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Lindman, Henrik, 1963-
(author)
Individually Tailored Toxicity-based Chemotherapy : Studies on Patients with Primary and Metastatic Breast Cancer
2003
Doctoral thesis (other academic/artistic) abstract
Standard dosing of chemotherapy based on body surface area (BSA) results in large individual differences in toxicity due to a large inter-patient variability in pharmacokinetics (PK) and pharmacodynamics (PD). This results in under-dosing in certain patients with a potentially weaker antitumoral effect.Three clinical studies of individually tailored dosing of chemotherapy, based on haematological toxicity were conducted. In the first study, 26 women with metastatic breast cancer were treated with tailored and dose-escalated 5-fluorouracil, epirubicin and cyclophosphamide, supported by G-CSF (dFEC). In the second study 525 patients with high-risk primary breast cancer were randomised between dFEC and high-dose chemotherapy with autologous bone-marrow transplantation. The feasibility of a FEC regimen with doubled cyclophosphamide dose to mobilise peripheral stem cells was investigated. In the third study, 44 metastatic patients were treated with tailored epirubicin and docetaxel (ET). PK and PD were also investigated in these patients. The potential effects of G-CSF on MRI tumour evaluation were studied in 18 patients with skeletal metastases.Toxicity-based dosing entailed an evenly distributed two- to three-fold range of tolerated doses in all three studies. Efficacy and toxicity were not correlated to tolerated dose-levels. Tailored dFEC resulted in a response rate of 81% and the same regimen resulted in fewer breast cancer relapses compared with standard FEC followed by high-dose therapy. Toxicity was manageable except for an increased rate of secondary leukaemia. The modified FEC could safely mobilise sufficient numbers of stem-cells. Tailored ET resulted in a response rate of 63%. The inter-individual variability in drug clearance was larger than the inter-occasion variability and a semi-physiological model of PK and PD could predict leukocyte nadir and duration. An increased diffuse MR signal in the long TE IR-TSE sequence was observed in normal bone-marrow during G-CSF treatment; this could be mistaken as disseminated metastatic disease and could obscure focal metastases.In conclusion, the concept of individually tailored toxicity-based dosage of chemotherapy was equally feasible in primary and metastatic breast cancer, in two different chemotherapy regimens and in treatment with or without G-CSF support and may provide a pragmatic way of overcoming the shortcomings of standard BSA-based dosing.
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Nilsson, Greger
(author)
Cardiovascular Side Effects of Radiotherapy in Breast Cancer
2012
Doctoral thesis (other academic/artistic) abstract
The aim of the thesis was to study cardiovascular side effects of radiotherapy (RT) in breast cancer (BC).In a study base of 25,171 women with BC diagnosed 1970-2000, we found a statistically significant 12% increase of stroke, compared to the stroke incidence in the background population.A case-control study of 282 cases with BC followed by a stroke and 1:1 matched controls with BC but not stroke was performed. In women irradiated to internal mammary chain (IMC) and supraclavicular lymph nodes (SCL) vs. a pooled group of women not irradiated or irradiated to targets other than IMC and SCL, a statistically significant increase of stroke with an odds ratio of 1.8 was observed. There were no associations between BC laterality, targets of RT, and hemisphere location of stroke. The radiation targets IMC and SCL, showed a statistically significant trend for an increased risk of stroke with daily fraction dose.A study of 199 patients with BC, examined by coronary angiography, detected a four- to seven-fold increase of high grade coronary artery stenosis in mid and distal left anterior descending artery (LAD), including distal diagonal branch, when comparing women with irradiated left-sided BC to those with right-sided. An increase of clinically significant coronary artery stenosis was found in pre-specified hotspot areas for radiation among women irradiated to the left breast/chest wall or to the IMC. Thus, the coronary arteries should be regarded as organs at risk in RT of BC.In a study of 15 BC patients treated with 3D conformal RT, a marked difference in dose distribution in mid and distal LAD between left- and right-sided BC was demonstrated. Irradiated right-sided BC mainly received low doses of scattered and transmitted radiation to the coronary arteries. On the contrary, tangential RT to the left breast without regional lymph node irradiation yielded coronary artery max doses of approximately 50 Gray to distal LAD, probably not safe concerning late radiation vascular effects.To conclude, we found cardiovascular side effects in women irradiated for BC, resulting in stroke and coronary artery disease, and showed an association between the targets for RT and the anatomical location of these vascular events.
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