核医学と放射線治療

The Additional Irradiation of the Tumor Bed "The Boost" in the Breast Cancer Conservative Treatment: What Techniques?

Abstract

Ahmedou Toulba, Iraqi M, Mouhajir N, Nouh M, Diakité A, Nkoua-Epala B, Kebdani T, Elgueddari B and Benjaafar N

Background: The breast cancer conservative treatment, rise importantly through screening and early diagnosis, neoadjuvant treatment, improved surgical techniques and adjuvant radiotherapy. The increase dose to the tumor bed after breast irradiation increases the rate of local control. Different techniques are used to deliver the boost to the tumor bed: the direct beam of electrons, photons with reduced tangential fields, low (LDR) and high dose rate (HDR) brachytherapy.

Purpose: To compare different boost techniques in local control and cosmetic results in breast cancer. Materials and methods: A retrospective study through a series of 74 patients treated at the National Institute of Oncology during 2007 for breast cancer and who received additional radiation to the tumor bed after whole breast irradiation.

Results: The median age of patients was 44.5 years (25-59), 81% were settled and 19% postmenopausal, 38% of tumors were stage T1, 60% T2, 1% T3, 1% T4, 62% N0, 37% N1 and 1% N2. For treatment: two patients received neoadjuvant chemotherapy (3%). Conservative surgery was lumpectomy in 54 cases (72%), quadrantectomy in 19(23%) and zonectomy in one. The oncoplastic remodeling was performed in 24 patients (32%) and reoperation in 19 patients (25%). It was an infiltrative ductal carcinoma in 90% of cases. Radiotherapy interested the breast and chest wall in 74 cases (100%), the supraclavicular fossa in 41 cases (55%), the internal mammary chain in 29 (39%) and axilla in 6 (8%). It was 50 Gy in 25 fractions in 53 patients (72%), 42 Gy in 15 fractions (2.8 Gy) in 21 patients (28%) with median of 37 days (19-60). The additional irradiation of the tumor bed was delivered by electrons at the dose of 15 Gy in five fractions in 38% of cases, or by HDR brachytherapy dose of 10 Gy in two fractions separated by 10 to 12 hours in 34%, or by LDR brachytherapy of 15 Gy in 4%, or by photons at the dose of 15 Gy in five fractions (9 patients) or six fractions in 24% (9 patients). The median time between breast irradiation and the complement was 11 days. The median follow-up was 52 months (3-47 months), 61 patients (82.5%) were in situation of good local control, three (4%) of local recurrence, 10 cases (13.5%) of distant metastases (four were always followed, two died, four lost sight) and nine (12%) were lost to follow-up. Side effects were type of fibrosis in 28 patients (38%), telangiectasia in 5 (7%), disorders of skin pigmentation in 11 (15%).

Conclusion: The increase in dose to the tumor bed after conservative treatment of breast cancer allows increasing the rate of local control without compromising too much the aesthetic results. The comparison between the different techniques of boost did not show significant differences. Randomized trials are needed to define the optimal technique.