The formation of malignant (cancerous) cells in the tissues of the pancreas causes pancreatic cancer. The exocrine cells in the pancreas produce the digestive juices, while endocrine pancreas cells produce the hormones. Pancreatic cancer majorly starts in the exocrine cells.
How radiotherapy works on pancreatic cancer:
Radiation therapy can be used to treat exocrine pancreatic cancers. The procedure involves usage of high energy X-rays to destroy cancer cells. This helps in slowing down and controlling the growth of cancerous cells, hence it is a treatment option if one is suffering from locally advanced pancreatic cancer. In the case of advanced pancreatic cancer stages like in stage III or stage IV, radiotherapy is used to help control pain and other such symptoms.
Types of radiotherapy for pancreatic cancer
Image guided radiotherapy (IGRT):
Image guided radiotherapy (IGRT) is usually used to treat pancreatic cancer. Images are taken before and during treatment to help make sure treatment is as accurate as possible.
3D conformal radiotherapy:
3D conformal radiotherapy involves shaping the radiation beam to the cancer. The aim is to treat the cancerous cells with a higher dose, and reduce the dose to normal cells.
Intensity modulated radiotherapy (IMRT):
IMRT projects the radiation beam very closely to the cancer. A minimum of 5 radiation beams are arranged at different angles so that the tumor receives major amount of radiation.
Volumetric modulated arc radiotherapy (VMAT) or rapidarc:
Volumetric modulated arc radiotherapy (VMAT) is a type of IMRT. The radiation is focused on the cancer and the treatment period is reduced. It generally involves a single beam of radiation. The machine used for treatment moves around the patient in a circle. This helps in reducing the amount of radiation to the surrounding organs.
Chemoradiotherapy:
Chemotherapy given concurrently with radiation therapy is called chemoradiation. If the person is suffering with borderline resectable pancreatic cancer, chemoradiotherapy can be used to diagnose and increase the chances of eliminating the cancer cells.
Stereotactic ablative radiotherapy (SABR):
This is a newer type of radiotherapy used for treating pancreatic cancer. This procedure involves delivering high dose of radiotherapy. Since the dose is higher, fewer sessions are required for this treatment. This treatment might seem comfortable and easier because of the less number of sessions, but has a lot more side effects than the other types of radiation therapies because of the higher intensity of radiation.
Side effects of radiation therapy:
Side effects of radiotherapy in treating pancreatic cancer could be:
Skin peeling and blistering in the radiated areas (rare)
- Nausea
- Vomiting
- Diarrhea
- Fatigue
- Loss of appetite and weight loss
- Makes the patient prone to infections
- Variation in the blood cell count
Dosage and Survival rate:
Survival rate after radiation therapy in the treatment of pancreatic cancer is low. The tumours of the pancreas have a very low resistance towards radiation therapy. They can just be tackled by targeting the tumours and help reduce their size. A recent study in 2017 has shown that patients who received a dose lesser than 45 Gy had a survival rate of 13 months, and those who received a radiation of 45-50 Gy had a survival rate of 21 months. The patients who received the highest radiation, that is, above 55 had a survival rate of 28 months. Hence, higher dose of radiation increases the effectiveness of the treatment.