Merkel cell carcinoma of skin: diagnosis and management strategies

Merkel cell carcinoma (MCC) of the skin is a rare form of cutaneous malignancy of neuroendocrine origin with a propensity to affect predominately elderly patients in sun-exposed areas. The tumour has an extremely aggressive growth pattern with the potential to seed into the dermal lymphatics at an early stage as well as spread to nodes and distant sites. Successful outcomes can be achieved with early diagnosis and a multidisciplinary approach to management. Patients with MCC should be carefully staged to exclude distant metastatic disease. Treatment should be approached with both the primary site and the lymph nodes in mind. The primary site should be excised with clear margins, followed by postoperative radiotherapy to the primary site and affected nodes. Addition of chemotherapy to patients perceived to be at high-risk of distant recurrence (e.g. those with involved nodes) has been considered, but evidence supporting this approach is relatively scant. This treatment strategy needs to be approached with caution in the elderly because of the risk of myelosuppression. An aggressive treatment approach is warranted at the first attempt to treat MCC as treatment for recurrent disease is less likely to be successful.

Mutualistic fungi control crop diversity in fungus-growing ants

Leaf-cutting ants rear clonal fungi for food and transmit the fungi from mother to daughter colonies so that symbiont mixing and conflict, which result from competition between genetically different clones, are avoided. Here we show that despite millions of years of predominantly vertical transmission, the domesticated fungi actively reject mycelial fragments from neighboring colonies, and that the strength of these reactions are in proportion to the overall genetic difference between these symbionts. Fungal incompatibility compounds remain intact during ant digestion, so that fecal droplets, which are used for manuring newly grown fungus, elicit similar hostile reactions when applied to symbionts from other colonies. Symbiont control over new mycelial growth by manurial imprinting prevents the rearing of multiple crops in fungus gardens belonging to the same colony.

Tirapazamine, Cisplatin, and Radiation versus Fluorouracil, Cisplatin, and Radiation in patients with locally advanced head and neck cancer: a randomized phase II trial of the Trans-Tasman Radiation Oncology Group (TROG 98.02)

PURPOSE

To select one of two chemoradiotherapy regimens for locally advanced squamous cell carcinoma (SCC) of the head and neck as the experimental arm for the next Trans-Tasman Radiation Oncology Group phase III trial.

PATIENTS AND METHODS

One hundred twenty-two previously untreated patients with stage III/IV SCC of the head and neck were randomized to receive definitive radiotherapy (70 Gy in 7 weeks) concurrently with either cisplatin (75 mg/m(2)) plus tirapazamine (290 mg/m(2)/d) on day 2 of weeks 1, 4, and 7, and tirapazamine alone (160 mg/m(2)/d) on days 1, 3, and 5 of weeks 2 and 3 (TPZ/CIS), or cisplatin (50 mg/m(2)) on day 1 and infusional fluorouracil (360 mg/m(2)/d) on days 1 through 5 of weeks 6 and 7 (chemoboost).

RESULTS

Three-year failure-free survival rates were 55% with TPZ/CIS (95% CI, 39% to 70%) and 44% with chemoboost (95% CI, 30% to 60%; log-rank P = .16). Three-year locoregional failure-free rates were 84% in the TPZ/CIS arm (95% CI, 71% to 92%) and 66% in the chemoboost arm (95% CI, 51% to 79%; P = .069). More febrile neutropenia and grade 3 or 4 late mucous membrane toxicity were observed with TPZ/CIS, while acute skin radiation reaction was more severe and prolonged with chemoboost. Compliance with protocol treatment was satisfactory on both arms.

CONCLUSION

Both regimens are feasible and are associated with significant but acceptable toxicity profiles in the cooperative group setting. Based on the promising efficacy seen in this trial, TPZ/CIS is being evaluated in a large phase III trial.

Tirapazamine, Cisplatin, and Radiation versus Fluorouracil, Cisplatin, and Radiation in patients with locally advanced head and neck cancer: a randomized phase II trial of the Trans-Tasman Radiation Oncology Group (TROG 98.02)

PURPOSE

To select one of two chemoradiotherapy regimens for locally advanced squamous cell carcinoma (SCC) of the head and neck as the experimental arm for the next Trans-Tasman Radiation Oncology Group phase III trial.

PATIENTS AND METHODS

One hundred twenty-two previously untreated patients with stage III/IV SCC of the head and neck were randomized to receive definitive radiotherapy (70 Gy in 7 weeks) concurrently with either cisplatin (75 mg/m(2)) plus tirapazamine (290 mg/m(2)/d) on day 2 of weeks 1, 4, and 7, and tirapazamine alone (160 mg/m(2)/d) on days 1, 3, and 5 of weeks 2 and 3 (TPZ/CIS), or cisplatin (50 mg/m(2)) on day 1 and infusional fluorouracil (360 mg/m(2)/d) on days 1 through 5 of weeks 6 and 7 (chemoboost).

RESULTS

Three-year failure-free survival rates were 55% with TPZ/CIS (95% CI, 39% to 70%) and 44% with chemoboost (95% CI, 30% to 60%; log-rank P = .16). Three-year locoregional failure-free rates were 84% in the TPZ/CIS arm (95% CI, 71% to 92%) and 66% in the chemoboost arm (95% CI, 51% to 79%; P = .069). More febrile neutropenia and grade 3 or 4 late mucous membrane toxicity were observed with TPZ/CIS, while acute skin radiation reaction was more severe and prolonged with chemoboost. Compliance with protocol treatment was satisfactory on both arms.

CONCLUSION

Both regimens are feasible and are associated with significant but acceptable toxicity profiles in the cooperative group setting. Based on the promising efficacy seen in this trial, TPZ/CIS is being evaluated in a large phase III trial.

Density-dependence and within-host competition in a semelparous parasite of leaf-cutting ants

Background

Parasite heterogeneity and within-host competition are thought to be important factors influencing the dynamics of host-parasite relationships. Yet, while there have been many theoretical investigations of how these factors may act, empirical data is more limited. We investigated the effects of parasite density and heterogeneity on parasite virulence and fitness using four strains of the entomopathogenic fungus, Metarhizium anisopliae var. anisopliae, and its leaf-cutting ant host Acromyrmex echinatior as the model system.

Results

The relationship between parasite density and infection was sigmoidal, with there being an invasion threshold for an infection to occur (an Allee effect). Although spore production was positively density-dependent, parasite fitness decreased with increasing parasite density, indicating within-host scramble competition. The dynamics differed little between the four strains tested. In mixed infections of three strains the infection-growth dynamics were unaffected by parasite heterogeneity.

Conclusions

The strength of within-host competition makes dispersal the best strategy for the parasite. Parasite heterogeneity may not have effected virulence or the infection dynamics either because the most virulent strain outcompeted the others, or because the interaction involved scramble competition that was impervious to parasite heterogeneity. The dynamics observed may be common for virulent parasites, such as Metarhizium, that produce aggregated transmission stages. Such parasites make useful models for investigating infection dynamics and the impact of parasite competition.

Assessment of the safety of foods derived from genetically modified (GM) crops

This paper provides guidance on how to assess the safety of foods derived from genetically modified crops (GM crops); it summarises conclusions and recommendations of Working Group 1 of the ENTRANSFOOD project. The paper provides an approach for adapting the test strategy to the characteristics of the modified crop and the introduced trait, and assessing potential unintended effects from the genetic modification. The proposed approach to safety assessment starts with the comparison of the new GM crop with a traditional counterpart that is generally accepted as safe based on a history of human food use (the concept of substantial equivalence). This case-focused approach ensures that foods derived from GM crops that have passed this extensive test-regime are as safe and nutritious as currently consumed plant-derived foods. The approach is suitable for current and future GM crops with more complex modifications. First, the paper reviews test methods developed for the risk assessment of chemicals, including food additives and pesticides, discussing which of these methods are suitable for the assessment of recombinant proteins and whole foods. Second, the paper presents a systematic approach to combine test methods for the safety assessment of foods derived from a specific GM crop. Third, the paper provides an overview on developments in this area that may prove of use in the safety assessment of GM crops, and recommendations for research priorities. It is concluded that the combination of existing test methods provides a sound test-regime to assess the safety of GM crops. Advances in our understanding of molecular biology, biochemistry, and nutrition may in future allow further improvement of test methods that will over time render the safety assessment of foods even more effective and informative.

Merkel cell carcinoma--current therapeutic options

Merkel cell carcinoma (MCC) is a rare, highly malignant skin tumour of neuroendocrine origin that occurs predominantly in elderly people in sun-exposed areas. It exhibits high levels of radiosensitivity and chemosensitivity both in vivo and in vitro. A variety of adverse prognostic factors have been identified which allow more aggressive therapy to be delivered to patients who are at higher risk of recurrence. The most powerful prognostic factor is the presence of nodal secondaries. Local disease should be excised, but there is some controversy over how wide the margins should be. Wide resection margins are not required provided postoperative radiotherapy is used. In the event of inoperable disease, patient refusal of surgery or frailty, radiotherapy can be used as the sole treatment modality, with a high likelihood of achieving local control. Patients with involved nodes have a higher risk of distant disease. Traditionally, involved nodes have been managed with resection but, currently, there are protocols exploring the use of synchronous chemoradiotherapy as definitive treatment. Although adjuvant chemotherapy has been used in this setting to reduce the risk of distant metastases, its role still remains under investigation. The presence of distant disease carries a grave outlook with responses to chemotherapy occurring frequently, albeit of short duration.

High-risk Merkel cell carcinoma of the skin treated with synchronous carboplatin/etoposide and radiation: a Trans-Tasman Radiation Oncology Group Study--TROG 96:07

PURPOSE

The effectiveness of synchronous carboplatin, etoposide, and radiation therapy was prospectively assessed in a group of patients with high-risk Merkel cell carcinoma (MCC) of the skin.

PATIENTS AND METHODS

Patients were eligible if they had disease localized to the primary site and nodes, and were required to have at least one of the following high risk features: recurrence after initial therapy, involved nodes, primary tumor size greater than 1 cm, gross residual disease after surgery, or occult primary with nodes. Radiation was delivered to the primary site and nodes to a dose of 50 Gy in 25 fractions over 5 weeks and synchronous carboplatin (area under the curve, 4.5) and intravenous etoposide 80 mg/m2 days 1 to 3 was given in weeks 1, 4, 7, and 10. The median age of the group was 67 (range, 43-86) years, and there were 39 males and 14 females. Involved nodes (stage II) were present in 33 cases (62%). The sites involved were head and neck (22 patients), occult primary (13 patients), upper limb (eight patients), lower limb (eight patients), and trunk (two patients).

RESULTS

Fifty-three patients were entered between 1996 and 2001. The median potential follow-up was 48 months. There were no treatment related deaths. The 3-year overall survival, locoregional control, and distant control were 76%, 75%, and 76%, respectively. Tumor site and the presence of nodes were factors that were predictive for local control and survival. Multivariate analysis indicated that the major factor influencing survival was the presence of nodes; however, this was not a significant factor in locoregional control.

CONCLUSION

High levels of locoregional control and survival have been achieved with the addition of chemotherapy to radiation treatment for high-risk MCC of the skin. The role of chemoradiotherapy for high-risk MCC warrants further investigation.

Acceptability of short term neo-adjuvant androgen deprivation in patients with locally advanced prostate cancer

PURPOSE

To determine the acceptability of short term neo-adjuvant maximal androgen deprivation (MAD) to patients treated with external beam radiation for locally advanced prostate cancer.

METHODS

Between 1996 and 2000, 818 patients with locally advanced, but non-metastatic, prostate cancer were entered into a randomised clinical trial (TROG 96.01), which compared radiation treatment alone with the same radiation treatment and 3 or 6 months neo-adjuvant MAD with goserelin and flutamide. Relevant symptoms, and how troublesome they were to the patient, were scored using a self-assessment questionnaire. This was completed by the patient at registration, and at specified times during and after treatment. Patients taking flutamide had liver function tests checked at regular intervals.

RESULTS

All patients have completed at least 12 months follow-up after treatment. Nearly all patients completed planned treatment with goserelin, but 27% of patients in the 6-month MAD treatment arm, and 20% in the 3-month arm, had to stop flutamide early. This was mainly due to altered liver function (up to 17% patients) and bowel side effects (up to 8% patients). However, although flutamide resulted in more bowel symptoms for patients on MAD, there was significant reduction in some urinary symptoms on this treatment. Acute bowel and urinary side effects at the end of radiation treatment were similar in all treatment arms. Side effect severity was unrelated to radiation target volume size, which was reduced by MAD, but symptomatology prior to any treatment was a powerful predictor. Of the 36% of patients who were sexually active before any treatment, the majority became inactive whilst on MAD. However, sexual activity at 12 months after radiation treatment was similar in all treatment arms, indicating that the effects of short term MAD on sexual function are reversible.

CONCLUSION

Despite temporary effects on sexual activity, and compliance difficulties with flutamide, short-term neo-adjuvant MAD was not perceived by patients to be a major inconvenience. If neo-adjuvant MAD in the way tested can be demonstrated to lead to improved biochemical control and/or survival, then patients would view these therapeutic gains as worthwhile. Compliance with short-term goserelin was excellent, confirming that LH-RH analogues have a potential role in more long-term adjuvant treatment. However, for more protracted androgen deprivation, survival advantages and deleterious effects need to be assessed in parallel, in order to determine the optimal duration of treatment.

A prospective trial of short-fractionation radiotherapy for the palliation of liver metastases

The purpose of this study was to prospectively examine the effectiveness and tolerability of a simple radiotherapy technique for the palliation of symptomatic liver metastases. Twenty-eight patients with symptomatic liver metastases were enrolled from seven centres, and received targeted (partial or whole) liver irradiation consisting of 10 Gy in two fractions over 2 days. Symptoms at baseline were hepatic pain (27 patients), abdominal distension (19), night sweats (12), nausea (18) and vomiting (eight). Twenty-two patients (76%) had failed previous treatment with chemotherapy, hormonal therapy and/or high-dose steroids. Symptoms and potential toxicities were prospectively assessed at the time of treatment, then 2, 6 and 10 weeks later. Individual symptom response rates were 53-66% at 2 weeks. Partial or complete global symptomatic responses were noted in 15 patients (54%) overall. The treatment was well tolerated with two patients (7%) experiencing grade 3 toxicity (one vomiting and one diarrhoea); however, four patients reported temporary worsening of pain shortly after treatment. This simple and well-tolerated treatment achieves useful palliation.

The effect of metapleural gland secretion on the growth of a mutualistic bacterium on the cuticle of leaf-cutting ants

In Acromyrmex octospinosus leaf-cutting ants the metapleural glands produce an array of antibiotic compounds that serve as a general defence against unwanted microbes on the cuticle. Leaf-cutting ants also grow mutualistic Pseudonocardiaceae bacteria on their cuticle that produce antibiotics controlling a microfungal parasite of their fungus gardens. Interaction between this bacterium and gland secretion therefore seems unavoidable. We document the typical development of bacterial growth on the cuticle of young major workers, show that growth starts a few days after eclosion, and that the maximal cover is reached after 2-3 weeks and gradually declines when workers mature. Experimental closure of the metapleural glands had no effect on the initial exponential growth phase of the bacterium, but significantly reduced the cover during the decline phase. The age-dependent abundance of the bacterium and its partial dependence on metapleural gland secretion support the hypothesis that the abundance of this mutualist is actively regulated.

Preservation of Form and Function in the Management of Head and Neck Skin Cancer

Optimal cosmetic and functional results are achieved through the appropriate selection of treatment modality and meticulous attention to technique in the treatment of skin cancers of the head and neck. A multidisciplinary approach is required in the more difficult cases. Adequate histologic analysis of margins and assessment of adverse prognostic features are crucial in the selection of therapy.

Subchronic oral toxicity study on the three flavouring substances: octan-3-ol, 2-methylcrotonic acid and oct-3-yl 2-methylcrotonate in Wistar rats

Groups of 10 male and 10 female rats were administered 0, 25, 100 or 400 mg octan-3-ol/kg body weight per day, 77 mg 2-methylcrotonic acid/kg body weight per day or 163 mg oct-3-yl 2-methylcrotonate/kg body weight per day by gavage for 90 days. Relative liver weights of high-dose octan-3-ol males, and males and females dosed with oct-3-yl 2-methylcrotonate were significantly greater than those of the control. In male and female rats dosed with the highest level of octan-3-ol and in male rats dosed with 2-methylcrotonic acid, incidences of bile duct proliferation were increased. In the kidneys of males dosed with mid- and high level of octan-3-ol and oct-3-yl 2-methylcrotonate, tubular karyomegaly and desquamation of tubular epithelial cells were observed. Based on increased liver weight and microscopic evaluation of the liver and kidney, a no-observed-effect level (NOEL) of 25 mg/kg for octan-3-ol in rats was established. The histopathological evaluation of the liver of rats dosed with oct-3-yl 2-methylcrotonate revealed lesions corresponding to the lesions seen in rats dosed mid-dose with octan-3-ol. This observation is in accordance with the general assumption that oct-3-yl 2-methylcrotonate is completely hydrolysed to octan-3-ol and 2-methylcrotonic acid. However, when comparing the liver histopathology of oct-3-yl 2-methylcrotonate and 2-methylcrotonic acid and the kidney lesions of all three substances, conflicting results were seen and the present study does not allow the conclusion to be drawn that oct-3-yl 2-methylcrotonate and structurally-related esters are completely hydrolysed, at least under the conditions of the present study.

Effect of insulin on protein phosphatase 2A expression in muscle in type 2 diabetes

BACKGROUND

Protein phosphatase 2A (PP2A) acts on a number of enzymes involved in the insulin regulation of glucose uptake and glycogen synthesis. This study was carried out to investigate the effect of insulin on PP2A expression in skeletal muscles of type 2 diabetic and control subjects.

MATERIAL AND METHODS

Ten type 2 diabetic and 10 matched, control subjects were studied using the euglycaemic-hyperinsulinaemic clamp technique combined with indirect calorimetry. Immunoreactive protein levels of the catalytic alpha subunit of PP2A (PP2A-C alpha) were measured in biopsies from the vastus lateralis muscle obtained in the basal and insulin-stimulated state.

RESULTS

In type 2 diabetic subjects insulin-mediated glucose disposal, glucose oxidation and nonoxidative glucose metabolism were reduced, whereas lipid oxidation was increased (all P < 0.05). Insulin down-regulated PP2A-C alpha expression in skeletal muscle of the control subjects (P < 0.05) but not in the type 2 diabetic subjects. In the control subjects, the insulin-mediated decrease in PP2A-C alpha correlated with the insulin-mediated increase in glucose disposal, glucose oxidation, nonoxidative glucose metabolism (all P < 0.05) and decrease in lipid oxidation (P < 0.01). In the type 2 diabetic subjects these relationships were absent.

CONCLUSIONS

Down-regulation of PP2A-C alpha expression by insulin in skeletal muscle seems to be associated with a normal insulin action on glucose storage, glucose and lipid oxidation. Impaired down-regulation of PP2A-C alpha expression by insulin may be a marker for insulin resistance and contribute to the pathogenesis of type 2 diabetes.

Is there a diminishing role for surgery for Merkel cell carcinoma of the skin? a review of current management

Merkel cell carcinoma is a highly malignant skin tumour that must be managed in a multidisciplinary forum. Excisional biopsy of the primary is recommended and this should be followed by postoperative radiotherapy to the primary site, in-transit areas and the draining lymph nodes. The tumour is quite radiosensitive and radiation doses of the order of 50 Gy offer high levels of local control. Resection margins of 3 cm are not required provided postoperative radiotherapy is used. In the event of inoperable disease, patient refusal of surgery or a frail patient, radiotherapy should be used as the sole treatment modality, with high likelihood of achieving local control. Patients with involved nodes have a higher risk of distant disease. Traditionally, involved nodes have been managed with resection but, currently, there are protocols exploring the use of synchronous chemoradiotherapy as definitive treatment. Although adjuvant chemotherapy has been used in this setting to reduce the risk of distant seeding, the benefits at this stage have not been confirmed conclusively. The presence of distant disease carries a grave outlook and responses to chemotherapy occur frequently, but are usually shortlived.

Analysis of toxicity of Merkel cell carcinoma of the skin treated with synchronous carboplatin/etoposide and radiation: a Trans-Tasman Radiation Oncology Group study

PURPOSE

The acute and late toxicities of synchronous carboplatin, etoposide, and radiation therapy were prospectively assessed in a group of patients with high-risk Merkel cell carcinoma of the skin.

PATIENTS AND METHODS

Forty patients from six different centers throughout Australia were entered into a Phase II study under the auspices of the Trans-Tasman Radiation Oncology Group. The trial was activated in 1996 and continues to accrue. Patients are eligible if they have disease localized to the primary site and nodes and are required to have at least one of the following high-risk features: recurrence after initial therapy, involved nodes, primary size greater than 1 cm, gross residual disease after surgery, or occult primary with nodes. Radiation was delivered to the primary site and nodes to a dose of 50 Gy in 25 fractions over 5 weeks, and synchronous carboplatin (area under curve [AUC] 4.5) and etoposide (80 mg/M(2) i.v.) were given on days 1-3 during weeks 1, 4, 7, and 10. The median age of the group was 67 years (43-78).

RESULTS

The median duration of follow-up was 22 months (2-45). There were no treatment-related deaths. Grade 3 or 4 skin toxicity occurred in 63% of patients (95% CI 48, 78). The most serious acute effect was on neutrophils with Grade 3 or 4 (neutrophils < 1 x 10(9)/L), occurring in 60% (95% CI 45, 75) of cases. Complications from neutropenia (fever and sepsis) occurred in 16 patients (40% of cases). The median time for neutropenic complications was 27 days (9-35), and 10/16 (62%) cases of neutropenic fever occurred after the second cycle of chemotherapy. The probability of Grade 3 or 4 late effects on platelets (<50 x 10(9)/L) and hemoglobin (<8 g/dl) was 10% (95% CI 1, 20) and 6% (95% CI 2, 15), respectively. Of the 40 patients, 35 were able to complete 4 cycles of chemotherapy. There were no factors predictive for neutropenic toxicity at a p value < 0.05.

CONCLUSIONS

The protocol has acceptable toxicity, and the treatment has been deliverable in a multi-institutional trial setting. Neutropenia is likely to occur with synchronous carboplatin/etoposide and radiation in this population of patients. The risk of a febrile neutropenia was greatest at the time of the second cycle of chemotherapy, when there was moist desquamation of skin or mucosal membranes that provided a portal for infection. This should be considered in the design of subsequent protocols with chemoradiotherapy.

The influence of simple sugars and starch given during pre- or post-initiation on aberrant crypt foci in rat colon

The aim of the present study was to investigate the enhancing effect of dietary sugar on the development of aberrant crypt foci (ACF) in male F344 rats initiated with azoxymethane (AOM). The potential role of sugar as either a co-initiator or a promoter was investigated by giving diets high in sucrose and dextrin (61%) during either the pre-initiation, the initiation, and/or the post-initiation stage of the ACF development. The colonic cell proliferation, activity of colonic phase II enzymes, and a biomarker of lipid peroxidation were additionally examined in order to obtain information on the specific mechanisms involved in the suggested effect of sucrose and dextrin on ACF development. The number of large sized and the total number of ACF were significantly increased by feeding sucrose and dextrin in the post-initiation period. No positive association between colonic cell proliferation and ACF was seen. The level of oxidative stress in the cytosol from the proximal colon and colonic glutathione transferase and quinone reductase was not affected by the sugar treatments. The overall results from this study show that sucrose and dextrin enhance the number of preneoplastic lesions in AOM-initiated rats, and act primarily as promoters in the development of ACF.

How do waiting times affect radiation dose fractionation schedules?

The purpose of the present paper was to evaluate the changing patterns of dose prescription at the Queensland Radium Institute from 1995 to 1998 inclusive. Data were analysed from the treatment files collected on each patient and these were compared with data on delay time. There has been an increased use of shorter fractionation schedules in the period studied. Paradoxically, radical treatments have become longer. The average number of fractions for all patients was 17.4 and for palliative treatments it was 7.4. The monthly delay varied from 0 to 22 working days and the average was 7 working days. When fraction number was compared to treatment delay, there was a negative linear correlation (R = -0.25). The correlation was stronger (R = -0.467) when palliative treatments were compared, indicating that clinicians were more prepared to alter palliative treatments in the presence of a treatment delay than curative ones.

Phase II multicenter study of brief single-agent methotrexate followed by irradiation in primary CNS lymphoma

PURPOSE

To assess, in a multi-institutional setting, the impact on relapse, survival, and toxicity of adding two cycles of intravenous methotrexate to cranial irradiation for immunocompetent patients with primary CNS lymphoma.

PATIENTS AND METHODS

Forty-six patients with a median age of 58 years and Eastern Cooperative Oncology Group performance status 0 to 3 were entered onto this phase II study. The protocol consisted of methotrexate 1 g/m(2) on days 1 and 8 followed by cranial irradiation on day 15. A whole-brain dose of 45 Gy was followed by a boost of 5.4 Gy. Intrathecal chemotherapy and spinal irradiation were given only to patients for whom cytologic examination of CSF was positive for CNS lymphoma. The median follow-up time was 36 months, with a minimum potential follow-up of 12 months.

RESULTS

Median survival was 33 months, with 2-year probability of survival 62% +/- 15% (95% confidence interval). Twenty patients have relapsed. The predominant site of relapse was the brain. Neither performance status nor age was found to influence survival. Six patients developed a dementing illness at a median of 16 months after treatment, and three of these died as a consequence.

CONCLUSION

A brief course of intravenous methotrexate before cranial irradiation is associated with 2-year and median survival rates superior to those reported for radiotherapy alone and similar to more intensive combined-modality regimens. Neurotoxicity remains an important competing risk for these patients.

A quality assurance audit: phase III trial of maximal androgen deprivation in prostate cancer (TROG 96.01)

In 1997 the Trans-Tasman Radiation Oncology Group (TROG) performed a quality assurance (QA) audit of its phase III randomized clinical trial investigating the effectiveness of different durations of maximal androgen deprivation prior to and during definitive radiation therapy for locally advanced carcinoma of the prostate (TROG 96.01). The audit reviewed a total of 60 cases from 15 centres across Australia and New Zealand. In addition to verification of technical adherence to the protocol, the audit also incorporated a survey of centre planning techniques and a QA time/cost analysis. The present report builds on TROG's first technical audit conducted in 1996 for the phase III accelerated head and neck trial (TROG 91.01) and highlights the significant progress TROG has made in the interim period. The audit provides a strong validation of the results of the 96.01 trial, as well as valuable budgeting and treatment planning information for future trials. Overall improvements were detected in data quality and quantity, and in protocol compliance, with a reduction in the rate of unacceptable protocol violations from 10 to 4%. Audit design, staff education and increased data management resources were identified as the main contributing factors to these improvements. In addition, a budget estimate of $100 per patient has been proposed for conducting similar technical audits. The next major QA project to be undertaken by TROG during the period 1998-1999 is an intercentre dosimetry study. Trial funding and staff education have been targeted as the key major issues essential to the continued success and expansion of TROG's QA programme.