Table 2. Current ASTRO guidelines for accelerated partial breast irradiation (63,64).
| Consideration | Suitable | Cautionary | Unsuitable |
|---|---|---|---|
| Age | ≥50 years of age | 40–49 years of age if meet all other “suitable” criteria or ≥50 years of age with one or more other cautionary feature | <40 years of age or 40–49 years of age and not meeting all other criteria |
| Genetics | BRCA 1/2 negative | – | BRCA 1/2 positive |
| Margins | ≥2 mm | <2 mm | Positive |
| DCIS | ≤2.5 cm, screen-detected, low-intermediate grade, margins ≥3 mm | ≤3.0 cm not meeting criteria for “suitable” | >3.0 cm |
| Size | ≤2.0 cm | 2.0–3.0 cm | >3.0 cm |
| LVSI | None | Limited/focal | Extensive |
| Hormone-receptor status | ER positive | ER negative | – |
| Histology | Invasive ductal | Invasive lobular | – |
| Extensive intraductal component | None | ≤3 cm | >3 cm |
| Focality | Clinically unifocal | – | Clinically multifocal or microscopically multifocal with total size >3.0 cm |
| Centricity | Unicentric | – | Multicentric |
| Nodal status | pN0 | – | pN+ |
| Neoadjuvant therapy | None | – | Any |
DCIS, ductal carcinoma in situ; LVSI, lymphovascular space invasion; pN0, pathologically node-negative; ER, estrogen receptor; pN+, pathologically node-positive.