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R Valdagni

Publications and source records attributed to R Valdagni.

At least 37 records · Page 2Linked to original sources
PubMed1991

Quality control in the conservative treatment of breast cancer: patient dosimetry using silicon detectors.

Twenty patients with early breast cancer were treated with external irradiation, delivered with two tangential beams (6 MV X-rays) using a half-beam block (HBB) and 3-D compensating filters. All patients were immobilized with individualized cellulose acetate casts. Patient dosimetry was performed using p-type silicon detectors. Midline doses were calculated by combined entrance and exit dose measurements. The mean ratio of the measured and the prescribed doses was 96.6 +/- 3.8% at the reference point, 96.8 +/- 4.3% at off-axis points on the central plane and 96.8 +/- 7.6% at off-plane points.

Breast Neoplasms↗
PubMed1991

Early breast cancer irradiation after conservative surgery: quality control by portal localization films.

A review of geometrical errors on portal localization films in 20 patients undergoing breast irradiation after conservative surgery is presented. Patients were immobilized using a cellulose acetate individual cast. Good precision in daily set-up has been noted with a mean ventrodorsal shift of 2.7 mm on medial films and 3.0 mm on lateral films; a mean craniocaudal shift of 1.8 mm on medial films and of 2.0 mm on lateral films have been also observed. The mean half-beam block rotation error has been minimal, ranging 0.8 degrees on medial and 1.1 degrees on lateral films. A new cast was made in 3/20 (15%) patients depending on variation of breast morphology during treatment and on geometrical errors noted by portal localization film check.

Breast Neoplasms↗
PubMed1991

Local-regional recurrences of breast cancer: treatment with radiation therapy and local microwave hyperthermia.

From October 1981 through September 1988, 31 local-regional recurrences of breast cancer in 26 patients were treated at the Oncology Center in Trento, Italy, with a combination of external radiation therapy (XRT) and superficial local microwave hyperthermia (Ht). The mean total XRT dose was 37.40 Gy, ranging from 19.80 to 60.00 Gy, depending on the extent of previous irradiation. Ht was delivered using the same superficial mw applicator, operating at frequencies between 280 and 480 MHz. The goal was to obtain a minimum intra- and peritumoral temperature of 42.5 degrees C for 30 min. Ht was applied immediately after XRT, 2 or 3 times per week for a total of 1-9 sessions (median 2). Thirty lesions (97%) could be evaluated for response 3 months after the end of the combined treatment. Twenty (66.6%) complete responses, seven (23.3%) partial responses, and three (10%) with no change were observed. No significant acute local side effects were noted, with the exception of two thermal burns and one ulceration. Patients achieving complete response show actuarial long-term local control of 87.8% at 3 years. In our experience, Ht combined with a low/moderate XRT dose may be particularly valuable in the palliation of recurrences in previously irradiated regions. Excellent response rates can be obtained when Ht is combined with a radical dose of irradiation.

Aged↗
PubMed1990

Evaluating radiation in combination with hyperthermia trials: the importance of clinical and technical parameters.

A proper evaluation of hyperthermia and irradiation trials is necessary to correctly interpret clinical results and to define limitations and properties of this new therapeutic approach. A better understanding of the "weight" of different technologic and clinical parameters that influence clinical response is thus clearly needed, particularly if future advances in hyperthermia technology and clinical results are to be expected. Patient variables, tumor variables, and treatment characteristics have been analyzed, and the difficulties of properly evaluating the "weight" of single parameters have been stressed. At the current state of knowledge, the Karnofsky index, site of disease (for regional heating), tumor status (recurrent versus metastatic disease) and XRT dose per fraction (for melanomas) seem to correlate with response. Tumor dimension, XRT total dose and thermal parameters reflecting the lowest tumor temperatures appear to statistically influence complete response rates of heated and irradiated tumors. In addition, a critical method of presenting results should be followed to enable comparison of data from different trials.

Clinical Trials as Topic↗
PubMed1990

Reduction of spinal metastases after preemptive irradiation in prostatic cancer.

For this study, 136 patients treated at Stanford University Hospital for prostatic cancer between 1971 and 1980 were selected for review. The patients had received no prior therapy, and had no evidence of bone metastases at time of radiation treatment based on radiographic studies and bone scan. Of this group, 71 patients received extended-field irradiation (paraaortic and pelvic fields), and 65 patients received pelvic irradiation. The pelvic field was treated to 50 Gy and the paraaortic field received 45 Gy to 60 Gy. All patients subsequently underwent routine follow-up examinations and studies at Stanford University Hospital: 1,513 follow-up X rays, bone scans, and CT-scans were analyzed for site-specific recurrence. The follow-up ranged from 14 months to 16 yrs from the time of initial treatment, with a mean follow-up of 7 yrs. Lower extremities and ribs were found to be the most common sites of bone metastases. Irradiation of the lumbar spine to a dose of 35 to 60 Gy, coincidental to irradiation of the paraaortic lymph nodes prevented or delayed the development of lumbar spine metastases. The potential mechanism and clinical implications are discussed.

Bone Neoplasms↗
PubMed1990

Absorption rate density (ARD) computation in microwave hyperthermia by the finite-difference time-domain method.

A mathematical model has been developed, which is able to predict power distributions in biological tissues during microwave hyperthermia delivered by waveguide applicators. The numerical solutions of Maxwell's equations was obtained by the finite-difference time-domain (FDTD) technique. Two improvements with respect to the standard implementation of FDTD were introduced: a separation between the source and load calculations (based on the Schelkunoff equivalence principle) and a simple routine that automatically recognises the steady state. Two commercially available applicators, a dual-ridged and a side-loaded waveguide, were modelled using their theoretical aperture fields. The absorption rate density (ARD) distributions delivered by these applicators were measured through phantom thermal dosimetry and compared with the patterns estimated by the simulation.

Computer Simulation↗
PubMed1990

Radiation therapy of carotid body tumors.

Chemodectomas of carotid artery bifurcation are generally managed with surgery, irradiation being reserved for inoperable, bulky, and recurrent tumors. Probably due to this "pretreatment" selection of patients, chemodectomas are anedoctally considered radioresistant tumors, although this concept is not supported by the recent literature. From 1968 to 1987, 13 carotid body tumors in seven patients were treated with irradiation as sole treatment (10 lesions) or as postoperative modality (three lesions). Familial occurrence and bilateral presentation were observed in 3 of 7 and in 6 of 7 patients, respectively. Total dose of irradiation was of 46-60 Gy (median 50 Gy, mean 52.25 Gy) with dose per fraction of 1.8-2.5 Gy. Local control (subjective or objective) was obtained in all the patients. Clinical results following World Health Organization (WHO) criteria were: 3 of 13 complete response, 7 of 13 partial response and 3 of 13 no change. Follow-up range is 1-19 years. Acute side effects were minimal and mid- or long-term toxicity was absent.

Adult↗
PubMed1990

[Personalized low-melting alloy shield for high-energy electrons in the treatment of superficial neoplasms of critical or esthetically important regions].

Individualized Cerrobend beam shapings for high-energy electrons have been utilized in the treatment of superficial tumours located in aesthetic or critical regions. Individualized cellulose acetate masks have been used as immobilization device. Measured transmissions through Cerrobend ranged from 0.5% at 4 MeV to 8.5% at 18 MeV. Phantom dosimetry showed a poor influence of Cerrobend on PDD (percentage depth doses). Output factor variations appeared to depend on electron energy and shielded area. It is very important to perform either empirical measurements or to adopt semiempirical models in order to exactly calculate those output factors. Three clinical examples are presented: the utilization of immobilization device and field shaping are illustrated with the main aim of sparing the dose to critical organs.

Electrons↗
PubMed1988

Important prognostic factors influencing outcome of combined radiation and hyperthermia.

Clinical experience with combined local-regional hyperthermia and radiation therapy has been rapidly accumulating over the past few decades. Its superior efficacy to the use of radiation alone has been demonstrated in several retrospective and prospective reports in the literature. It is evident now that there are several important factors that will influence the final outcome of the treated patients. The parameters that will be discussed in this paper include: I. Pretreatments factors: 1. tumor dimension 2. tumor histology 3. tumor site. II. Treatment factors: 1. radiation therapy dose 2. hyperthermia parameters: (a) thermal variables (b) number of heat treatments (c) sequence of hyperthermia and radiation treatments (d) hyperthermic device. Finally, evaluation of response and complications will also be discussed. The importance of abiding by an accepted reporting system will be emphasized, and clarification of times at which response assessments were made will also be discussed. With the availability of longer term follow-up, use of an actuarial method of reporting becomes more important. The future of hyperthermia and radiation remains very promising but a lot of questions still need to be answered by well-conducted and reported clinical trials.

Combined Modality Therapy↗
PubMed1988

Radical radiation alone versus radical radiation plus microwave hyperthermia for N3 (TNM-UICC) neck nodes: a prospective randomized clinical trial.

Between September 1985 and December 1986, 44 N3 (TNM-UICC) metastatic squamous cell cervical lymph-nodes were randomized to receive conventionally fractionated radical irradiation (RT) to a total dose of 64-70 Gy, or conventionally fractionated radical irradiation plus twice a week local microwave hyperthermia (Ht). The two major end points of this study were (a) local control rates evaluated at 3 months after the end of combined therapy and (b) incidence of acute local toxicity. Thirty-six nodes (82%) were evaluable as of December 1986, at which time there was a premature closure of this study due to ethical reasons. An interim analysis had revealed a statistically significant difference in complete response rates in favor of the combined arm (p = 0.0152). The complete response rates were 82.3% (14/17) for the combined treatment arm versus 36.8% (7/19) for the control irradiation arm, leading to an iso-dose thermal enhancement ratio (TER) value of 2.23. Both arms are comparable in average total RT dose delivered (RT: 67.05 Gy; RT + Ht: 67.85 Gy) and in average maximum node diameter (RT arm: 4.81 cm; RT + Ht: 4.88 cm). Acute local toxicities were similar in irradiated and heated plus irradiated neck regions; only one skin burn was observed. As possible treatment related death, one patient in the RT + Ht arm died 2 months after completion of therapy with a carotid rupture associated with extensive tumor necrosis. These results confirm previous non-randomized reports suggesting that hyperthermia in combination with full dose conventionally fractionated irradiation significantly enhances the chance of early local control of fixed N3 neck nodes without exhibiting an increase of acute local toxicity.

Adult↗
PubMed1987

Correlations of thermal washout rate, steady state temperatures, and tissue type in deep seated recurrent or metastatic tumors.

The rates of cooling ("thermal washout") in selected sites in tumor and adjacent normal tissues following the completion of clinical hyperthermia sessions were analyzed in ten patients treated with combined radiation and hyperthermia for deep seated recurrent or metastatic tumors. The temperatures were recorded at 10 second intervals for at least 2 minutes after the cessation of microwave power at the end of the 30-60 minute duration hyperthermia treatments. These thermal washouts were characterized by the slope of a log-linear relation between temperature elevation above the oral baseline temperature and time. Washout rates (expressed as a perfusion rate in ml/100g-min) significantly correlated with tissue categories as noted on CAT scan (i.e., tumor, normal tissue, tumor/normal tissue interface, hypodense tumor areas). Relationships between thermal washout rate and steady-state temperature elevation were tested and also showed significant correlations in general and for some specific tissue categories. The implications of these findings in explaining inhomogeneities in heating patterns, and in hyperthermia treatment modeling will be presented.

Combined Modality Therapy↗
PubMed1986

Neoadjuvant chemotherapy with vincristine, bleomycin and methotrexate combined with radiotherapy in advanced head and neck squamous cell carcinoma.

From September 1980 to August 1981, 25 patients with advanced head and neck squamous cell carcinoma were treated at the Centro Oncologico, Trento, by a chemo-radiotherapeutic combination. The treatment protocol consisted of 4-6 courses of VBM (vincristine, bleomycin and methotrexate) followed by conventional radiotherapy (65 Gy). Only to VBM responders (15 patients) were administered 10 cycles of vincristine-methotrexate. At the end of induction chemotherapy an overall response of 60% (12% complete, 48% partial) was obtained. At the end of radiotherapy the responses were 52.5% complete and 35.5% partial, for an overall response of 88%. The overall survival at 60 months was 8%. This combined approach, in spite of the satisfactory immediate local response rate, does not offer advantages for survival in comparison to conventional treatment modalities.

Adult↗
PubMed1986

Spindle-cell squamous carcinoma of head and neck region: a clinicopathologic and immunohistochemical study of eight cases.

Spindle cell squamous carcinoma is a highly malignant neoplasm, characterized by a biphasic appearance, due to the presence of a diffuse proliferative pattern of pleomorphic spindle cells with extremely rare foci of conventional squamous cell carcinoma. Epithelial markers in eight cases of spindle-cell squamous carcinoma of the head and neck region were studied by immunocytochemistry. Epithelial membrane antigen and cytokeratin resulted strongly positive in the spindle cells of the sarcoma-like areas demonstrating the epithelial nature of the neoplasm. In 6 of our patients who later died from widespread metastases, the neoplasm had poor prognosis with a mean survival rate of 14.7 months.

Antigens, Neoplasm↗