胃MALTリンパ腫の診断と治療―治療

Therapeutic Strategy for Gastric MALT Lymphoma

近年，胃MALTリンパ腫に対するH. pylori除菌療法の高い奏効率と良好な長期成績が報告されている．H. pylori陰性，t（11 ; 18）/API2-MALT1転座例では寛解率が低いが，除菌による寛解例が報告されていることから，低侵襲である除菌治療をまず試みるのが一般的である．一方，進行期はまれで治療に関するエビデンスに乏しいため，現在は低悪性度B細胞リンパ腫である濾胞性リンパ腫と同様の治療方針がとられる．低腫瘍量の場合にはwatch and waitを行い，高腫瘍量の場合はリツキシマブと化学療法の併用，またはシクロホスファミド単独経口投与が有効な治療法となる．最近ではR-chlorambucil療法やR-bendamustine療法も注目されている．

　Recently, the eradication of Helicobacter pylori was reported to lead to excellent long-term clinical outcome of gastric MALT（mucosa-associated lymphoid tissue）lymphoma. Although eradication is not effective for H. pylori-negative and t（11; 18）/API2-MALT1 cases, it is often recommended as the primary therapy.

　On the other hand, advanced MALT lymphoma is rare, and there is no established therapy for it. Treatment for patients with advanced MALT lymphoma is decided according to the treatment for follicular lymphoma. “Watch and wait” is recommended for patients with low tumor burden, whereas conventional chemotherapy with rituximab or single-agent chemotherapy using cyclophosphamide is useful for patients with high tumor burden. Recently, regimens that combine chlorambucil or bendamustine with rituximab have been expected to be useful as chemotherapy for patients with advanced MALT lymphoma.