Principles of radiotherapy

From Oncology for Medical Students
Ideal oncology curriculum > Principles of radiotherapy

Objective 5.3

At graduation, the student should be able to:

a) describe the principles of radiobiology
b) discuss the principles of radiotherapy: loco-regional treatment with either curative or palliative intent; when administered with curative intent it might be primary therapy or adjuvant to the primary modality
c) describe the salient features of delivering radiation treatment using equipment such as linear accelerators and brachytherapy machines. This should include a general description of treatment simulators, bunkers and the treatment planning departments
d) describe the general features of brachytherapy treatment, including the use of different isotopes placed with a variety of techniques in various anatomic sites, most prominently for ca cervix and ca prostate
e) recognise the clinical indications for radiotherapy
f) evaluate the outcomes of radiotherapy including: efficacy, short and long-term side effects, costs and quality of life
g) recognise the common complications of radiotherapy and understand their management
h) discuss the integration of radiotherapy with other modalities
i) demonstrate an understanding of the access problems associated with radiotherapy and how this may affect patient choice.

Representative questions that suggest the required depth of knowledge

1. List the symptoms that may effectively be palliated by radiotherapy for patients with metastatic malignant diseases.

Essential in answer:

  • Bone pain, and other pains, particularly neuropathic
  • Bleeding from ulcerated tumours
  • Symptoms of brain metastases
  • Symptoms of cord compression
  • Dysphagia
  • Shortness of breath due to compressive lung tumours
  • Haemoptysis
  • Compressive symptoms from tumour masses
  • Haematuria from bladder or prostate tumours

2. In what ways would the delivery of palliative radiotherapy for patients with metastatic disease differ from that of the delivery of radical or curative radiotherapy for patients with more localised cancer?

Essential in answer:

  • Fewer treatments
  • Fewer acute side effects and fewer late side effects
  • Less complex treatments
  • Less demanding of the patient

3. If a surgeon has successfully excised a carcinoma from the breast of a woman and dissected the lymph nodes out of the axilla, is there any place for postoperative radiotherapy to the breast, and if so, for what reason and for what benefit?

Essential in answer:

  • Yes, there is a place for postoperative radiotherapy
  • When high risk of local recurrence eg. large primary tumours, positive axillary lymph nodes, high grade of tumour, positive margin, lymphovascular invasion
  • To reduce local recurrence
  • Possibly to improve survival

4. A man in his early 60s has undergone a resection for a rectal carcinoma and is being recommended to undergo a postoperative course of adjuvant radiotherapy to the pelvis in conjunction with chemotherapy. What information should that patient be given in order to help him make an informed decision before he consents to the therapy proposed?

Essential in answer:

  • Potential benefit in terms of relative reduction and risk of local regional recurrence
  • Acute toxicity of treatment and late toxicity of treatment
  • Logistics of the details of treatment delivery, including planning on a “simulator”, planning beam arrangements and brief daily treatments in a specialist radiotherapy centre on a “linear accelerator” over the course of more than a month
  • Cost to the patient