Application of Radiotherapy In The Treatment Of Cancer

Application of Radiotherapy

Disclaimer: Notes recorded by Debby Blettner

By Dr Barry Cassidy 1999

This next lecture was from Dr. Barry Cassidy, a speaker from the Radiotherapy Institute who will discuss the application of Radiotherapy in the treatment of cancer.

Radiology and Chemotherapy work together, Radiation Oncology.

There are a few methods used:

1) Ionizing radiation

2) Teletherapy – external beam therapy. The machine rotates. Linear excellerators are used to give high energy x-rays, it spares the skin, and uses electrons.

3) Brachytherapy – short range needles, wires, etc. or intravenous, no long term results have been recorded. (In 1999)

4) Palliative Radiotherapy is used for symptom relief for bone pain, bronchial obstruction, bleeding, head and neck diseases.

• Tumors in the lung seem to respond to chemotherapy, but are not necessarily cured.

• There are new ways to minimize the bad effects from breast cancer, using new techniques.

• Wire implants are used for primary treatment, either implant or beam.

• Lymphoma is sensitive to radiation and responds rapidly.

• It is a team effort with the Oncologist.

• Chemoradiation is used as a primary treatment for the neck and head.

• Adjuvant therapy can be used for the breast, if cancer is in early stages, the smaller the tumor, the more curative the treatment.

• Receptor state: 1-4 scale, a tumor 2cm or less = 1^st grade.

(Check with your Oncologist for explanation)

• NB: Dr Cassidy said that it must be treated at this stage as it can develop into the tumors shown on the slides he projected to the audience.

• Early side effects of radiation treatment are nausea, skin reactions, hair loss, diarrhea, bone marrow depression.

• Late side effects – the lens of the eye is very sensitive, and it could develop cataracts, renal problems, skin and bones affected.

• Multifraction therapy: many types of radiation in one day.

• Brachy implants: have not studied long term results. (In 1999)

• Cancer cure with organ preservation is best.

• There have been experiments of lumpectomy with tamoxifen.

• Also experiments of lumpectomy with radiation.

• Experiments also with mastectomy.

All cures so far have been experimenting, while waiting for long term results.

• The patient will need to make an elective decision, to take or not to take the treatment.

• Mastectomy can still get cancer cells developing outside of the area removed.

The treatment should never be worse than the disease.

• Question for Radiotherapists from the audience:

• How effective is radiotherapy? (No notes taken here)

Chemotherapy:

• Adjuvant: with breast cancer, there is a high risk for relapse, due to the microscopic nature of the disease, the goal is to eradicate microscopic tumors.

• Curative: this is the intent for tumors, for them to be cured.

• Palliative: treatment is given to slow things down, yet it is not curative.

• Radiotherapy – is x-ray therapy, at a microscopic and chemical level.

• Normal cells are injured as well as cancer cells. The body’s DNA – has 2 strands –the double strand breaks after this treatment.

• There is damage to the cell, and they are unable to replicate, then they die.

• Radiation therapy is 100 years old.

• Breast cancer – secondary cancer – new drugs are available!

• New hormone drugs, tamoxifen has failed sometimes. (In 1999)

• Drugs leave body after 24 hours.

• Effects wear off 6-8 weeks after.

• It is the same with Radiotherapy.

• Carcinoma insitu – very early breast cancer. Some doctor’s wouldn’t even call it cancer as it is not invasive. Some cases of carcinoma insitu can be treated by radiation therapy.

• Beta carotene has been proven to reduce the risk of cancer.

End of Lecture by Dr Barry Cassidy

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