Hematology-Oncology - Volume 12, Part 1, Jan/Feb 2017

www.hpboardreview.com Hematology-Oncology Volume 12, Part 1 37
Soft Tissue Sarcoma: Diagnosis and Treatment

mining the TNM staging for 117 patients. They found that conventional imaging correctly classified 77% of patients, PET alone correctly classified 70%, PET/CT correctly classified 83%, and PET/CT combined with conventional imaging correctly staged 87%. 22

•;Which;subtypes;are;most;likely;to;metastasize?

Although the vast majority of sarcomas spread hematogenously, 3 have a propensity to spread lymphogenously: epithelioid sarcoma, rhabdomyosarcoma, and clear-cell sarcoma. Additionally, certain subtypes are more likely to metastasize: leiomyosarcomas, synovial sarcomas, neurogenic sarcomas, rhabdomyosarcomas, and epithelioid sarcomas. 23 Sarcomas metastasize to the lungs more frequently than to the liver. The metastatic pattern is defined primarily by sarcoma subtype and site of primary tumor. Sarcomas rarely metastasize to the brain (~1%).

MANAGEMENT CASE CONTINUED

The patient undergoes an ultrasound to better visualize the mass. Given the heterogeneous character of the mass, he is referred for an MRI to evaluate the mass and a CT scan of the chest, abdomen, and pelvis to evaluate for distant metastases. MRI reveals a 5. 1 cm × 4. 6 cm heterogeneous mass invading the superficial fascia of the rectus femoris muscle. No suspicious lymph nodes or other masses are identified on imaging. The patient next undergoes an image-guided core needle biopsy. Pathology from that procedure is consistent with a stage III, T2b- NxMx, grade 3, dedifferentiated liposarcoma.

•;What;is;the;best;management;approach;for this patient?

SURGERY

Surgery is the mainstay of treatment for STS.

Patients with the best prognosis are those who
undergo complete resection with negative sur-
gical margins. 24, 25 Goal tumor-free margin is 1
to 3 cm. 26 Complete resection confers the best
long-term survival. Both local and metastatic
recurrence is higher in patients with incomplete
resection and positive margins. 24, 25 In a study that
analyzed 2084 localized primary STSs, patients
with negative margins had a local recurrence
rate of 15% versus a rate of 28% in patients with
positive margins. This translated into higher
5-year local recurrence-free survival for patients
with negative surgical margins (82%) com-
pared to patients with positive margins (65%). 27
Another study similarly found that patients with
negative margins at referral to their institution
who underwent postoperative radiation had
high local control rates of 93% (95% confi-
dence interval [CI] 87% to 97%) at 5, 10, and
15 years. 26 Although radiation improves local
control, neither preoperative or postoperative
radiation has been shown to improve progres-
sion-free or overall survival. 28 Other factors that
are associated with risk of recurrence are tumor
location, history of previous recurrence, age of
patient, histopathology, tumor grade, and tumor
size. Approximately 40% to 50% of patients with
high-grade tumors (defined as size > 5 cm, deep
location, and high grade) will develop distant
metastases. 29

Zagars et al found that positive or uncertain resection margin had a relative risk of local recurrence of 2.0 (95% CI 1. 3 to 3. 1; P = 0.002), and presentation with locally recurrent disease (vs new tumor) had a relative risk of local recurrence of 2.0 (95% CI 1. 2 to 3. 4; P = 0.013). 26 Patients with STS of head and neck and deep trunk have higher recurrence rates than those with superficial trunk and extremity STS. A single-institution retrospective review demonstrated that patients with completely resectable retroperitoneal sarcomas have longer median survival (103 months) compared to patients with incompletely resected abdominal sarcomas ( 18 months). 25