Browsing by Department "Division of Radiation Oncology"
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- ItemOpen AccessAdjuvant chemotherapy for stage I non-seminomatous testicular cancer(1994) Abratt, R P; Pontin, AR; Barnes, RD; Reddi, BVThe International Society for Burns Injuries (ISBI) has published guidelines for the management of multiple or mass burns casualties, and recommends that 'each country has or should have a disaster planning system that addresses its own particular needs.' The need for a national burns disaster plan integrated with national and provincial disaster planning was discussed at the South African Burns Society Congress in 2009, but there was no real involvement in the disaster planning prior to the 2010 World Cup; the country would have been poorly prepared had there been a burns disaster during the event. This article identifies some of the lessons learnt and strategies derived from major burns disasters and burns disaster planning from other regions. Members of the South African Burns Society are undertaking an audit of burns care in South Africa to investigate the feasibility of a national burns disaster plan. This audit (which is still under way) also aims to identify weaknesses of burns care in South Africa and implement improvements where necessary.
- ItemOpen AccessContinuous low dose rate irradiation of the rat brain(1999) Madhoo, Jitesh; Blekkenhorst, Gerhardus HendrikusThe reported median survival time for patients who are diagnosed with high grade astrocytomas and who undergo postoperative radiotherapy is of the order of 24 to 40 weeks. The course of radiotherapy administered to these patients takes up a considerable portion of their expected survival time. Therefore, any means of reducing the treatment time may contribute to an enhanced quality of life for these patients. A potentially useful method for the reduction of the treatment time may be achieved with the use of continuous low dose rate external beam radiotherapy, where the treatment is administered over a 12 to 24 hour period. A relationship between fractionated and continuous low dose rate irradiation has been reported for skin, however, no such relationship has been reported for the brain. Low dose rate protocols that are equivalent in effect to fractionated (conventional) protocols can be derived using the linear quadratic theory, provided that quantitative radiobiological data for normal tissue (brain) is known. Thus, the aim of the current study is to test the radiation tolerance of the rat brain to low dose rate and fractionated radiation in order to establish the values for the parameters of the linear quadratic model.
- ItemOpen AccessDysphagia progression-free survival in patients with locally advanced and metastatic oesophageal cancer receiving palliative radiation therapy(2020) Bhim, Nazreen; Robertson, BarbaraPurpose: In patients with advanced oesophageal carcinoma palliation of dysphagia is important to maintaining a reasonable quality of life. The primary aim of this study was to determine the dysphagia progression-free survival (DPFS) in patients with advanced oesophageal carcinoma treated with palliative radiotherapy (RT). Methods: The medical records of all patients with oesophageal carcinoma presenting to Groote Schuur Hospital, Cape Town between January 2015-December 2016 were reviewed and patients who were not candidates for curative treatment and received palliative RT were selected. For these patients, the dysphagia score (DS) was recorded prior to RT, 6 weeks after RT and at each follow-up visit. The DPFS was calculated as the time from completion of RT to worsening in DS by ≥1 point or until death. Other outcomes measured were objective change in DS and survival post RT. Results: The study population comprised 84 patients. Squamous cell cancer was the primary histological subtype (93%). The median duration of DPFS after RT was 73 days, with approximately two-thirds of patients remaining able to swallow at least liquids and soft diet until death. The difference in median duration of DPFS was not statistically significant in stented versus non-stented patients (54 days vs 83 days; p =0.224). The mean change in DS was 0.45 ± 0.89 points following RT and the post RT survival was significantly shorter in patients with stent insertion (81 days vs 123 days; p=0.042). Conclusion: Palliative RT can be used successfully to prolong DPFS in patients with locally advanced and metastatic squamous cell cancer of the oesophagus.
- ItemOpen AccessThe effects of the modification of energy metabolism on cellular response to ionizing radiation(1997) Hunter, Alistair John; Blekkenhorst, Gerhardus HendrikusIt is generally accepted that energy is required for repair of radiation-induced damage in living cells. Some of this energy is probably provided by adenosine triphosphate (ATP), which is derived from energy substrates via energy metabolism. This dissertation follows two general avenues. The first explores the effect of radiation on ATP levels after irradiation of cells. The second investigates the effect of inhibitors of certain pathways associated with energy metabolism on radiation response. It was proposed that ATP levels might be raised after irradiation in some systems and that this rise in ATP might be due to compensatory mechanisms related to repair. Experiments were conducted using B16 melanoma cells in vitro and using normal murine liver and CaNT tumours in vivo. ATP concentration was measured in extracts of these cells after irradiation using the luciferase-luciferin method. No major changes from unirradiated controls were found. Several types of substrates exist from which cells can derive energy, including glucose and glutamine which are initially metabolised via glycolysis and glutaminolysis, respectively, before their products are further metabolised in respiration. Since energy is necessary for repair of radiation damage, it has been proposed that the inhibition of energy metabolism might alter the radiation response of cells. An inhibitor of glycolysis, 2-deoxyglucose (2DG), and an inhibitor of glutaminolysis, aminooxyacetic acid (AOA), were administered to CHO cells in vitro to determine the effects of these substances on cellular radiosensitivity and repair. Repair was assessed by means of a split radiation dose experiment. The design of such an experiment required that cells be exposed to inhibitory test media for different times between two fractions of radiation. Any changes in clonogenic survival with time between tween fractions could, therefore be as a result of repair effects or as a result of changes in radiosensitivity. A method of estimating and subtracting the effects of radiosensitivity to make conclusions concerning repair is presented and discussed. Most combinations of 2DG, AOA, glucose omission and glutamine omission in culture media resulted in reductions in repair rate but the extent of repair was found to vary from one medium variation to the next. In addition, the effects of various culture media on glycolysis/PPP (glycolysis/pentose phosphate pathway) and glutaminolysis were investigated by determining the production of CO2 and lactate from radiolabelled-glucose and -glutamine substrates. It was apparent that the presence of either of the inhibitors, 2DG or AOA, could inhibit the activity of glutaminolysis and reduce oxygen consumption. 2DG was shown to inhibit glycolysis/PPP but AOA was shown to stimulate glycolysis/PPP, suggesting a regulatory link between glutaminolysis and glycolysis/PPP. The presence of either inhibitor resulted in a reduction in the rate of radiation damage repair. The medium which had the most significant effect in respect of repair inhibition and increased radiosensitivity was medium lacking both glucose and glutamine and containing both 2DG and AOA. This medium was shown to inhibit oxygen consumption and to result in a depression of both cellular glycolysis/PPP and glutaminolysis. The effect of 2DG on the rate of growth and radiation induced growth delay of three murine tumours in vivo was assessed. 2DG alone inhibited the growth of B16 tumours. However, 2DG alone produced little if any change in the rates of growth of Fib/T tumours and rhabdomyosarcomas but the combination of 2DG and AOA produced an inhibition of growth in the Fib/T tumour. 2DG appeared to enhance the effects of radiation in the Fib/T and B16 tumours but not in the rhabdomyosarcoma, although, in the Fib/T, the combination of AOA, 2DG and radiation was less effective in inhibiting tumour growth than was radiation alone. The effects of radiation and 2DG did not appear to be additive in the Fib/T tumour and the B16 tumours which may imply an influence of 2DG on repair or radiosensitivity. This work suggests that the effects of radiation can be altered by manipulation of metabolic pathways associated with the supply of energy. However, a complex interaction of pathways is probably also involved and it is the detail of this interaction which may partially determine the severity of radiation response.
- ItemOpen AccessEpendymal tumours in childhood: outcomes and prognostic factors(2017) Nkosi, Zanele; Parkes, Jeannette; Hunter, AlistairOBJECTIVES: To retrospectively review the patient demographics, disease profile and treatment outcomes of paediatric patients treated for ependymoma at our institution. STUDY DESIGN AND METHODS: 51 eligible patients were treated between 1980 and 2013. The median age at presentation was 6 years. The majority of patients were male (66,7%), had infratentorial tumours (62,7%) and had low-grade tumours (70,6%). Gross total resection (GTR) was achieved in 22 patients (43,1%). Thirtyeight patients received adjuvant radiotherapy (76,5%) and 10 (19,6%) received adjuvant chemotherapy. RESULTS: The 5-year overall survival (OS) was 63,3 % (median follow up of 46 months). The 5 year progression free survival (PFS) was 50,70%. Seventeen (33,3%) patients experienced treatment failure, of which 13 (76,5%) represented local failure. The median time to first relapse was 20 months. The 5 year PFS for children > 3 was 50,0 % and 27,7% for children ≤ 3 years of age (p = 0.0356). GTR had a superior 5- year OS of 73,9% over subtotal resection with a value of 56,7% (p = 0.0016). Similarly an improved 5-year PFS of 70,3% versus 29,1% was observed with GTR over subtotal resection (p = <0.0001). Patients who received adjuvant radiotherapy (RT) had significantly better outcomes than those in whom RT was not given (p = <0.0001, 5 year OS of 69,7% versus 37,5%). CONCLUSION: This review confirms the finding that GTR is associated with improved outcomes and that adjuvant radiation therapy positively impacts survival. The worse outcomes in the younger age group requires further evaluation and possible change in treatment protocol for this group of patients.
- ItemOpen AccessThe influence of cisplatin dose variations during concurrent weekly chemo-radiation in stage IIB cervical cancer at Groote Schuur Hospital(2017) Jemu, Mtabeni; van Wijk, LeonObjective: To examine the effect of treatment and tumour factors on the overall survival (OS) of patients completing chemo-radiation (CRT) for stage IIB cervical cancer. Materials and methods: Retrospective audit of 228 patients with stage IIB cervical cancer treated between 1995 and 2010, who received CRT with at least 45 Gy external beam radiation, two to four brachytherapy insertions, and one or more cycles of concurrent weekly cisplatin (40mg/m², capped at 60 mg/week). Results: Mean tumour size was 5.5cm, bilateral parametrial involvement in 40% of patients, lateral parametrial involvement in 50%, and vaginal spread in 43%. Mean total dose to Point A was 83 Gy (range 61-96) linear quadratic equivalent dose to 2 Gy/fraction. Mean overall treatment time (OTT) was 45 days. The average weekly haemoglobin (AWHB) during treatment was 11.6 g/dL (range 8.8-15.5). Blood transfusions before or during chemo-radiation were given in 33% of patients. Two thirds of patients completed five or six cycles of weekly cisplatin. Reasons for fewer than five cycles were: scheduling failure, neutropaenia, and/or renal impairment. No outcome differences were observed for Monday vs. Thursday cisplatin administration. The 5-year OS was 60%. Patients completing fewer than six cycles had a worse OS (55 vs. 76%, p=0.02). By multiple regression analysis for OS, only six cycles of cisplatin, squamous histology, and AWHB>10g/dL were significant. Conclusions: Maintaining HB>10 and administering six cycles of weekly cisplatin at the dose regimen used appear to be requirements for maximal benefit during CRT of stage IIB cervical cancer.
- ItemOpen AccessOvert hypoadrenalism is uncommon in patients with stage 3 and 4 bronchogenic carcinoma(Health & Medical Publishing Group, 2003) Ross, Ian L; Marais, Suzaan; Raubenheimer, Peter; Abratt, Raymond; Isaacs, Sedick; Soule, StevenIntroduction. Lung cancer is the leading cause of cancer mortality in most countries. The adrenal glands are common sites of metastatic lung cancer as approximately 40% of subjects with stage 4 bronchogenic carcinoma have adrenal metastases. The prevalence of biochemical hypoadrenalism is, however, remarkably poorly documented. Objectives. Our study aimed to determine the prevalence of primary hypoadrenalism, as defined by a subnormal cortisol response to the 250 µg adrenocorticotrophic hormone (ACTH) stimulation test, in patients with stage 3 and 4 lung cancer. Methods. Thirty patients with stage 3 and 4 bronchogenic carcinoma were prospectively recruited from the bronchus clinic. Demographic data and electrolytes were recorded and each patient had a 250 µg ACTH stimulation test to determine the prevalence of overt adrenal insufficiency, defined as a +30 minute cortisol of less than 550 nmol/l. Results. The median age and quartile deviation was 62 (10) years and the median basal cortisol was 429.5 (321) nmol/l. The median peak cortisol was 828.5 (342) nmol/l (range 536 - 1 675 nmol/l). Twenty-eight patients (93.3%) had an appropriate rise of cortisol to greater than 550 nmol/l following 250 µg ACTH stimulation. Two patients (6.7%) had mild primary adrenal failure with a peak cortisol between 500 and 550 nmol/l associated with a raised plasma ACTH concentration (131.4 and 10.5 pmol/l, normal 2.2 - 10 pmol/l). Twenty-eight patients (92.9%) were normonatraemic, while the two hyponatraemic patients had biochemical evidence of the syndrome of inappropriate antidiuretic hormone secretion. Conclusion. In conclusion, despite evidence that the adrenal glands of patients with disseminated bronchogenic carcinoma are frequently affected by metastatic disease, biochemical evidence of clinically significant hypoadrenalism is relatively uncommon and is not accurately predicted by electrolyte abnormalities.
- ItemOpen AccessPostradiation sarcomas(1995) Murray, Elizabeth Margaret; Werner, I DThis report from Groote Schuur therefore sets out to review cases of postradiation sarcomas, including malignant mixed mullerian tumors (MMMT), presenting to the Radiation Oncology Departments of Groote Schuur Hospital and the affiliated hospitals (Frere Hospital, East London and Provincial Hospital, Port Elizabeth) or known to have occurred in patients initially treated in these hospitals. It aims [1] to establish the features of the initial malignancy as well as the latent period for the development of postradiation sarcoma, the type of postradiation tumor and the outcome of the disease; [2] to establish as accurately as possible dose levels at which the postradiation tumors have developed; and [3] to briefly describe possible risk factors such as a genetic predisposition to the development of malignancy, repeated courses of radiotherapy, surgery as part of the treatment of the initial tumor, and chemotherapy. Questions regarding the genesis of postradiation sarcomas cannot be answered by a review of 20 cases, even when combined with an analysis of literature. This review aims to add relevant information to the body of data from which the final answers may come. In view of the late diagnosis often made in cases of postradiation sarcoma (25, 94) the review also aims to heighten awareness of the condition so that it may be more often reported at a curable stage.
- ItemOpen AccessA retrospective review of outcomes in patients with node-negative stage IB cervical cancer treated with adjuvant standard pelvic field radiation versus small field pelvic field radiation(2017) Ralefala, Tlotlo; Van Wijk, LeonObjective: A retrospective review was conducted to ascertain whether there are differences in outcome or complications between node-negative patients with stage IB cervical cancer who were treated with adjuvant standard field as opposed to small pelvic field radiotherapy (RT). Study design: A retrospective observational study of patients with stage IB cervical cancer treated with radical surgery between 1984 and 2010 at Groote Schuur Hospital, Cape Town, South Africa. Two different pelvic radiation field sizes were used for adjuvant post-operative RT in node-negative patients during this period: standard whole pelvic fields (WPF), or with reduced-size, "small pelvic field" (SPF) RT since 1991. These two methods reflect changes in protocol over the period of this review. Cisplatin given concurrently with radiation has been used since 1999. Cancer control and grade 3 and 4 toxicities were compared between the two groups. The aim of this study was primarily to examine whether adjuvant SPF RT is a safe approach. A literature review was conducted on the subject of post-operative adjuvant RT, especially in node-negative patients; one aim was to discover how widely the SPF approach is used throughout the world. There was no indication in the literature that this approach has been used elsewhere in South Africa. Results: The SPF technique was first advocated by Prof Neville Hacker in Australia in 1991. The first publication by his group on SPF was in 1999, followed by several subsequent retrospective reports from Asian centers. In the current audit study, 31 patients were found in the WPF group, and 56 in the SPF group. The overall 5-year survival rate was 85%. No significant differences in survival rates were found between the WPF and SPF groups (log rank p=0.67) It was found that relapse patterns did not differ between the two groups and the same applied to the crude grade 3-4 treatment morbidity rates, although two patients in the WPF group (6%) died from their complications. Conclusions: The expected benefit of the SPF approach, which targets the central pelvic tumour bed, is a reduction in small bowel morbidity and lymphoedema. It is not possible to conclude from this study whether the SPF technique is unsafe by increasing out-of-field pelvic relapses, or whether it truly reduces complications. The literature review reveals that most studies of SPF involved relatively few patients and events were infrequent, whether recurrences or morbidity. A randomized controlled trial could theoretically settle this issue but it seems unlikely ever to be performed as a large sample size would be required. Intermittent single institution, or multi-institutional pooled comparisons, with historical WPF controls seem to be the best option.