Hypofractionation Flashcards
OCOG 93-010 (Canadian, Whelan)
Reason for Trial?
Radiobiological models suggest that hypo-fractionation may be just as effective as 50 Gy in 25 fxs
More convenient
Improve compliance
OCOG 93-010 (Canadian, Whelan)
How many yrs of data is available?
5 and 10 yr
OCOG 93-010 (Canadian, Whelan)
Inclusion Criteria?
Invasive carcinoma w/ -ve LNs
tx’ed with lumpectomy and ALND
OCOG 93-010 (Canadian, Whelan)
Exclusion Criteria?
IDC or DCIS with +ve margins
Tumors > 5 cm
Breast width > 25 cm
OCOG 93-010 (Canadian, Whelan)
Why was the breast width chosen as such?
Larger breasts can cause dose heterogeneity
OCOG 93-010 (Canadian, Whelan)
RT Regimen?
50/25 vs. 42.5/16. No boost
Delivered via 2 opposed tangential beams (2D planning)
No RT to the LNs( (Supraclav, IM, or axillary)
OCOG 93-010 (Canadian, Whelan)
Patient stratification?
Age (<50 yrs or >50 yrs) Tumor Size (<2cm or >2cm)
OCOG 93-010 (Canadian, Whelan)
Primary outcomes?
Local recurrence
OCOG 93-010 (Canadian, Whelan)
Secondary outcomes?
distant recurrence contralateral breast recurrence second cancers breast cosmesis late toxic effects of RT Death
OCOG 93-010 (Canadian, Whelan)
How was RT toxicity assessed?
Using Late Radiation Morbidity Scoring Scheme
OCOG 93-010 (Canadian, Whelan)
How was breast cosmesis asessed?
Using EORTC Cosmetic rating system
OCOG 93-010 (Canadian, Whelan)
Type of Trial?
Non-inferiority trial
OCOG 93-010 (Canadian, Whelan)
How many pts?
- LOL
OCOG 93-010 (Canadian, Whelan)
Pt characteristics?
25% < 50 yrs 33% T2 26% ER- 11% Chemo (5 FU, Cyclophosphamide, MTX) 41% tamoxifen
OCOG 93-010 (Canadian, Whelan)
Results: Local Recurrence of invasive disease?
10 yr LR
hypo: 6.2%
conv: 6.7%
OCOG 93-010 (Canadian, Whelan)
Results: Cosmesis?
10 yr Cosmesis
Excellent or good cosmetic outcome
hypo: 70%
conv: 71%
Older age and larger tumors were associated with worse outcomes
OCOG 93-010 (Canadian, Whelan)
Results: Skin G3 TOX?
10 yr TOX
hypo: 2.5%
conv: 2.7%
OCOG 93-010 (Canadian, Whelan)
Results: DSS?
10 yr DSS
hypo: 87%
conv: 87%
OCOG 93-010 (Canadian, Whelan)
Results: OS?
10 yr OS
hypo: 84%
conv: 84%
OCOG 93-010 (Canadian, Whelan)
Conclusion?
Hypo WB RT okay for -ve margin, -ve LN, and breast separation < 25 cm
OCOG 93-010 (Canadian, Whelan)
Was there any subanalysis?
Yes, subanalysis for high grade tumors (19% of tumors)
RT less effective for high-grade tumors
10 yr LR for HG
hypo: 15%
conv: 5%
OCOG 93-010(Canadian, Whelan)
Limitations of the trial
No patients with DCIS alone!
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How many trials?
2 PRT
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When was the study run?
1999-2002
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What does START stand for?
Standardization of Breast Radiotherapy
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What RT doses were assessed?
START A: 50/25 vs. 41.6/13 or 39/13 QOD
START B: 50/25 vs. 40/15
Both permit a 10 Gy boost
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Tumor characteristics?
pT 1-3a
pN 0-1
M0
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What does the N mean?
N1
mi: >0.2 mm and/or >200cells, but < 2mm
a: 1-3 axillary LNs
b: IM LN +ve pathologically but -ve clinically
c: pN1a + pN1b
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Primary end-points?
- Loco-regional relapse (relapse within the breast, chest wall, ip axilla, supraclav fossa, or within an irradiated volume
- Late normal tissue side-effects
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Secondary end-points?
- Distant relapse
- DFS
- OS
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of pt’s recrutied?
START A: 2236
START B: 2215
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How many LN +ve pts?
START A: 29%
START B: 23%
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How many % lumpectomy?
START A: 85%
START B: 92%
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START A: Important pt characteristics?
START A:
- Age 57 (25-85)
- Adjuvant Chemo 35%
- Tamoxifen 79%
- Lumpectomy 85%
- RT Boost 61%
- LN RT 14%
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How many yrs of data do we have?
5 and 10 yrs
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Results of START A?
START A: No sig difference
10yr LRR: 6.3% (41.6 Gy) vs. 8.8% (39 Gy) vs. 7.4 (50 Gy)
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START B: Important pt characteristics?
START B: Age 57 (23-86)
- Age 57 (23-86)
- Adjuvant Chemo 22%
- Tamoxifen 87%
- Lumpectomy 92%
- RT Boost 23%
- LN RT 7%
START A&B
Results of START B?
START B
- 10yr LRR: 4.3% (40 Gy) vs. 5.5% (50 Gy). No sig.
- 10yr distant relapse: 12.3% (40) vs. 16% (50). Sig
- 10 yr all-cause mortality: 7.9& (40) vs. 10.9% (50). Sig
- Local side effects were significantly less common with 40 than 50.
2 and 3 were not observed START A.
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Conclusions?
Hypo-fractionated WBI is safe and effective for early breast cancer. 40/15 is SOC in the UK.