The Full Scoop on Impending Radiation Treatment

Today I saw the radiation oncologist to get the full scoop on my impending course of radiation treatment. I've explained why I need the radiation, as well as what will be used and potential side effects, below.I was initially diagnosed with the most common subtype of Hodgkins Lymphoma, namely Nodular sclerotic, which accounts for 50-70% of cases. I was diagnosed at stage II (see "Ann Arbor" Staging Classification system above - click on the graph to make it bigger). Stage II is often characterised by a mediastinal mass (which is when a tumor forms in the area that separates the lungs).

Treatment for lymphomas at stage I usually involves radiation; for stage II and above, a combination of chemotherapy and radiation is used. Radiation therapy, with x rays or other high-energy rays, also is used when the disease involves a bulky mass, where chemotherapy drugs cannot reach all of the cancer.

I will be receiving the most advanced form of radiation treatment, available only since the late 1990's, called Intensity-Modulated Radiation Therapy (IMRT). Computer-controlled x-ray accelerators distribute precise radiation doses to malignant tumors or specific areas within the tumor. The pattern of radiation delivery is determined using highly-tailored computing applications to perform optimization (mathematics) and treatment simulation (treatment planning). The radiation dose is consistent with the 3-D shape of the tumor by controlling, or modulating, the radiation beam’s intensity. IMRT also improves the ability to conform the treatment volume to concave tumor shapes, for example when the tumor is wrapped around a vulnerable structure such as the spinal cord or a major organ. The radiation dose intensity is elevated near the gross tumor volume while radiation among the neighboring normal tissue is decreased or avoided completely. Because of this, IMRT allows for higher radiation doses to be delivered to the tumor while sparing healthy tissue as compared with conventional radiation therapy techniques. This in turn results in better tumor targeting, less side effects, and improved treatment outcomes.

The main reason for giving radiation treatment after chemotherapy is that even though the chemotherapy has caused tumor shrinkage, microscopic tumor cells can be left behind as the tumor shrinks, which could potentially grown into new tumors.

There are short term (during treatment) and long term (persisting after treatment) side effects from radiation treatment. For the radiation treatment I will be receiving, in the necessary areas (meaning the area of the size of the ORIGINAL TUMOR, plus a small additional area around this) the short term effects are:

• fatigue
• loss of appetite
• skin redness where the beams hit (front and back of chest)
• dry, sore throat and difficulty swallowing and eating

The long term effects which will almost certainly happen include:

• loss of lung tissue that is unavoidably hit by radiation (approximately 8% total volume, which in most people results in very little noticeable changes in functioning)
• risk of development of secondary cancers (while radiation is a potential cause of cancer, secondary malignancies are seen in a very small minority of patients; in the vast majority of cases, this risk is greatly outweighed by the reduction in risk conferred by treating the primary cancer).
  

In my case, given where the beams will be targeted, there is an increased risk of my later developing breast cancer or thyroid cancer; however, the risk is relatively small and these types of cancer develop 10-15 years after treatment. There is also about a 1 in 300 chance of my developing radiation pneumonitis, an uncommon type of lung inflammation, about 6 months after radiation treatment; again, it is a relatively small risk.

My last chemo treatment is 10th September. The treatment planning session for the radiation treatment is 17th September, with radiation scheduled to begin on 1st October. I'll have 20 treatments all up, in other words, 5 days a week for 4 weeks. Each radiation treatment lasts approximately 2-3 minutes.