|The following article features coverage from the Connective Tissue Oncology Society (CTOS) 2018 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.|
Active surveillance of primary sporadic desmoid tumors, also known as the “wait and see” or “watchful waiting” method, was confirmed to be a safe primary treatment approach for patients with these tumors, according to preliminary data from a prospective observational study conducted by an Italian sarcoma group. The findings were presented by Chiara Colombo, MD, of the Fondazione IRCCS Istituto Tumori Milano in Italy, during the Connective Tissue Oncology Society (CTOS) 2018 Annual Meeting in Rome, Italy.1
The findings built on previous research from the The Desmoid Tumor Working Group, which developed an evidence-based consensus approach for the management of desmoid tumors in adult and pediatric patients. This “no treatment” preliminary strategy was considered the least harmful among all potential treatment schemes, as employing this stepwise approach would not influence any subsequent therapeutic approaches.
The goal of that strategy was to avoid overtreatment; it outlined that active treatment should only be explored when a patient experiences persistent progression.2 The initial impetus for formation of the working group occurred at the CTOS 2017 Annual Meeting in Maui, Hawaii.
Tumor progression alone, the group reasoned, is not a sufficient reason to begin active treatment, “especially in the absence of specific symptoms and in noncritical anatomic sites.”2
Dr Colombo emphasized that most of the prior “wait and see” studies focused on this cancer subtype were retrospective studies, but pointed to 3 observational studies in Europe from Italian, French, and Dutch groups that looked at the influence of mutations in beta-catenin (ClinicalTrials.gov Identifier: NCT02547831), continuous monitoring in peripheral primitive fibromatosis (ClinicalTrials.gov Identifier: NCT01801176), and growth of aggressive fibromatosis in the absence of treatment (Nederlands Trial Register Identifier: NTR4714), respectively.
In the current study from the Italian sarcoma group, however, patients with desmoid tumors at any anatomical site were enrolled across 2 participating centers if their biopsy confirmed diagnosis or if residual disease from incomplete resection was observed. Patient tumors also had to have no association with familial adenomatous polyposis (FAP) and were required to be measurable by RECIST criteria (although RECIST was not used as a determinant of active treatment selection). From 2013 to 2018, 108 patients were successfully enrolled.
The most common tumor site was in the abdominal wall, with more than half (54%) of patients having tumors at this location.
The study’s primary end point was progression-free survival (PFS) via RECIST, and secondary end points were treatment-free survival (TFS), correlation with beta-catenin mutational status with outcome, and patient quality of life (QoL).
The investigators found that among the patients undergoing continuous monitoring alone, 40% experienced spontaneous remission. Strikingly, complete remission was observed in 8 patients. Additionally, 31% of patients who initially experienced tumor progression had subsequent spontaneous regression.
Based on the study outcomes, the researchers ruled that RECIST criteria are not appropriate for defining progression in primary sporadic desmoid tumors, or for determining if a patient should receive active therapy. Alternative methods should be considered for disease assessment, they noted.
A “balance between treatment-related, permanent side effects and a need for tumor shrinkage is critical,” Dr Colombo indicated. And, she emphasized, “Surgery could be avoided in all cases.”
Read more of Cancer Therapy Advisor‘s coverage of the CTOS 2018 meeting by visiting the conference page.
- Colombo C, Fiore M, Venesio T, et al. Can wait and see be the standard of care for initial approach to primary sporadic desmoid tumors? Preliminary data from an Italian sarcoma group prospective study. Presented at: CTOS 2018 Annual Meeting; Rome, Italy: November 14-17. Paper 029.
- Hohenberger P and Kasper B. The management of desmoid tumors: a joint global evidence-based consensus approach for adult and pediatric patients. Presented at: 2018 Desmoid Tumor Research Foundation (DTRF) International Desmoid Tumor Research Workshop; Philadelphia, Pennsylvania: September 23-24, 2018.