Masters Degrees (Radiation Oncology)

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Breast cancer diagnosed in women with the Human Immune-Deficiency Virus (HIV)
(Stellenbosch : Stellenbosch University, 2014-12) Langenhoven, Lizanne; Barnardt, Pieter; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Medical Imaging and Clinical Oncology. Radiation Oncology.
ENGLISH ABSTRACT: Background: HIV is the defining pandemic of our era, with an estimated 5.9 million people infected in South Africa according to World Health Organization (WHO) estimates for 2011. The expression and treatment of non-AIDS defining cancers has become an important consideration in this cohort, as antiretroviral therapy (ART) has prolonged survival in a subgroup previously at risk of early mortality. Study Design: A retrospective cohort study of all women seen at the Combined Breast Cancer Clinic at Tygerberg Hospital between January 2010 and December 2011, stratified into three subgroups based on HIV status. Methods: Of the 816 patients screened, 586 met inclusion criteria; of which 31 (5.3%) patients were HIV positive, 420 (71.7%) HIV negative, and 135 (23%) had an unknown HIV status. The disease phenotype was described in each subgroup, as well as toxicities associated with standard chemotherapy regimens, with an emphasis on completion rates of systemic cytotoxic treatment. The insult of cytotoxic therapy to the CD4 count was described for this cohort. Results: Women with HIV had a statistically significant (p<0.001) younger age at presentation of breast cancer with a median age of 42 years (range 39 – 45 years) in comparison with the HIV-negative cohort with a median age of 54 years (range 53 – 55 years) . No difference was detected in disease phenotype when stage at presentation (p=0.7874), histological subtype (p=0.3375), grade of differentiation (p=0.8297), nodal involvement (p=0.0998) or hormone-receptor positivity (p=0.6285) was considered. Completion rates for systemic chemotherapy were excellent (>90%) regardless of HIV-status and no statistically significant toxicity was observed. The median CD4 count at diagnosis was 477 cells/μL (range 234 – 807 cells/μL), with a nadir value of 333 cells/μL (range 62 – 713 cells/μL), representing a decrease of 30.2% during treatment. One case of suspected treatment-related mortality was recorded. Conclusion: This retrospective study confirmed that women infected with HIV had a younger age at breast cancer diagnosis when compared to women with a negative HIV-status. No difference in disease phenotype could be demonstrated for women with HIV, denoting the coexistence of two common chronic diseases. Chemotherapy was tolerated well, but caused a median decline in CD4-count of 30% during treatment.
Descriptive epidemiological study of head and neck cancers at a single institution in Southern Africa
(Stellenbosch : Stellenbosch University, 2019-12) Naidoo, Komeela; Simonds, Hannah M.; Afrogheh, A.; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Medical Imaging and Clinical Oncology. Radiation Oncology.
ENGLISH SUMMARY : Head and Neck Cancers (HNCs) constitute a major public health concern worldwide. The incidence is approximately two times more in less-developed regions as compared to more developed regions. The estimated incidence in sub-Saharan Africa is 27593 per 100000 with a cumulative risk of 0.66. We evaluated patient demographics, risk factors, tumours characteristics, prognostic factors, disease stage, treatment intent and treatment modality in a cohort of patients with HNC in Cape Town, SA. Records of all HNC patients that presented to Tygerberg Hospital oncology department between 1 January 2015 and 31 December 2017 were reviewed. The following variables were described: patient demographics, which include age, sex, HIV status, and socio-economic status as well as tumour characteristics, risk factors, treatment intent and treatment modalities. Data was collected from 854 patients seen between 2015 and 2017. There were 603 (71%) male and 251 (29%) female. The male to female ratio was 2.4:1. The age range was 10-89 years (median age 58 years). Smoking was a risk factor in 737 (86.3%) and alcohol in 634 (74.2%) of patients. Of the 167 patients with oropharyngeal primaries, 16 (9.58%) patients had p16 positive, 78 (46.70%) were p16 negative and the p16 status was unknown in 73 (43.7%). The most common site was the oral cavity (n=320) and the most common sub-site was the anterior tongue (n=137). Eleven patients had two separate primaries at the time of diagnosis. In total, 466 patients (53.87%) presented with locally advanced, stage IVA disease. The median age of diagnosis, the most predominate primary site; histological subtype and stage at presentation were consistent with that reported in the literature. We have demonstrated that the majority of patients present at a late stage, with locally advanced disease. This together with the predominate risk factors of smoking and alcohol consumption is a potential target for health campaigns and awareness programmes. This cohort will be followed up for treatment outcomes and survival rates.
Radiotherapy in the management of carcinoma of the vulva in HIV positive and negative patients : an institutional experience
(Stellenbosch : Stellenbosch University, 2015-04) Opakas, Jesse Elungat; Paris, Gerald; Stellenbosch University. Faculty of Health Sciences. Dept. of Medical Imaging and Clinical Oncology. Radiation Oncology.
ENGLISH ABSTRACT: Radiotherapy in the Management of Carcinoma of the Vulva in Human Immune-Deficiency Virus (HIV) Positive and Negative Patients: An Institutional Experience. Opakas J. Department of Medical Imaging and Clinical Oncology, Division of Radiation and Clinical Oncology, Tygerberg Academic Hospital and the University of Stellenbosch Background: Radiotherapy and chemotherapy are integral parts of the effective and optimal management of patients with vulva cancer, especially when initiated early in the course of this disease. Often, surgical resection alone cannot effect total removal of the tumour or may not be feasible. Human Immune-Deficiency Virus (HIV) infection has been an epidemic in sub-Saharan Africa. Highly Active Antiretroviral Therapy (HAART) is available in public health facilities in the region to arrest and control HIV infection, delaying the progression to AIDS and death. Infection with HIV has now been transformed into a manageable, chronic disease and this has allowed patients to live longer, healthier and more productive lives. Human Immune-Deficiency Virus (HIV) infection may further complicate the management of vulva cancer disease as patients are immunocompromised and may have difficulty in completing treatments prescribed. This study aims to identify and assess the outcomes, tolerances, toxicities and factors influencing treatment completion in both HIV positive and negative patients with vulva cancer treated at Tygerberg Academic Hospital. Study Design and Methods: This is a retrospective, observational, cross-sectional review of the factors influencing the completion of radical radiotherapy in the treatment of locally advanced cancer of the vulva. Patients are classified as either HIV positive or HIV negative. The period of the study was between 1st. January 2007 and 31st December 2012 and it was conducted at the Division of Radiation Oncology, Tygerberg Academic Hospital, Cape Town, South Africa. All the HIV positive patients were already on antiretroviral therapy at the outset. The disease and treatment characteristics are described as well as toxicities of treatment of patients undergoing radiotherapy and chemo-radiation. Treatment completion for the two groups is evaluated. The toxicities that led to treatment interruptions for these groups are also listed. Results: Of the 68 patients screened, 25 met inclusion criteria; of these patients, seven (28%) were HIV positive while the other 18 (72%) were negative. Vulva cancer patients infected with HIV presented at a younger age and with more locally advanced tumours compared to HIV negative patients. There is no statistically significant difference between the two groups in treatment completion rates and tumour failure rates. Conclusion: This retrospective study concludes that HIV positive patients with vulva cancer presented with a more locally advanced disease and at a younger age when compared to HIV negative patients. There was no statistically significant difference in overall therapeutic outcomes although cutaneous toxicities were more pronounced in the HIV positive subset. Chemo-radiotherapy sequentially or concurrently can be regarded as a standard of care in both HIV positive and negative patients provided that the HIV patients are on antiretroviral therapy.
A retrospective analysis of toxicity and outcomes following chemotherapy for the older population at a single institution
(Stellenbosch : Stellenbosch University, 2018-03) Pupwe, George; Fourie, Anna Elizabeth; Akudugu, John M.; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Medical Imaging and Clinical Oncology. Radiation Oncology.
ENGLISH SUMMARY: Introduction: Surgical treatment of colorectal cancer (CRC) in elderly patients has improved, but data on adjuvant and palliative chemotherapy tolerability and benefits in this growing population remains scarce. The elderly population is mostly underrepresented in clinical trials and results for this group of patients are seldom reported separately. Patients and method: Using a retrospective study, we analyzed demographics, compared toxicities in the age groups < 70 years and ≥ 70 years in colorectal cancer patients at Tygerberg Hospital (South Africa). We assessed tumor related mortality, progression free survival (PFS) and overall survival (OS) including predictive factors of OS. Results: A total of 50 patients received either adjuvant or palliative chemotherapy. Different chemotherapy regimens were used. There was no difference in overall or severe (Common Toxicity Criteria Grades 3-4) toxicity in both age groups. Out of the 50 patients, 8 (16%) had Grade 3-4 toxicity. Of these 4 (15%) were < 70years, 4 (17%) were ≥ 70 years. The progression free survival (PFS) and overall survival (OS) were measured using Kaplan-Meier curves. The mean follow-up time was 47.5 months (range: 14.4-80.8 months, 95% CI 41.5-53.5 months). The 5-year overall survival rate for Stage II&III patients <70 years and ≥70 years were 80.9% and69.5%, respectively, and not significantly different; P=0.5156; HR=0.65 (95% CI: 0.17-2.41). Also, no statistically significant difference emerged between the 5-year progression free survival rates of 70.7% and 58.8%; P=0.4920; HR=0.68 (95% CI: 0.23-2.04). For Stage IV patients, there were no significant differences in survival in both groups. There were no survivors beyond 40 months. Median survival rates were similar at 16.3 months (for < 70 years) and 15.9 months (for ≥ 70 years); P=0.8105; HR=1.14(95% CI: 0.35-3.81). There were also no progression free survivors beyond 23 months. Median PF survival rates were 11.1 months (for < 70 years) and 13.5 months (for ≥ 70 years), and were not significantly different; P=0.1743; HR=1.99 (95% CI: 0.66-9.67). Weight loss and performance status (PS) were evaluated as potential predictive factors of OS. For Stage II&III patients of <70 and ≥70 years of age, 68 and 84% of patients presented with a weight loss of <5%, respectively. The corresponding proportions of Stage IV patients were 75 and 100%. Also, 84 and 100% of Stage II&III patients <70 and ≥70 years, respectively, had a PS of 1. All Stage IV patients had a PS of 1. Conclusion: “Fit” elderly patients benefit, at least to the same extent, from adjuvant and palliative chemotherapy as younger patients in this cohort. Therefore, standardized adjuvant and palliative chemotherapy could be offered to elderly patients and they should not be excluded from clinical trials.
Treatment of advanced salivary gland tumours with neutron radiotherapy
(Stellenbosch : Stellenbosch University, 2016-12) Lombe, Dorothy Chilambe; Simonds, Hannah; Akudugu, John M.; Stellenbosch University. Faculty of Medicine and Health Science. Dept. of Medical Imaging and Clinical Oncology. Radiation Oncology.
ENGLISH SUMMARY : Background: Success rates in the treatment of salivary gland malignancies are associated with completeness of surgical resection with or without postoperative radiotherapy. For patients with unresectable tumours, radiotherapy is an option to attempt to gain local control and improve survival. Different modalities of radiotherapy are available and fast neutrons represent a form of radiotherapy effective in controlling locally advanced salivary gland malignancies. We report on 22 patients treated for locally advanced parotid gland malignancies at iThemba Laboratory for Accelerator Based Sciences via a tertiary institution in Cape Town, South Africa. Methods: Records of patients with unresectable parotid gland malignancies treated with neutron radiotherapy at a tertiary institution between January 1991 and December 2012 were reviewed retrospectively. Twenty-two patients were eligible for statistical analysis. Results: Complete, partial and no response rates were 64%, 14% and 22%, respectively. Of the 14 patients with a complete response, 3 recurred with the earliest recurrence being at 18 months. Locoregional control was 80% and 69% at 2 and 5 years respectively. Twelve out of the 22 patients died post treatment. Overall survival at 2 years was 40% and at 5 years 35%. Seven cases of CTCAE grade 3 and above late toxicities were observed. These included bone necrosis, eardrum perforation and skin ulceration. Conclusions: Treatment modality of this group of patients depends on availability. Response rates of parotid gland malignancy to neutron radiotherapy in this small cohort are comparable to historical controls.
Variation in radiosensitivities of different individuals to high energy neutrons and 60Cobalt γ-rays
(Stellenbosch : Stellenbosch University, 2012-12) Beukes, Philip Rudolph; Slabbert, Jacobus; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Medical Imaging and Clinical Oncology.
ENGLISH ABSTRACT: Background: The assignment of radiation weighting factors to high energy neutron sources is important as there is reason to believe that neutron relative biological effectiveness (RBE) may be related to the inherent radiosensitivity of different individuals. A study was undertaken to quantify the inherent radiosensitivities of lymphocytes obtained from different donors to 60Co y-rays and p(66)/Be neutrons. For this a novel semi-automated image analysis process has been employed. In addition the responses of lymphocytes with different inherent radiosensitivities have also been tested using Auger electrons emitted by 123I. Methods: The RBE of neutrons was determined from dose-response curves for lymphocytes from different donors. Isolated T-lymphocytes irradiated in vitro were cultured to induce micronuclei in binucleated cells and micronuclei (MN) formations numerated using a semi-automated Metafer microscope system. The accuracy in obtaining dose response curves with this method has been tested by evaluating dispersion parameters of MN formations in the response to the different treatment modalities. Differences in the inherent radiosensitivities of cells from different donors were ascertained using 95 % confidence ellipses. [123I]Iododeoxyuridine was prepared in a formulation that allows incorporation of 123I into the DNA of lymphocytes. Micronucleus formations to this treatment were evaluated in lymphocytes with established differences in inherent radiosensitivities. Results: The image analysis system proved to be consistent in detecting micronuclei frequencies in binucleated lymphocytes. As a result, differences in the inherent radiosensitivities of different individuals were distinctive and could be stated at the 95% confidence level. The inter-individual radiosensitivity variations were considerably smaller for blood cells exposed to high energy neutrons compared to 60Co y-rays. Relative biological effectiveness (RBEM) values between 2 and 13 were determined that are highly correlated with the inherent radioresistance of lymphocytes obtained from different individuals. As such radiation weighting factors for high energy neutrons cannot be based on cytogenetic damage determined in lymphocytes from a single donor. Dispersion parameters for micronuclei formations proved to vary according to ionization density. The variation in RBE with neutron dose changed according to theoretical considerations and automated image analysis detection of MN is thus a suitable method to quantify radiation weighting factors. A clear reduction in the variation in radiosensitivity is noted for lymphocytes exposed to Auger electrons compared to 60Co y-rays. The effectiveness of Auger electrons from [123I]IUdR to induce biological damage is demonstrated as the number of disintegrations needed to yield micronuclei formations was found to be more than two orders of magnitude less than that of other compounds. An increase in the RBE of Auger electrons with radioresistance can be inferred from these findings and constitutes a basis for therapeutic gain in treating cells compared to using radioisotopes emitting low-LET radiation.

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