難治性前立腺癌に対する治療の現状と問題点 : 再燃性前立腺癌に対する内分泌化学療法

Abstract

比較的若年の再燃性前立腺癌26例(年齢中央値67歳)に対して, cyclophosphamide(CPM), uracil+tegafur合剤(UFT), estramustine phosphate(EMP)併用療法を行った.PSAが50%以上下降したのは16例で, EMPを前治療とした7例では5例が下降した.骨シンチグラムで改善を示したのは16例中1例で, リンパ節転移3例では2例に部分緩解を認めた.骨痛の17例中5例は消失或いは改善した.骨転移, 貧血合併の37例(年齢中央値74歳)にはdexamethasone(DEX)単独投与を行い, PSA50%以上下降は23例, 骨シンチ改善は21例中4例で, リンパ節転移5例中1例がPRとなった.骨痛18例中11例は消失又は改善し, 血中Hb値は32例中10例で上昇した.他の再燃性前立腺癌44例(年齢中央値69歳)にはDEX, CPM, UFT併用を行い, 前治療はEMP投与19例, DEX単独3例であった.PSA50%以上下降は28例, 骨シンチ改善は30例中1例で, リンパ節転移7例中1例がPRとなった.骨痛は16例中9例が改善した

To our knowledge, no standard chemotherapy for patients with hormone-refractory prostate cancer (HRPC) has been established. Since most patients with HRPC are elderly and have bone metastasis, cytotoxic chemotherapy causes them to be at high risk for myelosuppression. Therefore, chemotherapeutic agents with low toxicity and good compliance should be elected. We conducted three regimens for HRPC on an outpatient basis. Eligibility criteria were defined as serial rising PSA values on 3 or more occasions at least 2 weeks apart or radiological new or extensive lesions under hormonal therapy. The first regimen is comprised of cyclophosphamide (CPM), 100 mg/day, UFT, 400 mg/day, and estramustine phosphate (EMP), 560 mg/day in two daily fractions. The second regimen is comprised of an oral administration of dexamethasone (DEX) (0.5-2 mg/day). The third regimen is comprised of DEX, 1 mg/day, cyclophosphamide, 100 mg/day and UFT, 400 mg/day in two daily fractions. Post-therapy prostate-specific antigen (PSA) level in serum, objective response on bone scan or measurable disease, and symptomatic response on bone pain were assessed. All regimens showed clinical efficacy with mild toxicity. Indications and limitations of these regimens are discussed. Further, the combination trials of taxane and EMP in patients with HRPC are reviewed.