Amphotericin B lozengers: prophylaxis for esophagitis in thoracic radiotherapy: a prospective study.

Background And Purpose: Esophagitis is an important side effect in thoracic radiotherapy, no preventive drug therapy has been established yet. The aim of the present study was to prospectively evaluate the effectiveness of prophylactic antimycotic treatment with amphotericin B lozengers.

Patients And Methods: 40 consecutive patients with high-dose thoracic radiotherapy for lung cancer were investigated in a nonrandomized study.

The management of painful bone metastases with biphosphonates and palliative radiotherapy: a retrospective evaluation of 372 cases.

Purpose: The objective of this study was to evaluate the palliation of pain of bone metastases with biphosphonates and different radiotherapy protocols in 372 cancer patients.

Patients And Methods: Patients were treated with one of the 3 different radiotherapy protocols: 30 Gy in 10 fractions (group A), 20 Gy in 5 fractions (group B) and 8 Gy in a single fraction (group C). Two patient groups were studied: one with radiotherapy alone and the second with biphosphonates plus radiotherapy.

Risk factors for breast cancer: is ionizing radiation among them?

All human beings are exposed to the influence of ionizing radiation from natural, medical and other artificial sources. Therefore, the influence of radiation as a risk factor for cancer development has been among the most studied external factors over the last 6 decades, particularly with respect to radiosensitive tissues and organs. It has been known that female breast tissue is highly sensitive to the carcinogenic effects of radiation, particularly when exposure takes place at younger age.

Kinetics of EGFR expression during fractionated irradiation varies between different human squamous cell carcinoma lines in nude mice.

Background And Purpose: Preclinical and clinical data indicate that high pretherapeutic EGFR expression is associated with poor local tumour control, possibly caused by a high repopulation rate of clonogenic cells during radiotherapy in these tumours. Previous data reported from our laboratory showed a correlation between EGFR expression and acceleration of repopulation in poorly differentiated FaDu human squamous cell carcinoma (SCC) during fractionated irradiation. To test whether this is a general phenomenon, two further SCC were investigated in the present study.

Differentiation status of human squamous cell carcinoma xenografts does not appear to correlate with the repopulation capacity of clonogenic tumour cells during fractionated irradiation.

Purpose: To investigate the magnitude and kinetics of repopulation in a moderately well differentiated UT-SCC-14 human squamous cell carcinoma [hSCC] in nude mice. This question is of interest because clinical data indicate a higher repopulation capacity in those SCC that have preserved characteristics of differentiation, which appears to be in contrast to results on FaDu and GL hSCC previously reported from this laboratory.

Methods And Materials: UT-SCC-14 tumours were transplanted subcutaneously into the right hind leg of NMRI nu/nu mice.

Recovery from sublethal damage during fractionated irradiation of human FaDu SCC.

Background And Purpose: The present study addresses whether recovery of sublethal damage in tumours may change during fractionated irradiation in FaDu human squamous cell carcinoma and whether such an effect might contribute to the pronounced time factor of fractionated irradiation previously found in this tumour.

Patients And Methods: FaDu tumours were transplanted s.c.

Selective inhibition of the epidermal growth factor receptor tyrosine kinase by BIBX1382BS and the improvement of growth delay, but not local control, after fractionated irradiation in human FaDu squamous cell carcinoma in the nude mouse.

Purpose: To investigate the effect of BIBX1382BS, an inhibitor of the epidermal growth factor receptor tyrosine kinase, on proliferation and clonogenic cell survival of FaDu human squamous cell carcinoma in vitro, and on tumour growth and local tumour control after fractionated irradiation over 6 weeks in nude mice. FaDu human squamous cell carcinoma is epidermal growth factor receptor positive and significant repopulation during fractionated irradiation was demonstrated in previous experiments.

Materials And Methods: Receptor status, receptor phosphorylation, cell cycle distribution, cell proliferation and clonogenic cell survival after irradiation were assayed with and without BIBX1382BS (5 microM) in vitro.

Impact of increased cell loss on the repopulation rate during fractionated irradiation in human FaDu squamous cell carcinoma growing in nude mice.

Purpose: To determine the impact of increased necrotic cell loss on the repopulation rate of clonogenic cells during fractionated irradiation in human FaDu squamous cell carcinoma in nude mice.

Materials And Methods: FaDu tumours were transplanted into pre-irradiated subcutaneous tissues. This manoeuvre has previously been shown to result in a clear-cut tumour bed effect, i.

Proliferation and micromilieu during fractionated irradiation of human FaDu squamous cell carcinoma in nude mice.

Purpose: Previous functional radiobiological experiments demonstrated a significant acceleration of repopulation after 3 weeks and reoxygenation after 12 days of radiotherapy of FaDu tumours. Owing to the temporal coincidence between repopulation and reoxygenation, it was hypothesized that the improved oxygenation status during fractionated irradiation might be the preceding stimulus for increased proliferation. The study investigated whether these changes in repopulation and re-oxygenation are reflected by histological parameters of proliferation and the tumour micromilieu.

New targets for the modulation of radiation response--selective inhibition of the enzyme cyclooxygenase 2.

The development of new chemotherapeutic agents and concepts of radiation therapy has led to new perspectives in cancer therapy. Recently developed novel agents interfere with molecular mechanisms that are altered in cancer cells. Cyclooxygenase-2 (COX-2) is an enzyme induced by a variety of factors including tumor promoters, cytokines, growth factors and hypoxia.

Impact of the tumour bed effect on microenvironment, radiobiological hypoxia and the outcome of fractionated radiotherapy of human FaDu squamous-cell carcinoma growing in the nude mouse.

Purpose: To investigate the impact of the tumour bed effect (TBE) on histological parameters of the micromilieu, radiobiological hypoxic fraction and local control after fractionated irradiation in FaDu squamous-cell carcinoma in the nude mouse. This tumour has previously shown a clear-cut TBE caused by increased necrotic cell loss at a constant cell production rate in the viable tumour compartment.

Materials And Methods: Human FaDu tumours were studied in the NMRI nude mouse.

Repopulation of FaDu human squamous cell carcinoma during fractionated radiotherapy correlates with reoxygenation.

Purpose: FaDu human squamous cell carcinoma (FaDu-hSCC) showed a clear-cut time factor during fractionated radiotherapy (RT) under ambient blood flow. It remained unclear whether this is caused solely by proliferation or if radioresistance resulting from increasing hypoxia contributed to this phenomenon. To address this question, repopulation of clonogenic FaDu cells during fractionated RT under clamp hypoxia was determined by local tumor control assays, and compared to the results after irradiation with the same regimen under ambient blood flow.

Radiobiological hypoxia, oxygen tension, interstitial fluid pressure and relative viable tumour area in two human squamous cell carcinomas in nude mice during fractionated radiotherapy.

Very little is known about the correlation between the radiobiological hypoxic fraction (rHF) and other measures of tumour oxygenation during fractionated irradiation. In the present study the rHF is determined in untreated human FaDu and GL squamous cell carcinoma in nude mice and in tumours irradiated with 10 fractions in 2 weeks and 20 fractions in 4 weeks, using tumour control as the experimental endpoint. The results were compared with measurements of the pO2, the interstitial fluid pressure (IFP) and the relative viable tumour area.

No evidence for a different magnitude of the time factor for continuously fractionated irradiation and protocols including gaps in two human squamous cell carcinoma in nude mice.

Background And Purpose: To study whether the magnitude of the time factor is different for continuously fractionated irradiation and for fractionation protocols including gaps.

Materials And Methods: Two human head and neck squamous cell carcinomas (SCCs), FaDu and GL, were transplanted subcutaneously into the right hindleg of NMRI (nu/nu) mice and irradiated with 30 fractions under ambient conditions within 2, 6 and 10 weeks. Irradiations within 6 and 10 weeks were given either as a continuous course or with a mid-course gap of 3 weeks.

Effect of changing the weekly dose intensity of fractionated irradiation on local control of two human squamous cell carcinomas in nude mice.

Purpose: To compare the effect of fractionated irradiation with increasing, constant or decreasing weekly dose intensity on local tumour control.

Materials And Methods: Human squamous cell carcinomas, FaDu and GL, were grown in nude mice. Thirty fractions were applied under ambient conditions with increasing, constant or decreasing weekly dose intensity within a constant overall treatment time of 6 weeks.

Impact of overall treatment time on local control of slow growing human GL squamous cell carcinoma in nude mice treated by fractionated irradiation.

Background And Purpose: The impact of overall treatment time of fractionated irradiation on local control of slow growing human GL squamous cell carcinoma (SCC) was determined.

Materials And Methods: Moderately well differentiated and keratinizing human GL SCC with a volume doubling time of 8 days were transplanted subcutaneously into the right hindleg of NMRI (nu/nu) mice and irradiated with 30 fractions under ambient conditions over 2, 3, 4.5, 6 and 10 weeks.

Clinical radiobiology of glottic T1 squamous cell carcinoma.

Purpose: Radiation therapy is the treatment of choice for early glottic squamous cell cancer in many institutions over the world. Despite a relatively homogenous clinical model of T1 glottic tumors for the fractionation studies, the relationships between dose-time parameters remain unclear. To analyze the influence of fractionation parameters and hemoglobin level on tumor cure, this study has been performed.

Hyperfractionated radiotherapy in head and neck cancer: a second look at the clinical data.

Hyperfractionated radiation therapy (HF) is one of the most promising modifications of conventional fractionation (CF). However, two recent reviews on the efficacy of HF reached opposite conclusions: Stuschke and Thames (Int. J.

Linear-quadratic analysis of tumour response to fractionated radiotherapy: a study on human squamous cell carcinoma xenografts.

Purpose: To compare values for the alpha/beta ratio in experimental tumours irradiated either under conditions of clamping and short overall time or under more 'clinically realistic' conditions.

Materials And Methods: Human squamous cell carcinomas, FaDu and GL, were grown in nude mice. Alpha/beta values were determined from local tumour control data after treatment with single doses and 2, 4, and 8 fractions under clamp hypoxia in 3.