cancer chemotherapy

at en Dr. Patnam Mahender Reddy Institute of Medical Sciences
22 de Nov de 2012
cancer chemotherapy
cancer chemotherapy
cancer chemotherapy
cancer chemotherapy
cancer chemotherapy
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cancer chemotherapy
cancer chemotherapy
cancer chemotherapy
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cancer chemotherapy
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cancer chemotherapy

Notas del editor

  1. Cancer is a disease in which there is uncontrolled multiplication and spread within the body of abnormal forms of bodys own cells. It is one of the major causes of death in developed nations atleast 1 in 5 of the population of europe and north america can expect to die of cancer. Cancers are more common in aged people as life expectancy is increasing the incidence of cancers is also increasing, with the present methods of treatment one third of the patients are cured with local modalities of treatment (surgery or irradiation therapy) which are quite effective when the tumor has not metastatized. In metastasis systemic chemotherpy is required along with surgery or irradiation at present 50 % of the patients of cancer can be treated with chemotherapy contributing to cure in 10 -15% of the patients. The terms cancer,malignant neoplasm and malignant tumor are synonymous
  2. Treatment of systemic infections /malignancy with specific drugs that have selective toxicity for infecting organisms /malignant cell with no or minimal effects on host cells
  3. Hence target selectivity is more difficult in cancer*(exception in lymphoma , there is substantial selectivity)
  4. Chemotherapy is essentially required with surgery or irradiation when metastasis has occurred
  5. Shrinkage of tumor , alleviation of symptoms
  6. Other factors – promoters cocarcinogen, hormones, -- likely hood of mutation
  7. Aimed at destroying all the malignant cells, leaving none (lack of participation of host defence/immune response)order kinetics i.e given dose of a drug destroys constant fraction of cells. Term log kill is used to describe this phenomenon e.g leukemia diagnosis made when load of cells is >109 consequently if t/t leads leads to kill 99.99% of the cells then 0.001% i.e 104 cells remain this is equivalent to 5 log kill i.e 100000 fold. At this point patient appears asymptomatic i.e patient is in remission. For most bacterial infections a 5 log fold reduction in no of micro-organisms leads to cure . Since immune system can eradicate remaining bacterial cells. However cancer cells are not so easily destroyed Pharmacological sancturies: leukemia or other tumor cells find sanctury in tissues like CNS in which some chemotherapeutic agents can not enter, because of its transport constraints so pt may require irradiation of cerebrospinal axis or intrathecal administration of drugs at that site Cells of solid tumors can be considered as belonging to 3 compartments Compartment A: Consists of dividing cells, possibly being continously in cell cycle Compartment B: consists of resting cell in Go phase , the cells though not dividing are potentially able to do so Compartment C: cells no longer able to divide but contribute to tumor volume Essentially only cells in compartment A which may form as little as 5 % of some solid tumors are currently susceptible to main available cytotoxic drugs. Log kill: destruction of cancer cells by chemotherapeutic agents follows first
  8. Overcrowding of cells: poor blood supply and nutrition and defective access of drugs
  9. Heterogenecity of cells –
  10. Majority of cytotoxic drugs have more profound effects on rapidly multiplying cells
  11. Sulfur mustard in 1917 was first used alkylating agent in WW-1, it was used as chemical warfare and caused severe skin vesication, vesication in mucous membrane , GI ulcerations and myelosupression. The pharmacological actions became evident only after world war 2.
  12. All alkylating agents have alkyl groups and they can transfer this alkyl group to suitable receptor site. Alkylating agents in neutral or alkaline solution form highly reactive carbonium ion which is quaternary ammonium derivative(The carbon atom has only six electrons in its outer space so highly reactive). This carbonium ion is highly reactive and can react with groups like NH2, SH, OH or PO4 in physiologically important molecules in cell and render them unavailable for normal metabolic reactions. One more property of this carbonium ion is its nucleophilicity it can react with nucleic acid bases and inhibit DNA synthesis . The nitogen at guanine position 7 is especially more susceptible. So this results in cross linking inhibits DNA replication . Abnormal base pairing (alkylated guanine pairs with thymine instead of cytosine) results in production of defective protein DNA strands breakage – decreased cell proliferation Alkylation also damages RNA and proteins Non cycle specific
  13. Alkylation of guanine bases in DNA MOA OF MECHLORETHAMINE
  14. Common to the alkylating agents Cytotoxic action in general damage nuclei of growing multiplying cells, hemopoetic system highly susceptible to this action leads to anemia, thrombocytopenia, leukopenia and in toxic doses bonemarrow supression., Net result similar mode of action may differ chlorambucil more effective against lymphoid series and busulfan more effective against myeloid series. These drugs also effect epithelial tissues like cornea, intestinal mucosa leading to desquamation and ulcers Hair follicles- alopecia’sprematogenesis, foetopathy sand ammenorrhoeaImmunosupressant action : supress antibody production Miscellaneous: nausea, vomitingRadiomimetic drugs: actions resemble that of biological or ionizing radiations, all alkylating agents different radiomimetic action.
  15. First nitrogen mustard to be used in cancer chemotherapy Very irritant drug: vesicant for skin, eyes, resp tract , should be given only IV , Special care sloughing can occur with extravasation Available as 10 mg HCL with 90 mg NACL should be reconstituted in 10 ml NS or distilled water and given immediately because it becomes active in few minutes Hodkins stage III and stage IV as a part of MOPP mechlor, oncovin (Vincristine), procarbazine, prednisoloneChronic myelogenous leukemia, chronic lymphoblastic leulemia Because of serious toxicity use replaced by less toxic drugs carmustineEstramustine: stable combination of estrogen & mustine designed to deliver mustine to estrogen receptor site of tumor like prostrate cancerAdvantage: both cytostatic and hormonal effect
  16. Also used in advanced ovarian tumor, otherwise toxic effects and properties similar to mechlorethamine
  17. Pharmacological actions similar to mechlorethamine Prodrug converted in body to active
  18. Hemorrhagic cystitis is specific toxicity of cyclophosphamide it is associated with dysuria, hematuria due to irritation of bladder mucosa by acrolein it is dose limiting toxicity. Mesna is also excreted in urine where it binds to and inactivates acrolein Should be given simultaneously and also 4-8 hrs after Acetyl cysteine can also be given Adequate hydration IV mesna (2 mercapto ethane sulfonate )
  19. Wegeners granulomatosis
  20. Less damaging to the platelets can also cause transverse ridging of nails, increased pigmentation Leucocyte count serves as guide to dosage adjustment in prolonged therapy neutrophil count = 500 to 1000cells /mm3 desired target
  21. 1g vial+3 mesna ampoules 200mg for IV Bronchogenic, Breast, Testicular, Bladder , Head & Neck Carcinomas, Osteogenic Sarcoma& some lymphomas
  22. Also used in hodkins and other solid tumors
  23. Unique in that in conventional doses of busulfan exert few pharmacological actions other than myelosupression Other use- polycythemia vera Pigmentation of skin
  24. Streptozocin indicated for T/t of islet cell carcinoma of pancreas 500mg/m2 for 5 days or 1000 mg/m2 weekly
  25. Acquired resistance to one alkylating agent often but not always imparts cross resistance to others Guanine –o-alkyl transferase
  26. Heavy metal complex has water soluble planar coordination complex containing central platinium atom surrounded by 2 cl and 2 nh3
  27. Nephrotoxicity can be reduced by hydration of patients and diuresis by litres of normal saline and mannitol, Hyperuricaemia can occur Neuropathy : large sensory fibres – numbness, tinglingfollowed by loss of joint position and disabling sensory ataxia Ototoxicity : tinnitus and hearing loss in high frequency range , more pronounce in children Rarely shock mutagenic, teratogenic , carcinogenic adverse events reversible on stoppage
  28. Excreted by kidneys t1/2 4to 6 hrs Oxaliplatin : less myelosupression but more paresthesia
  29. Chemical substance which takes part in cellular metabolic reactions is called metabolite Antimetabolite is a chemical substance which by virtue of its close structural resemblence to metabolite blocks its action it can achieve this by 2 methods By preventing the combination of metabolite with its specific enzyme By itself combining with specific enzyme and getting converted to either metabolically inactive or harmful to cell ( lethal synthesis)
  30. One of most commonly used anticancer agents Cell cycle specific drug acts in S phase Methotrexate has antineoplastic, immunosuoressant and anti-inflammatory action It produced the first striking although temporary remission of leukemia and first cure for choriocarcinoma Mechanism of action of methotrexate: methotrexate structurally resembles folic acid , it competitively inhibits dihydrofolate reductase enzyme and blocks conversion of DHFA to THFA THFA is an essential coenzyme required for one carbon transfer reactions in denovo purine synthesis and synthesis of thymidilate , amino acid conversions which are required for DNA SYNTHESIS it also inhibits RNA and protein synthesis. More toxic to rapidly dividing cells likw bone marrow
  31. Inhibit erythropoeisis, myelopoesis, and finally aplasia --- marked granulocytopenia , reticulocytopenia
  32. Calcium folinate or calcium levofolinate Thymidine also counteracts methotrexate toxicity
  33. Choriocarcinoma and tropoblast tumor in women xureRHEUMATOID ARTHRITIS :5-7.5MG PER WEEK ORALLY FOR 8 WEEKSPSORIASIS2.5-5MG AT 12HRLY INTERVALS WEEKLYAlso used in mycosis fungoides , Some role in AML and non hodgkins lymphoma MTP: 25 TO 50 MG ORAL THEN 3-7 DAYS LATER misoprostol 800 microgram vaginally in early part of forst trimester < 8 weeks of gestation
  34. 1. Nucleotide formation: To exert its antileukemic effect, 6-MP must penetrate target cells and be converted to the nucleotide analog, 6-thioinosinic acid TIMP. The addition of the ribose phosphate is catalyzed by enzyme, hypoxanthine-guanine phosphoribosyl transferase (HGPRT).2. Inhibition of purine synthesis: A number of metabolic processes involving purine biosynthesis and interconversions are affected by, TIMP. Like adenosine monophosphate (AMP), guanosine monophosphate (GMP), and inosine monophosphate (IMP), TIMP can inhibit the first step of de novo purine-ring biosynthesis (catalyzed by glutamine phosphoribosyl pyrophosphate amidotransferase) by feed back mechanism. TIMP also blocks the formation of AMP and xanthinuric acid from inosinic acid.3. Incorporation into nucleic acids: TIMP is converted to thioguanine monophosphate (TGMP), which after phosphorylation to di- and triphosphates can be incorporated into RNA. The deoxyribonucleotide analogs that are also formed are incorporated into DNA. This results in nonfunctional RNA and DNA.
  35. Well absorbed orally, metabolized rapidly by xanthine oxidase, use of xanthine oxidase inhibitor allopurinol decreases the inactivation of 6 MP, xanthine oxidase also required in uric acid synthesis, so allopurinol may be used in cancer chemotherapy to reduce dose of 6 MP and also decrease the hyperuricaemia 6 MP ALSO METABOLISED BY METHYLATION IN PRESENCE OF ENZYME THIOPURINE METHYL TRANSFERASE, GENTIC DEFICIENCY OF THIS ENZYME MAKES INDIVIDUAL MORE SUSCEPTIBLE TO 6 MP toxicity , while over expression is important method of resistance. Azathiprine is also substrate for xanthine oxidase but 6 thiguanine is not.
  36. Hyperuricaemia occurs due to massive destruction of cells of lymphoid series , urine should be maintained alkaline and its volume adequate. Other purine analogs like 6 thioguanine and azathiprine also posses cytotoxic actions how ever they do not have any advantage over 6 mercaptopurine as antileukemic agentsMercaptopurine with azathiprine decrease the dose by ¼ to ½ Azathiprine: ImuranUsed as immunosupressive agent in organ transplantation and autoimmune conditons like hemolytic anemia, glomerulonephritis, and rhe umatoid arthritis
  37. Promotes tumor apoptosis
  38. Extremely effective in complete remission of hairy cell leukemia iv 4 g/m2 alternate week , sufficient hydration 500 ml to 1 l of dextrose in 0.45 % saline
  39. 5 fluoro uracil is converted in body to corresponding nucleotide fluorodeoxyuridine monophosphate, Fluorinated analog of pyrimidine acts by inhibiting thymidilate synthesis Also gets incorporated into DNA in place of uracil Uses: topically intreatment of premalignant keratosis Even resting cells are more affected though rapidly multipling cells are more susceptible Toxic to bone marrow , alimentary epitheliumand CNS Administered by slow IV infusion to prevent first pass metabolism.
  40. ESPECIALLY IN ADULTS Uses : AML, Hodgkins & Non hodgkinsGemcitabineForms triphosphate that inhibits DNA synthesis Blocks DNA strand elongation Drug of choice in adenocarcinoma of pancreas 1000 mg/m2 over 30 min
  41. VX and VBL are both cell-cycle specific and phase specific, because they block mitosis in metaphase (M phase). Their binding to the microtubular protein, tubulin, is GTP dependent and blocks the ability of tubulin to polymerize to form microtubules. Instead, paracrystalline aggregates consisting of tubulindimers and the alkaloid drug are formed. The resulting dysfunctional spindle apparatus, frozen in metaphase, prevents chromosomal segregation and cell proliferationResistance: Resistant cells have been shown to have an enhanced efflux of VX, VBL, and VRB via P-glycoprotein in the cell membrane. Alterations in tubulin structure may also affect binding of the vinca alkaloids.
  42. AFE: Unpredictable oral absorption, extensively conc in platelets, vinca alkaloids are not well absorbed by oral routeHighly irritant drugs so given continously by iv infusion, vinca alkaloids are conc and metabolized by CYP450 in liuver excreted in bile in liver dysfunction decrease the dosePhenytoin, phenobarbitone, carbamezepine may induce the metabolism and griseofulvin inhibits metabolism Vinorelbine: semisynthetic derivative for ca breast, testicular cancer, epithelial ovarian cancers.
  43. Taxanes bind to beta tubulin subunits of microtubules at a site different from binding site of vinca alkaloids,colchicine, podophyllotoxin, unlike vinca alkaloids they promote polymerization of microtubules & inhibit depolymerization, leading to stabilization of polymerized microtubules and arrests cells in mitosis and eventually leads to activation of apoptosisThe stabilization of microtubules is damaging to cells because of disturbances in in the dynamics of various microtubule dependent structures that are required for functions like mitosis, maintainence of cellular morphology, locomotion and secretion.
  44. Dexamethasone, h1 antagonists supress the reaction Abraxane: Albumin bound form of paclitaxel no anaphylactoid reaction
  45. Type I topoisomerase cuts one strand of a DNA double helix, relaxation occurs, and then the cut strand is reannealed.Type II topoisomerase cuts both strands of one DNA double helix, passes another unbroken DNA helix through it, and then reanneals the cut strand.Testicular tumors in combination with bleomycin or cisplatinTenoposide used in ALL
  46. Topoisomerase I modulates supercoiling of DNA by complexing with it and nicking one of its strands
  47. Intercalation in the DNA: The drugs insert nonspecifically between adjacent base pairs and bind to the sugar-phosphate backbone of DNA. This causes local uncoiling and, thus, blocks DNA and RNA synthesis. Intercalation can interfere with the topoisomeraseII–catalyzed breakage/reunion reaction of supercoiled DNA strands, causing irreparable breaks.Generation of oxygen radicals: Cytochrome P450 reductase (present in cell nuclear membranes) catalyzes reduction of the anthracyclines to semiquinone free radicals. These in turn reduce molecular O2, producing superoxide ions and hydrogen peroxide, which mediate single-strand scission of DNA (Figure 39.18). Tissues with ample superoxide dismutase or glutathione peroxidase activity are protected.10 Tumors and heart tissue are generally low in SOD. In addition, cardiac tissue lacks catalase and, thus, cannot effectively scavenge hydrogen peroxide. Lipid peroxidation therefore may explain the cardiotoxicity of anthracyclines.
  48. Mechanism of action: The drug intercalates into the minor groove of the double helix between guanine-cytosine base pairs of DNA,8 forming a stable dactinomycin-DNA complex. The complex interferes primarily with DNA-dependent RNA polymerase, although at high doses, dactinomycin also hinders DNA synthesis. The drug also causes single-strand breaks, possibly due to action on topoisomerase II or by generation of free radicals.Adverse effects: The major dose-limiting toxicity is bone marrow depression. The drug is immunosuppressive. Other adverse reactions include nausea, vomiting, diarrhea, stomatitis, and alopecia. Extravasation during injection produces serious problems. Dactinomycin sensitizes to radiation, and inflammation at sites of prior radiation therapy may occur.
  49. Acute: ecg changes, arrhythmia, hypotension, delayed CCF Tissues with ample superoxide dismutase or glutathione peroxidase activity are protected.10 Tumors and heart tissue are generally low in SOD. In addition, cardiac tissue lacks catalase and, thus, cannot effectively scavenge hydrogen peroxide. Lipid peroxidation therefore may explain the cardiotoxicity of anthracyclines.
  50. Mixture of closely related glycopeptide antibiotics
  51. CLINICAL RESPONSE TO L-ASPARGINASE IS DISAPPOINTING, THOUGH REMISSIONINDUCED IN ACUTE LEUKEMIA IS SHORT LASTING , IT IS NOW USED WHWN OTHER DRUGS HAVE FAILED , INEFFECTIVE IN SOLID TUMORS
  52. Blocks enzyme Less GI toxicity
  53. Methyl hydrazine derivative, inactive as such but undergoes metabolic activation to highly reactive alkylating species which cause methylation of DNA
  54. Emit b and gamma radiations disrupt cellular metabolism and cause cellular destruction.
  55. Prevent anemia: prevent acceletatederythrocytic destruction, They effectively counter hemolytic and hemorrhagic complications accompanying chronic lymphocytic and malignant lymphomas, Prednisolone is generally started in doses of 60 – 100 mg daily in divided doses and then depending on response reduced to maintenance dose of 20 -40 mg /day The use of this compound in the treatment of lymphomas arose when it was observed that patients with Cushing's syndrome, which is associated with hypersecretion of cortisol, have lymphocytopenia and decreased lymphoid mass. [Note: At high doses, cortisol is also lymphocytolytic and leads to hyperuricemia due to the breakdown of lymphocytes.] Prednisone is primarily employed to induce remission in patients with acute lymphocytic leukemia and in the treatment of both Hodgkin's and non-Hodgkin's lymphomas.Glucocorticoids have some secondary role in hormone responsive breast cancers, they are also valuable for treatment of complications like treatment of hypercalcemia, hemolytic anemias, thrombocytopenia, incresed intracranial tension, mediastinal edema occuring after radiotherapy, they afford symptomatic relief by mood elevating and antipyretic effects and also adjuvants of antiemetics. Useful in treating cerebral edemas due to intracranial cerebral metastasis
  56. Fosfesterol is activated to slibesterol in prostatic tissue and acheives high conc in prostatic tissue thus it is used in prostrate cancerAdverse effects – impotence and gynaecomastia
  57. SERMS are non steroidal synthetic agents whose agonist or antagonist action on estrogen receptors are tissue selective, produces beneficial estrogenic actions in some tissues (bone, brain, liver), and prevent certain deleterious effect in breast and endometrium by exhibiting antagonistic or no action on ER Tamoxifen: Non steroidal antiestrogen related structuraly to slilbesterol, given orally it competes with the circulating estrogen for cytoplasmic estrogen receptor binding site, the metabolites of tamoxifen have much stronger affinity for receptors and are not easily displaced by circulating estradiol. At low concentration they have cytostatic effect on ER positive cells, higher conc cause cytotoxic effect . Because of antagonistic action in breast DOC in treatment of ca breast in ER+ AS WELL as some ER- breast cancer also male breast
  58. Well absorbed orally, biphasic half life 10 hrs and also 7 days, and long duration ofaction some metabolites of tamoxifen are more potent antiestrogens, the drug is excreted primarily in bile. Other SERMS- raloxifene – no risk of endometrial carcinoma, used as first line drug in treatment of postmenopausal osteoporosis, toremifene – new congener of tamoxifen with similar actions uses and adverse effects ORMELOXIFENE – dub, acts as antagonist in breast and uterus
  59. USES: Metastatic ER+ Breast Ca in postmenopausal women which has stopped responding to tamoxifenHigher affinity for ER probably accounts for efficacy in tamoxifen resistant cases
  60. Aromatization of A ring of testesterone and androstenedione is final and key step in production of estrogensestradiol and estrone in body, in addition to circulating hormone the locally produced hormone may play an important role in breast cancer development, exemestane also aromatase inhibitor