Name the most commonly employed cancer therapy.

Explanation

### Step-by-Step Solution:

1. **Understanding Cancer Therapy**: Cancer therapy refers to the various methods used to treat cancer, which is characterized by uncontrolled and abnormal cell growth.

2. **Types of Cancer Therapies**:
- **Surgery**: This involves the physical removal of cancerous tissue from the body. While effective, it can be difficult and may not be suitable for all types of cancer.
- **Radiotherapy**: This method uses high-energy rays, such as X-rays, to target and kill cancer cells. It can also involve the use of radioisotopes, like Iodine-131, which emit rays to treat cancer. Radiotherapy is known for having fewer side effects compared to other therapies.
- **Chemotherapy**: This involves the use of drugs that kill cancer cells. However, chemotherapy can have significant side effects, including hair loss.
...