RadOnc Resident Wiki/Breast/Breast overview

Clinically node negative

Or T3N1, No T4

Options:

• BCS followed by RT ± boost
• Mastectomy
  • RT
    • pN2a RT (≥4 axillary LNs)
  • Consider RT
    • 1-3 LN+
    • T3
    • Margin <1mm consider RT
• NAC if does not qualify for BCS

For systemic adjuvant therapy see below, chemo comes before RT

Clinically node positive

≥N2 | T4 (not inflammatory)

Options:

• NAC
  • Response: Mastectomy or BCS + RT
  • No Response: Individualize - more chemo, neoadj RT

For systemic adjuvant therapy see below, chemo comes before RT

Surgical LN Staging

• If cN+ after biopsy, all patients get axillary dissection lvl 1-2
• If gross lvl 2 or 3, dissect 3
• SNLB
  • Negative - no further needed
  • Positive
    • If ALL are met, no further needed, otherwise ALND lvl 1+2
      • ≤T2
      • 1-2 +SLN
      • Patient getting BCS + WBRT without NAC
  • Not found: ALND lvl 1+2

Adjuvant systemic therapy

Mainstays of treatment:

• Hormone Therapy (HT)
• Chemotherapy (CT)
• Trastuzumab (T)

Algorithm for treatment

1. ≤5mm - Consider HT
2. >5mm | N1mi - HT
   • Consider CT, Trastuzumab
3. ≥1cm | pN1 - All 3

Aberrations of above algorithm:

• If group 2 and HR+, do 21 gene assessment, then group 1,2,3 as ≤18, ≤30, >30 respectively
• If HR+, Mucinous or Tubular histology
  • ≤3cm Consider HT
  • ≥pN1 HT consider chemotherapy

Also

• If HR- no HT, if HER2- no T

Radiotherapy Methods (RT)

• Whole Breast RT (WBRT) or Chest wall RT (including reconstruction)
  • Standard is 50Gy/25Fx [46-50Gy/23-25Fx]
  • ±boost to cavity 10Gy/5Fx [10-16Gy/4-8Fxs]
• Hypofractionated
  • Consider for >50yo, ≤T2N0, no NAC
  • 40Gy/15Fxs [40-42.5Gy/15-16Fxs]

RNI

• ≥4 LN+: To all nodes (at risk axilla, IM, SCN)
• 1-3 LN+ strongly consider to all nodes or at least LVL 1-2
• T3 (>5cm) consider consider to all nodes or at least LVL 1-2

APBI

38.5Gy/10Fx BID or 34Gy/10Fx Brachy to tumor bed

• Needs to meet all criteria
  • Suitable
    • ≥50yo, -BRCA, ≤T2 (2cm), ER+, N0, no NAC, no EIC
    • DCIS allowed if screen-detected, low - int grade, <2.5cm, margins >3mm,
    • LCIS allowed
  • Cautionary 40-49 yo + all above, or ≥50 with only 1 of below:
    • 2.1-3cm invasive focus, T2, margins <2mm, limited LVSI, ER-, pure DCIS ≤3cm, EIC ≤3cm

Breast Conserving Therapy (BCS)

aka lumpectomy

Contraindications (CI):

• Can't get RT: i.e. prev RT, scleroderma, pregnant
• Diffuse suspicious microcalcifications
• R+ surgery predicted

Not CI (however considerations):

• Young
• Non-biopsied MRI findings
• Systemic lupus
• BRCA
• High grade/Trip negative