Planning and Delivery of Radiotherapy
- Treatment planning involves the use of CT scans to create a precise map, ensuring that radiation targets the cancer while sparing healthy organs like the heart and lungs.
- The goal of radiotherapy is to damage the DNA of cancer cells, preventing them from dividing and growing, and ultimately causing them to die.
- As noted in the guidelines, whole breast irradiation is strongly recommended after lumpectomy, with or without a boost to the tumor bed, for both node-positive and node-negative diseases, although the recommendation strength varies (category 1 for node-positive, category 2A for node-negative) 1.
Evidence-Based Practice
- The recommendation for whole breast irradiation is based on evidence showing a significant reduction in the risk of recurrence and breast cancer death, with a relative risk of 0.52 for recurrence and 0.82 for breast cancer death 1.
- This evidence supports the use of radiotherapy as a critical component of breast cancer treatment, particularly in reducing long-term risks associated with the disease.
From the Research
Treatment of Breast Cancer with Radiotherapy
Radiotherapy plays a significant role in the treatment of breast cancer, offering improvements in locoregional control and survival for women undergoing mastectomy who are at high risk of recurrence, and allowing for breast conservation in certain settings 2. The treatment of breast cancer with radiotherapy can be delivered through external beam radiation therapy (EBRT) or brachytherapy.
External Beam Radiation Therapy (EBRT)
EBRT involves the delivery of radiation to the whole breast, typically with a dose of 45-50 Gy, followed by an interstitial boost to the primary site 3. This approach has been shown to be effective in achieving local tumor control and overall survival, with a 5-year overall survival rate of 88% and local tumor control rate of 96% 3.
Brachytherapy
Brachytherapy involves the delivery of radiation directly to the tumor site through an implant, and can be used as a boost to the primary tumor site after EBRT 3. The use of high-dose-rate (HDR) iridium implantations has been shown to be a safe procedure, with no serious complications and no negative effect on cosmetic appearance 3. However, brachytherapy has been associated with a higher risk of infectious and noninfectious adverse events compared to EBRT, including seroma, breast pain, and rib fracture 4.
Key Points
- Radiotherapy is a significant component of breast cancer treatment, offering improvements in locoregional control and survival 2.
- EBRT and brachytherapy are two approaches to delivering radiotherapy, each with its own benefits and risks 3, 4.
- Brachytherapy has been associated with a higher risk of adverse events, including seroma, breast pain, and rib fracture, compared to EBRT 4.
- The choice of radiotherapy approach depends on individual patient factors, including tumor size, location, and patient preferences 2, 3, 4.