初回手術後遺残軟部肉腫に対する追加手術の治療成績―手術計画におけるMRIの有用性

Outcome of Additional Resection for Inadequately Treated Soft-Tissue Sarcoma : Usefulness of MRI in Planning the Surgical Margin

　抄録：初回に不十分な手術を施行された軟部肉腫症例は，不幸な転帰となることが多い．これらの症例に対して，予後を改善すべくMRIを用いて切除範囲を決定した後に追加手術が実施された18症例の治療成績について検討した．発生部位は体幹6例，四肢12例であった．術後経過観察期間は14～120カ月（中央値42.5カ月）であった．MRIは，主として造影MRI，あるいは脂肪抑制造影MRIが用いられた．追加手術後の切除縁評価では，広範切除縁が12例（67％），腫瘍辺縁部切除縁が6例（33％）あった．追加手術後の局所再発は4例（22％）に認められた．再発した4例のうち，重複例も含まれるが，脂肪抑制していないMRIを用いた3例，腫瘍辺縁部切除縁3例，および体幹発生が3例含まれていた．脂肪抑制していないMRIを用いて計画した再手術，腫瘍辺縁部切除縁，および体幹発生例に追加手術後の局所再発が多い傾向が認められた．

　Since planning the surgical margin in patients with soft-tissue sarcoma that has been inadequately resected previously is a very difficult problem, we assessed the usefulness of MRI in planning the surgical margin in such cases. Between 1991 and 1999, 18 patients with soft-tissue sarcoma that had been inadequately resected previously were treated in our hospital. Enhanced MRI, with or without fat saturation, was mainly used in performing the planning. The surgical margins were evaluated in the resected specimens, and their relation to treatment outcome was assessed. The postoperative surgical margins were evaluated as wide in 12 cases (67％) and marginal in 6 cases (33％). Local recurrence developed in 4 cases (22％) after the second operation. In 3 of them planning had been performed based on MRI studied without fat saturation；in 3 of them the margin was marginal；and in 3 of them was in the trunk. Recurrence after additional resection tended to the primary tumor develop in cases in which MRI had been performed without fat saturation, in which the surgical margin was marginal, and cases in which the primary tumor was in the trunk. In conclusion, enhanced MRI with fat saturation should be used to plan the surgical margin in patients with soft-tissue sarcoma, and the second operation should be performed with a wide margin.