Soft Tissue Cancer
Surgery
Surgical resection remains the mainstay of treatment for most patients with localized STS. Except for select sarcomas, such as the round cell types (i.e., extraskeletal Ewing’s sarcoma, malignant peripheral neuroectodermal tumor, embryonal and alveolar rhabdomyosarcoma, and neuroblastoma), which can be successfully treated with a combination of radiation and chemical agents, most STSs cannot be reliably eradicated without resection of gross disease. Historical experience with limited excision has demonstrated a high incidence of residual microscopic and even gross tumor and an incidence of local recurrence as high as 90%. The infiltrative nature of these tumors often dictates the use of radical surgical procedures.
In an attempt to rationalize surgery for STS, Enneking and colleagues48presented a classification of surgical procedures. This system was developed for lesions of the extremities; true radical resection is rarely possible for lesions arising in the head and neck, trunk wall, mediastinum, or retroperitoneum. The Enneking classification has two surgical procedures—local excision or amputation—and four surgical margins—intralesional, marginal, wide, or radical. The resulting eight combinations of terms describe the type of surgical procedure possible and the relationship between the plane of dissection, the lesion, its pseudocapsule, and surrounding normal tissues (Table 36-2). An amputation, for example, can range from a radical procedure, in which the level of amputation passes proximal to the origin of the muscles containing the lesion, to a debulking procedure, in which the level of amputation actually passes through the lesion itself. A local procedure can be equally radical in that the entire compartment containing the lesion is removed, or it may be incisional, wherein only a small portion of the lesion is removed for diagnostic purposes.
The terms wide or marginal reflect margins as outlined in Table 36-2. In practice, the terms amputation, radical compartmental resection (i.e., monobloc soft part resection), and wide local excision describe the majority of therapeutic surgical procedures performed for STS. The use of this terminology, however, is no substitute for pathologic assessment and designation of the final margin as positive or negative for disease.
As indicated, unsatisfactory early experience with limited excision resulted in the adoption of radical resection—radical monobloc soft part resection, radical compartment resection, and amputation—as the standard surgical procedures for STS. Table 36-3 summarizes the local control rates achieved with radical surgery as the sole treatment. In general, local recurrence of disease occurs in 10% to 25% of patients, depending on the surgical series. Amputation achieves local control in more than 90% of patients, whereas radical, nonamputative resection achieves local control in 75% to 85% of patients. Radical surgery alone can achieve high rates of local control. However, this salutary effect comes with significant morbidity and a rate of primary amputation of 50% in some series (see Table 36-3). Moreover, the expected survival time for patients treated with amputation has often been inferior to that for patients treated with less radical resection because patients who undergo amputation generally have large, high-grade lesions and a high incidence of micrometastatic disease. The high local control rate achieved by amputation has never been reflected in overall survival rates. The use of truly radical surgery is anatomically limited to extremity tumors and is rarely applicable to nonextremity sites.
Recognizing these problems, many investigators have explored the combination of conservative surgery and radiation therapy. Other surgical oncologists, however, have sought to redefine the selection criteria for tumors that might be adequately managed using less radical surgery—myectomy or function-sparing wide local excision—as the sole treatment. The results of both approaches are considered in the following paragraphs.
Adjuvant Radiation Therapy
Although radical surgery alone provides satisfactory local control, it does so at the expense of significant functional deficits, and it is rarely applicable to nonextremity tumors. By the 1960s, it was known that complete responses could be attained when radiation therapy was used alone for gross disease, dispelling the long-held belief that STSs were highly resistant to radiation. Clinical research then turned to combining limited (conservative or conservation) surgical excision with adjuvant radiation therapy. Suit and colleagues initially reported the successful use of this technique at The University of Texas M. D. Anderson Cancer Center in the early 1970s. Lindberg and colleagues updated that experience, reviewing 300 patients with STS treated with conservative surgical resection (excisional biopsy or wide local excision) and postoperative radiation. No patient was treated for gross disease, and radiation doses ranged from 60 to 75 Gy. The 5-year overall survival and local control rates of 61% and 78% were comparable to those attained by radical surgery alone but the combination of conservative surgery and postoperative radiation did not cause loss of limb function. The ultimate limb preservation rate of 84% is consistent with the 83%, 84%, 87%, and 90% rates reported by colleagues applying similar conservation techniques.
The only randomized trial comparing radical amputation with limb-sparing surgery plus radiation therapy was performed by the National Cancer Institute (NCI). In that trial, 43 adult patients with high-grade STS of an extremity were prospectively and randomly assigned, in a 2-to-1 fashion, to receive limb-sparing surgery plus radiation therapy (27 patients) or radical amputation (16 patients). Both randomization groups received doxorubicin, cyclophosphamide, and high-dose methotrexate chemotherapy. Patients in the limb-sparing group received 50 Gy to the entire anatomic area at risk, with a boost to the tumor bed of an additional 10 to 20 Gy. At a median follow-up time of 56 months, four local recurrences had occurred in the group given limb-sparing surgery plus radiation therapy, but no local recurrences of disease occurred in the amputation group (P =.06). Despite the slight difference in the incidence of local failure, no differences were found in disease-free or overall survival rates.