Any organ of the body can develop cancer. Benign cancers mostly remain confined to the primary site of origin, but malignant cancers can metastasize to other organs too. For example, lung cancer can metastasize to the bone, to form secondary cancer of bone. Such metastasis depends on many factors including the type of cancer, stage of cancer, organ involved, etc.
Bone is among the most common site for metastasis from advanced solid tumors. Mostly, the long bones are affected by such metastases. Vertebral columns that protects the spinal cord is also a major site of metastasis. Up to 10% of all patients with advanced stage of cancer suffer from metastasis to the vertebras, leading to spinal cord compression. It is a difficult symptom to treat as important nerves are exposed to external pressure. Multi-dose radiation therapy to treat spinal cord compression symptom have been conventionally tried. Recently, researchers proposed that a single dose of radiation can be equally effective in treating the condition.
A recently conducted study involved 688 patients with advanced stages of metastatic cancer of the prostrate, lung, gastrointestinal tract, and breast. Researchers randomly divided them into two groups, one to receive single dose of 8 Gy external beam radiation therapy, and the other to receive 20 Gy external beam radiation therapy (split in five doses over five days). The patients were then evaluated for their ambulatory status. Ambulatory status was measured in a four-point scale; from 1 being good i.e., able to walk normally, to 4 being worse i.e., dependent on wheel chair.
The results of the study showed almost equal effect. After eight weeks of treatment, 69.5% of the patients receiving single dose radiotherapy had ambulatory status 1 or 2, compared to 73.3% in the five-dose group. There was no statistically significant difference between both the groups with respect to overall survival. The proportion of patients, who suffered from severe side effects, were almost similar (20.6% v/s 20.4%) in both the groups. Mild side effects were less frequent in the single dose group. Lesser side effects and lesser duration of treatment meant fewer hospital visits.
The lead author of the study Peter Hoskin, an oncologist at the Mount Vernon Cancer Centre in Middlesex, United Kingdom, said that “Our findings establish single-dose radiotherapy as the standard of care for metastatic spinal canal compression, at least for patients with a short life expectancy”. Regarding benefits of long-course radiotherapy he said that “Longer radiation may be more effective for preventing regrowth of metastases in the spine than single-dose radiation. Therefore, a longer course of radiation may still be better for patients with a longer life expectancy, but we need more research to confirm this”.
1. A Single Radiation Treatment Sufficiently Relieves Spinal Cord Compression Symptoms [Internet]. ASCO. 2017 [cited 2017 Jul 11]. Available from: https://www.asco.org/about-asco/press-center/news-releases/single-radiation-treatment-sufficiently-relieves-spinal-cord
2. Metastatic Cancer [Internet]. National Cancer Institute. [cited 2017 Jul 11]. Available from: https://www.cancer.gov/types/metastatic-cancer
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