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Nathan Goodyear

Exposure to the environmental estrogen bisphenol A ... [Life Sci. 2003] - PubMed - NCBI - 0 views

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    Bisphenol A causes shift in ER-beta to ER-alpha through increase ER alpha transcription in the testis.  This only looked at ER expression in the testis.
Nathan Goodyear

Ibuprofen alters human testicular physiology to produce a state of compensated hypogona... - 0 views

  • The levels of LH in the ibuprofen group had increased by 23% after 14 d of administration
  • This increase was even more pronounced at 44 d, at 33%
  • We found an 18% decrease (P = 0.056) in the ibuprofen group compared with the placebo group after 14 d (Fig. 1A) and a 23% decrease (P = 0.02) after 44 d (Fig. 1C). Taken together, these in vivo data suggest that ibuprofen induced a state of compensated hypogonadism during the trial, which occurred as early as 14 d and was maintained until the end of the trial at 44 d
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  • We first investigated testosterone production after 24 and 48 h of ibuprofen exposure to assess its effects on Leydig cell steroidogenesis. Inhibition of testosterone levels was significant and dose-dependent (β = −0.405, P = 0.01 at 24 h and β = −0.664, P < 0.0001 at 48 h) (Fig. 2A) and was augmented over time
  • The AMH data show that the hypogonadism affected not only Leydig cells but also Sertoli cells and also occurred as early as 14 d of administration
  • Sertoli cell activity showed that AMH levels decreased significantly with ibuprofen administration, by 9% (P = 0.02) after 14 d (Fig. 1B) and by 7% (P = 0.05) after 44 d compared with the placebo group
  • Examination of the effect of ibuprofen exposure on both the ∆4 and ∆5 steroid pathways (Fig. 2B) showed that it generally inhibited all steroids from pregnenolone down to testosterone and 17β-estradiol; the production of each steroid measured decreased at doses of 10−5–10−4 M. Under control conditions, production of androstenediol and dehydroepiandrosterone (DHEA) was below the limit of detection except in one experiment with DHEA
  • Measuring the mRNA expression of genes involved in steroidogenesis in vitro showed that ibuprofen had a profound inhibitory effect on the expression of these genes (Fig. 3 B–D), consistent with that seen above in our ex vivo organ model. Taken together, these data examining effects on the endocrine cells confirm that ibuprofen-induced changes in the transcriptional machinery were the likely reason for the inhibition of steroidogenesis.
  • Suppression of gene expression concerned the initial conversion of cholesterol to the final testosterone synthesis. Hence, expression of genes involved in cholesterol transport to the Leydig cell mitochondria was impaired
  • A previous study reported androsterone levels decreased by 63% among men receiving 400 mg of ibuprofen every 6 h for 4 wk
  • We next examined the gene expression involved in testicular steroidogenesis ex vivo and found that levels of expression of every gene that we studied except CYP19A1 decreased after exposure for 48 h compared with controls
  • the changes in gene expression indicate that the transcriptional machinery behind the endocrine action of Leydig cells was most likely impaired by ibuprofen exposure.
  • Together, these data show that ibuprofen also directly impairs Sertoli cell function ex vivo by inhibiting transcription
  • ibuprofen use in men led to (i) elevation of LH; (ii) a decreased testosterone/LH ratio and, to a lesser degree, a decreased inhibin B/FSH ratio; and (iii) a reduction in the levels of the Sertoli cell hormone AMH
  • The decrease in the free testosterone/LH ratio resulted primarily from the increased LH levels, revealing that testicular responsiveness to gonadotropins likely declined during the ibuprofen exposure. Our data from the ex vivo experiments support this notion, indicating that the observed elevation in LH resulted from ibuprofen’s direct antiandrogenic action
  • AMH levels were consistently suppressed by ibuprofen both in vivo and ex vivo, indicating that this hormone is uncoupled from gonadotropins in adult men. The ibuprofen suppression of AMH further demonstrated that the analgesic targeted not only the Leydig cells but also the Sertoli cells, a feature encountered not only in the human adult testis but also in the fetal testis
  • ibuprofen displayed broad transcription-repression abilities involving steroidogenesis, peptide hormones, and prostaglandin synthesis
  • a chemical compound, through its effects on the signaling compounds, can result in changes in the testis at gene level, resulting in perturbations at higher physiological levels in the adult human
  • The analgesics acetaminophen/paracetamol and ibuprofen have previously been shown to inhibit the postexercise response in muscles by repressing transcription
  • Previous ex vivo studies on adult testis have indeed pointed to an antiandrogenicity, only on Leydig cells, of phthalates (41), aspirin, indomethacin (42), and bisphenol A (BPA) and its analogs
  • ibuprofen’s effects were not restricted to Leydig and Sertoli cells, as data showed that the expression of genes in peritubular cells was also affected
  • short-term exposure
  • In the clinical setting, compromised Leydig cell function resulting in increased insensitivity to LH is defined as compensated hypogonadism (4), an entity associated with all-cause mortality
  • compensated hypogonadic men present with an increased likelihood of reproductive, cognitive, and physical symptoms
  • an inverse relationship was recently reported between endurance exercise training and male sexual libido
  • AMH concentrations are lower in seminal plasma from patients with azoospermia than from men with normal sperm levels
  • inhibin B is a key clinical marker of reproductive health (32). The function of AMH, also secreted by Sertoli cells, and its regulation through FSH remain unclear in men
  • the striking dual effect of ibuprofen observed here on both Leydig and Sertoli cells makes this NSAID the chemical compound, of all the chemical classes considered, with the broadest endocrine-disturbing properties identified so far in men.
  • after administration of 600 mg of ibuprofen to healthy volunteers
  • 14 d or at the last day of administration at 44 d
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    ibuprofen alters genetic expression that results in decreased Testosterone production.
Nathan Goodyear

Aging and Luteinizing Hormone Effects on Reactive Oxygen Species Production and DNA Dam... - 0 views

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    Interesting rat model finds that stimulation of the leydig cells of the testis by LH induces ROS.  May be one of the mechanisms by which androgen therapy will induce long-term requirement for replacement.
Nathan Goodyear

PLOS ONE: The Gut Microbiota and Developmental Programming of the Testis in Mice - 0 views

  • The intra-testicular level of testosterone in GF mice was found to be significantly lower than in SPF and CBUT mice
  • This study establishes a novel role for the commensal gut microbiota in the regulation of testicular development and function
  • Absence of the normal microbiota influences the formation and the integrity of the BTB as well as the intra-testicular levels of testosterone and serum levels of LH and FSH.
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  • Nutritional, socioeconomic, lifestyle and environmental factors (among others) are involved in the regulation of normal spermatogenesis.
  • he gut microbiota is one such potential source of environmental factors/products that has developed an intimate symbiotic relationship with host's physiology.
  • Manipulation of the gut microbiotia through dietary modification, pre- and probiotics can therefore be beneficial for the host's reproductive health.
  • In the current study, colonizing GF mice with CBUT resulted in an increased sperm production, suggesting that bacterial products, e.g. of fermentation, directly or indirectly, can affect the testis.
  • the absence of gut microbiota influenced testosterone levels
  • A recent study demonstrated that dietary supplementation of the probiotics Lactobacillus reuteri increased and restored testosterone levels in aging mice
  • bacterial metabolites such as butyrate have been shown to increase the levels of LH [43] and FSH
  • This suggests that butyrate most likely regulates testosterone production at the testicular level by stimulation of gene expression in Leydig cells and with little or no effect at the pituitary- hypothalamic levels.
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    gut micro biome effects spermatogenesis, Testosterone production, and the brain-testicle-barrier.
Nathan Goodyear

Functional Importance of 1α,25(OH)2-Vitamin D3 and the Identification of Its ... - 0 views

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    Vitamin D plays role in healthy Testes function.  This signaling occurs through genomic and non-genomic signaling pathways.  Testosterone production is influenced, sperm motility and spermatogenesis is influenced.  
Nathan Goodyear

Testosterone: a metabolic hormone in health and disease - 0 views

  • E2 and the inflammatory adipocytokines tumour necrosis factor α (TNFα) and interleukin 6 (IL6) inhibit hypothalamic production of GNRH and subsequent release of LH and FSH from the pituitary
  • Leptin, an adipose-derived hormone with a well-known role in regulation of body weight and food intake, also induces LH release under normal conditions via stimulation of hypothalamic GNRH neurons
  • In human obesity, whereby adipocytes are producing elevated amounts of leptin, the hypothalamic–pituitary axis becomes leptin resistant
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  • there is evidence from animal studies that leptin resistance, inflammation and oestrogens inhibit neuronal release of kisspeptin
  • Beyond hypothalamic action, leptin also directly inhibits the stimulatory action of gonadotrophins on the Leydig cells of the testis to decrease testosterone production; therefore, elevated leptin levels in obesity may further diminish androgen status
  • Prostate cancer patients with pre-existing T2DM show a further deterioration of insulin resistance and worsening of diabetic control following ADT
  • ADT for the treatment of prostatic carcinoma in some large epidemiological studies has been shown to be associated with an increased risk of developing MetS and T2DM
  • Non-diabetic men undergoing androgen ablation show increased occurrence of new-onset diabetes and demonstrate elevated insulin levels and worsening glycaemic control
  • increasing insulin resistance assessed by glucose tolerence test and hypoglycemic clamp was shown to be associated with a decrease in Leydig cell testosterone secretion in men
  • The response to testosterone replacement of insulin sensitivity is in part dependent on the androgen receptor (AR)
  • Low levels of testosterone have been associated with an atherogenic lipoprotein profile, characterised by high LDL and triglyceride levels
  • a positive correlation between serum testosterone and HDL has been reported in both healthy and diabetic men
  • up to 70% of the body's insulin sensitivity is accounted for by muscle
  • Testosterone deficiency is associated with a decrease in lean body mass
  • relative muscle mass is inversely associated with insulin resistance and pre-diabetes
  • GLUT4 and IRS1 were up-regulated in cultured adipocytes and skeletal muscle cells following testosterone treatment at low dose and short-time incubations
  • local conversion of testosterone to DHT and activation of AR may be important for glucose uptake
  • inverse correlation between testosterone levels and adverse mitochondrial function
  • orchidectomy of male Wistar rats and associated testosterone deficiency induced increased absorption of glucose from the intestine
  • (Kelley & Mandarino 2000). Frederiksen et al. (2012a) recently demonstrated that testosterone may influence components of metabolic flexibility as 6 months of transdermal testosterone treatment in aging men with low–normal bioavailable testosterone levels increased lipid oxidation and decreased glucose oxidation during the fasting state.
  • Decreased lipid oxidation coupled with diet-induced chronic FA elevation is linked to increased accumulation of myocellular lipid, in particular diacylglycerol and/or ceramide in myocytes
  • In the Chang human adult liver cell line, insulin receptor mRNA expression was significantly increased following exposure to testosterone
  • Testosterone deprivation via castration of male rats led to decreased expression of Glut4 in liver tissue, as well as adipose and muscle
  • oestrogen was found to increase the expression of insulin receptors in insulin-resistant HepG2 human liver cell line
  • FFA decrease hepatic insulin binding and extraction, increase hepatic gluconeogenesis and increase hepatic insulin resistance.
  • Only one, albeit large-scale, population-based cross-sectional study reports an association between low serum testosterone concentrations and hepatic steatosis in men (Völzke et al. 2010)
  • This suggests that testosterone may confer some of its beneficial effects on hepatic lipid metabolism via conversion to E2 and subsequent activation of ERα.
  • hypogonadal men exhibiting a reduced lean body mass and an increased fat mass, abdominal or central obesity
  • visceral adipose tissue was inversely correlated with bioavailable testosterone
  • there was no change in visceral fat mass in aged men with low testosterone levels following 6 months of transdermal TRT, yet subcutaneous fat mass was significantly reduced in both the thigh and the abdominal areas when analysed by MRI (Frederiksen et al. 2012b)
  • ADT of prostate cancer patients increased both visceral and subcutaneous abdominal fat in a 12-month prospective observational study (Hamilton et al. 2011)
  • Catecholamines are the major lipolysis regulating hormones in man and regulate adipocyte lipolysis through activation of adenylate cyclase to produce cAMP
  • deficiency of androgen action decreases lipolysis and is primarily responsible for the induction of obesity (Yanase et al. 2008)
  • may be some regional differences in the action of testosterone on subcutaneous and visceral adipose function
  • proinflammatory adipocytokines IL1, IL6 and TNFα are increased in obesity with a downstream effect that stimulates liver production of CRP
  • observational evidence suggests that IL1β, IL6, TNFα and CRP are inversely associated with serum testosterone levels in patients
  • TRT has been reported to significantly reduce these proinflammatory mediators
  • This suggests a role for AR in the metabolic actions of testosterone on fat accumulation and adipose tissue inflammatory response
  • testosterone treatment may have beneficial effects on preventing the pathogenesis of obesity by inhibiting adipogenesis, decreasing triglyceride uptake and storage, increasing lipolysis, influencing lipoprotein content and function and may directly reduce fat mass and increase muscle mass
  • Early interventional studies suggest that TRT in hypogonadal men with T2DM and/or MetS has beneficial effects on lipids, adiposity and parameters of insulin sensitivity and glucose control
  • Evidence that whole-body insulin sensitivity is reduced in testosterone deficiency and increases with testosterone replacement supports a key role of this hormone in glucose and lipid metabolism
  • Impaired insulin sensitivity in these three tissues is characterised by defects in insulin-stimulated glucose transport activity, in particular into skeletal muscle, impaired insulin-mediated inhibition of hepatic glucose production and stimulation of glycogen synthesis in liver, and a reduced ability of insulin to inhibit lipolysis in adipose tissue
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    Great review of the Hypogonadal-obesity-adipocytokine hypothesis.
Nathan Goodyear

Vitamin D is associated with testosterone and hypogonadism in Chinese men: Results from... - 0 views

  • lower 25(OH)D level was significantly associated with lower total T, E2, SHBG, LH and FSH levels after adjusting for age, residence area, economic status and current smoker
  • association between 25(OH)D status and hypogonadism in Chinese men and confirms that this relationship is present in a large population
  • VDR knockout mutant mice showed gonadal insufficiencies
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  • High LH and FSH levels in the male mice indicated hypergonadotropic hypogonadism
  • Another mouse study reported a tendency towards low testosterone/LH ratio and Leydig cell hyperplasia in VDR null mice
  • The serum testosterone levels could increase to normal values in vitamin D-deficient rats replete with vitamin D
  • VDR knockout mice had decreased sperm count, reduced sperm motility, and histological abnormality of the testis
  • vitamin D supplementation increases testosterone levels in non-diabetic subjects
  • The data from the European Male Ageing Study [9] indicated that 25(OH)D is positively associated with total T
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    Study of 713 Chinese men finds a correlation between low vitamin D and low total Testosterone.
Nathan Goodyear

Gut Endotoxin Leading to a Decline IN Gonadal function (GELDING) - a novel theory for t... - 0 views

  • GELDING theory (Gut Endotoxin Leading to a Decline IN Gonadal function)
  • trans-mucosal passage of bacterial lipopolysaccharide (LPS) from the gut lumen into the circulation is a key inflammatory trigger underlying male hypogonadism
  • Obesity and a high fat/high calorie diet are both reported to result in changes to gut bacteria and intestinal wall permeability, leading to the passage of bacterial endotoxin (lipopolysaccharide- LPS) from within the gut lumen into the circulation (metabolic endotoxaemia), where it initiates systemic inflammation.
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  • Endotoxin is known to reduce testosterone production by the testis, both by direct inhibition of Leydig cell steroidogenic pathways and indirectly by reducing pituitary LH drive, thereby also leading to a decline in sperm production.
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    Ever heard of the GELDING theory?  This involves the link between LPS endotoxin from the gut and low Testosterone in obese men.
Nathan Goodyear

Leptin and Androgens in Male Obesity: Evidence for Leptin Contribution to Reduced Andro... - 1 views

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    increased leptin production results in reduced testosterone production.  Link between leptin associated obesity and resultant low testosterone.
Nathan Goodyear

Bisphenol A may cause testosterone reduction by adversely affecting both testis and pit... - 0 views

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    Bisphenol-A inhibits testosterone production through direct inhibition of the pituitary and the leydig cells.  This is similar to the way E2 acts on the the pituitary and the leydig cells.  
Nathan Goodyear

Phthalate-Induced Pathology in the Foetal Testi... [Reproduction. 2013] - PubMed - NCBI - 0 views

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    This study found a 2 fold increased in estradiol levels in rats exposed to phthalates in-utero.  This could have been due to increased aromatase activity and/or xenoestrogenic effect.  This study proposes a link between phthalate exposure in-uteruo, increased estrogen production and testicular dysgenesis syndrome.  Take home: in this model male testicles were altered prior to birth by phthalate exposure.
Nathan Goodyear

PLOS ONE: Probiotic Microbes Sustain Youthful Serum Testosterone Levels and Testicular ... - 0 views

  • Studies in both humans and rodents, however, suggest that low testosterone is due to age-related lesions in testes rather than irregular luteinizing hormone metabolism
  • Various dietary factors and diet-induced obesity have been shown to increase the risk for late onset male hypogonadism and low testosterone production in both humans and mice
  • Testosterone deficiency and metabolic diseases such as obesity appear to inter-digitate in complex cause-and-effect relationships
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  • dietary supplementation of aged mice with the probiotic bacterium Lactobacillus reuteri makes them appear to be younger than their matched untreated sibling mice
  • These results indicate that gut microbiota induce modulation of local gastrointestinal immunity resulting in systemic effects on the immune system which activate metabolic pathways that restore tissue homeostasis and overall health
  • all these studies we consistently observed that young and aged mice consuming purified L. reuteri organisms had particularly large testes and a dominant male behavior.
  • The testes of probiotic-fed aged mice were rescued from both seminiferous tubule atrophy and interstitial Leydig cell area reduction typical of the normal aging process. Preservation of testicular architecture despite advanced age or high-fat diet coincided with remarkably high levels of circulating testosterone. The beneficial effects of probiotic consumption were recapitulated by the depletion of the pro-inflammatory cytokine Il-17.
  • feeding of L. reuteri consistently increased the gonadal weights, consumption of a non-pathogenic strain of Escherichia coli (E. coli) K12 organisms did not affect testicular weight
  • mice with dietary L. reuteri supplements were rescued from diet-induced obesity and had normal body weight and lean physique
  • Despite the comparable numbers of ST profiles, we determined that testes from L. reuteri-treated mice had increased ST cross-sectioned profiles
  • the probiotic organism induced prominent Leydig cell accumulations in the interstitial tissue between the ST's
  • The probiotic-associated increase of interstitial Leydig cell areas was sustained with advancing age at 7 (CD vs CD+LR, P = 0.0025; CD+E.coli vs CD+LR, P = 0.0251) and 12 months
  • mice eating L. reuteri had profoundly increased levels of circulating testosterone regardless of the type of diet they consumed
  • blocking pro-inflammatory Il-17 signaling entirely recapitulates the beneficial effects of probiotics
  • previous studies we found that dietary probiotics counteract obesity [19] and age-related integumentary pathology [18] at least in part by down-regulating systemic pro-inflammatory IL-17A-dependent signaling
  • Testes histomorphometry and serum androgen concentration data were both suggestive of a probiotic-associated up-regulation of spermatogenesis in mice
  • Lactobacillus reuteri we discovered that aging male animals had larger testes compared to their age-matched controls
  • xamined testes of probiotic microbe-fed mice and found that they had less testicular atrophy coinciding with higher levels of circulating testosterone compared to their age-matched controls
  • Similar testicular health benefits were produced using systemic depletion of the pro-inflammatory cytokine Il-17 alone, implicating a chronic inflammatory pathway in hypogonadism
  • One specific aspect of this paradigm is reciprocal activities of pro-inflammatory Th-17 and anti-inflammatory Treg cells
  • Feeding of L. reuteri organisms was previously shown to up-regulate IL-10 levels and reduce levels of IL-17 [19] serving to lower systemic inflammation
  • insufficient levels of IL-10 may increase the risk for autoimmunity, obesity, and other inflammatory disease syndromes
  • Westernized diets are also low in vitamin D, a nutrient that when present normally works together with IL-10 to protect against inflammatory disorders
  • Physiological feedback loops apparently exist between microbes, host hormones, and immunity
  • The hormone testosterone has been shown to act directly through androgen receptors on CD4+ cells to increase IL-10 expression
  • studies in both humans and rodents suggest that hypogonadism is due to age-related lesions in testes rather than irregular LH metabolism
  • We postulate that probiotic gut microbes function symbiotically with their mammalian hosts to impart immune homeostasis to maintain systemic and testicular health [34]–[35] despite suboptimal dietary conditions.
  • Dietary factors and diet-induced obesity were previously shown to increase risk for age-associated male hypogonadism, reduced spermatogenesis, and low testosterone production in both humans and mice [2]–[4], [8]–[11], [14]–[17], phenotypic features that in this study were inhibited by oral probiotic therapy absent milk sugars, extra protein, or vitamin D supplied in yogurt.
  • Similar beneficial effects of probiotic microbes on testosterone levels and sperm indices were reported in male mice that had been simultaneously supplemented with selenium
  • L. reuteri-associated prevention of age- and diet-related testicular atrophy correlates with increased numbers and size of Leydig cells
  • the initial changes of testicular atrophy begin to occur in mice from the age of 6 moths onwards [7] and indicates that the trophic effect of L. reuteri on Leydig cells is a key event which precedes and prevents age-related changes in the testes of mice. This effect is reminiscent of earlier studies describing Leydig cell hyperplasia and/or hypertrophy in the mouse and the rat testis that were achievable by the administration of gonadotropins, including human chorionic gonadotropin, FSH and LH
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    Fascinating study on how the addition of Lactobacillus reuteri increased Testicular size, prevented testicular atrophy, increased serum Testosterone production and protected against diet-induced/obesity-induced hypogonadism.  This was a mouse model
Nathan Goodyear

Leptin inhibits testosterone secretion from adult rat testis in vitro. - PubMed - NCBI - 0 views

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    high leptin levels found to inhibit pituitary LH/FSH release.  Of note, high leptin levels inhibited leydig cell production of Testosterone following hCG stimulation.  This is a rat in vitro study.
Nathan Goodyear

The Contribution of Cytotoxic Chemotherapy to 5-year Survival in Adult Malignancies | C... - 0 views

  • In this group, the 5-year survivalrateduesolelytocytotoxicchemotherapywas14%
  • There is also no convincing evidence that usingregimens with newer and more expensive drugs are anymore beneficial than the regimens used in the 1970s
  • two systematic reviews of chemotherapy inrecurrent or metastatic breast cancer have not been able toshow any survival benefit
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  • The five most common adult malignancies (colorectal, breast, prostate, melanoma and lung cancer)
  • n breast cancer, the optimal regimen(s) for cytotoxicchemotherapy in recurrent/metastatic disease are still notdefined, despite over 30 years of ‘research’ and a plethora of RCTs since the original Cooper regimen was published in1969
  • The five most ‘chemo-sensitive’ cancers,namely testis, Hodgkin’s disease and non-Hodgkin’s lym- phoma, cervix and ovary
  • only 13 out of the 22 malignancies evaluated showed any improvement in 5-year survival, and theimprovement was greater than 10% in only three of those13 malignancies
  • the contribution of curative and adjuvant cytotoxic chemotherapy to 5-year survival in adults is 2.3% in Australia and 2.1% in the USA
  • a benefit of less than 2.5% is likely to be applicable in other developed countries
  •   Overview The Contribution o
  • the benefit of cytotoxic chemotherapy may have been overestimated for cancers of oesophagus, stomach,rectum and brain.
  • this reflects the presentation of results as a ‘reduction in risk’ rather than asan absolute survival benefit[89,90]and by exaggerating theresponse rates by including ‘stable disease’
  • recent studies have documented impaired cognitive function inwomen receiving adjuvant treatment for breast cancer
  • the 5-year survival rate due solely to cytotoxicchemotherapy was 1.6%
  • the value of palliative chemotherapy has beenquestioned
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    Incredibly low impact of cytotoxic chemotherapy despite its wide spread utilization.  This article referenced cost yet did not evaluate the cost of cytotoxic side effect.  The question to answer: is Cytotoxic chemotherapy a valid treatment, at all, for the majority of cancers.
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