Osteosarcoma

Osteosarcoma is a primary cancer of bone. It is an extremely rare disease as it affects 1 in 2 lac people per year. It is most common in the age group of 15 to so years and the commonest location is lower end of femur bone or upper end of tibia, i.e, the bone just above or below the knee joint. However, it can affect any bone and any age group of patient.

Exact cause of osteosarcoma is unknown. However, it has been linked to genetic mutations, some pre-existing lesions in bone and also radiotherapy. In majority, the exact cause cannot be reached.

It is diagnosed with the help of Xray, MRI and a needle biopsy – histopathology.

Once diagnosed, its staging is done. Staging means, to find out whether it has spread to any other part of body or not? For that, typically a CT scan of chest and a bone scan is done. However, with advent and availability of PET CT scans, even that can be done.

Following are the stages of osteosarcoma in simple terms.

Stage 1: Low grade osteosarcoma (i.e. the cancer is not very aggressive)

Stage 2: High grade osteosarcoma (i.e. the cancer is very aggressive) but has not spread within the same bone (skip lesion) or to any other part of the body

Stage 3: High grade osteosarcoma which has spread within the same bone (skip lesion) but hasn’t spread to other organs or nearby lymphnodes

Stage 4: Osteosarcoma which has spread to nearby lymphnodes or to distant organs like lung, liver brain or other bones

The treatment of osteosarcoma consists of chemotherapy and surgery. Duration of the treatment is approximately 6 to 9 months.

Patients are treated in staged manner, i.e. chemotherapy followed by surgery followed by further chemotherapy.

The treatment starts with chemotherapy which goes on for about 2and ½ month in cyclical manner. Once 3 or 4 cycles of chemotherapy are concluded, surgery is undertaken. About 3 decades ago, only surgery offered to the patient of osteosarcoma was amputation, i.e. removing the whole leg. In today’s era, a specialized type of “limb salvage surgery” is offered to the patient, i.e. the tumor is removed but the limb id saved. With this type of surgery, patient remains near normal and functional.

After surgery, patent receives further chemotherapy according to the standard protocol.

It depends on the stage of presentation. After optimum treatment, following are the chances of cure from osteosarcoma

1	Stage 2	90%
2	Stage 2	65%
3	Stage 3	10 – 15%
4	Stage 4	< 2 %

Once the treatment is over, patient needs to follow up on regular bases irrespective of any problems for next 10 years. It is only then, that the patient is declared free of cancer!

1	For first 2 years	3 monthly
2	For next 3 years	6 monthly
3	For next 5 years	1 yearly