Analgesic abuse, renal parenchymal disease and carcinoma of the kidney or ureter

Primary Ureteral Stump Carcinoma: Rare Presentation and Management

Primary ureteral stump carcinoma is a rare occurrence in patients who receive radical nephrectomy for renal cell carcinoma (RCC). Only 11 previous cases have been reported in the literature. We report a case of synchronous bilateral RCC and colon adenocarcinoma with the subsequent development of primary ureteral stump carcinoma that was treated with robotic ureterectomy and bladder cuff excision. To our knowledge, this is the first reported case of this presentation.

Oncology in nephrology comes of age: A focus on chronic dialysis patients

Dialysis is the commonest modality of renal replacement therapy for patients suffering from end-stage kidney disease. Different registry studies showed that the risks of overall cancer occurrence were significantly higher in chronic dialysis patients than in the age-matched general population. However, the frequency and pattern of different cancers may vary among different geographical areas. Since chronic dialysis patients tend to have multiple comorbidities and a shorter life expectancy, routine cancer screening in all dialysis patients may not be cost-effective; rather screening should be personalized according to the patient's expected survival, candidacy for kidney transplant together with patient preferences.

Chronic kidney disease and cancer: a troubling connection

Chronic kidney disease (CKD) and cancer are connected in a number of ways in both directions: cancer can cause CKD either directly or indirectly through the adverse effects of therapies; CKD may, conversely, be a risk factor for cancer; and both may be associated because they share common risk factors, often toxins. In this review, we briefly address the issue of paraneoplastic nephropathies as well as that of toxin-related cancers and CKD, including analgesic and aristolochic acid nephropathies. We then focus on the links between the various stages of CKD and cancer incidence, and critically examine major epidemiologic surveys in the field. Compared with the general population, kidney transplant recipients have a threefold to fourfold increase in overall cancer risk, and relative risks higher than 3 for about 20 specific tumors, most, but not all, of which are known or suspected to be caused by viral agents. After dialysis, cancer risk increases 10% to 80% according to studies, with relative risks significantly higher than in the general population, for about 10 cancer sites. There is emerging evidence for an excess risk of cancer in patients in early CKD stages.

Transitional cell carcinomas of the renal pelvis and the ureter: comparative demographic characteristics, pathological grade and stage and 5-year survival in a Taiwanese population

OBJECTIVE

To compare the predictive value for 5-year survival of demographic characteristics, pathological grade and stage between upper tract urothelial carcinoma (UTUC) of the renal pelvis (RPUC) and ureter (UUC) in a Taiwanese population.

PATIENTS AND METHODS

In this study (1986-98) we analysed 141 patients with UTUC, including 71 with RPUC and 70 with UUC (median age 59 years; median follow-up 54 months, SD 2.5). Prognostic indicators were examined by univariate and multivariate logistic regression analyses.

RESULTS

A significant percentage of patients had tumour on the right side and a high proportion of those with UUC were women. Gross haematuria and hypertension were the most common symptoms of RPUC. The sensitivity of intravenous pyelography in diagnosing RPUC and UUC was 49% (34/69) and 36% (25/70), respectively. However, in patients assessed by retrograde pyelography the diagnostic sensitivity was 85% (60/71) for RPUC and 89% (55/62) for UUC. The incidence of tumour recurrence after nephroureterectomy with bladder cuff excision was significantly higher in those with UUC (13%) than RPUC (3.6%). Distant metastasis was detected in 37 of 141 (26%) patients, the most common sites being bone (46%), lung (22%), liver (14%) and colon (8%). Univariate logistic regression analysis showed significant differences in the prognosis for high-grade and high-stage tumours. The prognosis was particularly poor in patients aged >60 years. According to the multivariate logistic regression analysis, tumour stage and grade were the best outcome predictors for RPUC, but stage and age were the best outcome predictors for UUC.

CONCLUSION

UUC is more common in women and has a more aggressive clinical outcome than RPUC after nephroureterectomy with bladder cuff incision. Tumour stage and grade are the best predictors of survival in patients with RPUC. Also, in patients with UUC the prognosis is poor in older patients and those with advanced stages of cancer.

Non-contrast-enhanced computerized tomography and analgesic-related kidney disease: report of the national analgesic nephropathy study

Previous studies suggested that the non-contrast-enhanced computerized tomography (CT) scan is a highly reliable tool for the diagnosis of analgesic-associated renal disease. However, this issue has not been addressed in the US population. A total of 221 incident patients with ESRD from different regions of the United States underwent a helical CT scan and detailed questioning about drug history. Specific renal anatomic criteria were developed to determine whether a constellation of CT findings (small indented calcified kidneys [SICK]) is linked to analgesic ingestion. For approximating use before the onset of renal disease, only analgesic ingestion at least 9 yr before starting dialysis was considered relevant. Fifteen patients met the criteria for SICK. This represented 7% of the enrolled patients and approximately 1% of the total ESRD population. There was a significant increase in the estimated risk among patients with a history of heavy aspirin ingestion (odds ratio [OR] 7.4 [95% confidence interval (CI) 1.2 to 43] for > or =1 kg lifetime; OR 8.8 [95% CI 1.2 to 66] for > or =0.3 kg/yr). Total analgesic ingestion of > or =0.3 kg/yr also was significantly associated with SICK (OR 8.2; 95% CI 1.5 to 45). These findings were accounted for largely by combination products that contained aspirin and phenacetin (used by three patients with SICK), which are no longer available. In addition, the CT finding of SICK was present only in a minority of heavy analgesic users, yielding a sensitivity of 5 to 26%. Findings of SICK are infrequent in the US ESRD population and do not occur among a sufficient proportion of heavy analgesic users to render the non-contrast-enhanced CT scan a sensitive tool to detect analgesic-associated kidney injury.

Phenacetin acts as a weak genotoxic compound preferentially in the kidney of DNA repair deficient Xpa mice

Chronic use of phenacetin-containing analgesics has been associated with the development of renal cancer. To establish genotoxicity as a possible cause for the carcinogenic effect of phenacetin, we exposed wild type and DNA repair deficient Xpa-/- and Xpa-/-/Trp53+/- mice (further referred as Xpa and Xpa/p53 mice, respectively), carrying a reporter lacZ gene, to 0.75% (w/w) phenacetin mixed in feed. Xpa mice completely lack the nucleotide excision repair pathway, and as such they are sensitive to some classes of genotoxic compounds. Phenacetin exposure induced a significant increase of lacZ mutations in the kidney of both Xpa and Xpa/p53 mice. A minor response was found in liver, whereas no lacZ mutation induction was observed in the spleen of these animals. Interestingly, the observed phenacetin-induced mutant frequencies were higher in male than those found in female mice. This gender difference is probably due to a difference in metabolic rate. Phenacetin-induced mutations mainly consisted of point mutations rather than deletions. The mutational spectra in the kidney of treated WT and Xpa mice were quite similar. Taken together, these results demonstrate that the human carcinogen phenacetin acts as a weak genotoxic agent in an in vivo mouse model system.

Regular use of analgesics is a risk factor for renal cell carcinoma

Phenacetin-based analgesics have been linked to the development of renal pelvis cancer and renal cell carcinoma (RCC). The relationship between non-phenacetin types of analgesics and kidney cancer is less clear, although laboratory evidence suggests that these drugs possess carcinogenic potential. A population-based case-control study involving 1204 non-Asian RCC patients aged 25-74 and an equal number of sex-, age- and race-matched neighbourhood controls was conducted in Los Angeles, California, to investigate the relationship between sustained use of analgesics and risk of RCC according to major formulation categories. Detailed information on medical and medication histories, and other lifestyle factors was collected through in-person interviews. Regular use of analgesics was a significant risk factor for RCC in both men and women (odds ratio (OR) = 1.6, 95% confidence interval (CI) = 1.4-1.9 for both sexes combined). Risks were elevated across all four major classes of analgesics (aspirin, non-steroidal anti-inflammatory agents other than aspirin, acetaminophen and phenacetin). Within each class of analgesics, there was statistically significant increasing risk with increasing level of exposure. Although there was some minor variability by major class of formulation, in general individuals in the highest exposure categories exhibited approximately 2.5-fold increase in risk relative to non- or irregular users of analgesics. Subjects who took one regular-strength (i.e. 325 mg) aspirin a day or less for cardiovascular disease prevention were not at an increased risk of RCC (OR = 0.9, 95% CI = 0.6-1.4).

Acetaminophen, some other drugs, some diseases and the risk of transitional cell carcinoma. A population-based case-control study

The purpose of this study was to investigate the risk of transitional cell carcinoma among subjects with an intake of acetaminophen, aspirin, some other drugs and with some intercurrent diseases. The source person-time ('study base') included subjects living in Stockholm in 1985-1987. The study included 325 subjects with a transitional cell carcinoma of the urinary tract and 393 controls randomly selected from the source person-time. Data were obtained by a postal questionnaire supplemented by a telephone interview. A relative risk (with a 95% confidence interval) of 1.6 (1.1-2.3) was obtained after an intake of acetaminophen, adjusted for age, aspirin, gender and smoking. Conversely, a 30% decrease in risk was obtained after an intake of aspirin. No details in the exposure substantiated the finding for acetaminophen. The inherent validity problems of observational studies, and the weak evidence in this and previous studies of the association between acetaminophen and transitional cell carcinoma, makes available epidemiological evidence insufficient to regulate the use of this commonly ingested analgesic. Increased risks were, in addition, found for tetracyclines, nitrofurantoin and a history of allergic asthma and a decreased risk found for rheumatic symptoms. The findings stress the nonepidemiological data concerning the potential carcinogenicity of acetaminophen and may be a foundation for future research of some other drugs and diseases.

Geographical distribution of cancers of the kidney and urinary tract and analgesic nephropathy in Australia and New Zealand

Age-standardised incidence rates for cancers of the renal parenchyma, renal pelvis and bladder and for end-stage renal failure due to analgesic nephropathy for the years 1982-83 were compared between the Australian states and New Zealand, and within New South Wales (NSW), to determine whether these rates paralleled the previous prevalence of consumption of phenacetin-containing analgesics. Whereas little variation was seen within Australasia in respect of the incidence of cancer of the renal parenchyma and bladder, both cancer of the renal pelvis and end-stage renal failure due to analgesic nephropathy had higher incidence rates amongst women in NSW and Queensland than in the other states or New Zealand. Within NSW, the average annual incidence rates during 1973-82 for renal pelvic cancer in the Hunter region of 1.3 (m) and 1.6 (f) per 100,000 were the highest in the state. These high incidence rates coincided with areas known to have had a high prevalence of consumption of compound analgesics containing phenacetin. In an international comparison with populations which had published incidence rates for each of the periods 1973-77 and 1978-82, the rate for cancer of the renal pelvis in women was highest in both time periods in NSW and had increased absolutely at a faster rate.

Epidemiology and mechanistic basis of analgesic-associated nephropathy

End-stage renal failure (ESRF) due to analgesic nephropathy is still a common clinical condition in several countries, but the prevalence in dialysis patients shows large geographical differences. The frequency of ESRF of unknown aetiology is the inverse of that linked to analgesic abuse, and data suggest that the occurrence of analgesic nephropathy may be underestimated. The study of analgesic nephropathy is difficult because the earliest damage to the kidney is a renal papillary necrosis (RPN), which cannot easily be diagnosed. Continued analgesic abuse generally leads to a progressive secondary cortical degeneration which is easier to diagnose. If analgesic abuse is stopped at an early enough stage in nephropathy, clinical symptoms stabilize or improve, and ESRF may be averted. A high incidence of upper urothelial carcinoma (UUC) is also observed in individuals with a history of analgesic abuse, but it is still not clear if the two have a related pathogenesis. Study of the mechanism of RPN in animals administered analgesics and nonsteroidal antiinflammatory drugs (NSAID) has been difficult owing to their extrarenal toxicity. Several model compounds cause identical clinical changes and have as their selective target the renal medullary interstitial cells; subsequently, other changes (including cortical and glomerular degeneration) develop as a secondary cascade. A number of mechanisms have been proposed to explain RPN (e.g., counter-current concentrating mechanism, ischaemic injury, altered prostaglandin metabolism, immunological changes), but peroxidative metabolism of papillotoxic chemicals within the interstitial cells seems to be the most likely cause. Analgesic abuse is a costly socioeconomic condition for which there is currently no clinical treatment. If it is diagnosed early enough, severe renal degeneration can be prevented. Additional epidemiological information is needed to establish the causative role of analgesics and other chemicals, in order to determine the relative risk of each. Additional animal experiments are needed in order to clarify the molecular pathogenesis of RPN and UUC, to differentiate the stages in progression to ESRF and to develop more sensitive and selective diagnostic criteria.

Genotoxicity of analgesic compounds assessed by an in vitro micronucleus assay

Several analgesic compounds and mixtures of analgesics were examined for both cytotoxicity and ability to induce chromosomal damage in the normal rat-kidney cell line NRK-49F. Chromosomal damage was assessed using an in vitro micronucleus assay. Of all the compounds tested, only N-hydroxyparacetamol caused a high degree of cell death at the concentrations used. 4 analgesic compounds were found to be inducers of micronuclei in NRK cells; in order of decreasing potency these were: N-hydroxyparacetamol, N-hydroxyphenacetin, caffeine and paracetamol. An aspirin, phenacetin, caffeine mixture (APC) failed to induce micronuclei above the background level, and a paracetamol-codeine combination did not increase the level of micronuclei induction above that induced by paracetamol alone. This report suggests paracetamol and some related compounds are capable of inducing chromosomal damage in mammalian cells in vitro, which is consistent with recent reports of a possible paracetamol-DNA interaction.

Transitional cell tumors of the renal pelvis and ureter associated with capillarosclerosis indicating analgesic abuse

An association between transitional cell tumors (TCT) and abuse of compound analgesics has been established during the past two decades. Recently thickening of basement membranes around subepithelial capillaries, known as capillarosclerosis, has been reported as a change in the urinary tract pathognomonic for a long-standing abuse of compound analgesics. Therefore the authors reviewed pathologic and clinical data in 59 patients treated for TCT of the renal pelvis or ureter. Capillarosclerosis was found in nine cases (15%) of the TCT group but not in any of the cases selected as controls. Capillarosclerosis is suggested as a valuable marker, which always should be looked for in bladder biopsy specimens. Whenever present it should arouse suspicion of analgesic abuse, and the associated increased risk for developing TCT of the renal pelvis or ureter should be borne in mind.

Inhibition of DNA, RNA and protein synthesis and chromatin alteration by N-hydroxyphenacetin

The effects of N-hydroxyphenacetin on DNA function and structure were investigated to elucidate the involvement of phenacetin in analgesic nephropathy and transitional cell carcinoma. N-Hydroxyphenacetin or a metabolite inhibited synthesis of DNA, RNA and protein; DNA inhibition was greater at higher pH. No single-strand breaks were detectable in DNA after N-hydroxyphenacetin treatment and no appreciable effect on cell viability was observed at concentrations up to 5 mM. N-Hydroxyphenacetin-induced alteration to chromatin structure was detected using nucleoid sedimentation analysis. Direct binding to plasmid DNA was not observed. These observations are consistent with a role for phenacetin metabolites in renal disease.

Phenacetin and papillary necrosis: independent risk factors for renal pelvic cancer

A case-control study was undertaken to determine whether renal papillary necrosis (RPN) is an essential step in the genesis of analgesic-associated cancer of the renal pelvis (CaP). Kidneys of 66 patients (and 86 cases of renal parenchymal cancer (CaK), for comparison) were examined for evidence of RPN. Information concerning past consumption of phenacetin-containing analgesics (PhA) was obtained from all cases and 751 population controls by means of a questionnaire. Separately, RPN and regular consumption of PhA each conferred a relative risk for CaP of 3-1/2 to 7, while together they increased the risk some 20 times that for non-consumers without RPN. This suggests that each factor has independent, and when they coexist sequential, effects. The risk for CaK was doubled by regular PhA consumption but was not increased by RPN.

Heavy phenacetin use and bladder cancer in women aged 20 to 49 years

We investigated the use of analgesics containing phenacetin or acetaminophen in 173 young women with urinary bladder cancer and 173 matched controls. The cases, who were 20 to 49 years old at the time of diagnosis of cancer, were 6.5 times more likely to report regular use of analgesics containing phenacetin at least one year before diagnosis than were their matched controls (odds ratio, 6.5; 95 per cent confidence interval, 1.5 to 59.2). Among the 15 women (13 cases and 2 controls) reporting regular use of phenacetin-containing drugs, 8 of the cases and 1 of the controls reported daily use for over one year (P = 0.04). Excessive use of analgesics containing acetaminophen was not reported. The increased risk of bladder cancer in young women who regularly used phenacetin-containing products remained present after adjustments for all other identified risk factors.

Chemically induced renal papillary necrosis and upper urothelial carcinoma. Part 1

In the past, renal papillary necrosis (RPN) has been commonly associated with long-term abusive analgesic intake, but over recent years a wide variety of industrially and therapeutically used chemicals have been shown to induce this lesion experimentally or in man. Destruction of the renal papilla may result in: (1) secondary degenerative cortical changes which precede chronic renal failure or (2) a rapidly metastasizing upper urothelial carcinoma, which has a very poor prognosis. This article will briefly review the published data on the morphology, function, and biochemistry of the normal renal medulla and the pathology associated with RPN, together with the secondary changes which give rise to cortical degeneration or epithelial carcinoma. It will then examine in detail those chemicals which have been reported to cause RPN in an attempt to delineate structure-activity relationships. Finally, the many different theories that have been proposed to explain the pathophysiology of RPN will be examined and an hypothesis will be put forward to explain the primary pathogenesis of the lesion and its secondary consequences.

Chemically induced renal papillary necrosis and upper urothelial carcinoma. Part 2

In the past, renal papillary necrosis (RPN) has been commonly associated with long-term abusive analgesic intake, but over recent years a wide variety of industrially and therapeutically used chemicals have been shown to induce this lesion experimentally or in man. Destruction of the renal papilla may result in: (1) secondary degenerative cortical changes which precede chronic renal failure or (2) a rapidly metastasizing upper urothelial carcinoma, which has a very poor prognosis. This article will briefly review the published data on the morphology, function, and biochemistry of the normal renal medulla and the pathology associated with RPN, together with the secondary changes which give rise to cortical degeneration or epithelial carcinoma. It will then examine in detail those chemicals which have been reported to cause RPN in an attempt to delineate structure-activity relationships. Finally, the many different theories that have been proposed to explain the pathophysiology of RPN will be examined and an hypothesis will be put forward to explain the primary pathogenesis of the lesion and its secondary consequences.

The role of metabolic activation of analgesics and non-steroidal anti-inflammatory drugs in the development of renal papillary necrosis and upper urothelial carcinoma

There has been no cogent hypothesis to explain the molecular basis of analgesic and non-steroidal anti-inflammatory drug (NSAID) associated renal papillary necrosis (RPN) and upper urothelial carcinoma (UUC). The microsomal cytochrome P-450 enzyme system may generate reactive intermediates which promote pathophysiological effects in the lung, liver and renal cortex, but the absence of P-450 activity in the medulla suggests that it is unlikely that similar events lead to RPN and UUC. Other enzymes (eg. peroxidases) convert substituted aromatics into benzoquinoneimines (an intermediate that has previously been defined in P-450-mediated toxicity). The medulla is rich in fatty acid peroxidases involved in the metabolism of arachidonic acid. NSAID and analgesics interact with key enzymes in this pathway, which could lead to the co-oxygenation of exogenous and endogenous compounds via the peroxidase, lipoxygenase, or prostaglandin hydroperoxidase enzymes. The generation of reactive molecules in the medulla could explain both RPN and UUC via the alkylation of macromolecules. The formation of free radicals would give rise to extensive lipid peroxidation, (there are large quantities of free polyunsaturated fatty acids in the medullary interstitial cells), an event of major potential importance to local cell destruction and genotoxic effects. At present this proposed mechanism of co-oxygenation offers the most attractive working hypothesis to explain the molecular pathogenesis of both RPN and UUC.

Renal effects of antipyretic analgesics

Most antipyretic analgesics can cause acute nephrotoxic effects, including acute tubular necrosis, acute interstitial nephritis, glomerular toxicity, and functional changes, such as "salicyl edema," following large doses of sodium salicylate. Most functional changes are related to acute suppression of prostaglandin synthesis, "the acute prostaglandin-effect," and have been primarily noted with the use of indomethacin. The association between prolonged and excessive consumption of compound analgesics and the development of renal disease and renal failure, characterized by renal papillary necrosis, is now well established. Studies in several countries have shown that the incidence of analgesic nephropathy as an indication for dialysis and transplantation corresponds to the per capita consumption of phenacetin in compound analgesics. Analgesic nephropathy, which is part of a wider clinical syndrome, the analgesic syndrome, is uncommon following the use of single analgesics. Analgesic nephropathy and the analgesic syndrome are discussed in detail, including the development of uroepithelial tumors.

Analgesics and tobacco as risk factors for cancer of the ureter and renal pelvis

In a case-control study of 36 men with cancer of the ureter and 307 male controls with the same age distribution tobacco smoking conferred a relative risk for this cancer of 2.9, whereas consumption of analgesics of any kind did not increase the risk. The relative risk for cancer of the renal pelvis, determined for 29 men, was 2.4 for tobacco and 6.0 for phenacetin-containing analgesics. Analgesics containing no phenacetin conferred no increased risk for cancer at this site. Data for 13 women with ureteral cancer, 5 of whom had taken phenacetin, are presented but not analyzed.

Phenacetin-containing analgesics and cancer of the bladder or renal pelvis in women

In a case-control investigation of 154 women with cancer of the bladder and 440 female population controls spanning the same age range, the relative risk for this cancer was 2.6 in consumers of phenacetin-containing analgesics and 2.7 in tobacco smokers. The relative risks for cancer of the renal pelvis, determined for 31 cases, were 5.4 with phenacetin and 4.7 with tobacco. Increasing consumption of either agent increased the risk for cancer at each of the two sites, while a synergistic rather than purely additive effect was apparent when both phenacetin-containing analgesics and tobacco had been taken. Consumption of analgesic preparations which contained no phenacetin did not increase the risk of developing cancer at either site. The evidence indicates that phenacetin is a clinically important carcinogen for the lower as well as for the upper urinary tract.

Epithelial abnormalities in the renal pelvis in experimental hydronephrosis and pyelonephritis

Unilateral hydronephrosis was induced by temporary ligature of the left ureter in 29 rabbits. In 21 animals so treated, chronic pyelonephritis was simultaneously induced by intravenous application of a suspension of E. coli. Histologic examination of renal pelvic epithelia in animals killed four weeks after the surgical intervention, revealed the following features: 1. Simple hyperplasia of urothelium in 12 cases, 2. atypical hyperplasia - (dysplasia) of urothelium in 10 cases, 3. v. Brunn's nests in 20 renal pelvises; 11 cases of cystic pyelitis, all combined with Brunn's nests, 4. metaplastic transformation of visceral mono- or bilayered epithelium into multi-layered urothelium-like structures in 19 renal pelvises. These changes are observed almost exclusively in the left renal pelvis of animals subjected to temporary ureteral ligature. Atypical urothelial hyperplasia is found only together with chronic pyelonephritis. Hyperplastic and dysplastic epithelial changes in the renal pelvis, the formation of Brunn's nests, and cystic pyelitis are interpreted as sequelae of postrenal obstruction or concomitant chronic inflammation.

Transitional cell carcinoma of the kidney

This paper presents 14 personal patients with transitional cell carcinoma of the kidney who were managed over a period of 13 years. Emphasis is placed on the diagnostic features, the great variety of radiological appearances of this neoplasm and the value of preoperative cytological examination of urine. In three patients the tumour started in the mucosa of peripheral calyces, and did not involve the surgical renal pelvis; this added to the diagnostic difficulty, and led to delay in diagnosis and treatment in one patient. The possibility that this tumour may be more common in Australia because of the high incidence of analgesic nephropathy is raised.

Analgesics and cancer of the renal pelvis in New South Wales

A lifetime history of analgesics and tobacco consumption was obtained by a questionnaire completed at interview from 67 patients with carcinoma of the renal pelvis (40 women, 27 men) and 180 control subjects drawn from two sources, friends of patients and persons attending a health screening clinic. Regular consumption of analgesics conferred a tenfold relative risk of renal pelvic cancer in women and in men a risk ratio of 4-8. The fraction of cases for which analgesic consumption was an attributable risk was 0.74 in women and 0.43 in men. The effect of tobacco, much less than that of analgesics, was significant only in women (risk ratio approximately four; attributable risk 0.4), and no dose-response relationship was demonstrated. Relative excess risks suggested a synergistic effect when both analgesics and tobacco had been consumed. Standardized risk ratios indicated a dose-response relationship for both phenacetin-containing and non-phenacetin analgesics: moderate consumption doubled the risk of renal pelvic cancer, and heavy consumption increased at risk to 6-16 times that for noncomsumers.

Inhibition of DNA synthesis and alteration to DNA structure by the phenacetin analog p-aminophenol

p-Aminophenol a structural analog and minor metabolite of phenacetin has previously been shown to be a potent nephrotoxic agent. In this report we have shown that p-aminophenol has a marked effect on DNA function and structure. DNA synthesis was inhibited in a dose-dependent manner in human lymphoblastoid cells after exposure to p-aminophenol. Results suggest that DNA synthesis is inhibited by the action of p-aminophenol on DNA structure. At low concentrations of p-aminophenol a reduction in the degree of supercoiling of cellular DNA is observed, as determined by sedimentation under neutral conditions. However at higher concentrations an increase in sedimentation of nucleoids (supercoiled molecules) is obtained which is indicative of an increased level of supercoiling or a more compact structural form of DNA due to folding or aggregation. The number of single strand breaks in DNA, when determined by sedimentation in alkaline sucrose gradients, increases with increasing dose of p-aminophenol. The increase in strand breakage observed at lower concentrations of p-aminophenol agrees with the reduced sedimentation rate obtained under neutral conditions. At higher concentrations of p-aminophenol the extent of breakage of DNA increases under alkaline conditions but an increase in sedimentation occurs under neutral conditions.

Renal pelvic neoplasms and atypical urothelium in patients with end-stage analgesic nephropathy

In a series of 772 renal transplant patients, 84 had analgesic nephropathy (AN). Four of them had renal pelvic carcinoma. The incidence of atypical urothelial changes of the renal pelvis was studied in 56 AN patients, the majority nephrectomized before or shortly after the renal transplantation. Urothelial atypia, usually bilaterally, was found in 27 patients. Multiple sections resulted in an even higher incidence (8/9). No atypical changes were found in normal kidneys or in end-stage diseased kidneys with other diseases, or in chronically rejected renal allografts. These findings further strengthen the association between intake of phenacetin-containing analgesics and the development of renal pelvic tumors. Patients with end-stage analgesic nephropathy are a high-risk group for developing urinary tract tumors and should be subjected to endoscopic and cytologic surveillance. After renal transplantation, prophylactic bilateral nephroureterectomy is advocated.

Unsuspected analgesic nephropathy in transitional cell carcinoma of the upper tract: a morphological study

Analgesic nephropathy is known to have a high incidence in Australia where, following the experience in Scandinavia, reports have been published for some time recording the association between analgesic nephropathy and urothelial malignancies. The morbid anatomical features of analgesic nephropathy are now sufficiently well accepted to allow a retrospective study of unselected nephrectomies for transitional cell carcinoma of the renal pelvis and ureter, in order to assess the incidence of analgesic-type changes in this well defined group of malignancies. The records of a large general histopathology department between 1972-1978 were searched and 24 consecutive transitional cell carcinomas in these sites treated by nephrectomy were selected for study. Of these, 21 were suitable for assessment and on review were shown to comprise II cases with papillary changes acceptable as analgesic in type and five which were suggestive of early analgesic change. Of these 16, seven were female, only two were known analgesic abusers and five were recorded as consuming analgesics on a regular basis. These findings suggest that analgesics may play a significant role in the pathogenesis of urothelial malignancy in the general population.

Clinical and pathological aspects of analgesic nephropathy

1 Analgesic nephropathy is part of the analgesic syndrome which has gastrointestinal, haematological, cardiovascular, psychological and psychiatric, and pregnancy and gonadal manifestations; premature ageing may also be a feature. 2 Analgesic nephropathy is a form of renal disease characterized by renal papillary necrosis, secondary chronic interstitial nephritis and renal failure with features of predominant tubulointerstitial dysfunction. 3 The percentage of patients with analgesic nephropathy who present with terminal renal failure is 12%. With appropriate management, 17% of analgesic nephropathy patients improve, 50% remain stable and 23% deteriorate. The 6 year cumulative survival is 70%. The major factors influencing deterioration are malignant hypertension, persistent proteinuria and small initial renal size. 4 The risk of renal papillary carcinoma in patients who regularly take analgesics is 8 per 100,000 patients per year. 5 Renal papillary necrosis is a consequence of the chronic toxicity of all non-steroidal anti-inflammatory drugs and results from medullary ischaemia secondary to suppression of prostaglandin E2 synthesis and from direct cellular toxicity. 6 Analgesic nephropathy is a preventable form of renal disease and renal failure. It can be prevented by limiting the abuse potential of analgesics rather than by making minor modifications in the composition of analgesic mixtures.

Renal pelvic carcinoma in the Hunter Valley

In the Hunter Valley, New South Wales, the incidence of renal pelvic carcinoma was found to be very high, and there appeared to be a causal relationship with analgesic abuse. The crude incidence rate was calculated at 1.6/100000 population per year. In half of the cases of renal pelvic carcinoma, there was evidence of analgesic abuse and/or analgesic nephropathy with papillary necrosis; in this group the male/female ratio was 1/2.6, and there was a tendency for the cancers to occur at a younger age. Tumours associated with analgesic nephropathy were more often poorly differentiated and in a more advanced stage at the time of diagnosis than those not associated with analgesic nephropathy. Multiple tumours were equally common in both groups, but coexistent flat carcinoma in situ tended to be more common in cases associated with analgesic nephropathy.