Bone cancer

Bone cancer usually means a malignant tumour that starts in the bone itself. Doctors use a more exact word — bone sarcoma — because it grows not from lining tissues, as most familiar tumours do, but from bone and cartilage, and it behaves differently. These tumours are rare, more common in teenagers and young adults, and their defining feature is a quiet beginning: the pain gets blamed on training, a knock or a growth spurt, and months pass between the first complaint and the diagnosis. That gap is exactly what deserves the closest attention.

What the name covers

There are several primary bone tumours, and they have little in common.

• Osteosarcoma is the commonest. It appears in teenagers during rapid growth, most often near the knee or in the upper arm. A second, far rarer peak occurs in older people, usually in a bone that is already diseased.
• Ewing sarcoma is likewise a disease of children and young adults. It grows in the pelvis, ribs, spine or long bones, and often comes with fever and weakness, so at first it is mistaken for a bone infection.
• Chondrosarcoma arises from cartilage, mostly after the age of thirty or forty, more often in the pelvis, thigh bone or shoulder. It grows more slowly but responds poorly to drugs, so surgery carries most of the weight here.

Something else matters too: most malignant bone lesions are not primary tumours at all but secondary deposits from the breast, lung, prostate, thyroid or kidney. In anyone over fifty, a bone lesion is far more likely to be exactly that, and the work-up then takes a different route — the original tumour is sought. Bone secondaries are also treated differently from sarcoma.

The pain that gets taken for an injury

Early signs are sparse, so it helps to know how the "wrong" kind of pain differs from the ordinary kind.

• Pain in the bone rather than in muscle or joint — deep, aching, hard to point to with a finger.
• Pain that grows worse at night and wakes you, and does not ease with rest: the single most concerning sign.
• Pain that builds week by week instead of settling the way a bruise settles.
• Swelling or a lump over the painful area, sometimes noticeable only to the fingers.
• A limp or restricted movement in the neighbouring joint.
• A fracture after minimal force — an uncommon but very telling sign, as the bone breaks exactly where the tumour has weakened it.

Less often, general symptoms join in: fever with no obvious infection, night sweats, weight loss, and tiredness that sleep does not fix. Bruises and strains settle within a week or two; pain that lasts longer than a month and keeps changing for the worse needs an X-ray, whether or not there was an injury.

When to see a doctor without delay

• bone pain has lasted more than two or three weeks, is worse at night, or has begun to interfere with walking;
• a lump or swelling has appeared over the bone and is getting bigger;
• a bone has broken after a minor knock or with no injury at all;
• back or pelvic pain comes with numbness, leg weakness or trouble passing urine — this may mean pressure on nerve structures and needs same-day attention;
• in a child or teenager, pain in a leg or arm has not settled for over a month, particularly if a limp has developed.

In the great majority of cases the cause turns out to be far more ordinary. But lost time is expensive here: the smaller the tumour and the earlier treatment starts, the more often the limb can be saved.

What raises the chances

In most people who develop these tumours no predisposing factor is ever found. Only a handful of circumstances genuinely raise the risk.

• Radiotherapy in the past, especially in childhood: a tumour may appear in the irradiated area ten or more years later.
• Paget's disease of bone, a remodelling of bone tissue in older people. It lies behind most late osteosarcomas.
• Inherited syndromes — hereditary retinoblastoma, Li-Fraumeni syndrome, Werner syndrome. If several relatives have had malignant tumours at a young age, the doctor must be told.
• Benign bone tumours and developmental abnormalities, above all multiple cartilage outgrowths: these are monitored because a proportion can change over time.

Neither injury, nor sport, nor diet causes a sarcoma. A knock sometimes simply draws attention to a place where the tumour was already growing.

How the diagnosis is confirmed

Investigation proceeds in stages, and the order matters.

• An X-ray is the first and most available step: a bone tumour almost always leaves visible changes on the film.
• An MRI scan shows the true extent of the tumour and its relationship to vessels, nerves and joint — which decides whether the limb can be preserved.
• A CT scan of the chest: the lungs are always checked, because that is where sarcomas spread first.
• A bone scan or PET scan to look for other deposits in the skeleton.
• A biopsy — a piece of the tumour examined under the microscope. Only this gives the final answer as to which tumour it is and how aggressive it is.

One thing about the biopsy rarely reaches popular articles yet bears directly on the outcome: it should be planned and performed by the same centre that will later operate. The needle leaves a track behind it, that track is considered contaminated with tumour cells, and it is removed along with the tumour. If it has been placed badly, saving the limb may no longer be possible. So the right move is not to have the biopsy done close to home, but to reach a centre that deals with bone tumours first.

What treatment involves

The plan is drawn up by a team: an oncologist, an orthopaedic surgeon, a radiotherapy specialist, a pathologist and a rehabilitation specialist. The mix depends on the type of tumour, its size, its site and whether it has spread.

Surgery remains the foundation. In most cases amputation can be avoided: the affected part of the bone is removed together with a margin of healthy tissue, and the gap is filled with a prosthesis or with bone from the patient or a donor. Children receive implants that can be lengthened as they grow. Amputation is needed where the tumour has grown into vessels and nerves — and even then, modern prosthetics and rehabilitation allow a return to an active life.

Chemotherapy in osteosarcoma and Ewing sarcoma is usually given both before and after surgery: it shrinks the tumour, makes the operation less destructive and clears microscopic deposits. How many tumour cells have died in the removed specimen tells the team how well it worked. In chondrosarcoma chemotherapy is generally of little use.

Radiotherapy matters most in Ewing sarcoma, which is sensitive to radiation: it is used if the tumour cannot be removed whole or sits in an awkward place such as the spine or pelvis. Targeted drugs are added for certain tumour types and when the disease returns, guided by testing of the tumour tissue.

Where the tumour has spread widely and cannot be removed completely, treatment aims at holding back its growth and controlling symptoms: pain relief, strengthening the bone and irradiating a painful deposit noticeably improve day-to-day life. Bringing in that kind of support early, rather than at the very end, is worth doing.

Questions worth asking early

• The ability to have children. Chemotherapy and irradiation of the pelvis affect fertility, and freezing sperm or eggs is discussed before the first cycle — afterwards it may no longer be possible.
• Rehabilitation. Recovery takes months and rests on work with a rehabilitation specialist; it is worth finding out in advance where this will happen.
• Long-term effects. Some drugs affect the heart, hearing and kidneys, and a prosthesis may need replacing over the years — a reason for planned follow-up, not for worry.
• Follow-up. Reviews and lung imaging are repeated to a schedule for several years: a recurrence found early is easier to treat. Talking to a psychologist, or to people who have been through the same thing, helps as well.

Online consultation

In an online consultation the doctor goes through the character of the pain and how it has changed, helps work out which signs call for an X-ray within days, explains reports you already have in plain words, and advises what to ask at a face-to-face appointment and why, when a bone tumour is suspected, it matters to reach a specialist centre from the outset.

This material is for information only and does not replace medical advice.