Radiotherapy Dose Fractionation, Access and Waiting Times in the Countries of the UK in 2005

AIMS

The Royal College of Radiologists has published a review of the evidence base for radiotherapy dose fractionation. We modelled the implications of changes in practice on radiotherapy demand and compared it with current activity, access and waiting times across the countries of the UK.

MATERIALS AND METHODS

We collected data on diagnosis, dose fractionation and waiting times on all patients in the UK starting a course of radiotherapy in the week commencing 26 September 2005. Excluding skin cancer, 2610 patients were prescribed 34,194 fractions.

RESULTS

Radiotherapy access rates were 38% in England, 43% in Scotland and 37% in Wales. These are all lower than the 52% of cancer patients recommended by modelling. To increase access to the recommended level, a 33% increase in activity is required across the UK. For each of 13 cancer diagnoses, we modelled optimum fractionation and compared it with current practice. To deliver the dose fractionation with the best evidence base, a further increase in activity of 37% is required. To take account of both access and optimal fractionation, the two factors should be multiplied (1.33x1.37=1.82) giving an overall increase of 82% for the UK. This would require 53,741 fractions per million population annually. The exact value depends on the cancer incidence in each country, but should be compared with current activity of 28,040 in England, 39 584 in Scotland and 31,228 in Wales. Limited capacity is reflected in waiting times. The percentage of patients exceeding the maximum recommended wait of 28 days for radical or adjuvant postoperative radiotherapy was 55% in England, 44% in Scotland and 74% in Wales.

CONCLUSIONS

To secure adequate access to treatment and optimal dose fractionation, substantial increases in radiotherapy activity of 92% in England, 61% in Scotland and 97% in Wales are required. Achieving this will require a planned programme of investment in staff, training and equipment.

CT of the chest can hinder the management of seminoma of the testis; it detects irrelevant abnormalities

To evaluate the role of chest CT in the initial staging of testicular seminomatous germ cell tumours. All patients referred to Addenbrooke's Hospital with testicular seminoma from 1 January 2000 to 31 December 2005 were included and case notes retrospectively reviewed. One hundred and eighty-two patients with testicular seminoma were identified, with a median age of 37 years (range 19–74). Most patients had stage I disease (86%). Twenty-four patients had abnormal abdominal CT findings. One hundred and fifty-eight had normal abdominal CT findings but, on initial staging, chest CT reported abnormalities in 13 patients, which, on further follow-up CT were deemed to be irrelevant to the diagnosis of seminoma. There was a further patient with a normal CT abdomen in whom chest CT detected obvious metastatic disease, which was seen on chest x-ray. Overall 18 cases required additional investigations and follow-up for abnormalities subsequently found to be benign. There was a false-positive rate of 10% for initial staging with chest CT. This is the largest reported series of staging CT chest in testicular seminoma. In all patients with normal abdominal CT, normal chest x-ray and abnormal chest CT, subsequent follow-up investigations demonstrated that the lung lesions were incidental findings.

Improving patient safety in radiotherapy by learning from near misses, incidents and errors

Radiotherapy incidents involving a major overdose such as that which affected a patient in Glasgow in 2006 are rare. The publicity surrounding this patient's treatment and the subsequent publication of the enquiry by the Scottish Executive have led to a re-evaluation of procedures in many departments. However, other incidents and near misses that might also generate learning are often surrounded by obsessive secrecy. With the passage of time, even those incidents that have been subject to a public enquiry are lost from view. Indeed, the report on the incident in Glasgow draws attention to strong parallels with that in North Staffordshire, the report of which is not freely available despite being in the public domain. A web-based system to archive and make available previously published reports should be relatively simple to establish. A greater challenge is to achieve open reporting of near misses, incidents and errors. The key elements would be the effective use of keywords, a system of classification and a searchable anonymized database with free access. There should be a well designed system for analysis, response and feedback. This would ensure the dissemination of learning. The development of a more open culture for reports under the Ionising Radiation (Medical Exposure) Regulations (IR(ME)R) is essential: at the very least, their main findings and recommendations should be routinely published. These changes should help us to achieve greater safety for our patients.

National survey of radiotherapy fractionation practice in 2003

AIMS

To document UK practice in radiotherapy fractionation.

METHODS

All radiotherapy centres in the UK participated in a 1-week audit from 29 September 2003. Fractionation data were collected for all patients starting external beam radiotherapy. This included 2498 patients who were prescribed 32 547 fractions.

RESULTS

For the radical treatment of non-skin malignancy (n = 708), the prescribed dose ranged from a single fraction of 8 Gy for total-body irradiation to 75 Gy in 43 fractions for prostate cancer. Postoperative treatment for breast cancer was dominated by three regimens: 40 Gy in 15 fractions; 45 Gy in 20 fractions; and 50 Gy in 25 fractions. Palliative treatment was given in a single fraction to 393 patients (36%) with doses of up to 15 Gy. Three hundred and ninety patients (36%) received four to seven fractions delivering 20-25 Gy. Only 89 patients (8%) received more than 10 fractions with palliative intent but used 29% of such fractions. In the treatment of bone metastases, the most common prescriptions were 8-10 Gy in a single fraction and 20 Gy in five fractions.

CONCLUSION

UK radiotherapy practice has become more uniform and moved closer to practice in North America and Europe over the past 15 years. For radical radiotherapy, 54% of prescriptions were for a fraction size of 1.8-2.0 Gy but the distribution was bi-modal and 20% of patients were prescribed fraction sizes of 2.7-3.0 Gy. Evidence-based practice now supports hypo-fractionated palliative treatment favouring single fractions for bone metastases and one or two fractions for many patients with advanced lung cancer. Two fractions are advised for some patients with brain metastasis. If these guidelines had been applied uniformly, then the number of treatments prescribed for palliation could have fallen by 36% from 5197 to 3313. This would have represented a 6% reduction in the overall radiotherapy workload. Not all patients are suitable for such hypo-fractionated treatments, but this is an area in which resource use can be improved. In the postoperative management of breast cancer, a change in practice to use 15 fractions uniformly would reduce overall radiotherapy workload by 4%. By contrast, a change to 25 fractions would increase overall workload by 7%.

Depletion of uracil-DNA glycosylase activity is associated with decreased cell proliferation

Uracil-DNA glycosylase (UNG) is the primary enzyme responsible for removing uracil residues from DNA. Increasing evidence suggests that UNG may be a potential target for the development of novel antiviral and/or anticancer agents. To determine whether the uracil-DNA glycosylase inhibitor protein (UGI) could be used to specifically target UNGs intracellularly, we developed a construct that expresses UGI as a fusion protein with the TAT-protein transduction domain and described a novel method for the purification of recombinant TAT-UGI. Treatment of several cell types with TAT-UGI resulted in a dose- and time-dependent decrease in UNG activity. A somewhat surprising effect of TAT-UGI treatment was the decrease in cell proliferation, but not in cell viability. The results of this study support the premise that UNG can be used as a potential therapeutic target and also demonstrate that protein transduction can be used to modulate UNG activity.

Adjuvant bleomycin, vincristine and cisplatin (BOP) for high-risk stage I non-seminomatous germ cell tumours: a prospective trial (MRC TE17)

Adjuvant BEP (bleomycin, etoposide, cisplatin) is effective treatment for high-risk clinical stage I (HRCS1) non-seminomatous germ cell tumours (NSGCT), but the known toxicities of etoposide, and the expansion of the HR group to any patient with vascular invasion (50% of patients), led the Medical Research Council to pilot the BOP regimen. Patients received two courses of BOP 14 days apart: cisplatin 50 mg m⁻² days 1 and 2, vincristine 1.4 mg m⁻² (max. 2 mg) days 2 and 8, bleomycin 30 000 IU days 2 and 8. Primary outcome was relapse rate; quality of life, fertility, hearing and lung function were assessed pre- and post-treatment. In all, 100 patients were required. A total of 115 eligible patients were registered, all received two courses of chemotherapy. Median follow-up is 70 months; two relapses have occurred and the 5-year relapse-free rate is 98.3% (95% confidence interval (CI) 95.5%, 99.9%). As assessed by clinicians during treatment, complete (reversible) alopecia was present in 20% of patients; World Health Organization (WHO) grade 1/2 neurotoxicity was present in 41%/5% of patients during treatment and 22%/1% at 6 months. However, 12% of patients reported ‘quite a bit’ or ‘very much’ pain/numbness/tingling in hands/feet 2 years after chemotherapy. Mature follow-up confirms high efficacy for two courses of cisplatin-based adjuvant chemotherapy in HRCS1 NSGCT. Substituting vincristine for etoposide decreases alopecia, but gives a low incidence of significant neuropathy. There are no clearcut advantages to 2 × BOP over 2 × BEP, except for patients who wish to maximise the chance of avoiding significant alopecia.

Primary central nervous system lymphoma: a single-centre experience of 55 unselected cases

AIMS

Current treatment for primary central nervous system lymphoma (PCNSL) involves high-dose methotrexate (HDMTX) with or without radiotherapy. Many published studies describing this approach include a highly selected group of patients. We report a single-centre experience of unselected cases of PCNSL.

MATERIALS AND METHODS

We retrospectively reviewed the case notes of 55 consecutive patients diagnosed with biopsy-proven PCNSL between 1995 and 2003 at Addenbrooke's Hospital Cambridge, UK. We describe the treatment and outcome, including survival, treatment-related toxicity and long-term functional disability.

RESULTS

At diagnosis, 45% of patients were considered unfit to receive treatment with HDMTX, owing to poor performance status or comorbidity. These patients had a median survival of 46 days and may not have been included in other published studies. The remaining patients were treated with a chemotherapy regimen, which included HDMTX. Patients who received at least one cycle of a chemotherapy containing HDMTX had a median survival of 31 months. Forty per cent did not complete planned chemotherapy owing to toxicity, disease progression or death. The median survival of patients treated with HDMTX aged 60 years compared with patients aged under 60 years was 26 months vs 41 months (P = 0.07), respectively. Younger patients treated with HDMTX, who achieved complete remission with chemotherapy, had a median survival of 56 months. We identified a high incidence of functional disability among survivors, resulting from a combination of the tumour itself, the neurosurgical procedure required for diagnosis and the late neurotoxicity of combined chemoradiotherapy.

CONCLUSION

The treatment of PCNSL is associated with significant early and late toxicity. Further attempts to improve treatment should address mechanisms to reduce this toxicity. In particular, the benefit of radiotherapy in patients who achieve complete remission with HDMTX will remain uncertain until it is addressed in a multicentre, randomised trial.

Down-regulation of human deoxyuridine triphosphate nucleotidohydrolase (dUTPase) using small interfering RNA (siRNA)

A small interfering double stranded RNA molecule (siRNA, 21 bp) corresponding to a portion (nucleotides 337 to 357) of domain 3 of the human dUTPase was synthesized and used to determine whether it could down-regulate dUTPase activity in human cells. Transfection of the siRNA into HeLa and HT29 cells resulted in a 56 +/- 3.6% decrease in dUTPase activity, while transfection of SW620 cells resulted in a 27 +/- 6% decrease in dUTPase activity when compared to non-treated controls.

Modulation of human dUTPase using small interfering RNA

Deoxyuridine triphosphate nucleotidohydrolase (dUTPase) is responsible for maintaining low intracellular levels of dUTP, thus preventing the incorporation of dUTP into DNA. A 21 bp double-stranded RNA molecule (siRNAdUT3) targeted against motif 3 of human dUTPase resulted in a time- and dose-dependent decrease in dUTPase activity in transfected cells. dUTPase activity was reduced approximately 95+/-5% in all cell lines tested 48 h after transfection with 2 microg siRNAdUT3 and it was maintained at this decreased level for at least 72 h. Down-regulation of dUTPase resulted in a significant increase in intracellular dUTP and a decreased proliferation of the transfected cells. Therefore, we conclude that dUTPase activity/expression can be down-regulated using siRNA specifically targeted to dUTPase mRNA and that this approach can be used to elucidate the role of dUTPase in DNA metabolism, as well as, to determine whether dUTPase is a valid target for drug development.

British National Lymphoma Investigation: pilot studies of neoadjuvant chemotherapy in clinical stage Ia and IIa Hodgkin's disease

In order to improve treatment in early Stage IA and IIA Hodgkin's disease, the British National Lymphoma Investigation (BNLI) has evaluated two neoadjuvant chemotherapy regimens with involved field radiotherapy. This article reports the results of the methotrexate, vinblastine and prednisolone (MVP) study in 39 patients and updates the previous report on vinblastine, bleomycin and methotrexate (VBM) in 30 patients. Both studies recruited clinical Stage IA or IIA Hodgkin's disease patients with intermediate risk of relapse into a prospective multicentre Phase II study. They received two cycles of chemotherapy followed by involved field radiotherapy and then four further cycles of chemotherapy. For MVP the 5-year survival is 97% and for VBM it is 93%. The 5-year event-free survival rates are 71% and 87% respectively. The acute pulmonary and haematological toxicity occurring with VBM was not acceptable and therefore the MVP study was performed. There was less toxicity with this regimen although modest acute pulmonary toxicity was still observed. However, in view of the length of treatment with MVP (9 months) and the excellent results reported by the Manchester group, future efforts of the BNLI are to be directed towards a new short course chemotherapy regimen, VAPEC-B (vincristine, doxorubicin, prednisolone, etoposide, cyclophosphamide and bleomycin).

Health literacy and performance on the Mini-Mental State Examination

The objectives of the study were to determine the relationship between functional health literacy and performance on the Mini-Mental State Examination (MMSE). New Medicare managed-care enrollees aged 65 years and older, living independently in the community in four US cities (Cleveland, Houston, Tampa, and Fort Lauderdale/Miami), were eligible to participate. In-home interviews were conducted to determine demographics and health status, and interviewers then administered the Short Test of Functional Health Literacy in Adults (S-TOFHLA) and the MMSE. We then determined the relationship between functional health literacy and the MMSE, including total scores, subscale scores (orientation to time, orientation to place, registration, attention and calculation, recall, language, and visual construction), and individual items. Functional health literacy was linearly related to the total MMSE score across the entire range of S-TOFHLA scores (R(2) = 0.39, p < 0.001). This relationship between health literacy and MMSE was consistent across all MMSE subscales and individual items. Adjustment for chronic conditions and self-reported overall health did not change the relationship between health literacy and MMSE score. Health literacy was related to MMSE performance even for subscales of the MMSE that were not postulated to be directly dependent on reading ability or education (e.g. delayed recall). These results suggest that the lower MMSE scores for patients with low health literacy are only partly due to 'test bias' and also result from true differences in cognitive functioning. 'Adjusting' MMSE scores for an individual's functional health literacy may be inappropriate because it may mask true differences in cognitive functioning.

The herpesvirus encoded dUTPase as a potential chemotherapeutic target

The human herpesviruses are a well characterized group of viruses that are responsible for a wide spectrum of human diseases. Included in this group of pathogens are the alphaherpesviruses (herpes simplex types 1 and 2 and varicella-zoster virus), the betaherpesviruses (cytomegalovirus, human herpesvirus types 6 and 7) and the gammaherpesviruses (Epstein-Barr virus and human herpesvirus 8). An important feature of these viruses is that they cause latent infections that can be reactivated to cause disease. The herpesviruses encode for a large number of structural and non-structural proteins, and several of the non-structural proteins, such as thymidine kinase, DNA polymerase, and ribonucleotide reductase, have been utilized as targets for the development of anti-herpesvirus agents. Another herpesvirus encoded enzyme that has received little attention as a potential target for the development of specific anti-herpesvirus agents is deoxyuridine triphosphate nucleotidohydrolase (dUTPase). Furthermore, little is known concerning the role of the herpesviruses' encoded dUTPases in virus replication and in modulating the chemotherapeutic efficiency of other anti-herpes agents. Because of recent advances in molecular virology and biochemistry, it is now possible to rationally develop "designer" drugs based upon the structural/functional interaction of the drug with a specific viral protein. The purpose of this review is to describe previous studies demonstrating the potential use of the herpesvirus encoded dUTPase as a drug target, to describe problems associated with using the dUTPase as a target and to discuss new approaches that can be used.

Total body irradiation using a modified standing technique: a single institution 7 year experience

We describe a simple standing technique for delivering total body irradiation (TBI) using large horizontal fields, made possible by the off-centre installation of a non-dedicated treatment unit in a pre-existing bunker. Patients are treated using anterior and posterior fields with customized lung compensators. This technique enables the dose to the lung to be accurately calculated and modified to avoid overdose and to minimize the risk of pneumonitis. From February 1991 to December 1997, 94 patients with a variety of haematological malignancies were given fractionated TBI using this technique prior to allogenic or autologous bone marrow transplantation. Patients received a total dose of 14.4 Gy given in eight fractions over 4 days, with at least 6 h between fractions. The prescribed dose to the lungs was reduced to 12 Gy in eight fractions. The technique was well tolerated, took less than 10 min to set up and did not disrupt the daily routine use of the machine. Doses to all measured points on the trunk and head were within +/-6% of the prescribed dose. Doses to the lungs were within +/-5% of the prescribed dose. There were no early respiratory deaths in the 37 autologous transplant patients. There were 10 (17%) respiratory deaths in the 57 allogeneic transplant patients, 3 of confirmed infectious aetiology.

An audit of clinic consultation times in a cancer centre: implications for national manpower planning

A departmental audit was conducted to assess the frequency, extent and causes of late completion of oncology clinics. Data were collected prospectively from clinical, medical, haematological and multidisciplinary oncology clinics. The data recorded included: clinic start and finish times, number of patients seen, type of consultation, number of doctors in each clinic, time spent by the doctor with the patient, and other factors that may have contributed to the late completion of clinics. A total of 848 patient consultations were recorded in 81 clinics. Of 67 clinics in which the finish time was recorded, 19 (28%) were completed on time, while 48 (72%) were late by a mean time of 49 minutes. The mean time spent by consultants with new, follow-up and chemotherapy patients was 37, 21 and 22 minutes respectively. This did not include time spent reviewing notes, dictating or ordering investigations. There was no significant difference in the time spent by specialist registrars compared with consultants, or clinical oncologists compared with medical oncologists and haematologists. The incidence of unforeseen problems such as difficult consultations, missing information, unplanned interruptions, late starts and overbooking of patients were not significantly different in those clinics that finished late compared with those that finished on time. The mean overrun of multidisciplinary clinics was longer than for non-multidisciplinary clinics (59 and 31 minutes respectively), despite a higher ratio of doctors to patients in the former (1:5.4 and 1:7 respectively). This audit showed that the main cause of late finishes in clinics in our department was the longer than anticipated time spent by doctors with patients. Consultations are taking longer because of the increasing complexity of non-surgical cancer treatments and the greater emphasis placed on patient information and informed consent. The Royal College of Radiologists (RCR) has calculated that, if a consultant oncologist sees a maximum of 315 new patients per year, the time available for each follow-up consultation would be 10 minutes. Our audit showed that follow-up consultations took an average of 21 minutes. These results suggest that the RCR recommendations for consultant expansion substantially underestimates the true number of consultants required for the treatment of cancer patients in the UK.

Novel antineoplastic isochalcones inhibit the expression of cyclooxygenase 1,2 and EGF in human prostate cancer cell line LNCaP

Experiments were conducted to determine the effects of novel anti-neoplastic isochalcones (DJ compounds), on cyclooxyegenase 1 and 2 (COX-1 and COX-2) enzyme expression in androgen receptor dependent human prostate cancer cell line LNCaP. Results from Western blot analysis and cell flow cytometry showed that DJ52 and DJ53 decreased the steady state levels of COX-1 and COX-2 protein levels in a dose dependent manner. In addition, DJ52 and DJ53 decreased the levels of epidermal growth factor (EGF) in LNCaP cells. In this study, we report that novel isochalcones decreased COX-1, COX-2 and EGF levels as well as LNCaP cellular growth in a dose responsive manner. Our findings indicate that relative decreases in COX-1, COX-2 and EGF expressions might serve as indicators of tumor growth inhibition in prostate neoplasms.

Reactive carbonyl formation by oxidative and non-oxidative pathways

The spectrophotometric protein carbonyl assay is used as an indicator of protein damage by free radical reactions in vitro and in a variety of pathologies. We investigated model proteins and a variety of oxidative and non-oxidative reactions, as well as what effects hemoglobin, myoglobin, and cytochrome c might have on levels of protein carbonyls. We show that oxidative as well as non-oxidative mechanisms introduce carbonyl groups into proteins, providing a moiety for quantification with 2,4-dinitrophenylhydrazine (DNPH). Bovine serum albumin exposed to oxidative scenarios, such as hypochlorous acid, peroxynitrite, and metal-catalyzed oxidation exhibited variable, but increased levels of carbonyls. Other non-oxidative modification systems, in which proteins are incubated with various aldehydes, such as malondialdehyde, acrolein, glycolaldehyde, and glyoxal also generated significant amounts of carbonyls. Furthermore, purified myoglobin, hemoglobin, and cytochrome c show high absorbance at the same wavelengths as DNPH. The high levels observed are due to the innate absorbance of hemoglobin, myoglobin, and cytochrome c near the assay spectra of DNPH. These studies show that carbonyl content could be due to oxidative as well as non-oxidative mechanisms and that heme-containing compounds may effect carbonyl quantification.

A tool to measure radiotherapy complexity and workload: derivation from the basic treatment equivalent (BTE) concept

Radiotherapy workload is poorly represented by simple parameters of patients, fractions or fields treated because these do not contain any measure of treatment complexity. However, complexity is increasing and there is an urgent need to quantify this. We have evaluated the basic treatment equivalent (BTE) model as a measure of radiotherapy workload and complexity. Radiotherapy treatment times, from the patient entering to exiting the treatment room maze, were measured for 1298 treatment sessions on 269 patients. The data were used to assess the original model and derive three new models for predicting treatment duration. The most complicated, the 'Addenbrooke's complex model', contained two additional predictor variables, including 'site/technique', in a linear additive form. Before the study, the department used a standard treatment appointment time of 10 minutes. However, 50% of the measured treatments took longer than 10 minutes, (mean 10.9). Summed over the working day, this discrepancy indicates that a standard 10-minute appointment is a poor basis for scheduling radiotherapy. The original BTE model was effective in predicting treatment times, although this was improved by refinement of the model. The Addenbrooke's complex model correctly predicted 70% of treatment times to within 2 minutes (55% for the original BTE model), 80% to within 2.5 minutes and 95% to within 4.7 minutes. The percentage of the variation in observed times accounted for by the model is 59.4%. The models can represent radiotherapy complexity, can improve scheduling on linear accelerators, and are likely to be applicable to other departments. They are thus tools to assess the impact of changes in complexity from new techniques, trial protocols (e.g. the Medical Research Council prostate radiotherapy trial RTO1), and possible time saving from advanced technology such as multileaf collimators (MLCs) or automated machine set-up. The replacement of manually-lifted shielding blocks by MLCs should save 1.1-1.5 minutes for a three- or four-field pelvic plan (i.e. 12%-13%). The models could also be used to aid planning for future linear accelerator provision and for costing radiotherapy treatment.

How much surplus capacity is required to maintain low waiting times?

Random fluctuations in demand make it impossible to see all patients in a very short time scale unless capacity exceeds the mean demand. We describe a model to estimate the capacity levels required as a function of mean demand. Random fluctuations were assumed to follow a Poisson distribution. A Monte Carlo analysis was used to model variations in length of waiting times. To see patients without a waiting list the capacity must exceed mean demand by an amount proportional to the square root of the mean; if capacity equals mean demand, then actual demand will exceed capacity almost half the time. The smaller the mean demand, the greater the percentage increase in capacity that is required. Thus, subdivision of numbers, for subspecialization or fast-tracking, demands greater overall capacity. When multiple serial steps are required, each step must have spare capacity if a waiting list is to be avoided. When capacity is only slightly greater than mean demand, random fluctuations mean that targets can be met for long stretches of time, but these are interspersed with periods when the waiting list rises substantially. Allowing a small waiting time (2-4 weeks) considerably reduces the excess capacity required. Targets such as the 2-week wait for cancer referrals can be achieved only if resource levels are set to give considerably more patient slots per week than mean demand. The level of spare capacity required depends on the level of demand and the maximum waiting time permitted. Without surplus capacity, waiting targets cannot be met. To meet the 2-week waiting target, capacity must exceed mean demand by two patient slots per week for 99% success, or by one slot per week for 90% success.

Production of brominating intermediates by myeloperoxidase. A transhalogenation pathway for generating mutagenic nucleobases during inflammation

The existence of interhalogen compounds was proposed more than a century ago, but no biological roles have been attributed to these highly oxidizing intermediates. In this study, we determined whether the peroxidases of white blood cells can generate the interhalogen gas bromine chloride (BrCl). Myeloperoxidase, the heme enzyme secreted by activated neutrophils and monocytes, uses H2O2 and Cl(-) to produce HOCl, a chlorinating intermediate. In contrast, eosinophil peroxidase preferentially converts Br(-) to HOBr. Remarkably, both myeloperoxidase and eosinophil peroxidase were able to brominate deoxycytidine, a nucleoside, and uracil, a nucleobase, at plasma concentrations of Br(-) (100 microM) and Cl(-) (100 mM). The two enzymes used different reaction pathways, however. When HOCl brominated deoxycytidine, the reaction required Br(-) and was inhibited by taurine. In contrast, bromination by HOBr was independent of Br(-) and unaffected by taurine. Moreover, taurine inhibited 5-bromodeoxycytidine production by the myeloperoxidase-H2O2-Cl(-)- Br(-) system but not by the eosinophil peroxidase-H2O2-Cl(-)-Br(-) system, indicating that bromination by myeloperoxidase involves the initial production of HOCl. Both HOCl-Br(-) and the myeloperoxidase-H2O2-Cl(-)-Br(-) system generated a gas that converted cyclohexene into 1-bromo-2-chlorocyclohexane, implicating BrCl in the reaction. Moreover, human neutrophils used myeloperoxidase, H2O2, and Br(-) to brominate deoxycytidine by a taurine-sensitive pathway, suggesting that transhalogenation reactions may be physiologically relevant. 5-Bromouracil incorporated into nuclear DNA is a well known mutagen. Our observations therefore raise the possibility that transhalogenation reactions initiated by phagocytes provide one pathway for mutagenesis and cytotoxicity at sites of inflammation.

Lung cancer after Hodgkin's disease: a nested case-control study of the relation to treatment

PURPOSE

To investigate the causes of the raised risk of lung cancer in patients who have had Hodgkin's disease, and in particular the relationship to treatment.

PATIENTS AND METHODS

A nested case-control study was conducted within a cohort of 5,519 patients with Hodgkin's disease treated in Britain during 1963 through 1993. For 88 cases of lung cancer and 176 matched control subjects, information on treatment and other risk factors was extracted from hospital case-notes, and odds ratios for lung cancer in relation to these factors were calculated.

RESULTS

Risk of lung cancer was borderline significantly greater in patients treated with mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) chemotherapy than those who did not receive this treatment (relative risk [RR] = 1.66; 95% confidence interval [CI], 0.99 to 2.82), and increased with number of cycles of MOPP (P =.07). Exclusion of lung cancers for which histologic confirmation was not available strengthened these associations (RR = 2.41; 95% CI, 1.33 to 4.51; P =.004 for any MOPP and P =.007 for trend with number of cycles of MOPP). Risks were not raised, however, after chlorambucil, vinblastine, procarbazine, and prednisone treatment. There was evidence that the raised risk of lung cancer occurring in relation to radiotherapy was restricted to histologies other than adenocarcinoma.

CONCLUSION

The results suggest that MOPP chemotherapy may lead to elevated risk of lung cancer, at least in certain subgroups of patients. The role of chemotherapy in the etiology of lung cancer after Hodgkin's disease deserves further investigation.