Prostate-Specific Antigen Decline After Withdrawal of Low-Dose Megestrol Acetate
Authors: Patrick A. Burch, Charles L. Loprinzi
Journal: Journal of Clinical Oncology (1999)

1 in the September 1998 issue of the Journal of Clinical Oncology.This report detailed 10 cases of recurrent desmoid tumor in children treated with combination therapy of vinblastine and methotrexate.We report five additional cases successfully treated with a regimen similar to that of Skapek et al.Currently, none of our patients has evidence of regrowth of their tumor 7 to 76 months after elective cessation of chemotherapy.Between 1990 and 1997, five boys aged 7 to 17 years with biopsy-proven desmoid tumors were referred to us because the tumors were not amenable to surgical resection or because amputation was considered after multiple courses of surgery had failed.Although desmoid tumors do not show neoplastic features in histologic sections, the use of high-dose radiotherapy or aggressive polychemotherapy vinblastine [VBL], dactinomycin, and cyclophosphamide 2 is commonly advocated in these situations.Similar to Skapek et al, concerns about the toxicity profile and quality of life associated with these types of therapy, especially in prepubertal children, led us to a low-dose chemotherapeutic regimen of VBL and methotrexate (MTX), as previously reported in eight adults. 3 The apparent advantage of this regimen is the minimal risk for acute and long-term toxicities.We administered both VBL (6 mg/m 2 ) and MTX (30 mg/m 2 ) by intravenous push once a week.The total duration of treatment was 12 months, provided that the mass did not grow during that interval.Two patients experienced complete responses, one patient had a partial response, one patient had a minor response, and one patient had stable disease (Table 1).Follow-up after completion of therapy was 7 to 76 months.Tumor regression after VBL/MTX was slow (2 to 6 months) and was preceded by softening of the tumor, first notable after several weeks of treatment.These observations are consistent with the slow growth of the tumor; therefore, the presence of persistent disease immediately after VBL/MTX should not be misconstrued as an indicator of treatment failure.Side effects, including nausea, vomiting, and moderate hair loss, were minor and never required dosage reduction.Tumor recurrence observed in one patient (patient no.4) was successfully re-treated with another course of VBL/MTX, and complete remission was achieved after 4 weeks.On the basis of our observations and those of Skapek et al, we agree that low-dose VBL/MTX should be considered in children with unresectable or multiply recurrent desmoid tumor who would otherwise require ablative surgery.At present, we do not know how many children will experience definitive cure with low-dose VBL/MTX chemotherapy.However, remission occurs for prolonged periods of time, and even recurrence can be successfully re-treated.In any event, the VBL/MTX combination offers the chance, as pointed out by Skapek et al, to treat young patients with minimal morbidity until they complete puberty.If recurrence occurs at that time, radiation can be expected to be fraught with less long-term toxicity.It is unfortunate that the rarity of this tumor has so far prohibited the accumulation of large series of patients treated with this VBL/MTX combination.To define long-term results regarding response and complications of this type of therapy, the establishment of international disease and treatment-specific registries are indispensable.A promising step in this direction is the initiation of a collaborative study by the Pediatric Oncology Group, as stated by Skapek et al.