BCT – Breast Conservation Therapy
BI-RADS - Breast Imaging Reporting and Data System
CT – Computed Tomography
CTV – Clinical Tumor Volume
DCIS - Ductal carcinoma in situ
DIBH – Deep Inspiratory Breath Hold
ER – Estrogen Receptor
FNA – Fine Needle Aspiration
GTV – Gross Tumor Volume
H&P – History and Physical
HER2 - Human Epidermal Growth Factor Receptor 2
HRT – Hormone Replacement Therapy
IDC – Invasive Ductal Carcinoma
IMN – Internal Mammary Nodes
Ki67 - percentage score defined as the percentage of positively stained tumor cells among the total number of malignant cells assessed, commonly used measure of cellular proliferation in breast cancer tissue
LN – Lymph Nodes
LVSI - Lymph-Vascular Space Invasion
MLC – Microleaf Collimator
MRI – Magnetic Resonance Imaging
N stage – Nodal Staging
OAR – Organs at Risk
OCP - Oral Contraceptive Pills
PBI – Partial Breast Irradiation
PCP – Primary Care Physician
PR – Progesterone Receptor
PTV – Planning Tumor Volume
RT – Radiation Therapy
SLNB – Sentinel Lymph Node Biopsy
T stage – Tumor Staging
USPSTF - United States Preventive Services Taskforce
V20 – Volume receiving 20 Gray
VATS - Video-assisted thoracoscopic surgery
WBI – Whole Breast Irradiation
Breast Screening Guidelines
USPSTF Breast Cancer Screening
Screening guidelines vary depending on organization. The USPSTF recommends a screening mammogram performed every other year for women 50-74 years old.
For those 40-49 years old, the decision for screening should be individualized, with higher value placed for those at higher risk, including those with a parent, sibling, or child with breast cancer.
The American Cancer Society recommends yearly screening from ages 45-54 and then every 1-2 years until life expectancy is <10 years.
“BI-RADS” is an acronym for the Breast Imaging Reporting and Data System score. It’s a scoring system radiologists use to describe mammogram results on a 7-point scale 0-6. A BI-RADS 0 represents an incomplete test requiring additional imaging. A BI-RADS 1-3 represent negative, benign, and probably benign findings. A BI-RADS 3 will likely buy you a short interval follow up imaging (~6 months). BI-RADS 4 is the start of our suspicious findings that likely will warrant further workup. Finally, a BI-RADS 5 indicates a very high suspicion of malignancy. BI-RADS 6 are for lesions we already know are cancer and biopsy proven.
When pursuing a biopsy, consider a core needle biopsy performed with image guidance. FNA’s or excisional biopsies are not ideal.
In this case, the patient gets a core needle biopsy and it shows invasive ductal carcinoma, ER+/PR+/HER2-, grade 2.
If the patient were premenopausal, consider a pregnancy test. In anticipation of upcoming treatment, should the patient be pre-menopausal and amenable to it, consider consultation with fertility specialists for future family planning.
Breast MRI or whole body staging, without symptoms, would not be indicated in this case.
For treatment options, broadly, surgery will be the mainstay of treatment, including breast conservation therapy as well as mastectomy. BCT will include lumpectomy and a SLNB +/- adjuvant RT, depending on the patient’s age and features on surgical pathology. Mastectomy would be considered if she exhibited multi-centric disease, required repeat margin excisions after lumpectomy, had contraindications to RT, or if this was the patient’s preferred approach. Given her age is 72, as per choosing wisely, routine SLNB is not indicated for those over age 70 who are clinically N0.
In this case, the patient was pT1c pN0 M0, stage IA. She would be classified as a Luminal A as this is estrogen receptor-positive and progesterone receptor-positive, HER2-negative, and has low level Ki-67.
Adjuvant treatment options include adjuvant whole breast radiotherapy, adjuvant accelerated partial breast, and hormone therapy alone.
For CT simulation, in this case, a headfirst, supine setup on a breast board with the patient’s left arm raised was performed. If a breast board is unavailable, a wingboard or vac-loc would be great alternatives for fixation. Consider wiring the scar and mark breast borders and given this is a left sided treatment, employ DIBH for heart avoidance. A prone setup can be considered as well.
Breast borders are marked with superior border at the level of the inferior clavicle head, medial border at the patient’s midline, lateral border at the mid-axillary line, and inferiorly, 1-2 cm below the inframammary fold.
Ensure relevant OARs were contoured such as the heart, lungs, and contralateral breast but the breast CTV itself does not necessarily need to be contours. Using the same borders that had been marked off, create opposing tangential fields and ensure the glandular breast tissue is well covered. This can be performed by setting the isocenter along the posterior border of the field to create a half beam block effect. If there are clearance or set up issues, the isocenter can be placed more anteriorly as well, with the beam angles adjusted so the posterior field edges align on a straight edge. Ensure there is at least a 2-3cm flash anteriorly. Evaluate how much lung and heart are involved in the field and adjust as fit to reduce dose without much compromise to coverage.
With treatment, acutely, discuss toxicities including fatigue and skin changes. Long term, monitor for radiation pneumonitis, increased risk for rib fracture, cardiotoxicity, changes in breast cosmesis, and a low risk for secondary malignancies.
Follow up her 1-4 x per year for a H&P for up to 5 years, then annually, with a clinical exam. Consider obtaining a mammogram at 6 months, then yearly.
Generally speaking, a tumor boost should be included in younger patients 50 or younger or older patients with grade 3 disease, positive margins. Other cases require individual patient decision making taking into account other parameters such as tumor biology, tumor size, close margins, etc.
Thank you to Dr. Michael Xiang.