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O R Monge

Publications and source records attributed to O R Monge.

At least 19 recordsLinked to original sources
PubMed2001

Dosimetric verification of a dedicated 3D treatment planning system for episcleral plaque therapy.

PURPOSE: Episcleral plaque therapy (EPT) is applied in the management of some malignant ocular tumors. A customized configuration of typically 4 to 20 radioactive seeds is fixed in a gold plaque, and the plaque is sutured to the scleral surface corresponding to the basis of the intraocular tumor, allowing for a localized radiation dose delivery to the tumor. Minimum target doses as high as 100 Gy are directed at malignant tumor sites close to critical normal tissues (e.g., optic disc and macula). Precise dosimetry is therefore fundamental for judging both the risk for normal tissue toxicity and tumor dose prescription. This paper describes the dosimetric verification of a commercially available dedicated treatment planning system (TPS) for EPT when realistic multiple-seed configurations are applied. MATERIALS AND METHODS: The TPS Bebig Plaque Simulator is used to plan EPT at our institution. Relative dose distributions in a water phantom, including central axis depth dose and off-axis dose profiles for three different plaques, the University of Southern California (USC) #9 and the Collaborative Ocular Melanoma Study (COMS) 12-mm and 20-mm plaques, were measured with a diode detector. Each plaque was arranged with realistic multiple 125I seed configurations. The measured dose distributions were compared to the corresponding dose profiles calculated with the TPS. All measurements were corrected for the angular sensitivity variation of the diode. RESULTS: Single-seed dose distributions measured with our dosimetry setup agreed with previously published data within 3%. For the three multiple-seed plaque configurations, the measured and calculated dose distributions were in good agreement. For the central axis depth doses, the agreement was within 4%, whereas deviations up to 11% were observed in single points far off-axis. CONCLUSIONS: The Bebig Plaque Simulator is a reliable TPS for calculating relative dose distributions around realistic multiple 125I seed configurations in EPT.

Brachytherapy↗
PubMed2001

Transillumination for accurate placement of radioactive plaques in brachytherapy of choroidal melanoma.

PURPOSE: To present a technique for accurate plaque placement in episcleral brachytherapy of choroidal melanoma. METHODS: The tumor margins are marked on the scleral surface, and a dummy plaque is temporarily sutured to the globe. A fiber optic light pipe is then wedged into the space between the sclera and the plaque. Because of the reflecting inner surface of the plaque, the perimeter of the plaque can easily be observed during indirect ophthalmoscopy as a circle of light surrounding the tumor. By this method, it is possible to determine the exact position of the entire plaque in relation to the tumor and make the necessary adjustments. When the correct position is found, the dummy plaque is replaced by a radioactive plaque. RESULTS: Since 1993, we have routinely used this procedure in episcleral brachytherapy. CONCLUSION: This modified transillumination technique facilitates a correct positioning of episcleral plaques.

Brachytherapy↗
PubMed1999

Chemotherapy in Ewing's sarcoma. The Scandinavian Sarcoma Group experience.

During the past 15 years the Scandinavian Sarcoma Group has treated 140 patients with Ewing's sarcoma. Two protocols have been used. SSG IV included 52 patients between 1984 and 1990 and SSG IX, 88 patients since 1990. After 5 years of treatment, local recurrences occurred in 19% of the patients (M0 + M1) in the SSG IV group and 10% in the SSG IX group. Distant metastases developed in 57% of the M0-patients in the SSG IV group and in 33% in the SSG IX group. Tumor-related survival (overall) of M0-patients was 49% in SSG IV and 70% in SSG IX, and the metastasis-free survival rate 45% and 58%, respectively. Patients having a localized extremity tumor had a survival rate of 90% (SSG IX). In both treatment groups, good responders to chemotherapy had a better survival rate than poor ones (SSG IV, p < 0.02, GI-II vs. G II-IV and SSG IX, p < 0.003, GI-III vs. G IV). In conclusions local control and survival rates were better with SSG IX than SSG IV.

Adolescent↗
PubMed1998

Ewing's sarcoma treatment in Scandinavia 1984-1990--ten-year results of the Scandinavian Sarcoma Group Protocol SSGIV.

A report on the long-term follow up of the first cooperative Scandinavian Sarcoma Group study in Ewing's sarcoma of bone is presented. Fifty-two previously untreated patients entered the study between 1984 and 1990. Half of the tumors were located in the extremities and one quarter in the pelvis. The combined modality treatment consisted of 5 cycles of chemotherapy--including vincristine, methotrexate, doxorubicin, cyclophosphamide, bleomycin and dactinomycin. The first two cycles were followed by local resection or amputation in 35 patients and by radiotherapy alone in 17 patients. When surgery was not performed, was incomplete or yielded poor margins radiotherapy was given at a dose of 40-60 Gy. Local tumor relapses developed in 10 patients and in all but one patient were accompanied by metastatic disease. Five patients had metastasis at diagnosis and distant metastases developed after primary treatment in 27 patients after a median of 14 months. The median follow-up time for the 20 surviving patients is 10 years. At 5 years the tumor-related survival was 46% and the metastasis-free survival 43%. Late tumor relapses occurred in 4 patients, which reduced the 10-year tumor related survival to 41% and the metastasis-free survival to 38%. Histopathological tumour response correlated with survival with 5-year metastasis-free survival rates of 73% for the good responders and 35% for the poor responders.

Adolescent↗
PubMed1997

Ifosfamide and continuous infusion etoposide in advanced adult soft tissue sarcoma. A Scandinavian Sarcoma Group Phase II Study.

The purpose of this study was to evaluate tumour response and toxicity to ifosfamide and continuous infusion etoposide in metastatic or locally advanced soft tissue sarcoma, with dose escalations under G-CSF (granulocyte colony-stimulating factor) support. Of 92 eligible patients (median age 51 years), 85% had tumours of high-grade malignancy and 82% had metastatic disease. Chemotherapy, the baseline dose, consisted of etoposide 600 mg/m2 as a 72 h infusion and ifosfamide 1500 mg/ m2/day for 3 days, followed by G-CSF support (VIG regimen). Stepwise 10% dose escalations were performed depending on haematological toxicity. For patients considered operable after induction chemotherapy, surgical resection of all identifiable residual tumour was attempted. Complete and partial response rates were 11% and 31%, for an overall response rate of 42% (95% CI 31-52%). Forty-eight per cent of courses were dose escalated by a median of 20%. Complete responders had significantly higher, and patients with progressive disease had significantly lower, dose levels than other patients. None of 20 patients with liver metastases responded despite high dose levels. Compared to a preceding pilot study, the addition of G-CSF led to significantly higher dose levels, improved schedule adherence and less haematological toxicity, but no apparent increase in response rate. In view of the modest dose of ifosfamide applied in this study, it is possible that the prolonged infusion of etoposide made a significant contribution to the regimen's antitumour activity, although this can only be determined definitively in a randomised study.

Adolescent↗
PubMed1997

Fibrosarcoma in children--a rare tumour with long-term survival even with advanced disease--a report of 3 cases.

Fibrosarcoma is a rare tumour in children. The potential of malignancy has been questioned. We present three cases of fibrosarcoma in children . The follow-up periods range from 10 to 37 years. The first patient had pulmonary metastases at the time of diagnosis in 1958. The primary tumour in fossa ischio-rectalis was resected in 1960. Lung metastases were resected in 1960 and 1989. Radiotherapy was given in 1992. He is still alive with metastases 37 years after the first manifestation of disease. The second patient had a primary tumour and several local recurrences in the mandible. He is alive without evidence of disease 4 years after resection of pulmonary metastases and 21 years after resection of the primary tumour. The third patient has no signs of recurrence or metastatic spread 10 years after a wide excision of subcutaneous tumours of the left upper arm. The cases demonstrate a special tumour-entity of low-grade malignancy, which show a good prognosis and a wide spectrum of biological behaviour.

Abdominal Neoplasms↗
PubMed1993

Prediction of treatment temperatures in clinical hyperthermia of locally advanced breast carcinoma: the use of contrast enhanced computed tomography.

PURPOSE: Nineteen patients with locally advanced breast carcinoma were subjected to computed tomography examinations prior to thermoradiotherapy. Pre- and postcontrast computed tomography images were obtained, and tumor contrast enhancement was studied in relation to tissue perfusion, PERF, and steady state temperature, TS, in an attempt to develop an assay for prediction of treatment temperatures in clinical hyperthermia of breast carcinoma. METHODS AND MATERIALS: PERF and TS were calculated from temperature data achieved during the first fraction of the heat treatment regimen. The computed tomography images were subjected to image analysis, and two parameters representing tumor contrast enhancement were calculated from the computed tomography numbers; the absolute increase in mean attenuation, delta N, and the fraction of the postcontrast attenuation values that was higher than the mean precontrast attenuation value, F+C. RESULTS: delta N and F+C were clearly correlated to each other. The two parameters differed considerably among the patients, showing that the accumulation of contrast medium was higher in some tumors than in others. Tumor contrast enhancement increased with increasing PERF, suggesting that the accumulation of contrast medium in the tumors was determined mainly by the effective tissue perfusion. There was also a clear correlation between tumor contrast enhancement and TS. The tumors showing a high accumulation of contrast medium were more difficult to heat than those showing a low accumulation. CONCLUSION: The results indicate that contrast enhanced computed tomography images may give information about the treatment temperatures that can be achieved in clinical hyperthermia of breast carcinoma. The computed tomography images may possibly be used to predict those tumors that can be heated to therapeutic temperatures.

Body Temperature↗
PubMed1991

Fractionated thermochemotherapy in vivo of a C3H mouse mammary carcinoma.

The interaction between fractionated heat treatment and fractionated drug treatment with cyclophosphamide (CTX) was investigated in a transplantable C3H mouse mammary carcinoma inoculated into the hind leg of C3D2F1/Bom mice. A tumour core temperature of 43.5 +/- 0.1 degrees C was achieved by immersing the tumour-bearing leg into a water bath thermostatically maintained at 43.7 +/- 0.1 degrees C. CTX was administered i.p. using the maximum tolerated dose (MTD) (LD 1%) for single fraction treatment (100 mg/kg) as the maximum fraction dose. For combined treatment CTX was given 15 min prior to heating. The endpoint was the time to reach a tumour volume of 5 times the volume at first treatment. Specific growth delay was used as effect parameter. In dose-effect experiments using total treatment time at 43.5 degrees C as dose parameter, drug enhancement ratio (DER) was determined as the ratio of the slope of the dose-effect curve for MTD of CTX plus heat to the slope of the curve for heat alone. In dose-effect experiments using total CTX dose as dose parameter, thermal enhancement ratio (TER) was determined as the ratio of the slope of the dose-effect curve for CTX plus 43.5 degrees C for 30 min to the slope of the curve for CTX alone. The regimens investigated were single fraction treatment and 3 and 5 fractions with time intervals of 3 and 5 days. For single fraction treatment DER was 1.4 +/- 0.1 and TER 2.3 +/- 0.2. The drug sensitization of the effect of heat treatment tended to increase with increasing number of fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Temperature distribution in locally advanced breast carcinoma during hyperthermic treatment: relationship to perfusion, vascular density, and histology.

Temperature distributions achieved during hyperthermic treatment of 16 patients with locally advanced breast cancer were analyzed in relation to tissue perfusion, vascular density, and histology of treated volume. Temperatures were measured using multi-sensor thermistor probes inserted in the center and periphery of the treatment volume. A steady state temperature, Ts, and a perfusion related parameter, PERF, were determined for each probe location. Vascular density and tissue composition were determined by histologic analysis of biopsies taken from the temperature probe locations before treatment. Both malignant and normal tissue were found in the biopsies, reflecting a diffusive tumor growth pattern. The malignant and normal tissue compartments were analyzed separately using stereologic techniques. Ts, PERF, vascular density, and tissue composition differed significantly between patients. There was a clear relationship between Ts and PERF, showing that the local tissue perfusion was decisive for the temperatures achieved. Ts and PERF showed a clear correlation with the normal tissue vascular density, but not with the malignant tissue vascular density; that is, the treatment temperatures achieved were mainly determined by the vascularization of the normal tissue compartment. Fraction of necrosis was the only tissue compartment parameter that showed a clear relationship to Ts and PERF. Ts increased and PERF decreased with increasing necrotic fraction.

Adult↗
PubMed1990

[Locally advanced breast cancer--primary treatment with tamoxifen].

Tamoxifen was given as primary systemic treatment to 28 patients with locally advanced breast cancer. In all tumours, receptors for estrogen (ER) and/or progesterone (PGR) were positive. All patients (15) with high levels of hormone receptors (ER greater than or equal to 100 mumols/g protein and/or PGR greater than or equal to 200 mumols/g protein) were alive after two years of observation as against 60% of the patients (13) with lower hormone receptor values.

Adult↗
PubMed1988

Thermochemotherapy in vivo of a C3H mouse mammary carcinoma: single fraction heat and drug treatment.

The interaction between water bath hyperthermia (43.5 degrees C) and six cancer chemotherapeutic agents in vivo was studied in a transplantable C3H mouse mammary carcinoma grown s.c. in the feet of C3D2F1/Bom mice. Due to differences in tumour regrowth rate between treatment groups, both tumour growth time (TGT) and specific growth delay (SGD) were used as effect parameters. The largest tumour response was observed when the drug was given 15 min prior to heat--this timing was used for dose-effect experiments. Enhancement ratios were the ratios of slopes of dose-effect curves subjected to linear regression analysis. The drug enhancement ratio (DER) was not significantly larger than 1.0 for LD 1% of adriamycin, 5-fluorouracil, methotrexate and vincristine. For cyclophosphamide (CTX) and mitomycin C (MMC) both DER and TER (thermal enhancement ratio) were significantly larger than 1.0. The TGT ratios (SGD ratios in parentheses) were: DER (LD 1%): CTX 1.4 +/- 0.1 (2.1 +/- 0.1), MMC 1.3 +/- 0.1 (1.4 +/- 0.1); TER (43.5 degrees C 30 min): CTX 1.6 +/- 0.1 (2.7 +/- 0.2), MMC 2.8 +/- 0.5 (3.3 +/- 0.7). The data support the choice of CTX and MMC in preference to the other drugs investigated for clinical thermochemotherapy studies.

Animals↗
PubMed1987

Epithelial ovarian tumor in a phenotypic male.

Laparotomy in a 41-year-old married man with non-treated left cryptorchidism revealed female internal genitals on the left side, and an epithelial ovarian tumor of intermediate malignancy. Germinal malignancies are frequent in intersexes, but non-germinal gonadal neoplasms are rare. This is the second reported case of epithelial ovarian tumor in intersexes, and the first case of epithelial ovarian tumor in an intersex registered as male.

Adult↗
PubMed1986

Sightsaving therapy in retinoblastoma. Experience with external megavoltage radiotherapy.

In Norway, sightsaving therapy in retinoblastoma has only been given to least affected eyes in bilaterally affected children. The results in 8 eyes given external high energy radiotherapy are reported. Additional focal therapy was given to 3 eyes for residual tumours and to one eye with new tumour at the ora serrata. Cataract was treated in 2 of the 3 eyes in which it developed. Vitrectomy was performed in 2 eyes with vitreous haemorrhage and persisting vitreous haze. Secondary enucleation has been avoided in all eyes 3-9 years after irradiation. One patient developed metastases in the temporal region at the enucleated side. Visual acuity is 6/12-6/6 if the macula has not been destroyed by tumour or focal therapy. Sightsaving therapy is presently also offered to unilateral cases and worst affected eyes in bilateral cases if the eyes belong to Reese-Ellsworth groups I-IV.

Child↗
PubMed1985

Survival curves after X-ray and heat treatments for melanoma cells derived directly from surgical specimens of tumours in man.

X-ray and heat survival curves were established for melanoma cells derived directly from surgical specimens of tumours in man by using the Courtenay soft agar colony assay. The plating efficiency for 11 of the 14 melanomas studied was sufficiently high (PE = 0.3-58%) to measure cell survival over at least two decades. Experiments repeated with cells stored in liquid nitrogen showed that the survival assay gave highly reproducible results. The melanomas exhibited individual and characteristic survival curves whether exposed to radiation or heat (43.5 degrees C). The Do-values were in the ranges 0.63-1.66 Gy (X-rays) and 33-58 min (heat). The survival curves were similar to those reported previously for human melanoma xenografts. The radiation sensitivity of the cells was not correlated to the heat sensitivity. Since the melanomas appeared to be very heterogeneous in radiation response in vitro as melanomas are known to be clinically, it is suggested that melanomas may be suitable for prospective studies aimed at establishing whether clinical radioresponsiveness somehow is related to in vitro survival curve parameters.

Adult↗
PubMedDate not supplied

The relevance of tumour and surrounding normal tissue vascular density in clinical hyperthermia of locally advanced breast carcinoma.

It follows from the present work that the vascularization of the normal tissue present in the treatment volume limits the temperatures achieved during heat treatment of invasive ductal breast carcinoma. The temperatures can often be increased by giving fractionated heat treatment because heat treatment may reduce the cooling capacity of the normal tissue vasculature. Significant damage to supplying vessels occurs at the heat doses necessary to cause necrosis in the tumour and surrounding normal tissue, indicating that secondary cell death is an important mechanism for cell inactivation following hyperthermic treatment of breast carcinoma.

Blood Vessels↗
PubMedDate not supplied

Thermochemotherapy in vivo of a C3H mouse mammary carcinoma: thermotolerant tumours.

The ability of cyclophosphamide (CTX) and mitomycin C (MMC) to modify the expression of thermotolerance in vivo at 43.5 degrees C was investigated in a transplantable C3H mouse mammary carcinoma grown s.c. in feet of C3D2F1/Bom mice. Dose-effect curves subjected to linear regression analysis were constructed for single-fraction treatment and for a second treatment 24 h after a priming heat treatment of 43.5 degrees C for 30 min. Tumour volume doubling time during regrowth showed no significant variation among treatment groups, justifying the use of tumour growth time as effect parameter. Thermotolerance ratio for heat alone was 11.6 +/- 2.3. Drug enhancement ratio in thermotolerant tumours was 6.2 +/- 1.4 for CTX (100 mg/kg) and 3.5 +/- 0.9 for MMC (3 mg/kg). These values are about 4 and 3 times larger than the corresponding enhancement ratios found for previously untreated tumours. Thermotolerance ratio for thermochemotherapy was 2.6 +/- 0.3 for CTX and 4.4 +/- 0.7 for MMC, i.e. the degree of thermotolerance was substantially reduced by both drugs, but not completely overcome. Thermal enhancement ratio for CTX and MMC was about equally large in thermotolerant and previously untreated tumours. Thermotolerant tumours showed a tendency for increased resistance to drug treatment alone. Both CTX and MMC may be used clinically to reduce the expression of thermotolerance, particularly in situations with inhomogeneous heating and short fractionation intervals.

Animals↗