01 March 2022, Tuesday

Is Bone Cancer Curable?

Overview:

Three major groups of cancers can affect a bone:

1. Primary bone cancer
2. Secondary bone cancer (skeletal metastasis)
3. Cancer affecting the bone marrow

When we say bone cancer, it refers to the first group of cancers mentioned above, called ‘primary bone cancer’. It belongs to a family of cancers called ‘Sarcoma’. These are true bone cancers, i.e., these cancers originate from the bone.

They are scarce and account for less than 0.2% of all cancers. There are different primary bone cancers. The three most common types are Osteosarcoma, Chondrosarcoma and Ewing’s Sarcoma. Before we proceed further, one must know that as compared to primary bone cancer, bone is a much more common site for benign (non-cancerous) bone tumors and tumour-like conditions (these are not considered as true tumors).

The second group, called secondary bone cancer, represents bone metastasis of other cancers. It means these are not true bone cancers. These are deposits of cancer cells that have spread to the bone from cancers of different organs and have grown there, causing damage to the bone.

It represents advanced cancer of those organs. This metastatic disease grows in the bone and can cause pain, swelling, and even make the bone vulnerable to fractures, spontaneously or with trivial injury. These are the most common causes of cancer in the bone.

The third group of cancers are those arising from the cells of the bone marrow. Again, these are not considered true bone cancers. These are cancers affecting the blood-forming cells in the bone marrow. These are represented by the different types of leukaemias and multiple myeloma. Of these, multiple myeloma can cause severe damage to the bone and result in significant morbidity in pain and pathological fractures.

When we discuss bone cancer in this article, we will talk about the first group of cancers, i.e., primary bone cancer.

What is the treatment for bone cancer?

As the treatment for most cancers, treatment for bone cancer is multidisciplinary. It involves treatment with chemotherapy, surgery and radiotherapy. Depending on the type of primary bone cancer being treated, the combination of these various modalities will differ.

For example, conventional osteosarcoma is treated with chemotherapy and surgery. There is no role of radiotherapy in the standard treatment of osteosarcoma. On the other hand, treatment involves chemotherapy, surgery, and radiotherapy for Ewing’s sarcoma. Al Ewing’s sarcoma patients have to receive chemotherapy.

Besides chemotherapy, they need treatment of the local disease, which is surgery or definitive radiotherapy. Some patients might need both surgery and radiotherapy. Depending on the location, size, extent of disease and the early response to chemotherapy, doctors decide on the best way to treat the local condition.

There is no beneficial role of chemotherapy or radiotherapy for conventional chondrosarcoma. Conventional chondrosarcoma is treated with surgery alone. Hence, it is vital to get the diagnosis right. However, before starting treatment for any cancer, an essential work-up called ‘Staging’ has to be done. Cancer treatment begins after doctors establish a precise diagnosis and stage the disease.

What is the staging of cancer?

Cancer’s problematic and dangerous behaviour is its ability to spread in the body to distant organs and tissues and form new growths in this location, affecting those organ systems. When the disease spreads to a different location, its treatment becomes complicated and challenging. So, once a cancer diagnosis is made, besides the thorough local imaging as X-ray and MRI of the affected area, certain other investigations are done to screen the whole body to look for any possible metastasis.

Primary bone cancer involves a bone scan and a high-resolution CT (HRCT) scan of the chest. Alternatively, nowadays, a whole-body PET-CT scan is often employed as a staging investigation. In those who have sought timely help, most patients show only the primary disease with no detectable metastasis.

In some, we may find only a single focus of disease spread; but often, such a spread of disease may be multiple and may involve over one distant organ or tissue. If the disease has spread to the lungs, one may find that it has affected various lung areas as many growths. In some, it may have spread to different organs, e.g., it may have spread to the lungs, bone, liver, brain, etc. These are called ‘metastasis’ or secondaries of that cancer. It also matters to know whether this metastatic disease is small or big.

So, we need to know whether the disease is metastatic. If metastatic, whether the spread is solitary, limited or extensive. Also, we need to know whether the spread is to one organ or multiple organs. Again, we need to know if this metastatic disease is small or large.

The outlook for the patient is best when there is no detectable metastasis on staging. Based on the nature of cancer, its size, location, the extent of local, regional and distant spread, and the patient’s age and general health, the treatment is planned.

One of the important decisions taken is the intended goal of treatment. Based on the findings of the staging investigations, the treating team decides whether the treatment is to be planned with a curative intent or with palliative intent. In those with the primary disease in inoperable locations, in those with extensive metastasis and the elderly with poor general health, treatment may be planned with palliative intention.

In some with borderline operable diseases and those with limited metastasis, we decide on the intention of treatment after assessing the response to the initial few cycles of chemotherapy.

When the treatment is with a curative intention, it achieves complete clearance of disease, and hence it’s a very aggressive attack on the condition. The treatment follows set protocols designed for treating that particular disease.

In palliative care, we aim to treat the symptoms of the disease and improve and maintain the patient’s quality of life. Palliative treatment is tailored to the patient’s needs and is not aimed at eradicating the disease. Often, we may offer no treatment to those with no symptoms until the patient starts having some discomfort, pain, or disability.

Can bone cancer be cured completely?

So, now we come to the point of answering the question, “is bone cancer curable?” Here, I need to clarify that we are talking only about the first group of cancers mentioned in the introduction–Primary Bone Cancer (also called ‘bone sarcomas’). To answer the question, in short, the answer is ‘YES’.

However, like for any other cancer, this ‘YES’ is conditional. As with almost all cancers, when treating an individual patient with curative intent, one can only entertain the possibility of cure, not its certainty. Despite an ideal status of the patient at the beginning of treatment and despite receiving and completing the best available treatment, all patients still have the risk of developing metastasis in the months/first few years following completion of treatment. Hence, the possibility of cure is expressed in statistical terms in cancer care.

It means that if a hundred patients with particular cancer undergo complete treatment, a certain percentage of these will get cured of their disease. It is impossible to say with certainty who among these hundred patients belong to this group. That is something we get to be relatively sure about, only after around five years from the completion of treatment. In localized osteosarcoma (with no detectable metastasis), with proper and complete treatment, the five-year survival rate is approx.. 65 to 70%.

Even in metastatic osteosarcoma (limited metastasis to the lungs), the five-year survival rate is approx. around 25%. So, even with osteosarcoma spread to the lungs, one out of four such patients may get potentially cured. In Ewing’s sarcoma, the five-year survival in those with localized disease is approx. 80%, and in those with metastatic disease (limited spread), the five-year survival rate is approx. a little above 35%. Conventional chondrosarcoma comes in different grades, and the survival differs between these types. However, averaging across the various stages of conventional chondrosarcoma, five-year survival for localized disease is almost 90%, and with the metastatic disease, it is approx. 20%.

Conclusion:

With proper treatment, a cure is certainly possible in primary bone cancer. One can improve the likelihood of survival with early detection and diagnosis of the condition, lowering the risk of developing metastasis. If you have any further queries, you can book an appointment to consult with our experts.