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Biomedical subjects

F Pozza

Publications and source records attributed to F Pozza.

At least 55 records · Page 3Linked to original sources
PubMed1985

Osteogenic osteosarcoma of the calvaria following radiotherapy for cerebellar astrocytoma: report of a case in childhood.

Sarcoma as a second malignant neoplasm following radiotherapy is a rare occurrence in childhood. A case of osteogenic osteosarcoma of temporoparietal bone that developed 56 months after irradiation for a cerebellar astrocytoma in a 10-year-old child is reported and the pertinent literature is briefly reviewed. The possibility of an association (in the same patient) between these two rather uncommon lesions is extremely unlikely. Therefore, it is possible that radiotherapy played a role in the induction of the sarcoma. The indolent course of the latter is stressed.

Astrocytoma↗
PubMed1985

Stereotactic radiosurgery utilizing a linear accelerator.

The authors have developed a radiosurgical technique based on multiple arc irradiations. The target is fixed to the rotational isocenter of a Varian 4 MV linear accelerator. The first irradiation is carried out while the radiating source is rotating on a 100-140 degrees arc. The patient is then rotated around a vertical axis passing through the target, and arc irradiations are repeated in different angular positions. By this technique it is possible to obtain very steep dose gradients at the borders of the target volume. High doses are usually delivered in two shots. 47 patients have been treated so far in a clinical trial that started in November 1982. The paper deals with the preliminary results (more than 6 months' follow-up) obtained in patients affected by nonresectable brain tumors and AVMs.

Adolescent↗
PubMed1985

External stereotactic irradiation by linear accelerator.

Stereotactic radiotherapy has two advantages: (a) the possibility of giving high radiation doses to small but spatially well-defined target volumes and (b) the presence of a stepped dose gradient between the target volume and the surrounding healthy tissues. To utilize these advantages, the authors built a new stereotactic head frame by which the intracranial target is fixed to the rotational isocenter of a 4-MV linear accelerator. The collimator openings are selected according to the volume and the three-dimensional configuration of the target, and the radiation dose is based on the radiosensitivity of the lesion. After the patient is fixed to the frame, the radiation source and the patient are rotated so that the target is irradiated through infinite portals distributed over the convexity of the skull. It is thereby possible to obtain very high radiation doses centered into the target with a stepped dose gradient. The preliminary radiodosimetric tests and the operative technique are described. The advantages of this technique compared to interstitial radiotherapy and Leksell's radiosurgery are emphasized. This noninvasive procedure has been used to treat a series of intracranial tumors.

Adolescent↗
PubMed1984

[Biopsy and stereotaxic radiotherapy of cerebral gliomas].

The Authors report their experience on a series of 125 patients that underwent stereotactic biopsy. The procedure has proved reliable and almost risk -free. The diagnosis obtained from the bioptic specimen by smear technique-cytological examination and by paraffin embedding-histological examination are compared. Neuropathologic data were also checked by the examination of the tumor bulk in cases that underwent surgical removal or autoptic verification. The preliminary results obtained in 8 patients with the new technique of external stereotactic irradiation by means of a linear accelerator are also shown.

Biopsy↗
PubMed1984

[Stereotaxic irradiation with a linear accelerator].

At least two fundamental requirements must subsist for every stereotaxic radiotherapy treatment: 1) a capacity to administer extremely high doses of radiation to small areas which have been precisely defined in three dimensions; 2) the presence of a steep gradient between adjacent isodose curves so that damage to the tissues close to the target may be reduced to the minimum. The authors have built a special stereotaxic device for the fixing of the head of the patient (together with the chosen intracranial target), once the indispensable neuroradiological evaluations and bioptic controls have been effected, at the isocenter of a linear accelerator (Varian Clinac 4). Once the dimensions of the collimator have been chosen in accordance with the volume and the three dimensional conformation of the target and the dose to be administered has been decided upon in accordance with the histological nature of the lesion, both the linear accelerator and the patient are rotated about the isocenter of the therapy unit. It this way it is possible to reach extremely high dosages with very steep isodose gradients, centered exclusively upon the target ("gamma knife"). The procedure employed is described in full. The dosimetric evaluations which preceded the use of the set-up in clinical practice are illustrated as well. The advantages that this technique offers when compared with interstitial brachytherapy and/or Leksell's radiosurgical procedures are stressed. The described procedure, which is entirely bloodless and thus applicable also to high vascularized lesions, has so far been used in a limited series of cases.

Brain Diseases↗
PubMed1983

Treatment of early stage Hodgkin's disease with radiation therapy plus short-cycle (3 MOPP) adjuvant chemotherapy.

Eighty-four consecutive, previously untreated patients with stage I, II A-B and IIIA Hodgkin's disease were treated with combined modality therapy including subtotal or total nodal irradiation, followed by three cycles of MOPP. MOPP was administered before radiotherapy in patients with systemic symptoms or with bulky disease. Seventy-six of 84 patients (90.5%) achieved complete remission, and 8 died from disease progression after a variable period of incomplete remission. Three of 76 (3.9%) relapsed, and 2 of them have been subsequently salvaged. Up to the present time, 70 patients are alive, without evidence of disease; 9 have died from Hodgkin's disease, 2 from acute non-lymphoblastic leukemia, and 3 from intercurrent causes. No death occurred from acute toxicity due to chemotherapy. Actuarial overall survival is 82.3% and freedom from relapse is 81.8% after 48 months' median observation (range: 12-111 months). No significant difference in survival and freedom from relapse has been observed with respect to age, sex, stage, presence or absence of unfavorable prognostic factors. The role of adjuvant chemotherapy and its use in a reduced number of cycles in early stage Hodgkin's disease are discussed.

Age Factors↗
PubMed1983

Treatment of 49 unrandomized patients with advanced Hodgkin's disease.

Forty-nine patients with previously untreated advanced Hodgkin's disease were treated in our Institution between 1973 and 1981. Treatment modalities of these patients were reviewed, and they were divided into 3 groups according to the treatment employed: 13 patients received MOPP only, 22 patients received MOPP plus involved field radiotherapy, and 14 received alternating MOPP/ABVD chemotherapy. The response rates for the 3 groups were respectively 38.5%, 63.6% and 78.6%. A longer follow-up is needed to assess a significant difference in survival curves. The advantages of adjuvant radiotherapy and alternating non-cross-resistant drugs in advanced Hodgkin's disease are discussed.

Adolescent↗
PubMedDate not supplied

Relationship of the epidermal growth factor-receptor to the growth fraction (Ki-67 antibody) and the flow cytometric S-phase as cell kinetics parameters, in human mammary carcinomas.

Epidermal growth factor (EGF) has been shown to have a mitogenic effect on some breast cancer cells lines in vitro. The growth of the subclass of human breast tumors which expresses the specific receptor for EGF seems to be mediated by autocrine mechanisms rather than steroid hormones. The expression of EGF-receptor, as detected by an immunocytochemical method, was compared with the Growth Fraction (GF) by the Ki-67 monoclonal antibody and the S-phase content as tumor proliferative activity indexes, and with DNA ploidy and some pathologic features in 86 stage I-II breast carcinomas. Overall 52 out of 86 (60%) of the tumors were EGF-receptor positive. There was no correlation between the cell kinetics parameters and the EGF-receptor status, suggesting that its expression may be unrelated to the proliferative activity of the tumor in these clinical stages and that the EGF-receptor GF and S-phase may be independent variables in breast cancer. In our series 57% of tumors were DNA aneuploid and only a trend was found towards EGF-receptor positivity (P = 0.08). There was no correlation between EGF-receptor expression and grading or node-status. The overall picture is that of an independent relationship between EGF-receptor with the cell kinetics parameters and ploidy, confirming the complex and heterogeneous biology of breast carcinoma. These results suggest the possibility of better recognition of subsets of patients with diverse tumor aggressiveness, combining together EGF-receptor status, cell kinetics and ploidy, with a better stratification for treatment options.

Antibodies, Monoclonal↗
PubMedDate not supplied

Conservative surgery and irradiation (QUART) in the treatment of 243 stage I-II breast cancer patients.

From 1980 to 1987, 243 evaluable patients with pT1, pT2 (less than 3 centimeters in diameter), N0, M0, invasive breast cancer were treated with "quadrantectomy" with axillary dissection followed by electron beam radiation therapy (QUART) at the St. Bortolo Hospital, Vicenza. Stage II patients received adjuvant chemotherapy (CMF) if preperimenopausal or hormonotherapy (tamoxifen) if postmenopausal. The median follow-up was 54 months (26 to 116 months). The 4.5-year overall survival (OS) and disease-free survival (DFS) were respectively 91% and 85%; the 10-year actuarially estimated OS and DFS was 77%. Thirty-three patients relapsed, 11 of whom had local recurrence, and 23 developed distant metastases. A significantly longer OS and DFS were observed in stage I versus stage II (p = 0.0008) and in pT1 versus pT2 (p = 0.001) tumors. No difference was found regarding menopausal status and histotype. The local control of disease was very high (95.5%), with a significantly higher local recurrence rate in premenopausal women compared to postmenopausal (10/117 versus 1/126; p = 0.009). Tumor size did not influence the frequency of local recurrence. No major complications occurred but a significantly higher rate of reversible radiation-pneumonitis occurred in patients treated with higher energies of electrons (17 to 20 MeV) compared with lower (6 to 13 MeV) (33/177 versus 7/66; p less than 0.05). Cosmetic results were judged as excellent in 20%, satisfactory in 68%, unsatisfactory in 6% and not evaluable in 6% of cases. We conclude first, that small pT2 breast carcinomas may also be safely treated with QUART, second, that the electron beam is a radiotherapeutic technique able to produce a good cosmetic result and to assure a satisfactory local control and, finally, that the use of tamoxifen in postmenopausal stage II breast carcinomas is safe and easy to combine with radiotherapy in the conservative management of early breast cancer due to the lower toxic effects, compared to those observed in premenopausal women treated with chemotherapy.

Aged↗
PubMedDate not supplied

Breast cancer cell kinetics: immunocytochemical determination of growth fractions by monoclonal antibody Ki-67 and correlation with flow cytometric S-phase and with some features of tumor aggressiveness.

In operable breast cancer, cell kinetics can be utilized in the prediction of the clinical outcome of patients. The discovery of monoclonal antibodies recognizing antigens related to cell proliferation has permitted the assessment of cell kinetics by rapid and practical immunocytochemical methods. It is claimed that the Ki-67 mouse monoclonal antibody recognizes an antigen expressed in proliferating cells but not present in quiescent (G0) cells. To study the relationship between Ki-67 score and DNA flow cytometric S-Phase Fraction (SPF), the latter being one of the most widely used methods to assess cell kinetics, we compared these two techniques of measurement in 122 breast carcinomas using both for each specimen. In this series 90% of tumors were Ki-67 positive, with a median value of 7.5% (range 1% to 70%). DNA flow cytometric analysis revealed that 69 tumors (57%) were aneuploid, whereas 53 were diploid. The median SPF value was 8% for diploid and 15% for aneuploid tumors (range 2% to 32%). Ki-67 scores were significantly higher in the DNA aneuploid compared to the diploid carcinomas (p = 0.015). Overall, a good correlation was found between Ki-67 and SPF values both in diploid (r = 0.60) and in aneuploid (r = 0.38) tumors. High Ki-67 scores were associated with the presence of axillary lymph node metastases (p = 0.0023) and poor histologic differentiation (p = 0.0028). Menopausal status, tumor size and peritumoral vessel invasion were unrelated to the Ki-67 score. Over-expression of the Epidermal Growth Factor receptor (EGF-r) and the c-erbB-2 oncogene were not correlated with Ki-67 staining. In conclusion, in this study Ki-67 immunostaining correlated with other indices of cell proliferation (SPF and Grade) and with some features of tumor aggressiveness (DNA aneuploidy and lymph node metastases) but seemed to be independent of some biological markers (EGR-r and c-erbB-2). Since the major objective for assessing proliferative status in Stage I-II breast carcinoma is to determine prognosis, it will have to be evaluated whether the determination of the Growth Fraction has comparable or even greater prognostic value than other cell kinetics markers.

Aneuploidy↗
PubMedDate not supplied

A retrospective analysis concerning physical aspects and clinical dosimetry in radiosurgery.

The authors have reviewed their experience with treatments of small intracranial lesions by unconventionally fractionated stereotactic radiotherapy using a 4 MV photon beam. Treatment is carried out by multiple non coplanar arc irradiation obtained rotating the target, while kept at the isocentre of a Linac, around a vertical axis. The outmost concentration of the dose within the target volume enables consistent reduction of the amount of the absorbed dose by critical structures of the intact brain. They analyse the dose distribution and the method to optimise the choice of the therapeutic dose. Finally, some radiobiological considerations are presented.

Humans↗
PubMedDate not supplied

Stereotactic radiosurgery of intracranial tumors in childhood.

The Authors have developed an original stereotactic technique by which the radiation dose erogated by a 4 MV linear accelerator is focused into the target volume with a steep dose gradient at its borders. The technique has been employed in a series of 30 patients affected by deep seated brain tumors and AVMs. The paper deals with the preliminary results obtained in a series of 10 patients in pediatric age.

Adolescent↗