Assessment of the radiation-equivalent of chemotherapy contributions in 1-phase radio-chemotherapy treatment of muscle-invasive bladder cancer.

Purpose: To estimate the radiation equivalent of the chemotherapy contribution to observed complete response rates in published results of 1-phase radio-chemotherapy of muscle-invasive bladder cancer.

Methods And Materials: A standard logistic dose-response curve was fitted to data from radiation therapy-alone trials and then used as the platform from which to quantify the chemotherapy contribution in 1-phase radio-chemotherapy trials. Two possible mechanisms of chemotherapy effect were assumed (1) a fixed radiation-independent contribution to local control; or (2) a fixed degree of chemotherapy-induced radiosensitization.

Radio-chemotherapy for bladder cancer: Contribution of chemotherapy on local control.

The purpose of this study was to review the magnitude of contribution of chemotherapy (CT) in the local control of muscle invasive bladder carcinoma in the studies where a combined radio-chemotherapy (RCT) was used (how much higher local control rates are obtained with RCT compared to RT alone). Studies on radiotherapy (RT) and combined RCT, neo-adjuvant, concurrent, adjuvant or combinations, reported after 1990 were reviewed. The mean complete response (CR) rates were significantly higher for the RCT studies compared to RT-alone studies: 75.

Palliative Hypofractionated Radiotherapy For Non-small-cell Lung Cancer (NSCLC) Patients Previously Treated By Induction Chemotherapy.

Aim: To investigate the effectiveness and toxicity of radiotherapy (RT) given as 17 Gy in 2 fractions, in patients with locally advanced non-small-cell lung cancer (NSCLC) previously treated by platinum-based chemotherapy (CHT) and the impact of total tumor volume (TTV) on symptoms control.

Materials And Methods: Patients with inoperable NSCLC resistant to induction platinum-based CHT, who developed symptoms during or just after radiotherapy, were treated by 17 Gy in two fractions one week apart. In 12/28 patients a minimal response (up to 20% of TTV) and in 16/28 a stable or locally progressive disease had been recorded after induction CHT.

Biologically effective dose-response relationship for breast cancer treated by conservative surgery and postoperative radiotherapy.

Purpose: To find a biologically effective dose (BED) response for adjuvant breast radiotherapy (RT) for initial-stage breast cancer.

Methods And Materials: Results of randomized trials of RT vs. non-RT were reviewed and the tumor control probability (TCP) after RT was calculated for each of them.

Use of the concept of equivalent biologically effective dose (BED) to quantify the contribution of hyperthermia to local tumor control in radiohyperthermia cervical cancer trials, and comparison with radiochemotherapy results.

Purpose: To express the magnitude of contribution of hyperthermia to local tumor control in radiohyperthermia (RT/HT) cervical cancer trials, in terms of the radiation-equivalent biologically effective dose (BED) and to explore the potential of the combined modalities in the treatment of this neoplasm.

Materials And Methods: Local control rates of both arms of each study (RT vs. RT+HT) reported from randomized controlled trials (RCT) on concurrent RT/HT for cervical cancer were reviewed.

Use of concept of chemotherapy-equivalent biologically effective dose to provide quantitative evaluation of contribution of chemotherapy to local tumor control in chemoradiotherapy cervical cancer trials.

Purpose: To express the magnitude of the contribution of chemotherapy to local tumor control in chemoradiotherapy cervical cancer trials in terms of the concept of the biologically effective dose.

Methods And Materials: The local control rates of both arms of each study (radiotherapy vs. radiotherapy plus chemotherapy) reported from randomized controlled trials of concurrent chemoradiotherapy for cervical cancer were reviewed and expressed using the Poisson model for tumor control probability (TCP) as TCP = exp(-exp E), where E is the logarithm of cell kill.

Radiobiologic modeling of cytoprotection effects in radiotherapy.

Purpose: To investigate the potential for mathematical modeling of the normal tissue-sparing effects of cytoprotective agents used in conjunction with radiotherapy and chemotherapy.

Methods And Materials: The linear quadratic model was modified to include a "cytoprotection factor," in two alternative ways. The published results on the incidence of treatment-related oral mucositis in patients treated for head-and-neck carcinoma using radiotherapy alone or combined with chemotherapy were assessed against the model to determine the likely values of the cytoprotection factor required to confer a reasonable degree of cytoprotection.

Monte Carlo dosimetric evaluation of high energy vs low energy photon beams in low density tissues.

Background And Purpose: Low megavoltage photon beams are often the treatment choice in radiotherapy when low density heterogeneities are involved, because higher energies show some undesirable dosimetric effects. This work is aimed at investigating the effects of different energy selection for low density tissues.

Patients And Methods: BEAMnrc was used to simulate simple treatment set-ups in a simple and a CT reconstructed lung phantom and an air-channel phantom.

Prognostic impact of tumor volumetry in patients with locally advanced head-and-neck carcinoma (non-nasopharyngeal) treated by radiotherapy alone or combined radiochemotherapy in a randomized trial.

Purpose: Tumor volume (TV) is one of the main reported factors determining the outcome of treatment in head-and-neck carcinomas. In this study, the prognostic impact of TV was explored in the context of a randomized trial with the patients assigned to receive standard radiotherapy (RT) alone or RT plus platinum compounds (RT alone, RT plus cisplatin, or RT plus carboplatin).

Methods And Materials: The tumor outlines were traced and digitized on each pretreatment CT slice for each of the 101 patients studied.

Re-irradiation in conjunction with liposomal doxorubicin for the treatment of skin metastases of recurrent breast cancer: a radiobiological approach and 2 year of follow-up.

Thirty patients with local relapses after radical mastectomy and radiotherapy and undergoing infusion of liposomal doxorubicin (40 mg/m(2) monthly for 6 months) were randomized to receive re-irradiation. Radiotherapy was with either 17 fractions of 1.8 Gy, 5 days a week (N=15, group A) or 4 Gy plus two fractions of 3 Gy the 1st week and six fractions of 3 Gy given every second day (N=15, group B).