What is the treatment approach for rectus sarcoma?

Treatment Approach for Rectus Sarcoma

The standard treatment for rectus sarcoma is wide surgical excision with negative margins (R0), followed by adjuvant radiation therapy for high-grade, deep tumors larger than 5 cm. 1

Initial Evaluation and Staging

• Imaging studies:

  • MRI of the primary tumor site for local staging 1
  • Chest CT scan to evaluate for lung metastases (mandatory) 1
  • Abdominal/pelvic CT scan for high metastatic potential subtypes 1
  • Consider additional imaging based on histologic subtype:
    • Spine/pelvic MRI for myxoid liposarcoma 1
    • Brain MRI for alveolar soft-part sarcoma, angiosarcoma, clear cell sarcoma 1

• Biopsy:

  • Percutaneous core needle biopsy is preferred 1
  • Review by specialist sarcoma pathologist for confirmation 1
  • Molecular/genomic analysis as appropriate 1

Treatment of Localized Disease

Surgical Management

• Wide excision with negative margins is the cornerstone of treatment 1

  • Aim for 1-2 cm margins where possible 2
  • Margins can be minimal at resistant anatomic barriers (fascia, periosteum, perineurium) 1
  • Complete en bloc resection with a rim of normal tissue 1

• Margin classification:

  • R0: No residual tumor (negative margins)
  • R1: Microscopic residual tumor
  • R2: Macroscopic residual tumor 1

• For positive margins:

  • Re-excision should be performed when possible for R1 or R2 resections 1
  • If re-excision is not feasible, consider adjuvant radiation therapy 1

Radiation Therapy

• Indications for adjuvant RT:

  • Standard for high-grade (G2-3), deep tumors >5 cm 1
  • Consider for deep tumors ≤5 cm or low-grade tumors in selected cases 1
  • May be omitted for G1, R0, <5cm, superficial tumors 1

• Timing and dose:

  • Postoperative: 60-65 Gy with shrinking field technique 1
  • Preoperative: 50 Gy 1
  • Consider preoperative RT for borderline resectable tumors 1

Chemotherapy

• Adjuvant chemotherapy:
  • Not standard treatment but can be considered for high-risk patients (G2-3, deep, >5 cm) 1
  • May improve or delay distant and local recurrence in high-risk patients 1
  • Consider histological subtype in decision-making (some types more chemosensitive) 1

Management of Advanced/Metastatic Disease

Systemic Therapy Options

• First-line treatment:

  • Standard: Single-agent doxorubicin 1
  • Alternative: Ifosfamide (if anthracyclines contraindicated) 1
  • Consider doxorubicin + ifosfamide combination when higher response rates are needed 1

• Second-line options:

  • Ifosfamide 1
  • Trabectedin 1
  • Gemcitabine + docetaxel or gemcitabine + dacarbazine 1
  • Selection based on histology, toxicity profile, and patient preference 1

Management of Oligometastatic Disease

• Consider local therapies:
  • Surgical resection of isolated lung metastases 1
  • Radiotherapy or ablative therapies (RFA, SABR, cryotherapy) 1

Follow-up

• Clinical evaluation every 3-4 months initially 1
• MRI of the resection site once a year 1
• Chest X-ray every 3-4 months in first 2-3 years, twice a year up to fifth year, then annually 1
• Consider chest CT for retroperitoneal sarcomas or sites difficult to follow clinically 1

Common Pitfalls and Special Considerations

• Inadvertent surgery: When sarcoma is discovered after unplanned excision, consider:

  • Full staging and MRI of surgical bed 1
  • Re-excision of surgical bed if adequate margins can be achieved with acceptable morbidity 1
  • Radiation therapy if re-excision not feasible 1

• Surgical complications:

  • Infection, deep venous thrombosis, skin necrosis, arterial occlusion 3
  • Preservation of normal tissue while maintaining oncologic principles is important 3

• Local recurrence:

  • Consider surgical resection when feasible 1
  • Multimodality approach for cases not amenable to wide margin resection 4

The treatment of rectus sarcoma requires a multidisciplinary approach by an experienced team at a sarcoma center, with decisions made collaboratively by surgeons, radiation oncologists, medical oncologists, and pathologists to optimize outcomes 1.