Treatment of Bone Cancer

Introduction 

Primary bone cancer (PBC) is a rare bone cancer that arises from primordial mesenchymal cells. It is idiopathic in most cases and accounts for around 0.2 per cent of all cancers globally. In their lifetime, 1 in 1,616 UK males and 1 in 1,351 UK females will be diagnosed with bone sarcoma. ^[1][2][3] Osteosarcoma (56%) is the most prevalent cancer in children and adolescents, followed by Ewing sarcoma (34%). PBCs include chordoma, undifferentiated pleomorphic sarcoma, adamantinoma, fibrosarcoma, and giant cell tumour of the bone. However, they are less common. PBC has a male preponderance, with a male-to-female osteosarcoma ratio of 1.43 to 1. ^{[1] [2]}

Bone cancer may be classified into three types:

• Osteosarcoma^[4] - Can arise in any bone, but the knee, thigh, shin, or upper arms are the most common sites. Any of these bone cells has the potential to become cancerous. Young adults and teenagers are more likely than younger children to be diagnosed with osteosarcomas.
• Ewing sarcoma^[5] - Can affect any bone; however, it is most commonly found in the thigh or shin bones and the pelvis. Soft tissue Ewing sarcoma can also occur. Young adults and teenagers are more likely to develop Ewing sarcomas than any other age group.
• Chondrosarcoma^[6] - Is a rare cancer that generally starts in the bones but can also originate in the soft tissue around the bones. The pelvis, hip, and shoulder are the most commonly affected areas. It can also happen in the bones of the spine, however, this is unusual. Usually, chondrosarcomas initially progress slowly, with few indications and symptoms. Some uncommon cancers develop quickly and have a high chance of spreading to other parts of the body, making treatment challenging.

What is it? Causes and symptom types

Who does it affect?

Bone cancer can strike people of any age. Some varieties, however, are linked to 'growth spurts,' which begin around the age of 10 and occur when bones expand fast.

What are the symptoms?

Primary bone cancer symptoms^[7] are sometimes confused with sports injuries, growing pains, or various other common disorders, including tendonitis or arthritis. They may also differ based on the tumour's location and size. Some patients report feeling discomfort or noticing swelling around the tumour. Moving that area of your body may be tough if the malignancy is near a joint. A bone that has been weakened by bone cancer may occasionally shatter - although this is highly unusual. The region is generally painful at first, and then the discomfort becomes an ache that persists; you may also notice a lump.

These symptoms might be caused by various ailments, so it's crucial to see your GP and be checked out.

How is it diagnosed?

Specialists at a hospital or a bone treatment centre are commonly responsible for diagnosing bone cancer. X-rays, a bone scan, a CT scan, and an MRI scan may be used to aid physicians in determining the size of the tumour and how far it has progressed, and the MRI is a gold standard for assessing the size of a local tumour.

The most common tests used to detect symptoms of bone cancer are X-rays and scans. However, a biopsy is the best technique to determine if bone cancer is the source of the illness; they will also need to extract a sample of bone to examine under a microscope. Taking a tiny sample of bone tissue and testing it, then carefully inspecting the cells under a microscope for symptoms of malignancy. This can be done with either a local anaesthetic (where the region is numbed) or a general anaesthetic (where you are given medicines to put you to sleep).  The sort of biopsy they do will determine the drug they use.

Secondary Bone Cancer

Cancer in the bones is frequently the result of cancer elsewhere in the body. For example, secondary bone cancer can occur when lung cancer^[8] has migrated to your bones. Metastatic cancer is any cancer that spreads from one place in your body to another. Cancers that commonly spread to bone include Breast cancer^[9], Prostate cancer^[10], and Lung cancer^[11].

Treatments

Limb-sparing surgery 

The arms and legs are the most common sites for primary bone malignancy. The main procedure for these cancers is limb-sparing surgery. This entails eliminating the cancerous tissue while leaving the afflicted limb or leg in place. It's also known as limb preservation surgery.

The surgeon removes the cancerous region of bone and replaces it with a metal implant called a prosthesis replacement bone, which can be from another part of the body or a bone bank. The damaged bone is removed, treated with radiation, and then re-implanted in some instances.^[1][12]

Complication

A complication of limb-sparing surgery is when the bone grafts or prostheses become loose or break. This is more common than bone surgery because the chemotherapy administered after and before surgery can increase the risk of infection and impair wound healing. 

Risk

Infection

Any bone surgery carries the risk of infection; in particular, chemotherapy patients are more vulnerable to infection. Your surgical team will consider everything possible to avoid these risks. Antibiotics are given to you during your surgery to help prevent disease. Once an infection has developed, it is difficult for the doctors to remove it from the bone or a metal implant. A severe infection might cause the bone around the prosthesis to break down. The prosthesis becomes loose and unstable as a result. Bone infections can occasionally be cured, although this typically requires extra surgery. Your doctor will need to remove the prosthesis, wait for the disease to cure, and replace it with a new one. If you can't bring the infection under control, you may have to have your limb amputated.

Other risks

There are other risks of having limb-sparing surgery. Your doctor will discuss these with you.

But your doctors will make sure the benefits of having limb-sparing surgery outweigh these possible risks.

Amputation

Most patients will use the above treatments for limb-salvage surgery (also known as limb-sparing surgery). Some individuals may require the amputation of a limb to remove the whole tumour. This is referred to as an amputation. Suppose the tumour has advanced to major blood arteries or nerves in the afflicted bone. If the patient is infected, there are difficulties after surgery, or limb-salvage surgery is not viable, an amputation is performed. After the wound has healed, a custom prosthetic (artificial) limb can be created for the patient.

The surgery will be personalized to each patient's needs to remove the tumour while keeping as much of the patient's pre-surgical look, aesthetic appearance, and functional capacity of the surgical site as feasible. If the initial bone cancer has progressed to other body parts, such as the lungs, surgery may be required. Because the size and location of the tumour determine the kind of surgery, chemotherapy and radiation may also be utilized to treat a secondary tumour.^[13][14]

Additional surgery may be required to rebuild the affected limb after the tumour has been removed and replace or extend a prosthesis as the patient develops, especially if the patient is young and still growing.

Infection

Surgical site infection following amputation is common, and it can have a detrimental impact on recovery, phantom pain, and the time it takes to get a prosthesis ^[15]. Diabetes, old age, and smoking are all prevalent denominators among amputees, and they all increase the risk of a stump infection ^[16]. The decision to use clips instead of sutures to install a drain is also linked to an increased risk of infection.

Revision surgery is a possible outcome of infection. This can lengthen hospital stays and raise the risk of secondary morbidities, including pneumonia or decreased function. In order to identify any symptoms of infection, wounds should be examined on a frequent basis.

It's also possible that the wound will open up along the surgical line (dehiscence). This occurs when the injury is not strong enough to withstand pressure, exposing muscle and bone. A direct fall (the most frequent), trauma, or shearing are examples of these pressures. Other reasons include premature removal of sutures or enlargement of the remaining limb. Total dehiscence typically necessitates surgical intervention. ^[18]

Pain

The pain that comes with amputation is unavoidable. Agony from an amputation might be localized to the remaining limb, or it can be phantom pain. Many people will experience pain not just due to the surgery's trauma but also as a neuropathic condition known as phantom limb pain (PLP). Co-existing damage to the same limb or other regions of the body might complicate amputation when it occurs due to a stressful experience, such as a catastrophe. 

Post-Amputation Pain: It's crucial to separate post-amputation pain from pain in the residual limb and phantom limb at the incision site. All three might happen at the same time after amputation.^[19]

RLP (Residual Limb Discomfort): Patients frequently experience pain or feelings in the areas around an amputated body part. This is referred to as RLP (remaining limb pain) or stump pain. It's frequently mistaken for PLP, and its strength is commonly connected with it. ^[20]

Phantom Limb Sensation: This is a common occurrence for most amputees. However, it is not a sensation that the patient may characterize as uncomfortable. It's often described as a gentle tingling feeling, and in these circumstances, reassurance is crucial.^[21]

RLP and post-amputation pain are characterized as nociceptive pain, whereas Phantom Limb Pain (PLP) is classified as neuropathic pain. Physical elements (pressure on the residual limb, time of day, weather) and psychological ones, such as emotional stress, might increase or induce PLP in the distal section of the phantom limb. Sharp, cramping, scorching, electrifying, leaping, crushing, and cramp are common characteristics.

Chemotherapy

Chemotherapy ^[22] is the treatment of cancer using drugs. Systemic Anti-Cancer Treatment is another name for it (SACT). These medications block cancer cells from growing and dividing or damaging their DNA, causing them to die. Additionally, when cancer cannot be treated, chemotherapy can be administered to alleviate symptoms, a practice known as palliative care.

The following are some of the most common and unpleasant side effects:

• Nausea and vomiting 
• Diarrhoea
• Hair loss
• Mouth sores
• An unusual taste in the mouth
• Tiredness (known as fatigue)

The doctor might prescribe medicine before and during chemotherapy to reduce some of these side effects.

Radiotherapy

Compared to surgery or chemotherapy, radiotherapy^[23] is utilized less commonly in treating primary bone tumours. However, it is  widely used to treat Ewing sarcoma and chordoma. After surgery, radiotherapy is occasionally used to treat osteosarcoma. Unlike chemotherapy, radiation is a 'local therapy,' which means it is only used to treat the tumour and not the entire body. A high-energy, focused radiation beam (typically an X-ray) is used to permanently damage the DNA inside tumour cells, preventing them from increasing and causing them to die.^[24]

Radiotherapy can be used to reduce a tumour before surgery, eradicate any leftover tumour cells after surgery, or help patients who cannot undergo surgery due to their tumour's location (for example, a tumour in the pelvis or spine). Patients may also benefit from radiation treatment to relieve bone pain and other symptoms associated with primary bone cancer. However, this benefit must be balanced against the risk of radiation-induced undesirable side effects for the patient. The adverse effects felt will vary depending on where the radiation was delivered.^[24][25]

The side effects of radiation can include: sore skin or a skin reaction, fatigue, a dry mouth, difficulty swallowing, nausea, loss of appetite, diarrhoea.

What happens after treatment?

You'll have to go to an outpatient clinic frequently. The specialist will look for any symptoms that cancer has returned. They'll also make sure the procedure has harmed no significant organs. Many people have a modest probability of developing health problems in the future, but some will have severe continuing medical demands. Consult your doctor about the treatment's potential long-term adverse effects. If you or your child has a prosthesis (metal bone or joint), it's critical to be aware of any indicators of infection, such as discomfort or fever. If you suspect your prosthesis is contaminated, contact a specialist as soon as possible.

What if it has metastasized? 

When cancer cells move to the bones (bone metastases), they can cause a variety of issues, including discomfort, shattered bones, and more serious complications. Almost all cancers can migrate to the bone, but breast, lung, prostate, kidney, melanoma, ovarian, and thyroid cancers are the most common.

Medication, radiation therapy, and surgery are all common therapies for bone metastases.

Bone-building drugs, intravenous radiation, chemotherapy, hormone therapy, pain medications, steroids, and targeted treatment are all used to treat persons with bone metastases.

Outlook for bone Cancer

Five-year survival rates vary significantly:  chordomas and chondrosarcomas have the greatest survival (70% and 69%), osteosarcomas has the worse survival rate (38%), and Ewing has intermediate 5-year survival at 62%.^[26] Remember that survival numbers are simply estimates based on people who have previously experienced bone cancer.

You'll need to go to regular follow-up appointments once your treatment finishes to ensure the cancer hasn't returned.

In the first two years after treatment ends, you'll be expected to attend regular visits every three months. As time passes, they will become less common.

Summary

Here are a few key points to keep in mind when it comes to primary bone cancer:

• Primary bone cancer is a rare kind of cancer that begins in the primary mesenchymal cells of the bone;

• Orthogonal plain film radiographs should be done on all individuals with chronic bone discomfort;
• An MRI is a gold standard for assessing the size of a local tumour;
• A multidisciplinary team should manage primary Bone Cancer at a specialized bone cancer centre;
• In the treatment of Primary Bone Cancer, chemotherapy and radiation are routinely utilized as additions to surgical excision.