Posters— Medical Oncology

AGGRESSIVE FIBROMATOSIS: A CONSERVATIVE APPROACH TO INOPERABLE DISEASE BASED ON LOW-DOSE CHEMOTHERAPY WITH METHOTREXATE + VINBLASTINE

Azzarelli A, Gronchi A, Bertulli R, Casali PG, Lozza L, Baratti D, Pennacchioli E, Rasponi A, Dileo P, Rolfo CD, Pilotti S, (Istituto Nazionale Tumori, Milan, Italy)

Intervention: Over a 10-year span from 1989, 30 pts with inoperable aggressive fibromatosis were conservatively treated with chemotherapy alone, in the framework of a pilot study on Methotrexate + Vinblastine.

Patients: Thirty patients (median age = 27 years; M/F = 13/17), with primary (20%) or recurrent (80%) inoperable aggressive fibromatosis (arising from scapular girdle in 12 pts, limbs in 8, head&neck in 3, pelvis in 3, paravertebral regions in 2, chest wall in 2), were treated conservatively, by administering Methotrexate 30 mg/m2 + Vinblastine 6 mg/m2, given every 7-10 days for a median interval of one year (range = 4-27 mos). Only 2 pts underwent surgery, with a debulking intent in both cases, followed by radiation therapy. Radiotherapy was given to other 2 pts as well. All the other pts received chemotherapy alone.

Results: Eighteen patients (60%) showed stable disease or minor tumor shrinkage with symptom relief. Partial response was detected in 12 patients (40%). While no complete response was observed, no patient had tumor progression during treatment. After a median follow-up of 75 months, the 10-year actuarial progression-free interval is 67%. Toxicity was mild, including neutropenia, increase in transaminases, paraestesias. Subjective intolerance to such a long-term treatment was of major concern: in 15 pts the decision was shared to stop their treatment after less than 40 courses. However, progression was detected in 4 out of 6 pts who stopped after less than 20 courses.

Conclusions: A low-dose chemotherapy regimen like Methotrexate + Vinblastine allowed us to conservatively manage aggressive fibromatosis in two thirds of pts with inoperable disease. Optimal treatment length is left to be determined, though it seems that some threshold for effectiveness does exist. Tolerability might increase with recently proposed similar regimens, like Methotrexate + Vinorelbine. Low-dose chemotherapy stands amongst currently available choices in aggressive fibromatosis, and may constitute a reasonable option in the subset of pts with inoperable disease.