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CHEMOTHERAPY
Dr.M.TorfehnezhadPediatrician
Definition:
Chemotherapy• The treatment of cancer using specific
chemical agents or drugs that are destructive to malignant cells and tissues. The term comes from two words that mean "chemical" and "treatment."
Cytotoxic• literally translated means ‘toxic to cells’.
The Cell Cycle
The Cell Cycle
Mitosis
Cell Biology: Mitosis
A cell in mitosis
Normal Cell Characteristics:
Metabolism. Strictly controlled & predictable
Maturation & Specialisation. Occurrs before dividing. Strictly controlled.
Reproduction = Cell deathContact Inhibition. Mechanism for
switching off division when in contact with different cells
Recognition. Like cells stay together.
Cancer Cell Characteristics:
Unchecked & Uncontrolled GrowthLoss of contact inhibitionLoss of capacity to differentiateIncreased growth fractionChromosomal InstabilityCapacity to metastasiseAltered biochemical properties
Chemotherapy and Cancer Cells
Cell Cycle specific :Most active against cells in a specificphase therefore need prolonged exposureor repeated doses.
Cell Cycle Non-specific:Most effective against actively dividingcells
Chemotherapy
Chemotherapy may be used conventionally to:
Cure patientsProlong survivalPalliative care symptom control
Chemotherapy
Combination Therapy. Prevents resistance.Adjuvant Therapy. Administered after primary therapye.g.SurgeryNeo adjuvant Therapy: Given before surgery to reducetumour size.
Chemotherapy
Over 50 different chemotherapy drugsAdministered as an outpatient or inpatientdepending on toxicity
Modes of administration include: Oral e.g. Methotrexate, Hydroxyurea IV: Canula/Indwelling Central Venous Catheter Sub cut Intracavity e.g pelvic cavity, bladder Intrathecal. Can be fatal if wrong drug
administered!
Intrathecal Chemotherapy
Drugs Used in Cancer Chemotherapy
Cytotoxic AgentsAlkylating AgentsAntimetabolitesCytotoxic antibioticsPlant derivatives
HormonesSuppress nat’l hormone secr’n or
antagonize hormone actionMisc (mostly target oncogene products)
Rand 50.3
Alkylating Agents
Contain chemical groups that bind cell nucleophiles
Alkylating Agents
Cisplatin (Platinol), Mechlorethamine (Mustargen) and Cytoxan are commonly used agents in this category
Carboplatin- more myelotoxicAction: substitutes an alkyl chemical
structure for a hydrogen atom in the DNAThis results in a cross-linking of each
strand of DNA, thus preventing cell division
Alkylating Agents, con’t
Effective against lymphomas, leukemias, myelomas, ovarian, testicular, breast, and pancreatic cancers
Cause bone marrow suppression, alteration in mucous membranes, severe N&V, alopecia
Alkylating Agents, con’t
Can also cause ototoxicity and nephrotoxicity. Be sure the patient is well hydrated before receiving these agents
Cyclophosphamide
Most commonProdrug – liver metab by CYP P450
MFO’sEffects lymphocytes
Also immunosuppressantOral or IV usuallySE’s: n/v, bone marrow dpression, Cytoxan can cause hemorrhagic cystitis
(give MESNA to protect the bladder)
Antimetabolites
These drugs have a structure similar to a necessary building block for the formation of DNA.
These drugs are accepted by the cell as the necessary ingredient for cell growth, but because it is an imposter, it interferes with the production of DNA.
Antimetabolites
Kill cells in S phaseThree main groups
Folate antagonistsPyr analogsPur analogs
Folic Acid Analogs
Folic acid essential for synth purines, and thymidylate
Methotrexate
Higher affinity for enz than does FH2 Inhib’n DNA synth
Pyrimidine Analogs
5-Fluorouracil Competitive inhibitor for thymidylate
synthetase active siteDecr’d DNA synthesis
Gemcitabine
Inhib’s ribonucleotide reductase decr’d nucleotide synth
Cytosine arabinoside (cytarabine) Inhibits DNA polymerase
Gemcitabine – araC analogFewer SE’s
Purine Analogs6-Mercaptopurine, 6-Thioguanine
Inhibit enz’s necessary for purine synthFludarabine
Converted to triphosphateMech action sim to ara-C
Pentostatin Inhibits adenosine deaminase
Catalyzes adenosine inosine Interferes w/ purinemetab, cell prolif’n
Antibiotic Antineoplastic Agents
These agents actually bind DNA, thus inhibiting DNA and RNA synthesis and therefore inhibiting cell growth.
Sadly, these drugs have great potential to cause irreversible cardiomyopathies.
Doxorubicin (Adriamycin) is used for acute leukemias, soft tissue/bone cancers, lymphomas, and breast cancer
Antibiotic Agents, con’t
Adriamycin is also a potent vessicant (will cause tissue necrosis if it infiltrates)
Most dangerous side effect is decreased ejection fraction (normal is 70%). Must do baseline CV assessment prior to beginning Adriamycin (EKG, echo, angiography).
Must reduce the dose of chemo at the first sign of heart failure
Antibiotic agents, con’t
Other side effects include stomatitis, alopecia, bone marrow suppression, hepatic impairment.
Antibiotic agents, con’t
Dactinomycin Interferes w/ RNA polymerase movement decr’d transcr’n
BleomycinGlycopeptideChelates Fe, which interacts w/ O2 Gen’n superoxide and/or hydroxyl radicalsRadicals degrade DNA fragmentation, release of free
basesMost effective in G2, also active against cells in G0Little myelosuppression BUT pulmonary fibrosis
Mitotic Inhibitors
These drugs are also called Vinca-Alkaloids
Work by inhibiting mitosis during cell division
Vinblastine (Velban) and Vincristine (Oncovin) are commonly used agents for ALL, lymphomas, rhabdomyosarcoma)
Mitotic Inhibitors, con’t
Neurotoxicity is a specific side effect for this classification of drugs. Peripheral neuropathy, alteration in bowel and bladder tone (including paralytic ileus), headache, tingling of fingers/hands/toes, ataxia.
Constipation is common due to effects on the autonomic nervous system
Vinca Alkaloids
Etoposide, teniposideFrom mandrake root Inhibit mitoch function, nucleoside
transport, topoisomerase IICampothecins: irinotecan, topotecan
Irinotecan requires hydrolysis active form
Bind, inhibit topoisomerase II
Hormonal Agents
Used to treat neoplasms that are sensitive to hormonal growth controls of the body.
They interfere with growth-stimulating receptors on target tissues.
Corticosteroids are considered hormonal agents. They retard lymphocytic proliferation, so they help with lymphocytic leukemias and lymphomas.
Hormonal Agents, con’t
Corticosteroids also decrease edema associated with tumor growth, especially in or around the brain, spinal cord, and mediastinum. Will decrease cerebral edema.
Androgens (testosterone) may be used to treat advanced breast cancer
Hormonal Agents, con’t
Anti-Estrogen drugs (Tamoxifen) block the uptake of estrogen and therefore are good for tumors that contain high concentrations of estrogen receptors
Estrogen may be used to treat androgen-sensitive cancers, such as prostate cancer
Progestins (Depo-Provera and Megace) are used to treat endometrial cancer
Chemotherapy Side Effects
Chemotherapy targets cells which are dividing rapidly.
Chemotherapy cannot distinguish between normal cells and cancer cells
Healthy Cells which have a high rate of growth and multiplication include cells of the bone marrow, hair, GI mucosa and skin.
Side effects greatest in other rapidly-dividing cellsBone marrow toxicity Impaired wound healingHair follicle damage Gi epith damage Growth in childrenGametesFetus
May themselves be carcinogenic
Chemotherapy Side effects contd…
Side effects may be drug specific e.g. anthracyclines and cardiotoxicity, vinca alkaloids and neuropathy/constipation, bleomycin and pulmonary fibrosis
Severity of side effects varies between drugs.
Side effects often occur 7-14 days post treatment.
Side Effects: Acute
Tumour Lysis Syndrome. A Metabolic Emergency.Occurrs due to rapid cell lysis (death) &
large amounts of cell metabolites in blood.
If untreated can lead to acute renal failure, cardiac arrest and death.
Side Effects: Acute
Neutropenic Sepsis:Occurs due to Bone Marrow Failure andpoor immune response to infection. Predisposing factors include:NeutropeniaUnderlying diseaseChemotherapyVenous access devices
Neutropenic Sepsis
Severe overwhelming infection where inadequate blood flow to the tissues results in cellular dysfunction and, if not reversed, eventual organ failure.
Most common micro organism is gram negative
Mortality rate 40-90%
Side Effects: Acute
Haemorrhage• Invading tumours e.g gastric MALT
lymphomas• Haemorrhagic Cystitis related to high
dose Cyclophosphomide
Anaphylactic Reaction
Side Effects:Bone Marrow
Neutropenia:
Increased risk of infection.
Anaemia:
Tiredness, lethargy & breathlessness
Thrombocytopenia:
Increased risk of bleeding
Side Effects: Gastro-Intestinal
Nausea & VomitingDiarrhoea & constipationLoss of appetiteTaste ChangesMucositis
Side Effects
Example of Grade 4 Mucositis
Side Effects: Body Image
Hair LossWeight Loss/ Weight GainLong term central venous cathetersSkin changes (colour, rashes, sensitivity
to sunshine, dry)
Side Effects: Other
Fatigue: Often multi-factorialPeripheral neuropathyAltered Kidney FunctionChanges in hearing (high dose Cisplatin)Cardiac Toxicity (Doxorubicin/
Idarubicin)Late Effects: Infertility, secondary
malignancy, growth retardation.
Key Points:
Chemotherapy is a major treatment in curing or prolonging survival in cancer patients
It has a wide range of side effects depending on the drugs given.
Nurses have a key role to play in caring for a patient receiving chemotherapy
Safety issues are paramount in administration.
Summary:
The potential benefit to the patient of treatment as an option must
always outweigh the toxic effects.
Thank You
NCCN2012 Recommendations by Risk Category
High (>90% emetic risk)High (>90% emetic risk)
Including AC containing regimensIncluding AC containing regimens
Three-drug combination of a HTThree-drug combination of a HT33
serotonin receptor antagonist, serotonin receptor antagonist, (palonosetron preferred-NCCN) (palonosetron preferred-NCCN) dexamethasone, and aprepitantdexamethasone, and aprepitant
Moderate (>30% to 90% emetic Moderate (>30% to 90% emetic risk)risk)
Two-drug combination of a HTTwo-drug combination of a HT33
serotonin receptor antagonist and serotonin receptor antagonist and dexamethasone (+/-aprepitant for dexamethasone (+/-aprepitant for selected patients)selected patients)
Low (10% to 30% emetic risk)Low (10% to 30% emetic risk) Dexamethasone 8-12 mgDexamethasone 8-12 mg
Minimal (<10% emetic riskMinimal (<10% emetic risk No antiemetic routinelyNo antiemetic routinely
Thank YouThank You
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