Radiation Oncology

Chemotherapy is used in different ways at different times. These include:

• Before surgery or radiation therapy to shrink tumours. This is called neoadjuvant chemotherapy. Neoadjuvant chemotherapy may help in downstaging the disease, enhancing the patient’s tolerance and response to the surgery or radiation therapy, reducing the recurrence rates and improving the overall survival rates.

• After surgery or radiation therapy to destroy any remaining cancer cells. This is called adjuvant chemotherapy. Adjuvant chemotherapy helps reduce the risk of recurrence and improve the chances of a positive clinical outcome.

• As the only treatment. For example, to treat cancers of the blood or lymphatic system, such as leukaemia and lymphoma.

• For cancer that comes back after treatment, called recurrent cancer.

• For cancer that has spread to other parts of the body, called metastatic cancer.

The goals of chemotherapy depend on the type of cancer and how far it has spread. Sometimes, the goal of treatment is to get rid of all the cancer and keep it from coming back. If this is not possible, you might receive chemotherapy to delay or slow cancer growth.

• Delaying or slowing cancer growth with chemotherapy also helps manage symptoms caused by the cancer. Chemotherapy given with the goal of delaying cancer growth is sometimes called palliative chemotherapy.

In recent times, oncologists are also adopting innovative chemotherapy approaches such as metronomic chemotherapy, wherein chemo drugs are administered in low doses over a long period, this approach is being used for patients who cannot tolerate high dose chemotherapy sessions.

A radiation oncologist may use External beam radiation therapy or brachytherapy to treat cancer. External beam radiation therapy can be generated by a Linear Accelerator (a machine that accelerates electrons to produce x-rays or gamma rays).
Radiation therapy given by radioactive sources that are put inside the patient is called brachytherapy. The radioactive sources are sealed in needles, seeds, wires, or catheters, and implanted directly into or near a tumour on a temporary or permanent basis. Brachytherapy is a common treatment for cancers of prostate, uterus, cervix or breast.
Some cancer patients may be treated with radiation as their primary treatment. In some cases, radiation therapy is given at the same time as chemotherapy.
Chemotherapy used with radiation therapy can improve the local response and reduce metastatic disease. In other cases, radiation therapy is given before (neoadjuvant treatment) or after (adjuvant treatment) surgery.

Preparation for radiation therapy is focused on targeting the radiation dose to the cancer as precisely as possible to minimize side effects and avoid damaging normal cells.

Types of Radiation Oncology
Using a linear accelerator or a high energy x-ray machine, targets the powerful radiation beams on the tumour in the body. This is the standard technology of radiation therapy. Some forms of cancers may however use radiation that can be directed internally to target the tumour more accurately.
The Department of Radiation Oncology at Amor Hospitalss Kukatpally Hyderabad, has specialists who are experts in the following types of radiation therapy:

– External Beam Radiation Therapy:
This therapy procedure uses an external machine, to target the tumour with radiation beams. The subtypes of this includes:
The types of external-beam radiation therapy are:
Three-dimensional conformal radiation therapy (3D-CRT). Detailed 3-dimensional pictures of the cancer are created, typically from computed tomography (CT) or magnetic resonance imaging (MRI) scans. This allows the treatment team to aim the radiation therapy more precisely. It often means that they can safely use higher doses of radiation therapy while reducing damage to healthy tissue. This lowers the risk of side effects. For instance, dry mouth is common after radiation therapy for head and neck cancer. But 3D-CRT can limit the damage to the salivary glands that causes dry mouth. Intensity modulated radiation therapy (IMRT). This is a more complex form of radiation. With IMRT, the intensity of the radiation is varied within each field unlike conventional 3D-CRT, which uses the same intensity throughout each beam. IMRT targets the tumour and avoids healthy tissue better than conventional 3D-CRT.
Volumetric Modulated Arc Therapy (VMAT) uses photons (W-rays) generated by a medical linear accelerator. Very small beams with varying intensities are aimed at a tumour and then rotated 360 degrees around the patient. This results in attacking the target in a complete three-dimensional manner.

Internal Radiation Therapy:
Internal radiation therapy is also called brachytherapy. This type of radiation therapy is when radioactive material is placed into the cancer or surrounding tissue. Implants may be permanent or temporary and may require a hospital stay.

Types of internal radiation therapy include:
Permanent implants. These are tiny steel seeds that contain radioactive material. The capsules are about the size of a grain of rice. They deliver most of the radiation therapy around the implant area. But some radiation may exit the patient’s body. This requires safety measures to protect others from radiation exposure. Over time, the implants lose radioactivity. And the inactive seeds remain in the body.
Temporary internal radiation therapy. This is when radiation therapy is given in one of these ways:
• Needles
• Tubes, called catheters that carry fluid in or out of the body
• Special applicators

What are other radiation therapy options?
Intraoperative radiation therapy (IORT). This treatment delivers radiation therapy to the tumor during surgery using either external-beam or internal radiation therapy. IORT allows surgeons to move away healthy tissue in advance. This treatment is useful when vital organs are close to the tumour. Systemic radiation therapy. Patients swallow or receive an injection of radioactive material that targets cancer cells. The radioactive material leaves the body through saliva, sweat, and urine. These fluids are radioactive and people in close contact with the patient should take the safety measures recommended by the health care team. An example of this is radioactive iodine therapy (RAI; I-131) for thyroid cancer.
Radioimmunotherapy. This is a type of systemic therapy. It uses monoclonal antibodies, which are proteins that are attracted to very specific markers on the outside of cancer cells, to deliver radiation directly to the tumors. Because the treatment uses these special antibodies, there is less effect on surrounding normal tissue. An example is ibritumomab (Zevalin), which is used in the treatment of some lymphomas.
Radiosensitizers and radioprotectors. Researchers are studying radiosensitizers. These are substances that help radiation therapy better destroy tumors. Radioprotectors are substances that protect healthy tissues near the treatment area. Examples of radiosensitizers include fluorouracil (5-FU, Adrucil) and cisplatin (Platinol). Amifostine (Ethyol) is an example of a radioprotector.

There are many reasons someone with or suspected of having cancer may undergo surgery. Surgical oncology may be used to:
• Diagnose cancer (diagnostic surgery or biopsy)
• Remove a tumor or a portion of the cancer (curative or debulking surgery)
• Determine where the cancer is located, whether it has spread and whether it is affecting the functions of other organs (staging surgery)
• Remove body tissue that may become cancerous (preventive surgery)
• Support other types of treatment, such as installing an infusion port (supportive surgery)
• Restore the body’s appearance or function (reconstructive surgery)
• Relieve side effects (palliative surgery)