Prognosis and Survival for Bone Cancer Patient
Prognosis: Prognosis is the prior knowledge of the outcome of a disease. It is a study which helps health professionals to determine how a disease is likely to behave, with or without treatment. Prognostic scoring is used for cancer outcome predictions. A prognosis is the doctor’s best estimate of how cancer will affect a person, and how it will respond to treatment. A prognostic factor is a clinical or biologic characteristic that is objectively measurable and that provides information on the likely outcome of the cancer disease in an untreated individual.
A prognostic factor is an aspect of the cancer or a characteristic of the person that the doctor will consider when making a prognosis. A Manchester score is an indicator of prognosis for small-cell lung cancer. For Non-Hodgkin lymphoma, physicians have developed the International Prognostic Index to predict patient outcome.
A predictive factor influences how a cancer will respond to a certain treatment. Prognostic and predictive factors are often discussed together and they both play a part in deciding on a treatment plan and a prognosis.
The following are prognostic and predictive factors for bone cancer.
a) Extent of the tumour: The extent of the tumour is the most important prognostic factor for bone cancer. Metastases are associated with a poorer prognosis. However, the location of metastases is also important in determining prognosis.
b) Lung metastases have a more favourable prognosis than metastases to other distant sites, such as the brain and other bones.
c) Metastases to the lymph nodes or bone marrow are a less favourable prognostic factor.
d) Size of the tumour: Smaller tumours have a more favourable prognosis than larger tumours.
e) Grade of the tumour: Low-grade tumours are associated with a more favourable prognosis than high-grade tumours.
f) Location of the tumour: Tumours that occur in bones farther away from the centre of the body, such as the limbs (distal tumours), have a more favourable prognosis than tumours that occur close to the central part of the body (proximal tumours), such as the skull, vertebrae, sternum, ribs and pelvis.
Response to Chemotherapy
Chemotherapy is often given before surgery. After surgery, the tumour is examined to see how many cells were killed by chemotherapy (necrosis).
In people with Ewing sarcoma, response to chemotherapy can often be assessed by an MRI before surgery to see how much the tumour has shrunk. People with at least 90% necrosis in the primary tumour after chemotherapy have a more favourable prognosis than those with less necrosis.
Tumours that are completely removed, with no cancer cells in the margins around the tumour, have a much more favourable prognosis.
Age is a significant prognostic factor for osteosarcoma and Ewing sarcoma. Younger people may have a more favourable prognosis. Patients under the age of 40 have better survival chances.
Prognosis depends on many factors, including:
- a person’s medical history
- type of cancer
- stage and grade
- characteristics of the cancer
- treatments chosen
- response to treatment
- The results can facilitate clinical decision-making, for example, by providing the information necessary to select appropriate treatment.
- A more accurate prediction of disease outcomes facilitates patient education and counselling
- Prognostic studies may also allow subgroups of patients to be defined who are at particular risk of specific disease outcomes, leading to improved study designs and analysis of clinical trials through risk stratification.
- There is considerable variation in the quality of prognostic studies.
- The results may not be true in each individual’s case.