Where do you cut to avoid damage and minimize recurrence?

Standard treatment for primary soft-tissue sarcomas involves surgical excision of the tumor with a margin of surrounding tissue (Fig. 1). During resection, the surgeon also seeks to avoid damage to nearby structures, such as bone, nerves, and blood vessels. Unfortunately, no consensus exists as to what constitutes an adequate surgical margin.

Presenters at the 2011 Musculoskeletal Tumor Society (MSTS) specialty day session, “Margins in Sarcomas,” moderated by Sybil Biermann, MD, debated the issue of “How much is enough?”

Less is more
Wide margins are not always possible or necessary, according to Terrance D. Peabody, MD. “Operative management has evolved away from amputation, radical resection, and wide resection and toward marginal resection with adjuvant therapy, such as radiation,” he explained.

According to Dr. Peabody, understanding the significance of local recurrence is important. Does it inevitably lead to metastatic disease? Does it have an effect on subsequent recurrence? Based on surgical technique and adjuvant therapy, is local recurrence preventable?

Although the literature shows that local recurrence does predispose additional subsequent recurrences, said Dr. Peabody, no direct correlation has been found between local recurrence and survival. Thus local recurrence is not necessarily a source of distant metastases, and a lack of margins may be tolerable.

Dr. Peabody also noted that in a prospective analysis of soft-tissue sarcomas, Yang et al found that radiation therapy lowered local recurrence in all tumors and that radiation therapy and wide margins resulted in no incidences of local recurrence. Although radiation therapy reduces the risk of local recurrence, it does not improve survival.

“So local recurrence may be preventable, at least in soft-tissue sarcomas. But,” he continued, “local recurrence related to margin is likely not preventable without doing amputations.”

The factors that are associated with local recurrence, he said, are very complicated. Local recurrence is related to the grade, size, and location of the tumor. It is also associated with positive margins, but not all patients with positive margins will have a local relapse. He added that the ability to accurately assess margins is somewhat limited and that an adequate margin is as much about quantity as it is quality.

“Sarcomas are known for histologic camouflage—they tend to hide out in different areas that can be misread as reactive tissue. The surgeon is in the best position to judge margins—I think the pathologist is too far removed. Surgeons have the three-dimensional view and a sense of the quality of the margin,” he said.

More is better
“Larger surgical resections of soft-tissue sarcomas can actually save tissue,” said Bruce Rougraff, MD. “Larger resections potentially save the patient radiation treatment, potentially reduce the risk of local recurrence, and may eventually save the patient from amputation.

“The goal is to have no ink on tumor—ink on tumor is the strongest predictor of local failure,” he added.

When determining margins, he said, points for debate include resection or reconstruction of bone, vessels, and nerves; radiation; and amputation.

“As surgeons, we cannot always choose how wide a margin to take,” he said. “But we can choose whether or not to do an amputation, whether or not to perform a skin graft, and whether or not to remove bone, vessels, or nerves.”

When contemplating bone resection, Dr. Rougraff ensures that no preoperative cortical changes have occurred and that the periosteum can be easily elevated off with gauze. “Skeletal reconstruction can result in very slow allograft healing if it is combined with radiation, and if an endoprosthesis is irradiated, a higher infection rate is the result,” he said.

Surgeons considering vascular resection should accept only vessels that can be bluntly dissected away from the sarcoma, Dr. Rougraff advised. “Although vascular reconstruction is not so bad in younger patients, it can be a very morbid procedure in older patients who have had radiation,” he cautioned.

According to Dr. Rougraff, every high-grade sarcoma should be considered for radiation, preferably preoperatively, although histologically, preoperative radiation does not make close margins safer.

He added that nerves should only be resected when the tumor occurs in the nerve and that sciatic nerve or brachial plexus encasement are indications for amputation.

“The goal for all of us is to try to have resections with no ink on tumor,” Dr. Rougraff concluded. “I would not cut through a sarcoma to preserve nerves, vessels or bone, regardless of the adjuvant therapy.”

Although the two positions were “less is more” versus “more is better,” both surgeons agreed that the goal of surgical management of a soft-tissue sarcoma is a negative margin. How that margin is achieved—whether by centimeters or by cell layers—and how the margin is quantified still remain topics of debate.

Disclosures: Dr. Peabody—Journal of Bone and Joint Surgery–American; American Orthopaedic Association; Musculoskeletal Tumor Society; Dr. Rougraff—AAOS.

Bottom line

• There is no consensus on adequate surgical margin in soft-tissue-sarcoma resection.
• The goal of surgical management of soft-tissue-sarcomas is negative margins.
• Surgeons are in the best position to judge the quality and quantity of margins.

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

Reference:

1. Yang et al:  Randomized prospective study of the benefit of adjuvant radiation therapy in the treatment of soft tissue sarcomas of the extremity. J Clin Oncol 1998; vol. 16 no. 1 197-203.