乳房小線源療法はインプラント硬化のリスクを軽減する

乳房小線源療法は乳房インプラント術後の女性の早期乳がんを治療し乳房の外観も維持する
Brachytherapy can successfully treat early-stage breast cancer in women with implants and preserve the breast's appearance
小線源療法で治療を受けた豊胸術後の早期乳がん女性は、乳房全体の放射線療法を受けた患者と比較し、美容上の予後が良好でありインプラント硬化のリスクを回避できるとのスタディ結果が、Radiological Society of North America （RSNA）学会で発表された。腫瘤摘出術後の乳房全体の放射線照射は選択肢ではあるが、痛みを伴い外見も損なう被膜拘縮の実質的なリスクがある。米国の研究者らはサイズの小さな早期乳がんと診断され、腫瘤摘出術後に小線源療法で治療された女性65人を組み入れた。患者らは高線量率イリジウム192小線源療法を1日2回（34Gyの照射を6時間以上空けて）5日間受けた。経過観察期間（平均16ヵ月）中に再発した者はいなかった。美容上の評価は全ての患者において、good（良）からexcellent（優秀）まで100%の患者に対して行った（95%が優秀、9%が良と評価され、fair（普通）または良と評価されたのは0%）。被膜拘縮が認められた患者および乳房内またはリンパ節内再発の認められた患者はいなかった。
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Women with early-stage breast cancer who have undergone breast augmentation may be treated successfully with brachytherapy, according to a study presented at the annual meeting of the Radiological Society of North America (RSNA). Patients treated with brachytherapy have better cosmetic outcomes and avoid the risk of the implant hardening, compared to patients who undergo whole-breast radiation therapy.

"We are seeing an increasing number of breast cancer patients with augmentation," said Robert R. Kuske Jr., M.D., clinical professor at the University of Arizona Health Sciences Center and radiation oncologist at Arizona Oncology Services in Scottsdale, Ariz. "By nature, these women are concerned about their appearance and we need to have options for them."

Approximately one in eight women who undergo breast augmentation will develop breast cancer at some point in their lives.

The most common breast cancer treatment for patients with breast implants is skin-sparing mastectomy and implant exchange. Whole-breast radiation therapy after lumpectomy is an option, but carries a substantial risk of capsular contracture, which is both painful and distorts the appearance of the breast.

Dr. Kuske set out to determine if partial-breast radiation with brachytherapy might offer a better outcome for women with implants wishing to avoid mastectomy.

Breast brachytherapy can be given in higher doses to a small, targeted area of the breast after lumpectomy. Scar tissue is minimal, the implant remains unaffected and treatment time is shortened from 6½ weeks with whole-breast radiation therapy to five days with brachytherapy.

For the study, 65 women who were diagnosed with small, early stage malignant tumors were treated with brachytherapy after a lumpectomy. The women received two doses per day, separated by six hours, over a five-day period. Follow-up was six months to five years. None of the patients experienced tumor recurrence during the follow-up period. Cosmetic outcome was determined to be good to excellent in 100 percent of patients with 95 percent judged excellent. Implant hardening was not observed in any of the patients.

"Compared to traditional treatments, brachytherapy offers an excellent alternative for these women," Dr. Kuske said. "It offers very high rates of tumor control with fewer side effects and is easier on their lifestyle."