Clinical features and treatment outcome of desmoid-type fibromatosis: based on a bone and soft tissue tumor registry in Japan

Surgical treatment for extremity rhabdomyosarcoma: longitudinal national questionnaire survey in Japan

BACKGROUND

Extremity rhabdomyosarcoma differs from other soft tissue sarcomas, being highly sensitive to chemotherapy and radiotherapy and having a high rate of metastasis to lymph nodes. Therefore, the treatment modality differs from that of other soft tissue sarcomas. The purpose of this study was to conduct a longitudinal questionnaire survey of orthopedic oncologists in charge of surgical treatment for extremity rhabdomyosarcoma in Japan to determine whether the treatment modality chosen here is in line with the international and national treatment ones.

METHODS

Questionnaire surveys were conducted in 2012 and 2019 to orthopedic oncologists of Japanese Orthopaedic Association and Japanese Musculoskeletal Oncology Group.

RESULTS

Responses were obtained from 80 facilities and 76 facilities, respectively. Fewer than 50% of the facilities treated one or more patients a year in both years. Many facilities first performed diagnostic biopsy, but most did not perform pretreatment re-excision. The number of facilities that provided radiotherapy in addition to surgery increased significantly from 2012 to 2019 (P = 0.028), but it was still 21% in 2019. The number of facilities performing excision and lymph node dissection was 19% in both 2012 and 2019, which was a very low result without improvement. The departments responsible for follow-up have been changed to pediatrics and orthopedic oncology in tandem (P = 0.0004).

CONCLUSIONS

Radiotherapy and pathological evaluation of lymph nodes are important for improving the prognosis of patients with extremity rhabdomyosarcoma. It is necessary to continue and develop more efficient educational activities on the appropriate medical treatment modalities for extremity RMS.

A phase 1 trial of xentuzumab, an IGF-neutralizing antibody, in Japanese patients with advanced solid tumors

Xentuzumab is an insulin‐like growth factor (IGF) ligand‐neutralizing antibody. This phase 1 trial assessed xentuzumab in Japanese patients with solid tumors. Patients aged ≥20 y old with solid tumors that were refractory or not amenable to standard therapy were enrolled. Patients received xentuzumab intravenously at a starting dose of 750 mg/wk. Dose escalation used a 3 + 3 design with dose de‐escalation. The primary endpoint was to determine the maximum tolerated dose (MTD) of xentuzumab. Safety, pharmacokinetics, pharmacodynamics, and anti‐tumor activity were also assessed. Fifteen patients received xentuzumab in the dose escalation part (750 mg/wk [n = 6]; 1000 mg/wk [n = 3]; 1400 mg/wk [n = 6]). There were no dose‐limiting toxicities at any dose; the MTD of xentuzumab was not reached. Xentuzumab 1000 mg/wk was recommended as the relevant biological dose. Six further patients received xentuzumab 1000 mg/wk in an expansion cohort. Of 21 patients, 13 (61.9%) experienced a drug‐related adverse event, most commonly fatigue (23.8%), neutropenia (19.0%), diarrhea, nausea, white blood cell count decrease, and muscle spasms (14.3% each). No relevant deviations from dose linearity of xentuzumab exposure were observed during dose escalation. Total IGF‐1 and IGF‐2 levels increased and bioactive IGF levels decreased from baseline to 24 h after the first infusion in cycle 1. Partial response was observed in 2 (9.5%) patients with desmoid‐type fibromatosis. Disease control was achieved in 6 (28.6%) patients (median duration 42.4 mo). Xentuzumab monotherapy was well tolerated in Japanese patients and showed evidence of anti‐tumor activity. This study was registered with www.clinicaltrials.gov (NCT02145741).

Less-invasive fascia-preserving surgery for abdominal wall desmoid

The mainstay of treatment for desmoid has been shifted to active surveillance (AS). However, surgery is still being performed on abdominal wall desmoid with a wide surgical margin. The purposes of this study are to clarify the treatment results of less-invasive, fascia preserving surgery for patients with abdominal wall desmoid, and to propose a new treatment modality. Since 2009, 34 patients with abdominal desmoid have been treated in our institution. Among them, as a final treatment modality, 15 (44%) were successful with AS, 15 were subjected to less-invasive surgery, and 4 methotrexate and vinblastine treatment. The clinical results of less-invasive surgery were clarified. In the surgical group, although the surgical margin was all microscopic positive (R1), only one patient (6.7%), who has the S45F mutation type of CTNNB1, showed recurrence, at a mean follow-up of 45 months. There were no patients with familial adenomatous polyposis (FAP)-related desmoid in this cohort. Only two patients (13%) required fascia lata patch reconstruction after removal of the tumor. In patients with non FAP-related abdominal wall desmoid, less-invasive, fascia preserving surgery is recommended as a favorable option as active treatment. Based on the results of this study, multi-institutional further research is warranted with an increased number of patients.