乳がんの反応は若年女性においては異なる（Abstract # S3-1）

若年の乳がん女性は高齢の乳がん女性よりも術前補助化学療法への反応が良好である
Young women with breast cancer respond better to neoadjuvant chemotherapy than older women
35歳以下の乳がん女性は高齢女性よりも術前補助化学療法後の病理学的完全寛解に達しやすいとのデータが2012 CTRC-AACRサンアントニオ乳がんシンポジウムで発表された。研究者らは、手術可能または局所進行非転移性乳がんに対し術前補助化学療法を施行された女性8,949人を含むドイツの8つのスタディのデータを評価した。彼らは35歳以下の女性704人からなるサブグループの病理学的完全寛解および無病生存率を高齢女性のそれらと比較した。病理学的完全寛解率は非常に若年の女性において有意に高かった（23.6%に対し高齢女性では15.7%）。この差はトリプルネガティブ乳がんおよびルミナル乳がん女性に限られた。腫瘍生物学は病理学的完全寛解や生存率を予測するのに重要な役割を果たすようであった。ルミナルA型がんの女性の無病生存率は病理学的完全寛解ではなく年齢により予測された。しかし、無病生存率が最も不良なのはこのタイプのがんで、病理学的完全寛解に達しなかった35歳未満の女性であった。無病生存率が最も良好だったのは病理学的完全寛解に達した35歳未満の女性であった。
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Women with breast cancer aged 35 or younger were more likely than older women to achieve a pathological complete response after neoadjuvant chemotherapy, according to data presented at the 2012 CTRC-AACR San Antonio Breast Cancer Symposium.

"Young women with breast cancer are rare, and some data indicate that their prognosis is worse than it is for older women," said Sibylle Loibl, M.D., Ph.D., an associate professor at the University of Frankfurt in Germany. "This is not only because their tumors tend to be more aggressive, but because breast tumors that arise in women who are young seem to be a special biological entity."

Loibl and colleagues evaluated data from eight German studies that included 8,949 women with operable or locally advanced, nonmetastatic breast cancer who were treated with neoadjuvant chemotherapy. The researchers compared pathological complete response and disease-free survival for the subgroup of 704 women aged 35 or younger to those of older women. The subgroup of younger women included a greater proportion of triple-negative breast cancer cases and a smaller proportion of luminal A-type breast cancer cases than in the group of women aged older than 35 (26 percent versus 19 percent and 21 percent versus 27 percent for triple-negative and luminal A-type, respectively).

The pathological complete response rate was significantly higher in very young women — 23.6 percent compared with 15.7 percent among older women. Through further analysis, the researchers found this difference was isolated to women with triple-negative breast cancer and luminal-like breast cancer.

They found no difference in disease-free survival according to age among those patients who achieved a pathological complete response. However, disease-free survival was significantly worse among young women who did not achieve a pathological complete response.

In addition, tumor biology seemed to play an important role, especially in young women, for predicting pathological complete response and survival, according to Loibl. Age, but not pathological complete response, predicted disease-free survival in women with luminal A-type cancer. However, the worst disease-free survival rate was among women with this type of cancer who were younger than 35 and did not achieve a pathological complete response. The best disease-free survival rate was among women younger than 35 who did achieve a pathological complete response.

"The most surprising finding was that young women with a luminal-type tumor — hormone receptor-positive and HER2-negative — who achieved a pathological complete response had a better survival rate than the patients with nonpathological complete response," Loibl said. "This is not true for other age groups, which indicates that breast cancer in the young — even when a luminal-type breast cancer — is chemosensitive."