Breast Cancer Treatment

Studies of Breast Conservation: Role of Radiation

Meta-analysis (EBCTCG – Lancet 2005.)

Treatment Arms BCS + RT BCS only
Isolated local recurrence at 5-yrs 7.3% 25.9%
Node-negative 3.7% 22.9%
Node-positive 11.0% 41.1%
Breast cancer mortality at 15-yrs 30.5% 35.9%
Non breast-cancer mortality at 15-yrs 15.9% 14.6%
  • 4-to-1 ratio of absolute effects (ie. 20% reduction in 5-yr local recurrence leads to 5% reduction in 15-yr breast cancer mortality).

Conclusions

  • L (lumpectomy) + RT superior to L in both LC and OS Benefit

RT significantly increased incidence of

  • contralateral breast cancer (9·3% vs 7·5% at 15 years)
  • lung cancer

RT significantly increased non breast-cancer mortality (15·9% vs 14·6% at 15 years)

  • due to heart disease
  • due to lung cancer

Compared to Mastectomy (NSABP B06)

Eligibility

  • Stage I/II < 4 cm breast CA with margins (-)

Treatment and Results

  • Node positive patient received chemotherapy
Treatment Arms 20-LRR 20-IBTR (including cosmetic) 20-OS 20-Event Free Survival
Mastectomy 14.8% 47% 37%
Lumpectomy 17.5% 39% 46% 35.6%
Lump + 50 Gy RT 8.1% 14% 46% 37%
p-value <.01 < 0.001 N.S. 0.07 (L + RT vs lump)
  • LRR: local and regional recurrence, excluding cosmatic (ie. in breast)
  • IBTR: ipsilateral tumor recurrence including breast recurrence

CONCLUSION
• RT reduces in-breast recurrence by ~ 66% but does not effect EFS or OS.
• RT reduces in-breast recurrence and nearly EFS but advantage is partially offset by other deaths (? Cardiac).

Compared to Breast Conserving Surgery Only

Local Recurrence with Surgery alone for Tumors < 1 cm

  • 25% 8-local recurrence rate (B-06)
  • 22.5% 10-local failure rate (JNCI 96) [1]

Local Recurrence with Surgery alone for Elderly

CALGB, Mass Gen

  • study of > 70 y.o. stage I women with ER+ on Tamoxifen
  • showed 1% vs 4% local control benefit with RT vs no RT at 5 years.

Canadian (Princess) study

  • for > 50 y.o stage I/II women.
  • Showed a 7% local control benefit for this group.
  • Number Need to Treat for single benefit (NNT) for 70-79 yr female in good health is 21 to 22 (very typical for most medical treatment). NNT for > 85 is 125; so we would not treat these people.

My thoughts are that like prostate we may only treat patients with > 5 year life expectancy.
Lobular carcinoma would not qualify for this as their local failure at 5 years is 16% with no RT vs 0.38 with RT.

Bibliography
1. Clark RM, Whelan T, Levine M, Roberts R, Willan A, McCulloch P, Lipa M, Wilkinson RH, Mahoney LJ. Randomized clinical trial of breast irradiation following lumpectomy and axillary dissection for node-negative breast cancer: an update. Ontario Clinical Oncology Group. J Natl Cancer Inst. 1996 Nov 20;88(22):1659-64. PMID: 8931610
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