Radiation-induced cancer: a modern view

Diagnostic medical radiation has been the most rapidly increasing component of population background radiation exposure in Western countries over the past decade. This trend is set to increase as CT scanning is readily available with burgeoning use in everyday clinical practice. Consequently, the issue of cancer induction from the doses received during diagnostic medical exposures is highly relevant. In this review we explain current understanding of potential cancer induction at low doses of sparsely ionising radiation. For cancers that may be induced at low doses, a mechanistic description of radiation-induced cancer is discussed, which, in combination with extrapolation of data based on population cohort studies, provides the basis of the currently accepted linear no-threshold model. We explore the assumptions made in deriving risk estimates, the controversies surrounding the linear no-threshold model and the potential future challenges facing clinicians and policy-makers with regards to diagnostic medical radiation and cancer risk, most notably the uncertainties regarding deriving risk estimates from epidemiological data at low doses.

Evaluation of meglumine gadoterate-enhanced MR angiography (MRA) compared with time-of-flight MRA in the diagnosis of clinically significant non-coronary arterial disease: a pooled analysis of data from two clinical trials

OBJECTIVES

We analysed pooled data from two clinical trials to assess the diagnostic accuracy and safety of meglumine gadoterate (Gd-DOTA)-enhanced MR angiography (MRA) relative to those of non-enhanced time-of-flight (TOF) MRA for non-coronary arterial disease. Both techniques were compared with X-ray angiography as the gold standard.

METHODS

Patients were of both sexes, were aged at least 18 years and had suspected non-coronary arterial disease. Each patient was his/her own control and underwent TOF MRA followed by Gd-DOTA-enhanced MRA, and then X-ray angiography. MRA was performed at 1.5 T (USA study) or 3 T (Republic of Korea study). The primary criterion used to evaluate efficacy was the degree to which the MRA examination agreed with X-ray angiography in assessing non-coronary arterial lesions. The performance of Gd-DOTA over TOF was assessed using a one-sided paired t-test. We also evaluated the specificity, sensitivity, image quality, examination duration and clinical safety of both MRA procedures.

RESULTS

In total, 192 patients were enrolled and received Gd-DOTA. In the intent-to-treat population (n=162), within-patient accuracy was significantly greater for Gd-DOTA than for TOF (85.8 ± 19.8% agreement between Gd-DOTA and X-ray angiography compared with 78.3 ± 24.9% agreement between TOF and X-ray angiography; p=0.0001). The sensitivity, specificity, image quality and examination duration were also better for Gd-DOTA than for TOF. There were no serious drug-related adverse events.

CONCLUSION

We conclude that Gd-DOTA-enhanced MRA is a safe and accurate procedure for detecting arterial stenosis at both 1.5 T and 3 T.

Hepatitis B-associated nephrotic syndrome in Jamaican children

Between December 1984 and November 1996, 171 children under 12 years old presented to the University Hospital of the West Indies with nephrotic syndrome. Hepatitis B surface antigen (HBsAg) was found in ten (6%) of these children, eight of whom had membranous nephropathy (MN), and one each had mesangial proliferative glomerulonephritis (MesN) and minimal change nephrotic syndrome (MCNS). Only those children with MesN and MCNS were steroid-sensitive. The HBsAg-positive status was identified incidentally on screening. At a mean follow-up of 34 months, seven of ten children had experienced complete or partial remission and three had persistent nephrotic syndrome, although none was in renal failure. Six of the ten had biochemical hepatitis. All the children were still HBsAg-positive. Hepatitis B virus (HBV) is a factor contributory to nephrotic syndrome in Jamaican children. As diagnostic clinical markers for HBV-associated nephropathy are usually absent, all children presenting with nephrotic syndrome should be screened for HBsAg. A policy should be implemented in Jamaica for screening pregnant women and at-risk groups for HBsAg, as well as for immunising susceptible neonates, in order to reduce the incidence of HBV-associated pathology.

Human T-cell lymphotropic virus-1-associated renal disease in Jamaican children

This report documents the clinicopathological features in two Jamaican children who presented with infective dermatitis, glomerulonephritis, renal failure and human T-cell lymphotropic virus (HTLV-1) seropositivity. Severe hypertension with hypertensive encephalopathy was the most impressive clinical feature. Histological findings from renal biopsy specimens in both cases revealed significant glomerulosclerosis with fibrosis, chronic inflammatory cell infiltrates in the interstitium, and arteriolar hypertensive changes. Membranoproliferative glomerulonephritis (MPGN) was demonstrable in case 1 and marked focal glomerulosclerosis in case 2. Case 1 developed end stage renal failure and died within 3 years of diagnosis. Case 2 remains hypertensive and in chronic renal failure. Although a causal relationship between HTLV-1 infection and renal disease cannot be proven by these two cases, it appears that renal involvement in children with HTLV-1 infection is severe, with the potential for chronic renal failure and malignant hypertension. HTLV-1 nephropathy should be suspected in children with infective dermatitis and renal disease.

Thyroid papillary carcinoma arising in a branchial cleft cyst

We describe the clinico-pathological features and discuss the possible pathogenetic mechanism of thyroid papillary carcinoma arising in a branchial cleft cyst. This has been described only once previously in the literature.

Idiopathic focal and segmental glomerulosclerosis in Jamaica. A 10-year review

Idiopathic focal and segmental glomerulosclerosis (IFSGS) in a predominantly black population does not appear to behave any differently than in Caucasian patients. Response to steroid therapy and cyclophosphamide had favourable prognostic significance. There may be a subgroup of IFSGS which responds more slowly to steroids. The duration of steroid therapy should extend beyond four months.

Glomerulonephritis after human parvovirus infection in homozygous sickle-cell disease

Glomerulonephritis with proteinuria of sufficient degree to manifest the nephrotic syndrome followed aplastic crises induced by human parvovirus (B19) in seven patients with homozygous sickle-cell disease, within 7 days in five patients and 6-7 weeks in two. Segmental proliferative glomerulonephritis was found in all four patients who underwent acute renal biopsies and focal segmental glomerulosclerosis was found in the fifth patient who had a biopsy 4 months later. One patient recovered completely, one died in chronic renal failure after 3 months, and the others had impaired creatinine clearance, four with continuing proteinuria.

Splenic cysts--a Jamaican experience

A total of eleven (11) cases of non-parasitic splenic cysts have been studied at the University Hospital of the West Indies by routine haematoxylin and eosine and immunohistochemical staining, using epithelial markers (cytokeratin, low molecular weight keratin and epithelial membrane antigen). The majority (eight of eleven) were found to be epithelial or true cysts. This is in contrast to findings previously reported in the literature, based on light microscopic examination, that the majority of splenic cysts are non-epithelial in origin. We therefore suggest that immunohistochemical studies should be used routinely to accurately define the nature of all splenic cysts.

Outcome of solid renal tumours in children at the University Hospital of the West Indies

Of the twenty-nine children with solid renal tumours treated at the University Hospital of the West Indies (UHWI) between January, 1972 and December, 1991, there were twenty-eight cases of nephroblastoma and one of mesoblastic nephroma. Peak incidence was between the ages of two and four years. Twenty-five children had radical nephrectomy while one had bilateral partial nephrectomy. In thirteen cases, pre-operative chemotherapy +/- radiotherapy was used. Post-operative chemotherapy and radiotherapy were used in 24 and 13 cases, respectively. Stage of the tumour was the most decisive factor influencing the outcome. Whereas there was a 100% cure rate in Stages I and II, Stage III had only a 55.5% survival rate and none of the Stage IV survived. Bilateral (Stage V) tumours are curable if individual tumours are localised, as in one of the two cases. The benign mesoblastic nephroma, in a one-month-old infant, was cured by nephrectomy alone. While the present therapy of radical nephrectomy along with combination chemotherapy is satisfactory for early stages, more aggressive adjuvant therapy is needed for improving the results in Stages III and IV.

Inflammatory pseudotumour of the spleen. Report of a case and review of the literature

A case of inflammatory pseudotumour of the spleen in a 34-year-old female patient is described. We have briefly reviewed the literature on the subject and discussed aetiopathogenesis, pre-operative differential diagnosis and treatment modalities.

Adult T-cell leukemia/lymphoma in a renal transplant recipient: an opportunistic occurrence

A 42-year-old man with chronic renal failure and homograft transplantation developed adult T cell lymphoma in one native kidney. The role of transfusion in the acquisition of human T-lymphotropic virus type I and its role in the early development of adult T cell lymphoma, particularly on the background of chronic immunosuppression, are discussed. To our knowledge, this is the first such case.

Mortality of Jamaican patients with systemic lupus erythematosus

A retrospective study of all patients with systemic lupus erythematosus (SLE) who died at the University Hospital of the West Indies over a 14-year period is presented. The major cause of death was infection followed by renal failure. Gram-negative organisms were the major microbiological agents causing infections. Side-effects of therapy were common, in particular bone marrow depression and haemorrhage related to anticoagulants. It appears that controlling severe lupus activity without increasing the risk of lifethreatening complications remains an important goal in the treatment of SLE.

Membranous glomerulonephropathy with crescents in systemic lupus erythematosus

Over a 2-year period percutaneous renal biopsies were carried out on 23 patients with systemic lupus nephritis. When classified by immunofluorescence, and light and electron microscopy, 4 patients had mesangial disease, 1 had focal and segmental proliferation, 5 had diffuse proliferation and 5 had membranous changes. 3 biopsies were unclassifiable with end-stage changes and 5 showed an unusual combination of pure membranous changes in association with significant crescent formation. The outcome of the latter group of patients was uniformly poor. We think that this group represents a distinct histological entity with a poor prognosis.

Proteinuria and glomerular disease in Jamaica

Clinical, laboratory and renal biopsy data on 50 adult patients investigated in Jamaica because of proteinuria of more than 1 g/day were reviewed. Primary glomerular disease was present in 23 cases and the most common histological pattern was mesangial proliferation. Proteinuria was part of a systemic disease in 27 patients of whom 19 had systemic lupus erythematosus (SLE). Urinary protein excretion was less in patients with systemic diseases than in those with primary glomerulonephritis, but hypoalbuminemia, renal function and presence of edema were not helpful in distinguishing types and causes of renal disease. By comparison with other countries SLE and mesangial proliferative glomerulonephritis are common causes of proteinuria and nephrotic syndrome in Jamaica whereas idiopathic membranous glomerulonephropathy appears to be rare.