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Management of Cancer
Surgery
►Diagnostic
►Primary Treatment
►Prophylactic
►Palliative
►Reconstructive
Radiation Therapy
Ionising radiation - interrupts cell growth
►May be curative, prophylactic or palliative
Principles
► Ionising radiation breaks the DNA helix, leading to cell death or inability of cell
reproduction
► It also injuries the cell membrane
► It is effective on tissue directly within the path of the radiation beam.
► Body tissues undergoing frequent cell
division are more sensitive
e.g. bone marrow
lymphatic tissue
epithelium of the GI tract
hair cells
gonads
► Less sensitive (radio-resistant) tissues
e.g. muscle
cartilage
connective tissue.
► Tumours that are well oxygenated are also more radio-sensitive
► Certain chemicals can also act as radio-sensitizers
► It aims to minimise the exposure to normal cells to the damaging effect of radiation
►Methods of Delivery
1. External Therapy or Teletherapy
2. Internal Therapy or Brachytherapy
Two Types of Energy Emitted
1. Particles
b. Beta:
- cannot pass through the skin
- is more penetrating than alpha
- radioactive isotopes for internal radiotherapy
2. Gamma Rays: Electromagnetic and X-rays
- Penetrate deeper areas of body
- Most common form for external therapy
What Happens during the Radiation Therapy?
►It ionises constituents of body fluids, leading to the formation of free radicals and irreversible damage to DNA
►Cell may die immediately or may initiate cellular suicide (apoptosis), a genetically programmed cell death
►Cells are most vulnerable to the disruptive effects of radiation during DNA synthesis and mitosis
External Radiation Therapy
► also called “beam radiation”
►The client does not emit the radiation and does not pose a hazard to anyone else
►The higher the energy the deeper the penetration
►Linear accelerators & betatron machines produce higher energy x-rays and deliver their dosage to deeper structures with less damage to the skin and less scatter to body tissues
►Kilovoltage therapy – deliver maximal dose to superficial lesions
►IORT: Intra-operative radiation therapy
- Single dose of high fraction radiation therapy to the exposed tumour bed while the body cavity is open
Internal Radiation
► The radiation source is within the client
► The contact is direct, continuous and for a specific time
► The client emits radiation and pose a hazard to others
►Two Sources
1. Sealed
May be implanted in form of needles, seeds, beads, catheters into body cavities or compartments. May also be inserted orally.
2. Unsealed
administration via the oral and IV route or by instillation into body cavity
Factors Regarding Safety
►Half-life
► Time
► Distance
► Shielding
► Risk: Internal v.s. External Sources
Radiation dosage
►Dosage dependent on sensitivity of target tissues to radiation and on tumour size
►Lethal tumour dosage = eradicate 95% of tumour, yet preserve normal tissue
►Dosage normally delivered over several weeks
Side Effects & Nursing Intervention
Side effects can be localised and systemic
►Skin
- Alopecia, erythema, skin shedding
- keep skin free from foreign substances
- avoid pressure and soap
- educate client to avoid exposing skin to heat, cold and sunlight
►GI tract
- anorexia, nausea, vomiting and diarrhoea
- arrange mealtime so they do not follow and precede therapy
- encourage bland foods
- administer antiemetics
► Bone marrow
- anaemia, leukopenia, thrombocytopenia
- isolate from known infections
- avoid injury
- assess bleeding
- monitor FBC, WBC and platelets
►Systemic effects – fatigue and malaise
Chemotherapy
► Anti-neoplastic or chemotherapeutic agents destroy and inhibit the reproduction of tumour cells
► They also attack and kill normal cells
► The effects are systemic
► May be of cure, control, palliation
Cell Kill and the Cell Cycle
►Each time a tumour is exposed to a chemotherapeutic agent, a percentage of tumour cells (20% to 99%, depending on dosage), is destroyed.
►Repeated doses are necessary over a prolonged period of time to achieve regression of the tumour.
Four Phases of the Cell Cycle
-G 1 - RNA & protein synthesis
-S - DNA synthesis
-G 2 - Pre-mitotic phase, DNA synthesis complete
-Mitosis
Classification of Chemotherapeutic Drugs
► According to the effects to cell cycle phases
1. Cell cycle phase-specific
- specific to certain phases of cell circle
- most in S phase: RNA and DNA synthesis
2. Cell cycle phase-nonspecific
- act independently of the cell cycle phases
- have prolonged effects
►According to chemical groups
1. Anti-metabolites
2. Alkylating agents
3. Plant alkaloids
4. Antitumour antibiotics
5. Steroids and sex hormones
Administration
►Topical, oral, IV,
►Depends on type of agent, dosage, type, location and extent of tumour being treated.
►Often delivered via an implanted vascular access device
Toxicity
► Can be acute or chronic
► GI system
► Haematopoietic System: bone marrow suppression
► Cardiopulmonary System
-Anti-tumour antibiotics cause irreversible cumulative toxicities
-Cardiac ejection fraction and signs of CHF need to be monitored closely
-Pulmonary fibrosis can be a long-term effect of prolonged dosage with certain Agents
► Renal System
-Excretion of toxins and end products of tumour cell lyses
► Integumentary System
- alopecia
- not permanent
► Reproductive System
-Testicular and ovarian function can be affected
-Fertility problems may be temporary or permanent
-Reproductive cells may be damaged during treatment, resulting in chromosomal abnormalities in off-spring
►Neurologic System
-May occur with repeated dosage
-Peripheral neuropathies
-Loss if deep tendon reflexes
-Paralytic ileus
-Usually reversible and disappear after completion
► Systemic
FATIGUE
Affect quality of life
Last for months after treatment.
Reference
►Farrell, M. (2005). Smeltzer & Bare’s textbook of medical-surgical nursing.
►Phipps, W., Monahan, F., Sands, J., Marek, J., & Neighbors, M. (2003). Medical-surgical nursing: Health and illness perspective.
►Relph, D., Pedder R. & DeLacey L. (1989). A textbook for senior biology: life science.
►Silvestri,