Low-dose dacarbazine-doxorubicin therapy against intra-abdominal desmoid tumors

Intra-abdominal desmoid tumor is a life-threatening disease. Studies have shown that dacarbazine (DTIC)-doxorubicin (DOX) (D-D) therapy is the most effective treatment. However, myelosuppression is a major problem, and cardiac muscle disorders due to DOX limit the number of administration cycles, whereas it usually requires a long time to achieve tumor shrinkage. To resolve these issues, we introduced low-dose D-D therapy to 3 patients employing 50 mg/m ² DOX and 600-700 mg/m² DTIC per cycle, which permits repeated administration cycles up to 10-11 times. Case 1 was a 23-year-old female with a sporadic recurrent mesenterium desmoid tumor located in the pelvis (maximum diameter, 8 cm). Cases 2 and 3 were a 33-year-old female and a 36-year-old male. Both patients had intra-abdominal mesenterium desmoid tumors (maximum diameter 9.6 and 9.0 cm, respectively) that were generated after proctocolectomy due to familial adenomatous polyposis. No severe adverse events occurred during the therapy. With the aid of sulindac and tamoxifen after low-dose D-D therapy, the first two patients achieved a complete response, and the third patient achieved a partial response and awaits further tumor shrinkage. Our experience indicates that low-dose DT-D therapy is a safe and effective regimen for patients with intra-abdominal desmoid tumors.