Wednesday, August 10, 2022

Radiation Therapy According To Cancer Types

Brachytherapy

Brachytherapy

Brachytherapy, also known as internal radiation, is another way to deliver Radiation therapy. Instead of aiming radiation beams from outside the body, a device containing radioactive Seeds or pellets is placed into the breast tissue for a short time in the area where the cancer had been removed (tumour bed).

For certain women who had breast-conserving Surgery (BCS), brachytherapy can be used by itself (instead of radiation to the whole breast) as a form of accelerated partial breast irradiation. Tumour size, location, and other factors may limit who can get brachytherapy.

Types of brachytherapy

  • Intracavitary brachytherapy: This is the most common type of brachytherapy for women with Breast Cancer. A device is put into the space left from BCS and is left there until treatment is complete. There are several different devices available, most of which require surgical training for proper placement. They all go into the breast as a small catheter (tube). The end of the device inside the breast is then expanded like a balloon so that it stays securely in place for the entire treatment. The other end of the catheter sticks out of the breast. For each treatment, one or more sources of radiation (often pellets) are placed down through the tube and into the device for a short time and then removed. Treatments are typically given twice a day for 5 days as an outpatient. After the last treatment, the device is deflated and removed.
  • Interstitial brachytherapy: In this approach, several small, hollow tubes called catheters are inserted into the breast around the area where the cancer was removed and are left in place for several days. Radioactive pellets are inserted into the catheters for short periods of time each day and then removed. This method of brachytherapy has been around longer (and has more evidence to support it), but it is not used as much.

Early studies of intracavitary brachytherapy as the only radiation after BCS have had promising results as far as having at least equal cancer control compared with standard whole breast radiation, but may have more complications including poor cosmetic results. Studies of this treatment are being done and more follow-up is needed.

Possible side effects of intracavitary brachytherapy

As with external beam radiation, intracavitary brachytherapy can have side effects, including:

  • Redness and/or bruising at the treatment site
  • Breast pain
  • Infection
  • Damage to fatty tissue in the breast
  • Weakness and fracture of the ribs in rare cases
  • Fluid collecting in the breast (seroma)

External beam radiation therapy

The most common way to give radiation for these cancers is to carefully focus a beam of radiation from a machine outside the body. This is called external beam radiation therapy or EBRT. To reduce the risk of side effects, doctors carefully figure out the exact dose needed and aim the beam as accurately as they can to hit the tumour.

Before your treatments start, the radiation team will take careful measurements to determine the correct angles for aiming the radiation beams and the proper dose of radiation. Radiation therapy is much like getting an x-ray, but the radiation is stronger. The procedure itself is painless. Each treatment lasts only a few minutes, although the setup time — getting you into place for treatment — takes longer.

Treatments are usually given 5 days a week for 6 to 7 weeks. But sometimes other schedules are used, for instance:

Hyperfractionation refers to giving the total radiation dose in a larger number of doses, for example giving two smaller doses per day instead of one large dose a day.

Accelerated fractionation means giving two or more doses each day so that the radiation treatment is completed faster (3 weeks instead of 6 weeks, for instance).

Hyperfractionation and accelerated fractionation schedules may reduce the risk of cancer coming back in or near the place; it started (called local recurrence) and might help some people live longer. The drawback is that treatments given on these schedules also tend to have more severe side effects.

Radiation is commonly given using techniques that help doctors focus the radiation more precisely, such as such as three-dimensional conformal Radiation therapy (3D-CRT) and intensity modulated Radiation therapy (IMRT). These use the results of imaging tests, like MRI, and special computer programs to precisely map the cancer’s location. Radiation beams are then shaped and aimed at the tumour from several directions, which makes the treatments less likely to damage normal nearby tissues than older ways of giving external beam radiation.