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Biomedical subjects

G Saeter

Publications and source records attributed to G Saeter.

At least 55 records · Page 3Linked to original sources
PubMed1996

Extremity and non-extremity high-grade osteosarcoma -- the Norwegian Radium Hospital experience during the modern chemotherapy era.

Of 103 patients with high-grade osteosarcoma, 27% had tumours localized outside the extremities. Non-extremity patients were significantly older at diagnosis than patients with extremity tumours (median 38 vs. 17 years). More than 90% of patients with extremity tumours received adequate treatment (aggressive chemotherapy plus at least marginal surgery), compared with only 25% of patients with non-extremity tumours. Failure of adequate treatment was due to inoperable tumour, intralesional surgery and age preventing aggressive chemotherapy. There was a highly significant difference in both local tumour control and overall survival, both favouring patients with extremity tumours. Within the extremity tumour group, patients who were treated in prospective multicentre trials had a significantly better outcome than non-trial patients. Our results show that the fraction of patients with high-grade tumours that fall outside trials designed for 'classical osteosarcoma' may be larger than is usually acknowledged, and that the results reported for the classical group are by no means representative of the whole patient population. Improved and new treatment approaches are needed for patients with non-extremity tumours, particularly in the older age groups.

Adolescent↗
PubMed1995

Systemic relapse of patients with osteogenic sarcoma. Prognostic factors for long term survival.

BACKGROUND: A retrospective study of long term outcome after the development of metastases from osteosarcoma was performed, with emphasis on the impact of different treatment strategies and the identification of prognostic factors. METHODS: From 1975 to 1993, a population-based series of 60 patients with distant metastases (relapse) from high grade, extremity-localized osteosarcoma was treated at The Norwegian Radium Hospital. Six patients relapsed after surgery alone, 28 patients relapsed after primary chemotherapy of low potency, and 26 patients after modern, intensive chemotherapy. Lung metastases were present in 88% of the patients, 52% had bilateral lesions, and the median number of lesions was three (range, 1-25 lesions). Forty-seven percent of patients had complete surgical excision of all identifiable metastatic nodules and 54% of these had additional second line chemotherapy defined as adequate. Adequate chemotherapy included further dose escalations of methotrexate in approximately half of the patients, usually from 8 to 12 g. The rest were exposed to novel agents such as cisplatin, etoposide, and ifosfamide. Of the operated patients, 43% had additional thoracotomies after subsequent relapses. RESULTS: The projected 5-year survival rate from the first metastatic event was 24% for all patients and 50% for patients who underwent complete metastasectomy. In a multivariate analysis, the factors with independent predictive value for improved overall survival were the presence of a solitary metastasis, the accomplishment of complete metastasectomy, and the administration of adequate salvage chemotherapy. CONCLUSIONS: Complete metastasectomy is mandatory for long term survival of patients with metastatic osteosarcoma, and repeated lung resections are necessary in nearly half the patients. Second line chemotherapy and following primary treatment with modern intensive chemotherapy protocols may improve survival further.

Adolescent↗
PubMed1995

Treatment of advanced, high-grade soft-tissue sarcoma with ifosfamide and continuous-infusion etoposide.

A total of 33 patients (median age, 44 years) with high-grade, adult soft-tissue sarcoma were treated with etoposide given at 600 mg/m2 in a 72-h continuous infusion and ifosfamide given at 1500 mg/m2 per day for 3 days every 3 weeks. Dose escalation/reduction was protocolled depending on the level of hematological toxicity observed in the preceding course. Overall, 90% of patients had metastatic disease, and the most common histologies were malignant fibrous histiocytoma and leiomyosarcoma. A median of 5 (range, 1-9) courses were given. Of 30 patients who were evaluable for response, 12 (40%) obtained a partial remission, and the median time to progression was 8 (range, 4-13) months. Grade 3-4 leukopenia and thrombocytopenia were seen after 89% and 8% of the courses, respectively; neutropenic fever was seen in half of the patients (15% of courses); and 32% of courses had to be postponed by 7 days or more due to myelosuppression. Dose reduction to below the standard had to be performed in 46% of courses, and dose escalation was achieved in only 13%. The reduced toxicity seen after the addition of granulocyte colony-stimulating factor (G-CSF) in five patients indicates that growth-factor support may enhance the dose intensity of the regimen. The results indicate significant activity for this regimen in adult soft-tissue sarcoma, which may in part be a result of the escalated dose and prolonged mode of administration of the phase-specific agent etoposide. As a result of this pilot series, a phase II study with ifosfamide, etoposide, and G-CSF in advanced adult soft-tissue sarcoma has been initiated by the Scandinavian Sarcoma Group.

Adult↗
PubMed1995

Alterations at chromosome 17 loci in peripheral nerve sheath tumors.

Little is known about the molecular genetic changes in malignant peripheral nerve sheath tumors (MPNST). Inactivation of the TP53 gene in 17p has been reported in a few tumors. The MPNST is one of the manifestations of neurofibromatosis 1 (NF1), suggesting that the NF1 gene in 17q might be important. We present a study of 15 neurofibromas and MPNST from nine individuals. Seven patients had NF1, and six of these developed MPNST. Genetic alterations at nine polymorphic loci on chromosome 17 were examined. Allelic imbalance was detected only in the malignant tumors from NF1 patients (4/6). Complete loss of heterozygosity of 17q loci was found in three of these tumors, all including loci within the NF1 gene. Two of the malignant tumors also showed deletions on 17p. No mutations were detected within exon 5-8 of the TP53 in any of the MPNST, and none of them were TP53 protein-positive using immunostaining with mono- and polyclonal antibodies against TP53. The numbers of chromosome 17 present in each tumor were evaluated by use of fluorescence in situ hybridization (FISH) on interphase nuclei with a centromere-specific probe. A deviation from the disomic status of chromosome 17 was observed in two of the MPNST from NF1 patients. These results support the hypothesis of inactivation of both NF1 gene alleles during development of MPNST in patients with NF1. In contrast to other reports, we did not find evidence for a homozygous mutated condition of the TP53 gene in the same tumors. Finally, FISH analysis was in accordance with the DNA analysis in the deduction of the numbers of chromosome 17 in these tumors.

Adolescent↗
PubMed1994

[Treatment of chondrosarcoma. A retrospective study at the Norwegian Radium Hospital].

The authors present a retrospective analysis of 59 chondrosarcoma patients treated at the Norwegian Radium Hospital during the period 1981 to 1993. 31 patients were admitted with untouched tumour, seven after fine needle cytology and 20 after open biopsy or partial excision. One patient had recurrent local disease. Only 20% of the tumours were of high grade malignancy. 51 patients were treated by surgery. Reconstructions were performed in 16 patients, using allografts or endoprostheses. Amputations were performed in six cases and wide excision in 12 cases. In these 18 patients local recurrence appeared in one case, and two developed lung metastases. Only one of the 18 patients operated by amputation or wide excision has since died from chondrosarcoma. Marginal excisions were performed in 26 cases. Nine of these patients developed a local recurrence, five developed metastases and three have died. Six patients had partial excisions. Postoperative radiotherapy was given to one patient only. Five of the six are alive. In one case, the quality of the margins could not be evaluated. A total of 45 of the 51 patients treated for the primary tumour by surgery are alive. The median observation time is four years. Treatment of nonmetastatic chondrosarcoma should be surgical. Chondrosarcoma patients show wider variations in age, localization of tumour and tumour growth rate than patients with other bone sarcomas. Although wide excisions provide the best local control of any grade of malignancy, the mutilation or risk involved may be so great that some patients may benefit from marginal or even partial excision.

Adult↗
PubMed1993

[Diagnostic aspects of subacute osteomyelitis in children and adolescents. Clinical and radiographic resemblance to primary malignant tumors].

During a six-year period, 17 patients younger than 20 years of age, with a final diagnosis of subacute osteomyelitis, were admitted to the Norwegian Radium Hospital because of an initial suspicion of primary malignant bone tumour. The most common localizations were the metaphyses of long bones (eight patients) and the clavicle (four patients). Pain was the dominating symptom. Common radiological findings were localized osteolysis and/or sclerosis, cortical bone destruction, periosteal reaction and an adjacent, often palpable soft tissue mass. Clinical signs of infection were generally absent, and a positive bacterial culture was obtained from the biopsy material in only one patient. Following extensive investigations, a malignant bone tumour (especially Ewing's sarcoma) remained a differential diagnosis, and open biopsy was indicated in all cases. The patient material illustrates the difficulty in distinguishing between subacute osteomyelitis and malignant bone tumours, and it is stressed that diagnostic investigations for this type of patients should be performed in an oncological centre with experience of bone tumours.

Adolescent↗
PubMed1993

Genetic alterations in a malignant schwannoma from a patient with neurofibromatosis (NF1).

In a patient with neurofibromatosis (von Recklinghausen disease; NF1), normal lymphocytes, five cutaneous neurofibromas, and tumour tissue from a recurrence of a malignant schwannoma were analysed for genetic alterations. Eleven DNA markers located on chromosome 17 and nine randomly chosen markers representing chromosomes 1, 2, 3, 4, 5, 6, and 11, were analysed. High resolution Giemsa banding of lymphocytes revealed no chromosomal rearrangement. The DNA from the neurofibromas were all found to have the same restricted fragment length polymorphism pattern as the constitutional DNA from the patient. In the malignant schwannoma a complete loss of one allele was found at polymorphic loci on chromosome arm 17p. One gene copy of the TP53 gene (17p13.1) and the NF1 gene (17q11.2) was lost, as was one copy of the PGA gene (11q13). No mutations were detected in the mutational hotspots of the TP53 gene. Partial losses were detected at three loci on chromosomes 1, 2 and 6, indicating a clonal variation within the tumour since histological evaluation disclosed no normal tissue in the analysed specimen. Our data indicate that the NF1 gene may function as a tumour suppressor gene, and that, either by effect of dose reduction or complete inactivation, both the NF1 gene and the TP53 gene may be critical for the progression of a neurofibroma to a malignant schwannoma. The observations made are consistent with the concept of stepwise multigenetic changes in tumour progression.

Adult↗
PubMed1992

High-dose methotrexate in the treatment of malignant mesothelioma of the pleura. A phase II study.

From 1984 to 1989, 63 patients with diffuse, malignant mesothelioma of the pleura were treated with 4-8 courses of high-dose methotrexate (HDMTX, 3 g total dose) and citrovorum factor rescue. There were 61 male and two female patients of median age 60 years. CT scan was performed before and after treatment and used for response evaluation. Of 60 patients evaluable for response, 37% showed partial or complete remission, 32% showed no change and 32% showed progressive disease. Median survival from start of treatment for all patients was 11 months, for 42 patients with the epithelial type 12 months, and for 20 patients with sarcomatous or mixed types only 5 months. Toxicity was acceptable, with only five patients (8%) terminating therapy due to toxicity. One toxic death occurred. We conclude that HDMTX is an active regimen in malignant pleural mesothelioma. The significantly shorter survival for patients with the sarcomatous or mixed subtypes indicates that further investigations on the activity of HDMTX in mesothelioma should be limited to patients with the epithelial subtype.

Dose-Response Relationship, Drug↗
PubMed1992

The treatment of osteosarcoma: present trends. The Scandinavian Sarcoma Group experience.

The study comprised 97 patients treated by the Scandinavian Sarcoma Group for high-grade, extremity-localized osteosarcoma. Chemotherapy was according to the T-10 protocol, with four courses of high-dose methotrexate (HDMTX) given preoperatively at weekly intervals. Seventeen percent of the patients obtained a good (grade III or IV) histologic response, 62% a moderate (grade II) response and 21% a poor (grade I) response. Grade II-IV responders had significantly higher serum MTX levels than grade I responders. Good responders had significantly better survival than moderate/poor responders, and had a trend towards both lower recurrence rate and longer time to recurrence. Five-year overall and relapse-free survival for all patients was 63% and 53%, respectively. Within a group of patients with similar primary tumour response, there was a trend for better survival with increasing serum MTX levels, indicating that individualization of MTX doses according to renal excretion rates may be indicated. The present results underline the importance of introducing effective chemotherapy from the start of osteosarcoma treatment, and that HDMTX alone seems to be insufficient preoperative therapy. The toxicity of HDMTX is generally mild, but we have by cerebral MRI found signal changes in white matter in 14/22 patients; changes that may represent subclinical MTX CNS toxicity. In the subsequent SSG osteosarcoma protocol, cisplatin and doxorubicin has been added to HDMTX from the start of treatment. Our data also suggest that an aggressive approach involving second-line chemotherapy and surgery is indicated for metastatic disease and that such an approach may lead to long-term survival in up to 30% of patients.

Adolescent↗
PubMed1991

Diploid growth pattern of hepatocellular tumours induced by various carcinogenic treatments.

Hepatocellular carcinomas from rats of different strains, subjected to a variety of carcinogenic treatment regimens in different laboratories (initiation by diethylnitrosamine or dimethylhydrazine, promotion by phenobarbital, 2-acetylaminofluorene, nafenopin, orotic acid or deoxycholic acid, growth stimulation by partial hepatectomy or necrogenic CCl4 treatment), were all found to be predominantly diploid by flow cytometric analysis, in contrast to normal liver tissue in which polyploid nuclei were predominant. A switch from polyploidization to diploid growth would thus seem to be a common property of malignant liver tumours. Benign neoplastic liver nodules were likewise predominantly diploid, with the exception of nodules induced by long-term deoxycholic acid treatment in Fischer rats. In addition to containing a majority of polyploid cells, the latter nodules failed to progress to the carcinoma stage.

Animals↗
PubMed1991

Osteogenic sarcoma: MR signal abnormalities of the brain in asymptomatic patients treated with high-dose methotrexate.

The advent of lesions with high signal intensity in periventricular white matter was incidentally observed on T2-weighted images in one patient who underwent magnetic resonance (MR) imaging of the brain after administration of high-dose methotrexate (HDMTX) for osteogenic sarcoma. Twenty-one additional symptom-free patients who had been treated with the same regimen and 10 patients who had undergone cisplatin-based chemotherapy for testicular cancer also underwent examination. Fourteen of the patients with osteosarcoma showed high-signal-intensity lesions in white matter on T2-weighted images. The interval between the last course of chemotherapy and MR imaging was a factor in this finding, as 12 of 14 patients who underwent examination within 2 years after chemotherapy had a positive finding, as opposed to two of eight patients who underwent examination later. The patients with testicular cancer had normal MR images. The occurrence of MR imaging abnormalities in asymptomatic patients treated with HDMTX for osteogenic sarcoma may be subclinical evidence of treatment-related central nervous system toxicity.

Brain↗
PubMed1991

Treatment of osteosarcoma of the extremities with the T-10 protocol, with emphasis on the effects of preoperative chemotherapy with single-agent high-dose methotrexate: a Scandinavian Sarcoma Group study.

From 1982 to 1989, 97 patients with extremity-localized, high-grade osteosarcoma were treated according to the T-10 protocol. Two thirds of the patients consisted of the near-complete national patient materials from Norway and Finland. Eighty patients (82%) received four courses of high-dose methotrexate (HD MTX, 8 to 12 g/m2) at weekly intervals as their only preoperative treatment, and 77 patients (79%) were assessable for histologic response grading according to Rosen et al (Cancer 49:1221-1230, 1991). Observed histologic response was no certain chemotherapy effect (grade I) in 21%, grade II effect in 62%, and grade III or IV effect in 17%. Nonresponders had significantly lower serum MTX concentrations after 24 and 48 hours than responders; the significance of the difference at 48 hours was maintained in a multivariate analysis. After a median follow-up of 45 months, projected 5-year overall and relapse-free survival for all patients were 64% and 54%, respectively. Patients with a good response to preoperative chemotherapy (grade III/IV) had a significantly better survival than grade I/II responders, despite a switch to postoperative cisplatin/doxorubicin chemotherapy in the latter group. These results were obtained in a largely nonselected group of patients. We conclude that a good initial chemotherapy effect is important for the final outcome in osteosarcoma, and that HD MTX alone is insufficient preoperative treatment for the majority of patients. The individual MTX excretion rate is of importance for tumor response, suggesting a dose-response relationship for HD MTX treatment.

Adolescent↗
PubMed1990

Liver tumor promoters stimulate growth of transplanted hepatocellular carcinomas.

Cell suspensions or tissue fragments from primary hepatocellular carcinomas and benign neoplastic nodules, induced by treating rats with chemical carcinogens, were transplanted by intraportal injection or subcapsular implantation in the livers of syngeneic host rats. Both nodule and carcinoma transplants produced high numbers of hepatocellular carcinomas in the hosts 2 to 5 mo after transplantation. Treatment of the host rats with liver tumor promoters (phenobarbital or 2-acetylaminofluorene) greatly stimulated tumor outgrowth, demonstrating that even established carcinoma cells can be promoter-sensitive. Tumor outgrowth was also stimulated by partial hepatectomy of the hosts, the regenerative stimulus interacting synergistically with the tumor promoters.

2-Acetylaminofluorene↗
PubMed1990

Management of patients with poor-prognosis nonseminomatous germ cell cancer.

The treatment and outcome of 57 patients with poor-prognosis metastatic nonseminomatous germ cell cancer were reviewed. The patients were treated between 1980 and 1986. Poor-prognosis patients were characterized by the presence of at least one of the following findings: (1) retroperitoneal tumor mass greater than 10 cm; (2) greater than 3 lung metastases, the largest being greater than 2 cm; (3) extrapulmonary, extralymphatic, metastases; and (4) extragonadal primary tumor. The intended treatment consisted of cisplatin-based combination chemotherapy followed by secondary surgery. From 1980 to 1983 a modified Einhorn regimen was used (cisplatin 100 mg/m2 per cycle; CVB). In case of unacceptable vinblastine toxicity, this drug was substituted by VP-16 (500 mg per m2 per cycle; BEP20). From October 1983 the intention was to replace at least 3 of the CVB/BEP20 cycles by BEP60 cycles (days 1-3: cisplatin 60 mg/m2, days 1-3: VP-16 120 mg/m2; days 1, 5, 15: bleomycin 30 mg). There were 33 patients in the CVB/BEP20 group and 24 patients in the BEP60 group. Two patients of the CVB/BEP20 group and 6 patients of the BEP60 group were not evaluable for response, but are included in the survival analysis. The reasons for exclusion from response evaluation were that these patients could not receive the intended chemotherapy in appropriate doses due to severely reduced pretreatment general condition or due to early death. Fourteen patients with multiple lung metastases but no other poor-prognosis criteria had a 93% survival indicating that they did not represent poor-prognosis germ cell cancer. After excluding these 14 patients, the 4-year survival was 58% for 19 CVB/BEP20 patients and 72% for BEP60 patients. This difference did not reach the level of statistical significance in this limited series. The introduction of high-dose cisplatin had thus not led to clearly superior treatment results as compared to CVB/BEP20.

Adolescent↗
PubMed1989

Diploid nature of hepatocellular tumours developing from transplanted preneoplastic liver cells.

Hepatocyte suspensions were transplanted to the livers of syngeneic Wistar Kyoto rats by means of intraportal injection. Labelling of the donor cells with 51Cr or tritiated thymidine showed that 20% of the cells survived the transplantation procedure and were permanently retained by the recipient liver. Hepatocytes transplanted from normal livers produced no tumours, whereas donor cells from preneoplastic livers of rats treated with the carcinogens diethylnitrosamine and 2-acetylaminofluorene produced neoplastic nodules and hepatocellular carcinomas in the recipients. The number of tumours per host liver was proportional to the number of hepatocytes transplanted. Treatment of the host rats with phenobarbitone accelerated tumour development, causing liver cancer in the majority of the animals within three months. As opposed to the polyploid surrounding liver, both phenobarbitone-promoted and unpromoted host tumours contained predominantly (70-90%) diploid cells, regardless of the wide range of transplant ploidies (10-80% diploid cells) achieved by means of centrifugal elutriation. The results indicate that all host tumours arise from diploid donor hepatocytes and that the acquisition of a constitutive, predominantly non-polyploidising growth pattern may be a characteristic property of hepatocellular tumours.

2-Acetylaminofluorene↗
PubMed1989

Neuroendocrine dysdifferentiation and bombesin production in carcinogen-induced hepatocellular rat tumours.

Primary rat hepatocellular tumours, induced by a combination of diethylnitrosamine and 2-acetylaminofluorene, were examined for the presence of neuroendocrine peptides by immunocytochemical methods. Two-thirds of the tumours showed positive immunostaining for either neuron-specific enolase (NSE), protein S-100 or bombesin. NSE was commonly observed both in hepatocarcinomas and in neoplastic nodules, whereas protein S-100 was more frequently seen in carcinomas (49% positive) than in nodules (13% positive). Bombesin, previously shown to function as an autocrine growth factor in small-cell carcinoma of the lung, was present in neurosecretory granules in 13% of the nodules and 29% of the carcinomas. Normal, preneoplastic and peritumorous liver tissue, including the frequent atypical foci present in the latter two categories, was uniformly negative for all neuroendocrine markers. The foci, like the nodules and carcinomas, generally stained positively for the liver tumour marker glutathione S-transferase type P (GSTP). The results suggest that dysdifferentiation of altered hepatocytes in a neuroendocrine direction may be a common, late event in liver carcinogenesis which could possibly contribute to tumour formation, e.g. by establishing autocrine or paracrine circuits.

Animals↗
PubMed1988

Changes in ploidy distributions in human liver carcinogenesis.

Cellular and nuclear DNA content was measured by flow cytometry and the fraction of binucleated cells by fluorescence microscopy in normal adult human livers, hepatocellular carcinomas, cirrhotic livers surrounding tumors, and in some benign liver conditions. In five normal livers about one-half of the hepatocytes were polyploid; the majority of these were binucleated tetraploids containing two diploid nuclei. Thus, polyploidization in human liver does not progress as far as, for example, in the rat, where 80%-90% of adult hepatocytes are polyploid, mostly with tetraploid or octoploid nuclei. In five human euploid hepatocellular carcinomas and one investigated case of focal nodular hyperplasia, the percentage of polyploid cells was significantly reduced. Four other carcinomas exhibited a prominent aneuploid (hypotetraploid) peak in addition to the diploid peak. An abnormally low fraction of binucleated cells was also indicated in these tumors. Liver tissue surrounding the tumors had a ploidy distribution similar to that of normal liver. The results suggest that, like in several models of experimental hepatocarcinogenesis, human hepatocellular tumor growth is associated with a decreased polyploidization tendency and a corresponding increase in diploid, divisional growth, which may give the tumors a growth advantage relative to the surrounding liver.

Adolescent↗