HOLLYWOOD, FL—Many desmoid fibromatosis tumors can be best managed by close observation rather than systemic, radiation, or surgical therapies. That is the word from the National Comprehensive Cancer Network panel that updated the organization‘s guidelines for those cancers.
“The take home points from our updated guidelines are that watchful waiting may be appropriate for tumors that are not causing morbidity, that are not causing pain, and that are not causing functional limitations,” said Panel Chair Margaret von Mehren, MD, Professor of Oncology and Director of the Sarcoma Program at Fox Chase Cancer Center, speaking here at the NCCN‘s 16th Conference on Clinical Practice Guidelines and Quality Cancer Care,
In her presentation of the algorithm, Dr. von Mehren also suggested that a watch-and-wait approach could be used if the desmoid tumors were of a smaller size, were not located on the trunk, and if surgery could cause excess morbidity.
“While we encourage watchful waiting for these tumors—which are locally aggressive but rarely metastasize, that does not mean sending patients home and not seeing them for years on end—that is not appropriate,” she said.
Desmoid tumors are relatively uncommon, she noted. “They can cause problems with infiltration, because they often occur in areas that are very difficult to manage. Because of that, we felt it was appropriate that patients be evaluated by a multidisciplinary team with expertise in sarcoma.”
Desmoid tumors are defined as clonal fibroblastic proliferation with an infiltrative growth pattern. “In the past, standard of care primarily focused on surgical resection, but if you look at the literature the issue with surgical resection is that even if that is technically feasible, you do see a high rate of recurrence—up to 60 percent at five years,” Dr. von Mehren said.
“This has led the field to ask if we are doing our patients a disservice with surgery. Some have hypothesized that the reason we see recurrences has to do with the cytokine milieu following surgery, which may allow for the appropriate background for the tumor to recur in that local spot.”
Changes in the guidelines were prompted by research from institutions in France and Italy that performed retrospective reviews of patients who were treated without surgery or radiation, she noted. “Those treated with systemic therapy were compared with patients who received no therapy at all, and we just closely watched for symptomatic or imaging changes.
The retrospective review appeared to show that patients who received medical therapy had similar outcomes compared with patients treated on a “watch and wait” protocol. “The data appear to indicate that use of observation in selected patients would be appropriate,” Dr. von Mehren said.
Patients with tumors in the trunk or who had large tumors—a median 100 mm diameter—had lesions that were much more likely to recur. “So perhaps these patients should not be observed,” she said.
Dr. von Mehren said that when phsyicians are working up patients suspected of having desmoid tumors they need to be aware while doing their history and physical workup that the tumor may be related to Gardner‘s syndrome—i.e., familial adenomatous polyposis—and the extracolonic tumors may include desmoid tumors.
In addition to the information about a normal workup, the NCCN guideline also suggests use of computed tomography and magnetic resonance imaging of the primary tumor site as clinically indicated.
Decisions about whether to resect the tumor may be determined by size and location, particularly if resection is going to result in unacceptable morbidity, she noted.
“If the patients are stable after surgery, then they can be followed with observation,” Dr. von Mehren said. “If you are going to choose observation it has to be in a patient who is asymptomatic or not at risk of losing some function if the tumor grows.”
Doctors who select a treatment modality have options of surgery in conjunction with radiation or with systemic therapy. “The decision on treatment is usually based on what you are left with after the initial resection,” she said.
The new guideline suggests that:
- If the surgeon has removed the entire tumor, then observation or postoperative radiation therapy would be appropriate.
- If there is a minimal tumor remaining, observation is an option, as is re-resection or radiotherapy if radiation was not performed earlier in the treatment regimen.
- If gross tumor remains, definitive radiation therapy, systemic therapy, or radical surgery are treatment choices—provided that surgical outcome would not result in an unsatisfactory outcome.
For desmoid histology, Dr. von Mehren said that in patients who cannot be resected, definitive radiation would require a dose of 58 Gy—”which is somewhat lower than we would use for a standard soft-tissue sarcoma.”
Because of the locations of the tumors, part of follow-up includes the need for rehabilitation services, and patients should be evaluated for rehabilitation. so they can achieve maximum function.
“These patients need to be monitored with imaging,” she said. “It is hard to know how long you should continue to monitor a person who has had a large tumor. If the tumor has been resected and there is nothing there, I think you can be comfortable in decreasing the intensity of imaging studies down the road. It is a harder question in cases where the tumor persists.
“If the tumor recurs or progresses, you get back to the beginning of the algorithm again and start the decision-making again on how to best manage this disease.
”The guidelines offer several options for systemic therapy including treatment with sulindac or other non-steroidal anti-inflammatory drugs including celecoxib; tamoxifen; toremifene; methotrexate and vinblastine; low-dose interferon; doxorubicin-based regimens, and imatinib.