Soft Tissue Sarcoma Clinical Practice Guidelines (NCCN, 2018)

The clinical practice guidelines on soft tissue carcinoma were released in May 2018 by the NCCN.^[1]

STS of the Extremities, Superficial Trunk, or Head and Neck

Imaging studies should include cross-sectional imaging to provide details about tumor size and contiguity to nearby visceral structures and neurovascular landmarks. The panel recommends MRI with contrast, with or without CT with contrast. Other imaging studies such as CT angiogram and plain radiographs may be warranted in selected circumstances.

Surgery

The goal of surgery for patients with STS of extremities should be functional limb preservation, if possible, within the realm of an appropriate oncologic resection. Limb-sparing surgery is recommended for most patients with STS of extremities to achieve local tumor control with minimal morbidity. Amputation may improve local control in patients who might not be candidates for limb-sparing surgery and should be considered with patient preference, or if the gross total resection of the tumor is expected to render the limb nonfunctional.

When external-beam RT (EBRT) is used, sophisticated treatment planning with intensity-modulated RT (IMRT), tomotherapy, and/or proton therapy can be used to improve therapeutic effect. RT is not a substitute for definitive surgical resection with negative margins, and re-resection to negative margins is preferable.

The usual dose of preoperative RT is 50 Gy in 1.8 to 2.0 Gy per fraction. If the patient has not previously received RT, one could attempt to control microscopic residual disease with postoperative RT if re-resection is not feasible. If wide margins are obtained, postoperative RT may not be necessary. For patients treated with preoperative RT followed by surgery, the guidelines recommend consideration of observation in addition to postoperative RT boost for patients with positive margins.

The recommended EBRT boost doses are 16 to 18 Gy for microscopic residual disease and 20 to 26 Gy for macroscopic residual disease. Brachytherapy boosts should be delivered several days after surgery, through catheters placed at surgery, with doses of 16 to 26 Gy for low dose-rate (LDR) brachytherapy and 14 to 24 Gy for high-dose rate (HDR) brachytherapy, based on the margin status. Alternatively, IORT (10–12.5 Gy for microscopic residual disease and 15 Gy for gross residual disease) can be delivered immediately after resection to the area at risk, avoiding the uninvolved organs.

For patients who have not received preoperative RT, the postoperative choices include EBRT (50 Gy irrespective of surgical margins in 1.8–2.0 Gy per fraction), intraoperative RT (IORT)w (10–16 Gy followed by 50 Gy EBRT), or brachytherapy. The guidelines recommend 45 Gy LDR brachytherapy or HDR equivalent for patients with negative margins. LDR brachytherapy (16–20 Gy) or HDR equivalent is recommended for patients with positive margins followed by EBRT. EBRT after IORT or brachytherapy is delivered to the target volume to a total dose of 50 Gy, after surgical healing is complete (3–8 weeks).

For patients treated with postoperative EBRT, the guidelines recommend an additional EBRT boost (unless prior IORT) to the original tumor bed based on the margin status (10–16 Gy for negative surgical margin; 16–18 Gy for microscopic residual disease; and 20–26 Gy for grossly positive margins). However, many institutions are no longer giving a boost after preoperative RT to patients who have widely negative margins, based on local control rates approaching 95% with preoperative RT at 50 Gy and negative margins. The panel also emphasizes that RT is not a substitute for suboptimal surgical resection, and re-resection is preferred for patients with positive surgical margins.

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