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Biomedical subjects

J W Denham

Publications and source records attributed to J W Denham.

At least 37 records · Page 2Linked to original sources
PubMed1998

A pilot study of dermofilm in acute radiation-induced desquamative skin reactions.

Dermofilm (Innovatec, Australia Pty Ltd) is a topical preparation containing hydrophilic and lipophilic agents that enhance the barrier functions of damaged skin. It has been assessed in a pilot study of 50 patients with desquamative skin reactions to establish whether it is a suitable candidate to test against an existing, widely used alternative in a randomized controlled trial. Symptomatic improvement, compliance and healing time were the study endpoints. Symptomatic improvement occurred in 49 patients and compliance with the prescribing instructions was uniform. The range of healing times observed at all sites was large but a relationship with the size of the initial desquamated area was noted. It is concluded that a randomized trial comparing Dermofilm with a widely used and cheaper alternative would require a multicentre effort involving approximately 400 patients (200 per arm). Other trial design considerations are discussed.

Acute Disease↗
PubMed1997

Response of human hair cortical cells to fractionated radiotherapy.

Hair cortical cell counting (HCCC) represents a non-invasive, in-vivo measure of cell kill in the human integument. Sixty-six patients undergoing conventionally fractionated, external beam radiotherapy for early stage carcinoma of the prostate had groin hair samples counted. This technique is a sensitive and reproducible measure of radiation effect and may have applicability as an in-vivo prediction tool or in the field of biological dosimetry. A repopulative follicular response occurring at 3-4 weeks may explain flattening of the dose response curve.

Dose-Response Relationship, Radiation↗
PubMed1997

A phase III double-blind randomised study of rectal sucralfate suspension in the prevention of acute radiation proctitis.

BACKGROUND AND PURPOSE: A limited number of studies have suggested that oral sucralfate reduces the acute and late gastro-intestinal side-effects of pelvic radiotherapy and sucralfate enemas ameliorate symptoms of chronic proctitis. Sucralfate may act via local bFGF at the mucosal level in promoting angiogenesis and reducing epithelial associated microvascular injury. This multi-institutional study was designed to test the hypothesis that sucralfate given as an enema would have a significant protective effect against acute radiation induced rectal injury by direct application to the mucosa. MATERIALS AND METHODS: Eighty-six patients having radiotherapy for localised carcinoma of the prostate were randomised in a double-blind placebo-controlled study to receive either 15 ml of placebo suspension or 3 g of sucralfate in 15 ml suspension, given as a once daily enema during and for 2 weeks following radiotherapy. Assessment was based on the EORTC/RTOG acute toxicity criteria and a patient self-assessment diary. RESULTS: There was no significant difference between placebo and sucralfate for peak incidences of EORTC/RTOG proctitis. For the placebo and sucralfate arms 95 and 88% (difference 7 +/- 11%) suffered some degree of proctitis, with 71 and 61% (difference 10 +/- 19%) reaching grade 2, respectively. The median period to onset of grade 2 proctitis was 33.5 and 36 days, with the median duration being 9.5 and 15 days, respectively, again these difference being non-significant. Thirty-five and 37% of patients rated the effect of radiotherapy on bowel habit as 'a lot' with a moderate or severe effect on normal daily living in 52 and 49%, respectively. CONCLUSION: This study suggests that sucralfate given as a once daily enema does not substantially reduce the incidence of symptoms associated with acute radiation proctitis and its routine clinical use cannot be recommended. This cohort of patients will be followed to determine if any difference develops in relation to late toxicity.

Acute Disease↗
PubMed1997

A combined modality approach to the management of oesophageal cancer.

This study aims to update the experience of multimodality approaches in the management of oesophageal cancer that have been adopted in several Australian and New Zealand hospitals. Between 1984 and 1985, 92 patients received pre-operative radiotherapy (30-36 Gy over 3 weeks) and one of two chemotherapy regimes (one or two courses of i.v. cisplatin 80 mg/m2 plus a 4-5 day continuous i.v. of fluorouracil 5-800 mg/m2/day) concurrently prior to surgery. Eighty-two patients (89%) underwent resection as planned. Operative specimens were microscopically free of residual tumour in 18 patients. Eight patients (9%) had treatment-related deaths: seven from surgery and one due to pre-operative chemoradiation. The Kaplan-Meier 5-year cause-specific survival estimates were 32.9 +/- 7.8% for the 58 patients with squamous cancer and 0% for the 32 with adenocarcinoma. Complete pathological response to the pre-operative regime was more common in females and was associated with a survival advantage. Five-year cause-specific survival expectation in patients who experienced a complete pathological response was 71.5 +/- 12.4%, whereas it was only 15.9 +/- 5.6% in patients who had residual cancer in their surgical specimens. Although less toxic the pre-operative regime utilizing only one cycle of chemotherapy was no less efficacious either in producing a complete pathological response or in terms of survival expectation. This uncontrolled pilot study has produced encouraging long-term results, especially for patients with squamous carcinoma that experienced a complete response to pre-operative synchronous chemoradiotherapy. A randomized controlled study comparing surgery alone with (one cycle) chemoradiation followed by surgery is now underway.

Adult↗
PubMed1996

Factors influencing outcome following radio-chemotherapy for oesophageal cancer. The Trans Tasman Radiation Oncology Group (TROG)

BACKGROUND AND PURPOSES: To define new directions, the Trans Tasman Radiation Oncology Group (TROG) has conducted a detailed analysis of its unrandomised experience with radio-chemotherapy in oesophageal cancer. METHODS AND PATIENTS: Since 1984, 373 patients with oesophageal cancer have been treated on three prospective, but unrandomised, protocols involving radiation with concurrent cisplatin and infusional fluorouracil. Centres in Australia and New Zealand have contributed patients. Reasons for case selection have been examined in detail and prognostic models have been examined in the light of biases exposed. RESULTS: Cause specific survival in 92 patients treated pre-operatively with 35 Gy, infusional fluorouracil and cisplatin was 25.5 +/- 6.0% at 5 years and similar to the 5 year expectations of 169 patients treated with 60 Gy and two courses of the same chemotherapy (23.8 +/- 4.7%). Analysis of failure in these groups suggests that local relapse precedes the development of metastases and competes as a cause for ultimate failure. Although patients treated surgically were less likely to relapse locally, survival was no better because more developed metastases. Some of the 112 patients treated "palliatively" with 30-35 Gy concurrent with chemotherapy without surgery have become long-term survivors with 5 year survival figure in this group 7.7 +/- 3.4%. Apart from variables related to disease stage and performance status at presentation, tumour site emerged as a strong predictor of outcome. Prognosis worsens the nearer the tumour is to the stomach. In addition, indications of a radiation dose response relationship emerged. CONCLUSIONS: Concurrent radio-chemotherapy protocols can improve outcome in patients fit enough to tolerate these approaches. New strategies remain necessary, however.

Adenocarcinoma↗
PubMed1996

Underprediction of human skin erythema at low doses per fraction by the linear quadratic model.

BACKGROUND AND PURPOSE: The erythematous response of human skin to radiotherapy has proven useful for testing the predictions of the linear quadratic (LQ) model in terms of fractionation sensitivity and repair half time. No formal investigation of the response of human skin to doses less than 2 Gy per fraction has occurred. This study aims to test the validity of the LQ model for human skin at doses ranging from 0.4 to 5.2 Gy per fraction. MATERIALS AND METHODS: Complete erythema reaction profiles were obtained using reflectance spectrophotometry in two patient populations: 65 patients treated palliatively with 5, 10, 12 and 20 daily treatment fractions (varying thicknesses of bolus, various body sites) and 52 patients undergoing prostatic irradiation for localised carcinoma of the prostate (no bolus, 30-32 fractions). RESULTS AND CONCLUSIONS: Gender, age, site and prior sun exposure influence pre- and post-treatment erythema values independently of dose administered. Out-of-field effects were also noted. The linear quadratic model significantly underpredicted peak erythema values at doses less than 1.5 Gy per fraction. This suggests that either the conventional linear quadratic model does not apply for low doses per fraction in human skin or that erythema is not exclusively initiated by radiation damage to the basal layer. The data are potentially explained by an induced repair model.

Aged↗
PubMed1996

The follicular non-Hodgkin's lymphomas--I. The possibility of cure.

The follicular lymphomas pursue an indolent course in many patients. Long-term follow-up in large series is therefore necessary to establish whether cure is taking place, and if so, at what stage in the dissemination of the disease process it becomes unlikely. The time to, and site of relapse, together with its impact on survival has been studied in 398 patients entered into the British National Lymphoma Investigation limited and disseminated disease trials between 1974 and 1980. Relapse data were compared with various models to obtain maximum likelihood estimates of the proportions permanently remaining relapse-free following treatment. Long-term relapse-free survival was observed in 54.8 +/- 14.9% (95% CI) of patients at 15 years with Ann Arbor stage I disease, 29.2 +/- 13.6% in patients with stage II disease, 18.1 +/- 6.6% with stage III and 13.0 +/- 5.9% with IV disease. Relapse time-course data for all trial arms conform closely to lognormal distributions allowing maximum likelihood estimates of proportions remaining permanently relapse-free to be derived. Using this methodology, over a quarter of patients treated with involved radiotherapy alone or radiotherapy plus 6 months of chlorambucil in the limited disease (Ann Arbor stage I and II) trial are unlikely to relapse at any time in the future. Over 10% of patients treated in the disseminated disease trials with disease classified as Ann Arbor stage III are also statistically unlikely to relapse. The finding that a proportion of patients is statistically unlikely to experience a clinically obvious relapse is consistent with clinical cure. It is especially interesting that a small proportion of patients with disseminated disease and treated by chemotherapy have fallen into this category, but additional data are required to know at what point statistical cure becomes unlikely. Whether "clinical cure" is the same as "pathological cure" in this disease remains uncertain.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

The follicular non-Hodgkin's lymphomas--II. Prognostic factors: what do they mean?

The Ann Arbor staging classification has long been recognised to have shortcomings when used to stage the follicular lymphomas. To date, the identification of important prognostic variables has not succeeded in producing a superior staging classification that reflects the stages of dissemination of these processes in a way that can be used in the testing of new therapeutic strategies. A fresh look is taken at these factors. Data from 398 patients entered into the British National Lymphoma Investigation trials between 1974 and 1980, were analysed to evaluate the performance of the Ann Arbor staging classification. Multiple regression and proportional hazards techniques were used to determine what factors independently influence response to initial treatment, the durability of that response and ultimate survival, and to isolate factors that relate to disease progression from those that have other mechanisms of action. The Ann Arbor staging classification fared poorly, minimally separating relapse-free and cause-specific survival probabilities in patients with the largest staging groupings, III and IV. Significant prognostic heterogeneity was seen in both of these stage groupings, with 22% of patients with stage IV disease on the basis of marrow involvement having slightly better outcomes than patients with stage III disease. Significant differences in outcome were also observed between patients of different age and sex in each Ann Arbor stage grouping. Increasing number of lymph node regions involved, constitutional symptoms, the presence of splenomegaly and increasing age were observed to have powerfully independent adverse influence on probability of complete response to treatment and cause-specific survival. The evolution of the follicular lymphomas is reflected at the clinical level by an increase in the number of lymph node regions involved and splenomegaly. Simple classifications based on simple counts of lymph node regions involved and splenomegaly are more successful than the Ann Arbor staging classification in subdividing the series into patient subgroups that, regardless of gender or age, experience significantly different probabilities of responding completely to therapy and, as a consequence, relapse-free and cause-specific survival expectations. The definition of poor prognosis in subgroups may be of value in selecting patients for newer and more intensive therapeutic approaches.

Age Factors↗
PubMed1996

Mucosal regeneration during radiotherapy. Trans Tasman Radiation Oncology Group (TROG).

BACKGROUND AND PURPOSE: Regeneration of the aerodigestive mucosa is known to occur during conventionally fractionated radiotherapy. The circumstances surrounding its time of onset and magnitude are not well understood, however. MATERIAL AND METHODS: Mucosal reactions were observed in 100 patients undergoing conventionally fractionated treatment at 2 Gy/day over 7 weeks and 88 receiving accelerated treatment at 1.8 Gy twice daily over 3 1/2 weeks on the Trans Tasman Radiation Oncology Group head and neck cancer trials. Similar observations in 61 patients treated palliatively at dose rates between 0.8 and 240 Gy/h using ten 3.0-4.2 Gy fractions over 2 weeks are compared. RESULTS: Several findings emerged from these studies: 1. Reactions evolved more quickly at oropharyngeal sites than in the hypopharynx. 2. Reactions at both sites evolved more rapidly at greater rates of dose accumulation. 3. The timing of reactions suggested the presence of a strong regenerative mucosal response that started before the manifestation of "patchy' (grade II) mucosal reactions. 4. The regenerative response was strong enough to "make good' damage accumulated at a rate of 2 Gy/day in over a third of cases. 5. The linear quadratic model without time correction failed to provide an adequate prediction of the frequency or intensity of mucosal reactions produced by any of the regimes. A simple model of the regenerative response is presented. CONCLUSIONS: This study suggests that the timing and magnitude of the regenerative response vary between sites and individuals but are linked to the amount of epithelial cellular depletion occurring during treatment.

Head and Neck Neoplasms↗
PubMed1996

Low dose rate teletherapy: updated tumour response.

This report presents an update of tumour response experience in patients with locally advanced head and neck cancer treated on the low dose rate teletherapy project at the Mater Misericordiae Hospital, Newcastle. Long-term progression-free survival figures are disappointing in all dose rate/total dose groupings and offer little encouragement that an improvement in therapeutic ratio can be achieved for head and neck cancer patients using teletherapy apparatus adjusted to treat at low and intermediate dose rates.

Cesium Radioisotopes↗
PubMed1996

Concurrent chemoradiation for oesophageal cancer: factors influencing myelotoxicity.

Concurrent chemotherapy and radiation (CT/RT) for localized oesophageal cancer can cause life-threatening myelosuppression. This non-randomized study examines 95 patients from three Australasian centres treated on the Trans-Tasman Radiation Oncology "definitive' chemoradiation study. Duration of fluorouracil infusion and patient age were independently predictive of myelotoxicity after the first cycle of CT/RT. Overall rates of grade III and IV neutropaenia were 23% and of thrombocytopaenia 8% following the first cycle of chemotherapy. Five neutropaenic septic episodes followed the first cycle and six the second. All five patients recovered after the first cycle but there were four treatment-related deaths occurring after the second cycle of CT/RT. Recommendations are made concerning initial dosing, dose reductions and delays to minimize adverse patient outcomes from myelosuppression.

Age Factors↗
PubMed1996

Evaluation of rectal shielding in a Henschke system applicator.

PURPOSE: To assess the effectiveness of avoid shielding in the Henschke intracavitary gynaecologic 3-channel applicator. MATERIAL AND METHODS: An acrylic phantom was used with our locally modified 3-channel Henschke applicator so that standard treatments with caesium-137 sources could be simulated. Thermoluminescent dosimeters were used to measure point A and rectal doses with and without ovoid shielding to assess the benefits of this shielding. Unshielded measurements were also compared to our planning computer calculations to assess its accuracy. The thermoluminescent dosimeters were calibrated against a caesium teletherapy unit. An estimate of shielding effect produced by the ovoid shielding when using iridium-192 wire was also determined. RESULTS: Doses received at points in the plane containing the rectal point as defined by the ICRU in its report 38 [4] show a reduction ranging from 5% to 15% over the area measured due to the ovoid shielding. As expected this benefit is more pronounced when using iridium-192 sources. Given the steep dose gradients, good agreement is found between computed and measured values of point A doses. CONCLUSION: While ovoid shielding will never provide a large reduction in rectal dose using caesium-137 sources, our results indicate that it can be a worthwhile option when using the Henschke applicator.

Brachytherapy↗
PubMed1995

Clinical use of carbon-loaded thermoluminescent dosimeters for skin dose determination.

PURPOSE: Carbon-loaded thermoluminescent dosimeters (TLDs) are designed for surface/skin dose measurements. Following 4 years in clinical use at the Mater Hospital, the accuracy and clinical usefulness of the carbon-loaded TLDs was assessed. METHODS AND MATERIALS: Teflon-based carbon-loaded lithium fluoride (LiF) disks with a diameter of 13 mm were used in the present study. The TLDs were compared with ion chamber readings and TLD extrapolation to determine the effective depth of the TLD measurement. In vivo measurements were made on patients receiving open-field treatments to the chest, abdomen, and groin. Skin entry dose or entry and exit dose were assessed in comparison with doses estimated from phantom measurements. RESULTS: The effective depth of measurement in a 6 MV therapeutic x-ray beam was found to be about 0.10 mm using TLD extrapolation as a comparison. Entrance surface dose measurements made on a solid water phantom agreed well with ion chamber and TLD extrapolation measurements, and black TLDs provide a more accurate exit dose than the other methods. Under clinical conditions, the black TLDs have an accuracy of +/- 5% (+/- 2 SD). The dose predicted from black TLD readings correlate with observed skin reactions as assessed with reflectance spectroscopy. CONCLUSION: In vivo dosimetry with carbon-loaded TLDs proved to be a useful tool in assessing the dose delivered to the basal cell layer in the skin of patients undergoing radiotherapy.

Carbon↗
PubMed1995

Combined modality therapy for esophageal carcinoma: preliminary results from a large Australasian multicenter study.

PURPOSE: This report updates local control and survival experience and focuses on treatment toxicity in 294 patients with esophageal cancer who have been treated at six Australasian centers using three prospective unrandomized protocols that used concurrent radiation, cisplatin, and modest dose infusional fluorouracil. METHODS AND MATERIALS: Protocol 1--"definitive" chemoradiation. One hundred and thirty-seven patients have been treated with "definitive" radiation to 60 Gy in 6 weeks plus two courses of cisplatin (80 mg/m2) and infusional fluorouracil (800 mg/m2/day over 4 days) during the first and fourth weeks of radiation. Protocol 2--"preoperative" chemoradiation and surgery. Seventy-eight patients received chemoradiation using the same chemotherapy, but 30-35 Gy in 3-4 weeks prior to surgery. Protocol 3--"palliative" chemoradiation. Seventy-nine patients deemed incurable were treated "palliatively" with the same chemoradiation protocol without surgery. Follow-up ranges from 6 months to 7 years (mean 22 months) in live patients. RESULTS: Durable palliation of dysphagia in all three treatment groups has been reflected by encouraging 3-year survival expectations of 43.2 +/- 5% in definitively treated patients, 40.3 +/- 7.65% in surgically treated patients, and 8.5% +/- 3.9% in the palliatively treated patients. There are early indications that female patients have fared better than males. Toxicity levels were modest in all three groups. Following definitive treatment, severe myelotoxicity (World Health Organization grades 3 and 4) occurred in 19%, severe esophagitis (World Health Organization grade 3) in 11%, and moderate or severe benign stricture in 17%, depending upon age and sex of the patient (being worse in female patients). CONCLUSIONS: These studies demonstrate that the concurrent addition of modest dose cisplatin and infusional dose fluorouracil to radiation in the definitive, preoperative, and palliative settings contribute to high rates of durable dysphagia-free survival, with overall survival comparable to (and possibly better than) the chemoradiation arm of the recently reported Intergroup Study, but at the cost of less morbidity.

Adenocarcinoma↗
PubMed1995

Simultaneous adjuvant radiation therapy and chemotherapy in high-risk breast cancer--toxicity and dose modification: a Transtasman Radiation Oncology Group Multi-Institution study.

PURPOSE: To establish the toxicity profile of simultaneously administered postoperative radiation therapy and CMF chemotherapy as a prelude to a randomized controlled study addressing the sequencing of the two modalities. METHODS AND MATERIALS: One hundred and thirty eight breast cancer patients at high risk of locoregional, as well as systemic relapse, who were referred to three centers in Australia and New Zealand were treated with postoperative radiation therapy and chemotherapy simultaneously. Acute toxicity and dose modifications in these patients were compared with 83 patients treated over the same time frame with chemotherapy alone. In a separate study the long-term radiation and surgical effects in 24 patients treated simultaneously with radiation therapy and chemotherapy at Newcastle (Australia) following conservative surgery were compared with 23 matched patients treated at Newcastle with radiation therapy alone. RESULTS: Myelotoxicity was increased in patients treated simultaneously with radiation therapy and chemotherapy. The effect was not great, but may have contributed to chemotherapy dose reductions. Lymphopenia was observed to be the largest factor in total white cell depressions caused by the simultaneous administration of radiation therapy. Postsurgical appearances were found to so dominate long-term treatment effects on the treated breast that the effect of radiation therapy dose and additional chemotherapy was difficult to detect. CONCLUSION: Studies addressing the sequencing of radiation therapy and chemotherapy will necessarily be large because adverse effects from administering the two modalities simultaneously are not great. The present study has endorsed the importance in future studies of stratification according to the extent and type of surgery and adherence to a single strict policy of chemotherapy dose modification.

Adult↗