Browsing by Author "Hunter, Alistair"

Now showing 1 - 7 of 7
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    Breast conservation treatment at Groote Schuur Hospital : treatment outcome
    (2005) Elhaj, Ahmed Mohammed; Werner, I D; Murray, Elizabeth; Hunter, Alistair
    Includes bibliographical references (leaves 56-62).
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    Ependymal tumours in childhood: outcomes and prognostic factors
    (2017) Nkosi, Zanele; Parkes, Jeannette; Hunter, Alistair
    OBJECTIVES: 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.
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    Mitochondrial dynamics in the radiation response of cancer cells
    (2017) Parker, Michelle; Hunter, Alistair
    Mitochondria are involved in the regulation of key cellular processes that determine the response of cells to damage. Mitochondrial fission and fusion are associated with cell cycle regulation, apoptosis, cellular bioenergetics and redox status, which contribute to cellular homeostasis and damage response. The study aimed to describe and correlate cancer cell mitochondrial features and inherent radiosensitivity, and to determine the effect of modulation of mitochondrial dynamics on radiation response using a fission inhibitor, Mdivi-1. Methods: Mitochondrial status in a number of cancer cell lines was characterised by assessment of mitochondrial morphology, respiration and membrane potential using MitoTracker® Red staining, respirometry and JC-1 ratiometric staining, respectively. Correlations with radiation sensitivity were performed. Radiation- and Mdivi-1-induced changes in mitochondrial morphology were also examined. Responses to various schedules of radiation and Mdivi-1 treatment were assessed using clonogenic survival. Microscopy was used to quantify apoptosis, micronuclei and mitotic features, while cell cycle dynamics were analysed using flow cytometry. Results: Notably, modulation of mitochondrial fission using Mdivi-1 significantly increased radiation response in A549 cancer cells. Mdivi-1 reduced fragmentation, increased membrane potential and induced cytotoxicity, cytogenetic damage, apoptosis and G2/M cell cycle arrest. However, with the exception of survival, sub-additive responses were consistently observed when Mdivi-1 was combined with radiation. Sub-lethal damage repair was unaffected by Mdivi-1. Characterisation of cancer cell lines revealed inherent diversity in radiation response and mitochondrial morphology, membrane potential and respiration, and several correlations were identified. Discussion and conclusions: Inhibition of mitochondrial fission was shown for the first time to enhance radiosensitivity in cancer cells, and to induce cytotoxicity. Mitochondrial modulators may therefore have therapeutic application. However, the sub-additive responses observed with Mdivi-1-radiation interactions suggest that optimisation of treatment scheduling may be important. The Mdivi-1-induced mitotic arrest may, in part, be responsible for the observed radiosensitisation, as cells accumulate in a radiosensitive cell cycle phase. In addition, the finding that Mdivi-1 treatment induced micronuclei suggested that the radiosensitisation may result from the interaction of cytogenetic damage induced by each agent. Overall, mitochondrial dynamics appears to significantly influence radiation response.
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    Radiation biology-An important science for an advanced nuclear nation like South Africa
    (2012) Hunter, Alistair
    The sustainability of radiation biology (radiobiology) is under threat in South Africa because of underdevelopment in the discipline, despite the fact that South Africa has been a user of radiation since radioactivity and X-rays were discovered. The widespread use of radiation in medicine, nuclear reactors, particle accelerators and other sophisticated nuclear facilities in South Africa makes it imperative that the interaction of radiation with biological systems is understood. For example, radiobiology is critical in radiation oncology and cancer treatment. Radiobiology is a distinctly biological science and its uniqueness and value should be highlighted to provide insight for authorities and other relevant parties. Regrettably, radiobiology has been largely neglected despite the importance of maintaining expertise and competence in this discipline. Many radiation-associated disciplines require radiobiology for their training and practice yet few radiobiologists are available nationally. The scientific community needs to be informed of the predicament of radiobiology in South Africa so that the situation can be addressed. Radiobiology is a scarce skill that needs to be developed to support South Africa’s mature radiation infrastructure. The country has too few radiobiologist training programmes and there is a lack of succession planning. Radiobiology is required for training and practice in a number of disciplines that use radiation, but, as a result of a shortage of qualified personnel, teaching of radiobiology has frequently been conducted by non-experts. To reinvigorate radiobiology in South Africa, a collective effort by government, academia, industry and allied professionals is required.
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    A retrospective study of patients with Stage IB2 cervical cancer treated at Groote Schuur Hospital 1993-2008
    (2013) Alleyne-Mike, Kellie; van Wijk, Leon; Hunter, Alistair
    Includes abstract. Includes bibliographical references.
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    Sino-Nasal Squamous Cell Carcinoma (SNSCC): a retrospective review of the treatment outcomes of patients treated at Groote Schuur Hospital, Cape Town, South Africa
    (2022) Nagar, Bhavesh; Dalvie, Sameera; Hunter, Alistair
    Purpose: Cancers of the sinonasal tract are rare, comprise a diverse group of histologies and are known for their poor prognostic outcomes. The primary aim of this study was to evaluate the 2- and 5-year overall survival (OS) rates in patients treated with radical and palliative intent for sinonasal squamous cell carcinoma (SNSCC). Methods: A retrospective review of medical records of all patients presenting to Cape Town's Groote Schuur Hospital between January 2003 and December 2013 was carried out. All patients with histologically proven squamous cell carcinoma (SCC) of the maxillary sinus and nasoethmoidal complex who underwent treatment at Groote Schuur Hospital and/or iThemba LABS (Laboratory for Accelerator Based Sciences) were included. Fifty-five patients with cancers of the sinonasal tract were identified from the electronic patient system; 23 were excluded either because of different histologies, lack of histology or having initiated treatment outside of Groote Schuur Hospital. The medical records of 32 patients were utilised for final analysis. 2- and 5-year OS was calculated using Kaplan-Meier analysis. Results: The majority (75%) of patients had an ECOG performance status of 1 with facial asymmetry secondary to tumour mass or swelling being the most common presenting symptom (present in 68,75% of cases). 62,50% of cases originated within the maxillary antrum and 56,25% of cases were classified as keratinizing SCC. Twenty-six (81,25%) patients presented with stage IV disease; nodal disease was seen in 13 (40,63%) patients and distant metastasis in 4 (12,50%) patients. Most patients underwent palliative intent treatment with only 11 (34,38%) having radical treatment. The cumulative 2- and 5-year OS from the date of treatment initiation was 26% and 19% respectively. Median OS for the entire cohort was 7,7 months and was statistically significant between intent groups at 5,19 months (95% CI:3.43– 6.95) for palliative compared to 35,45 months (95% CI: 0.00–138.52) for radical patients (c2 = 7.80, p = 0.005). Conclusion: Despite a decline in incidence of disease over the last 30 years and the improved diagnostic and therapeutic modalities available today, the prognosis and survival outcomes for SNSCC remains poor.
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    Treatment outcomes of young patients with invasive breast cancer treated radically at Groote Schuur Hospital from 2013-2017: A single centre study
    (2022) Tangane, Gomolemo; Tselane, Thebe; Hunter, Alistair
    Treatment outcomes of young patients with invasive breast cancer treated radically at Groote Schuur Hospital from 2013 to 2017: A single centre study Background: Breast cancer is the leading cause of cancer- related deaths globally, and the commonest cancer in women under 40 years. There is currently a lack of data relating to treatment outcomes of young women with breast cancer particularly in low-and middle-income countries. Aim: This study aims to evaluate the treatment outcomes of young patients (under 40 years) treated radically for invasive breast cancer in a low-and middle-income setting. Settings: Groote Schuur Hospital, Cape Town, South Africa Methods: A retrospective review of 101 women under 40 years, with invasive breast cancer treated radically, between 2013 and 2017 was conducted. Patient characteristics, tumour characteristics, disease stage, treatment, and follow-up were recorded. Primary objectives included evaluating overall and disease free survival, and analysing recurrence patterns and clinicopathological features. Results: The five-year overall and disease free survival for the entire cohort was 77% and 51%, respectively. Five-year overall survival by molecular subtype showed that Luminal A had the best survival, while triple negative breast cancer had the worst overall survival. Conclusion: Young women with breast cancer have poor survival outcomes despite early presentation. There is limited data regarding breast cancer treatment outcomes in patients under forty years.