Dr. Bhooshan Zade is a post graduate in Radiation Oncology from the prestigious Tata Memorial Hospital, Mumbai.
A radiation oncologist is a medical doctor who has special training in management of patients with cancer, in particular involving the use of radiotherapy, as one area of their cancer treatment.
They also have expertise in the treatment of noncancerous conditions using radiotherapy. Radiation oncologists are responsible for monitoring the patient and organising imaging and other tests, in order to create and action a management plan for a patient.
Radiation oncologists work closely with other medical specialists, especially surgeons, medical oncologists and palliative care physicians, as part of a team caring for patients with cancer. Radiation oncologists also work closely with radiation oncology medical physicists and radiation therapists to plan and deliver radiotherapy.
Radiation oncologists have an important role in communicating with patients,their family members and other carers in the management of the patient's cancer and overall care.
Radiotherapy is a process in which high-energy ionizing radiation is focused at the tumor in order to kill the cancerous cells. Almost half of all people with cancer have radiotherapy included within their treatment plan. Radiotherapy can be classified into two distinct categories
External beam Radiotherapy (EBRT)- The radiation is delivered from an external source in this procedure, usually a machine called a linear accelerator, which focuses high energy X-rays onto the tumor site
Internal radiotherapy- A small piece of radioactive material is placed temporarily inside the body near the tumor during this procedure, known as brachytherapy. Or a radioactive liquid may be used, which could be swallowed or injected into the body
Radiotherapy may be administered for curative purposes, involving the elimination of the tumor, preventing recurrence, or both. It may also be administered for palliative purposes, which do not intend to eliminate the tumor, but relieve the symptoms that may be experienced as a consequence of cancer. Some examples of palliative radiotherapy involve-
Radiation given to the brain to shrink tumors formed because of metastasis
Radiation given to diminish a tumor growing within a bone or pressing the spine, which may cause pain
Radiation therapy works by damaging the DNA of cells. The damage is caused by a photon, electron, proton, neutron, or ion beam directly or indirectly ionizing the atoms which make up the DNA chain. Indirect ionization happens as a result of the ionization of water, forming free radicals, notably hydroxyl radicals, which then damage the DNA.
In the most common forms of radiation therapy, most of the radiation effect is through free radicals. Because cells have mechanisms for repairing DNA damage, breaking the DNA on both strands proves to be the most significant technique in modifying cell characteristics. Because cancer cells generally are undifferentiated and stem cell-like, they reproduce more, and have a diminished ability to repair sub-lethal damage compared to most healthy differentiated cells. The DNA damage is inherited through cell division, accumulating damage to the cancer cells, causing them to die or reproduce more slowly. One of the major limitations of radiotherapy is that the cells of solid tumors become deficient in oxygen. Solid tumors can outgrow their blood supply, causing a low-oxygen state known as hypoxia. Oxygen is a potent radiosensitizer, increasing the effectiveness of a given dose of radiation by forming DNA-damaging free radicals. Tumor cells in a hypoxic environment may be as much as 2 to 3 times more resistant to radiation damage than those in a normal oxygen environment.