Sixty-three patients were randomised into two groups each receiving the same 40-h sequential chemotherapy regimen (methotrexate or 5-FU, followed by vinblastine and cyclophosphamide). In the group receiving influsions of chemotherapeutic agents at times taking into account the circadian rhythm of tumoral proliferation, the antitumoral effectiveness appeared significantly better with respect to both tumoral regressions (85% contrasting with 58% in the other group) and the duration of response and survival.