GP and academic Dr Meena Rafiq considers the rare cancer diagnosis in the latest of our ‘Once in a Lifetime’ series
What is it?
Sarcomas are rare cancers that develop in the body’s connective tissues, including muscle, bone, fat, blood vessels, nerves and tendons. They can arise almost anywhere in the body, and their rarity combined with often vague symptoms means they are frequently diagnosed late.
There are two broad categories: soft tissue sarcoma, which accounts for around 85% of cases, and bone sarcoma. Over 100 subtypes exist, with varying behaviours, prognoses and treatment pathways.
Because of this diversity, and because early signs are often mistaken for benign or mechanical problems, sarcoma is sometimes referred to as the ‘forgotten cancer’.
How rare is it?
Fewer than 1,000 GPs in the UK will see a sarcoma diagnosis each year. That is fewer than one case per practice per decade. But the stakes are high: around 5,300 people are diagnosed with sarcoma annually in the UK, and 40% of them will die within five years.
Importantly, a sizeable proportion of sarcomas occur in children and younger adults, in whom cancer often appears lower down on the list of differentials. Patients typically experience multiple consultations before diagnosis. Earlier recognition is essential and can reduce the need for radical treatment such as limb amputation, and can improve survival.
Clues for early detection
The most common presentation of soft tissue sarcoma is a painless lump, usually in the limbs or trunk. Bone sarcoma often causes deep, persistent pain, especially at night or at rest.
Symptoms can be subtle. Key indicators include:
- Soft tissue lumps that are growing, firm, deep or over 5cm in diameter.
- Bone pain without obvious trauma, especially if persistent or worse at night
- Symptoms not responding to usual conservative treatments.
- Recurrence or persistence of a lump that was previously thought to be benign.
May be confused with…
Sarcomas are frequently misdiagnosed as:
- Lipomas or cysts, especially if a lump is superficial and non-tender. However, lipomas and cysts are usually soft and mobile, whereas sarcomas tend to be firmer and fixed.
- Muscle strains or sports injuries, particularly in active patients with limb pain.
- Bursitis or haematoma, if swelling follows trauma.
- Growing pains, in children and adolescents with intermittent bone pain.
These common differentials are understandable, but repeated presentations or a change in the clinical picture should prompt reconsideration and urgent imaging or referral.
Red flags
GPs should be alert to:
For soft tissue sarcoma, lumps that are:
- Over 5cm (roughly the size of a golf ball).
- Firm, fixed or deep to fascia.
- Increasing in size.
- Painful, recurrent or persisting after trauma.
For bone sarcoma, bone pain that is:
- Persistent, lasting more than two weeks.
- Worse at night or at rest.
- Without any clear mechanical trigger or trauma.
- Accompanied by swelling or reduced joint mobility.
Diagnosis and referral
The key is not to watch and wait if any red flags are present. In England, patients should be referred using urgent suspected cancer referral pathways (previously known as two-week-wait).
If rapid imaging is locally accessible, an urgent ultrasound (for soft tissue) or X-ray (for bone pain) should be arranged as soon as possible. Alternatively, GPs can refer directly to a sarcoma specialist centre.
Case example: A patient attended a follow-up GP consultation with me for a presumed lipoma. While awaiting routine imaging, the lump rapidly increased in size. When I examined them, the lump felt unusually firm and fixed. I requested an urgent ultrasound and made an urgent cancer referral to a sarcoma specialist centre. It was sarcoma. That second consultation, where something just did not feel right, made all the difference.
Usual treatment and prognosis
Management is led by a multidisciplinary team at specialist sarcoma centres. Treatment often involves surgical excision, sometimes with radiotherapy or chemotherapy, depending on the type and stage.
For bone sarcomas such as osteosarcoma or Ewing’s sarcoma, chemotherapy is often used before and after surgery. For soft tissue subtypes, surgery with clear margins is the priority.
Prognosis depends on size, grade, and whether the cancer has spread. Early diagnosis improves outcomes significantly. For every 1cm increase in the size of a sarcoma at diagnosis, there is a 3-5% decrease in the chance of a cure. It’s important to act fast and have a low threshold for imaging and referral if there are red flags or concerning features in patients with soft tissue lumps or bone pain.
Key points for GPs
- Think sarcoma, especially for persistent lumps or unexplained pain.
- Refer early using urgent imaging or suspected cancer pathways.
- Trust your instincts if something does not feel right – arrange an urgent x-ray (bone pain) or urgent ultrasound (lumps).
- Use available support such as Sarcoma UK’s clinical resources.
Dr Meena Rafiq is a GP and researcher at UCL
Useful resources
Sarcoma UK provides guidance for GPs, including resources, referral criteria and a Support Line staffed by healthcare professionals.
- Support Line: 0808 801 0401
- GP referral guidance: sarcoma.org.uk/gp-sarcoma
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A man in his 60s came to see me with a large, hot, firm, round, fixed, mass on one buttock. I thought it was a deep seated abscess and sent him into A and E immediately. It was a sarcoma.