GEC-ESTRO Breast Cancer Working Group APBI patient selection recommendations
TL;DRUpdated APBI selection criteria collapse to two groups (low-risk eligible, high-risk contraindicated), widening eligibility to pT1-2 ≤30mm, pN1mi, any histology.
The eligibility boundary moved, not the technique: pN1mi and multifocal disease within 2 cm are now inside the low-risk group, and the ceiling is 30 mm across all histologies. The 2010 intermediate tier is gone, so the contralateral question at consent is binary. BRCA 1-2 carriers are contraindicated regardless of age.
In a woman over 40 post-lumpectomy with a 25 mm pT2 pN1mi tumor and clear margins, this supports offering APBI where the 2010 criteria would not have; it does not extend to triple negative, BRCA carriers, or an unstaged axilla.
The eligibility boundary moved, not the technique: pN1mi and multifocal disease within 2 cm are now inside the low-risk group, with a 30 mm ceiling across all histologies. The intermediate tier is gone, so the APBI-vs-whole-breast conversation is binary. No dose, fractionation or target volume is specified in source.
Margin status is the surgical lever: a negative invasive margin qualifies, but DCIS requires ≥ 2 mm, so a close DCIS margin decides re-excision vs losing APBI eligibility. Unknown axillary status (pNx) is a contraindication, so skipping staging forecloses the option; pN1mi does not.
9 details
Evidence-based recommendation update from the GEC-ESTRO Breast Cancer Working Group. Systematic search 2010 to 2024 across PubMed, Medline, Scopus and Cochrane returned 618 articles, supplemented by reference lists, conference abstracts and book chapters. Ten prospective randomized trials and seven retrospective comparative studies with ≥ 5 yr median follow-up formed the evidence base.
Applies to pts after breast-conserving surgery being considered for partial breast irradiation. The low-risk group is age > 40 yr, unifocal or multifocal within 2 cm, pTis or T1-2 (≤ 30 mm), pN0 or pN1mi, all histology types, no EIC, no extensive LVI, negative invasive margins (≥ 2 mm for DCIS).
The document addresses who gets APBI, not how. No dose, fractionation, technique (brachytherapy vs external beam) or target-volume recommendation is given in the source text.
Two categories replace the prior scheme: low-risk good candidates and high-risk contraindicated. Contraindications are BRCA 1-2 mutation, age < 40 yr, positive invasive margins (< 2 mm for DCIS), multicentric or > 30 mm disease, triple negative, EIC positive, extensive LVI, and ≥ pN1a or pNx.
| Criterion | Low risk (APBI suitable) | High risk (APBI contraindicated) |
|---|---|---|
| Age | > 40 years | < 40 years |
| Germline | not specified | BRCA 1-2 mutation |
| T stage / size | pTis, T1-2 (≤ 30 mm) | > 30 mm |
| Focality | unifocal or multifocal within 2 cm | multicentric |
| Nodal status | pN0 or pN1mi | ≥ pN1a, or unknown axilla (pNx) |
| Histology | all histology types | triple negative |
| EIC | absent | EIC positive |
| LVI | no extensive LVI | extensive LVI |
| Margins | negative for invasive (≥ 2 mm for DCIS) | positive for invasive (< 2 mm for DCIS) |
Recommendation strength per criterion is not reported in the source text, so a reader cannot tell which thresholds rest on randomized data and which on panel opinion. The evidence base mixes ten randomized trials with seven retrospective comparative series without stated weighting.
The direction of travel is eligibility expansion: the authors state the 2010 criteria can be significantly expanded so more pts may receive APBI in routine practice. What the document does not settle is whether the widened boundary holds at the margins it moved most, node-micrometastatic and multifocal disease, where the randomized APBI trials enrolled few pts.
- IBTR outcomes for APBI in pN1mi disease
- Whether multifocal disease within 2 cm carries equivalent in-field control
- Whether triple negative warrants blanket APBI exclusion
📚 Sources · 📄 1 paper
Abstract
The longer read
The useful way to read this is as a boundary document, not an evidence document. Nothing here is a new result; what changed is where the working group is willing to draw the line, and the line moved outward on nearly every axis it names. Size goes to 30 mm, nodal status admits micrometastatic disease, multifocality is tolerated when the foci sit within 2 cm, and histology is no longer a gate at all, with lobular carcinoma no longer excluded by type. Each of these was a hard exclusion or a caution in the 2010 iteration, and the authors are explicit that the expansion is the point: more pts should be candidates in routine practice.
The structural change matters as much as the criteria. The 2010 scheme carried three tiers, and the middle one absorbed most of the clinical ambiguity. Removing it forces a binary at the point of consent, which is honest but unforgiving. A pt who would previously have been counselled as intermediate now sits in the low-risk group and gets offered APBI, or sits in the high-risk group and does not. That shifts real decisional weight onto the specific thresholds, and the thresholds are where the confidence is least even.
The evidence base the authors describe is asymmetric with respect to the expansion. Ten randomized trials with at least five years of median follow-up is a genuinely mature literature for APBI as a strategy, but those trials largely enrolled the narrow population the old criteria described: node-negative, unifocal, small, older. The criteria that moved furthest, pN1mi and multifocality within 2 cm, are precisely the ones that population contributed the fewest events to. Seven retrospective comparative studies are doing more work at those margins than the randomized count implies, and the source text does not report a strength of recommendation per criterion, so the reader cannot separate a threshold anchored in randomized data from one anchored in panel judgment. That is the single most consequential gap in the document for anyone applying it prospectively.
The contraindication list is worth reading as a statement about what the group thinks drives out-of-target failure rather than in-field failure. BRCA 1-2 carriage and age under 40 are not markers of a larger index lesion; they are markers of field risk across the whole breast, and excluding them is a coherent position for a partial-breast technique whatever the tumor looks like. Triple negative sits less comfortably in that frame. It is included as a blanket exclusion by receptor status alone, with no size or grade qualifier stated, and triple negative disease fails more often distantly and in-field than it does elsewhere in the breast. A reader may reasonably conclude that criterion is carrying a general prognostic anxiety rather than a specific argument about partial-breast coverage.
What would have to be true for the expansion to be wrong is that ipsilateral recurrence in the newly admitted groups is driven by disease outside the tumor bed rather than at it. That is testable and not tested here. Until it is, the practical read is that the document reliably identifies who should not receive APBI, and is more provisional about the pts it newly lets in.