Missing tissue compensation with wax filter compensators in radiotherapy of the head and neck regionDaša Grabec
, Primož Strojan
, 2005, original scientific article
Abstract: Background. In the conventional radiotherapy of the head and neck region, the inhomogeneity of the absorbed dose in certain clinical situations can exceed ?5% of the nominal dose. Depending on the pattern of dose inhomogeneity, treatment related toxicity is more pronounced and disease control reduced. Theaim of our report is to present the wax filter compensation technique used in our department. Case report. A 46-year-old male with inoperable carcinoma of the oropharynx of clinical stage T3N2c was irradiated with 5 MV linear accelerator photon beams and conventional 3 field technique. In order to obtain more homogenous dose distribution in treated volume, the opposed lateral fields were modified using 2Dwax filter compensators. Results. Using conventional wedge filter compensation, the planed absorbed dose deviations inthe treated volume were in the range of 94% to 113% of the prescribed dose. By modification of the opposed lateral fields with 2D wax filter compensators,the variations of the absorbed dose were reduced to the range from 93% to 105% of the prescribed dose. In the article, the planning and manufacturing as well as dosimetric checking of wax filter compensators are described. Conclusions. With the use of 2D wax filter compensators, the inhomogeneity of absorbed dose distribution was significantly reduced, and thequality of treatment considerably improved.
Published in DiRROS: 14.02.2024; Views: 77; Downloads: 18
Full text (502,94 KB)
Cathepsins and their inhibitors as tumor markers in head and neck cancerPrimož Strojan
, 2004, review article
Abstract: The invasion and metastasizing of tumor cells is closely connected with the disintegration of basement membranes and extracellular matrix. The carriers ofthese processes are different proteolytic enzymes, among them cysteine and aspartic cathepsins B, H, L and D as well, a group of ubiquitous lysosomal proteases, and endogenous inhibitors of the former, cystatins. The aim of the present review was to collect the current knowledge on the predictive and prognostic value of cathepsins and their inhibitors in squamous cell carcinomaof the head and neck. In this particular tumor type, the UICC/AJCC TNM-classification system and histopathological characteristics of the tumors were found inadequate to reliably predict either the response to therapy or patients' survival. Moreover, to date, no factor within the wide spectrum of biochemical and histological factors has yet been idenrified as reliably predicting the natural course of the disease or its response to therapy. To construct a prognostically meaningful tumor profile, new markers are intensively investigated.
Published in DiRROS: 13.02.2024; Views: 69; Downloads: 20
Full text (99,21 KB)
Cysteine proteinase inhibitors stefin A and stefin B in operable carcinoma of the head and neck : Inhibitorji cisteinskih proteinaz stefin A in stefin B pri operabilnem karcinomu glave in vratuPrimož Strojan
, Marjan Budihna
, Alojz Šmid
, Branka Svetic
, Ivan Vrhovec
, Janko Kos
, Janez Škrk
, 2002, original scientific article
Abstract: Purpose. To evaluate the significance of cysteine proteinase inhibitors stefins (Stefs) A and B for a treatment decision and prognosis in operable squamous cell carcinoma of the head and neck (SCCHN). Patients and methods. Stefs A and B concentrations were determined immunobiochemically using ELISAs in cytosols prepared from the tumor and adjacent normal mucosa from 91 patients with operable SCCHN. The median follow-up period of patients alive atthe close-out date was 5.8 years (range, 5-9.3 years). Results. Stef A concentrations were significantly higher in tumor compared to normal mucosa (FM.05). When a subgroup with clinically palpable nodes) at presentation was taken into consideration (n=57), a significant difference in Stef A (P=0.03) and Stef B (P=0.02) concentrations between those with negative and positive necks, as determined on histopathological examination, was observed. On the univariate survival analysis, higher Stefsć concentrations turned to be prognostically advantageous. Stef A proved its independent prognostic significance also on multivariate setting. Conclusions. With the capability todifferentiate between the pN0- and pN+-stages of the disease in the patientsoriginally presented as node-positive, Stefs A and B could be useful markers when deciding on the extent of neck surgery. In addition, both Stefs proved to be reliable prognosticators for survival in patients with operable SCCHN.
Published in DiRROS: 31.01.2024; Views: 87; Downloads: 21
Full text (114,91 KB)
Extramedullary plasmacytoma of the larynx : a report of three casesPrimož Strojan
, 2002, short scientific article
Abstract: Purpose. To report three cases of extramedullary plasmacytoma of the larynx treated at the Institute of Oncology in Ljubljana between 1969-1999. Results. All three patients were treated with radiotherapy only, whieh resulted in permanent local and regional control of 7.8, 4.7 and 3.5 years. The funetion of the larynx was preserved in all of them. Two patients died, both to the causes other than plasmacytoma. In none of the patients disease progressed to multiple rnyeloma. Conclusions. Extramedullary plasmacytoma of the larynx is arare disease, highly curable when radiotherapy is used. Moderate radiation doses and limited fields ensure excellent cosmetic and funetional result.
Published in DiRROS: 31.01.2024; Views: 83; Downloads: 22
Full text (74,68 KB)