Topics 8-10: Surgery, Radiotherapy, and Systemic Therapy in Cancer Treatment Flashcards
What advantage do anti-cancer drugs usually have over surgical or radiotherapy?
Anti-cancer drugs act systemically, thus can reach distant metastases. Surgery and radiotherapy are more local, but in some cases can be used on distant metastases.
However, drug therapies are more rarely curative than surgery or radiotherapy
- Surgical Cancer Treatment
What are the 3 potential purposes of surgical oncology?
- Prophylactic / preventative surgical interventions (before malignancy, e.g. polyp removal, preventative mastectomy)
- Diagnostic surgical interventions
- Therapeutic surgical interventions
- Surgical Cancer Treatment
What are the 4 surgical tumor diagnostic methods?
- aspiration cytology
- core needle biopsy
- incisional biopsy
- excisional biopsy
- Surgical Cancer Treatment
What is the difference between incisional and excisional biopsy?
Incisional takes a small sample from a macroscopically-visible tumor
Excisional attempts to remove the entire primary tumor with a single operation, which means it can potentially be curative as well as used in the histological diagnosis
- Surgical Cancer Treatment
What are the two main types of therapeutic surgery?
(same division applies for radiotherapy and chemotherapy)
- curative (completely remove tumor)
2. palliative (mitigate a life-threatening condition, or temporarily improve patient’s quality of life)
- Surgical Cancer Treatment
What is the technical difference between resectability and operability?
- Resectability: refers to the tumor; is the tumor technically capable of being removed?
- Operability: refers to the patient; is the patient capable of undergoing surgery safely?
- Radiotherapy for Cancer
What is the theory behind / purpose of radiotherapy?
To selectively destroy dividing tumors using ionizing radiation, while protecting healthy tissues as much as possible
- Radiotherapy for Cancer
About what percentage of patients require radiotherapy at least once during the course of the disease?
60%
- Radiotherapy for Cancer
What are the two main modalities of radiotherapy?
- external beam radiotherapy (teletherapy)
2. internal radiotherapy (brachytherapy)
- Radiotherapy for Cancer
What are the 4 types of brachytherapy?
- interstitial brachytherapy
- intracavitary brachytherapy
- intraluminal brachytherapy
- superficial (“moulage” brachytherapy
- Radiotherapy for Cancer
What are low, medium, and high dose rates used in brachytherapy, as measured in Grays?
Low: 0-2 Gy/hour
Medium: 2-12 Gy/hour
High: >12 Gy/hour
Often brachytherapy is delivered in “pulsed dose-rates” - short spikes of high doses
- Radiotherapy for Cancer
Biophysics review: What are Grays?
Joule/kg of energy absorbed by an irradiated sample of matter.
Grays are the unit used to measure absorbed dose
- Radiotherapy for Cancer
When considering radiotherapy based on the time of surgical treatment, what are the three types of radiotherapy?
- preoperative
- postoperative
- definitive (primary) radiotherapy: don’t get surgery, hoping that radiotherapy is enough to cure the patient
- Radiotherapy for Cancer
Palliative radiotherapy:
- 2 examples to mitigate a life-threatening situation?
- 2 examples to improve quality of life?
- Mitigate life-threatening situation: reduce size of tumor for SVC syndrome, transverse spinal cord lesion
- Quality of life: painful bone metastases, ensuring that esophagus or trachea are not compressed / wide enough to be comfortable
- Radiotherapy for Cancer
What is radiotherapy called if it is administered at the same time as chemotherapy?
Simultaneous or concomitant radiochemotherapy
Similarly, can have radiobiotherapy or radioimmunotherapy
- Radiotherapy for Cancer
When radiotherapy is curative, about what total radiation (in Gy) is typically required?
High doses, 60-80 Gy
Very high doses are more likely to be performed at a nuclear medicine center instead of radiotherapy (at least in Hungary)
- Systemic Cancer Treatment
What are the 4 major options for systemic drug cancer treatment?
- Chemotherapy
- Hormonal therapy
- Targeted anticancer therapy (biological therapy)
- Immunotherapy
- Systemic Cancer Treatment
- What is chemotherapy?
- How is it delivered?
- What are some typical side effects?
- Chemotherapy = delivering toxic chemicals to cells (cytotoxic agents or cytostatics), which preferentially harms rapidly-dividing cells
- Delivered usually IV or orally, sometimes intra-arterially
- SE: either general (nausea, vomiting, diarrhea, poor blood count, poor mood, poor appetite), local (oral mucositis, hair loss) - similar to “carpet bombing”
- Systemic Cancer Treatment
What are 2 examples where hormone therapy might be useful? (being very general)
- Hormone-sensitive breast cancer: use estrogen and/or progesterone blockers to prevent growth (e.g. Tamoxifen)
- Prostate cancer: using anti-androgens (e.g. Bicalutamide)
- Systemic Cancer Treatment
What are the 2 main types of targeted therapy / biologics?
- Small molecules, e.g. imatinib (a tyrosine kinase inhibitory usually used for CML)
- Monoclonal antibodies, e.g. trastuzumab (targets Her2 for breast cancer)
Generally have much milder side effects than chemotherapy
- Systemic Cancer Treatment
What is the goal of immunotherapy?
Immunotherapy attempts to get the body’s own immune system to begin to target the cancer more effectively
- Systemic Cancer Treatment
What are some very general ways that tumors weaken the natural immune system response, so that the tumor can continue to exist?
- Decreasing tumor antigen expression
- Decreasing antigen presentation
- Secreting immunosuppressive cytokines
- Inhibiting T cells
- Systemic Cancer Treatment
What are 3 general ways that immunotherapy is carried out?
- Antibody therapy: e.g. Rituximab (anti-CD20, can target neoplastic B cells but won’t fully kill the cell without the body’s own immune response like ADCC). Checkpoint inhibitors fit here too.
- Cytokine therapy: e.g. interleukin-2 (for melanoma) or interferon alpha (for some leukemias, melanoma) - upregulate immune system
- Cellular immunotherapy: taking own immune cells and in vitro training them to recognize the cancer, then re-introducing them back into the body
Note all 3 of these topics are basically summary topics for later ones that go into more specific details.. not much else is in the e-book from these chapters
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