Bone & Soft Tissue Neoplasia

 

• Background

  • Most bone cancer is secondary, as they are a common site of metastases.
  • Sarcomas – connective tissue neoplasms – account for most primary bone cancers, and can also arise in soft tissue. They represent only 1% of all cancer, however.

• Bone metastases

  Primary sites

  • Bones are a common site of metastases.
  • Common primary sites: breast (commonest), prostate, lung, kidney, thyroid.

  Signs and symptoms

  • Constant or progressive pain, including bursts.
  • Fractures.
  • Spinal cord compression.
  • Reduced mobility.
  • Symptoms of ↑Ca2+ and anaemia.

  Investigations

  • X-ray, if specific location suspected.
  • Bone scan (aka bone scintigraphy) to detect all metastases. A type of radionucleotide imaging, in which technetium-99m-labelled methylene bisphosphonate is injected IV, and taken up in areas of ↑turnover and blood flow e.g. mets, fractures, infection, Paget's.

  Management

  • Analgesia ± steroids to relieve symptoms.
  • To prevent complications (e.g. fractures, cord compression) and further relieve symptoms: radiotherapy, chemotherapy, surgical stabilization, bisphosphonates/denosumab. In rare cases, chemotherapy may also modestly prolong survival.

• Bone sarcoma

  Types and epidemiology

  • Osteosarcoma (OS): an osteoid-producing neoplasm which is the commonest primary bone tumour overall. Mostly in the young (especially age 10-20) but has second peak among elderly, when it is associated with Paget's or prior radiotherapy.
  • Ewing sarcoma (ES): 2nd commonest bone tumour in the young (especially age 10-20). Due to t(11;22) translocation and resulting EWS-FLI1 gene fusion.
  • Chondrosarcoma (CS): cartilaginous tumour, commonest primary bone tumour in older adults.

  Presentation

  • Pain and/or mass.
  • Can occur anywhere, but common sites are femur (distal if OS or ES, proximal if CS), proximal tibia (OS and ES), humerus, and pelvis (ES and CS). 25% of ES arise in soft tissue.
  • Pathological fracture.
  • Signs and symptoms of metastases, commonly lungs or bone (including marrow), including systemic symptoms (fever, weight loss).

  Investigations

  Diagnosis:

  • Often first seen on X-ray, but diagnosis usually involves MRI or CT.
  • Typical features: bone destruction (may have permeative or moth-eaten pattern), periosteal reaction (may have sunburst [OS] or laminated ['onion skin'] appearance [ES]), intralesional calcifications and endosteal scalloping (CS).
  • Biopsy

  Staging:

  • CT chest and bone scan for metastases (20% at presentation), with many centres also using whole-body MRI or FDG-PET.
  • Bilateral bone marrow biopsy for ES.

  Other investigations:

  • FBC: may show cytopenia if bone marrow involvement.
  • ↑ALP (useful prognostic marker in OS) and ↑LDH.

  Management

  • Surgery for most, which may involve amputation.
  • Chemotherapy for all with OS and ES, but little role in CS.

  Prognosis

  5 year survival: 80% with localised tumours, 20% with metastases at presentation.

• Soft tissue sarcoma

  Types and epidemiology

  Over 50 types, but commonest are:

  • Liposarcoma (fat).
  • Leiomyosarcoma (smooth muscle): typically uterine or retroperitoneal.
  • Fibroplastic sarcomas (fibrous tissue): includes undifferentiated pleomorphic sarcoma (aka fibrous histiocytoma).
  • Rhabdomyosarcoma (skeletal muscle): commonest soft tissue sarcoma in kids.
  • Gastrointestinal stromal tumours (GIST): see other upper GI tumours.

  Benign soft tissue growths are over 100 times commoner.

  Presentation

  • Large (often >5 cm), expanding lump in soft tissue. Can be painful.
  • May be deep to fascia, becoming less prominent on muscle contraction.
  • Can be anywhere, but common sites include limbs (legs > arms), buttocks, groin, and torso.
  • Presentation of visceral tumours is organ-dependent e.g. PV bleeding if uterine leiomyosarcoma.

  Investigations

  • Urgent US for any unexplained, expanding lump.
  • Diagnosis: MRI plus core needle biopsy. CT may be better if visceral or retroperitoneal.
  • Staging: CT chest for all (lungs are commonest site of metastases), bone scan and bilateral bone marrow biopsy for rhabdomyosarcoma.

  Management

  • Surgery plus radiotherapy for most. Amputation needed in some cases.
  • Add chemotherapy if rhabdomyosarcoma or metastatic.

  Prognosis

  5 year survival 50%.