Biomedical subjects

H J Hoekstra

Publications and source records attributed to H J Hoekstra.

At least 91 records · Page 5Linked to original sources

PubMed1999

Computer-assisted cytogenetic analysis of 51 malignant peripheral-nerve-sheath tumors: sporadic vs. neurofibromatosis-type-1-associated malignant schwannomas.

Cytogenetic studies in small groups of patients with malignant peripheral-nerve-sheath tumors (MPNST) revealed complex karyotypes with no consistent changes. A computer-assisted cytogenetic analysis using a cytogenetic database was performed to determine recurrent cytogenetic alterations in 51 MPNSTs (44 from the literature and 7 new cases) and to allow direct cytogenetic comparison between NF-1-associated and sporadic MPNSTs. Significant loss (p < 0.05) was observed in the chromosomal regions 9p2, 11p1, 11q2 and 18p1. Also, loss in 1p3, 9p1, 11q1, 12q2, 17p1, 18q1-q2, 19p1, 22q1, X and Y was detected. Gain of chromosomal material was found in chromosome 7, especially 7q1 (p < 0.05). Most involved breakpoints were: 1p13, 1q21, 7p22, 9p11, 17p11, 17q11, 22q11. Cytogenetic differences between NF-1-associated and sporadic MPNSTs included a relative loss of chromosomal material in NF-1-associated MPNSTs in 1p3, 4p1 and 21p1-q2 and a relative gain in 15p1-q1. Differences in breakpoints between the NF-1 associated and the sporadic MPNST group were observed in 1p21-22 (28% of NF-1 vs. 0% of sporadic MPNSTs), 1p32-34 (17% vs. 0%), 8p11-12 (7% vs. 27%) and 17q10-12 (24% vs. 7%). This approach, in which the cytogenetic results of various reports are combined, shows that losses in 9p2 and gains in 7q1 could be of oncogenetic importance in MPNSTs. Loss of 17q1, on which the NF-1 gene has been located (17q11.2), is not a common cytogenetic finding in NF-1-associated MPNSTs. The observed differences between NF-1-associated and sporadic MPNSTs might reflect different oncogenetic pathways.

Adolescent↗

PubMed1999

The short and long term effects of intraoperative electron beam radiotherapy (IORT) on thoracic organs after pneumonectomy an experimental study in the canine model.

PURPOSE: The tolerance of mediastinal structures and thoracic organs to intraoperative radiotherapy (IORT) was investigated in the canine model. METHODS AND MATERIALS: Twenty-two adult beagles divided into three groups were subjected to a left pneumonectomy and IORT (10 MeV electrons) at doses of 20 Gy (n = 9), 25 Gy (n = 4), or 30 Gy (n = 9). Intraoperative electron beam radiotherapy was delivered through a 5 cm circular lucite cone encompassing a mediastinal field including the bronchial stump, aorta, esophagus, heart, phrenic nerve, contralateral hilar structures, and lung. Clinical monitoring was performed with regular chest X-ray, ECG, bronchoscopy, esofagoscopy, and fluoroscopy. From the different treatment dose groups, dogs were electively sacrificed at 1.5, 6, 12, and 72 months with complete autopsies. RESULTS: There was no bronchial stump dehiscence or acute morbidity. Four dogs developed radiation induced esophagitis (18%), one in the 20 Gy IORT group (11%) and three in the 30 Gy IORT group (33%). There were six IORT related mortalities (27.5%), one esophagoaortic fistula (4.5%) and five bronchovascular fistulas (23%): two in the 20 Gy IORT group (22%), two in the 25 Gy IORT group (50%) and two in the 30 Gy IORT group (22%). Histopathological findings in uncomplicated follow-up showed marked myointimal fibrosis in the muscular arteries, submucosal fibrosis of the esophagus, and interstitial fibrosis of bronchial and lung tissue, especially in the higher dose group. CONCLUSION: The mediastinal vascular, bronchial and esophageal structures are relatively sensitive to doses > 20Gy IORT. The IORT related morbidity found in this study may be lower when the current clinically used IORT doses of 10-15 Gy are applied. Further clinical application of IORT in the future treatment strategies for resectable nonsmall cell lung cancer may be worthwhile to investigate.

Animals↗

PubMed1999

[Palliative care for cancer patients with refractory ulcerating malignant skin tumors and skin metastases].

Coping with ulcerating or bleeding skin tumours or metastases not suitable for surgical, radiotherapeutical or chemotherapeutical treatment is a difficult problem for patients, doctors and nursing staff. The care should focus on limiting local and systemic infection, combating unpleasant smells and reducing bleeding. Palliative amputation is sometimes a solution. The treatment depends on the nature and site of the tumour, it should preferably be adapted to the individual patient and be carried out in consultation with the patient, the specialist in charge or the GP, and the (oncological) nurse. The purpose of all this is to optimize the quality of life in the terminal phase.

Adult↗

PubMed1999

Hyperthermic isolated limb perfusion with tumor necrosis factor alpha, interferon gamma, and melphalan for locally advanced nonmelanoma skin tumors of the extremities: a multicenter study.

BACKGROUND: Hyperthermic isolated limb perfusion (HILP) with tumor necrosis factor alpha (TNF-alpha), interferon gamma, and melphalan has proved to be useful in the treatment of recurrent malignant melanoma and of locally advanced soft tissue sarcomas of the extremities. OBJECTIVE: To determine whether this modality is also effective in the treatment of locally advanced nonmelanoma skin tumors of the extremities. PATIENTS AND METHODS: Fifteen patients with locally advanced primary, recurrent, or metastatic skin tumors of the extremities (12 with squamous cell carcinoma and 3 with Merkel cell carcinoma) underwent HILP with TNF-alpha, interferon gamma, and melphalan. Six tumors were localized in the upper extremity (40%), and 9 in the lower extremity (60%). Treatment-related complications, limb salvage rate, local recurrence, and regional and distant metastases were scored during a median follow-up of 20 months. RESULTS: After HILP, 9 patients (60%) showed a complete response (with histopathological confirmation). Four patients (27%) showed a partial response (with histopathological confirmation in 1 patient), and 2 patients (13%) showed no change (with histopathological confirmation in 1 patient and with clinical evidence in 1 patient). Two patients (13%) showed treatment-related complications. The limb salvage was achieved in 12 patients (80%), and the local recurrences developed in 4 patients (27%). During follow-up, regional lymph node metastases were observed in 2 patients (13%) and distant metastases in 2 patients (13%). CONCLUSION: Based on our results, HILP with TNF-alpha, interferon gamma, and melphalan should be considered as a limb-saving treatment modality in patients with locally advanced nonmelanoma skin tumors of the extremities who would otherwise be candidates for ablative surgery.

Adult↗

PubMed1999

Surgery versus surveillance in stage I non-seminoma testicular cancer.

Today, the standard treatment for patients with clinical Stage I non-seminomatous testicular germ cell tumors (NSTGCT) following orchidectomy is either primary retroperitoneal lymph node dissection (RPLND) or close surveillance with cisplatin-based polychemotherapy in case of a relapse. Both treatment modalities provide excellent overall survival rates up to 100%. Consequently, selection of the most appropriate management option is not primarily guided by survival considerations. The choice between the available options, each having its merits and its drawbacks, should be made based on a number of factors including treatment-related morbidity, views and expertise of the physician, patient preferences, the expected degree of patient compliance, and prognostic factor analysis. To date, the role of adjuvant chemotherapy as an alternative management option for patients with clinical Stage I NSTGCT at high risk of occult metastases is limited. This systemic treatment modality would be a realistic alternative if the reliability of prognostic factors to identify high-risk Stage I patients could be improved. This review addresses relevant issues in the management of patients with clinical Stage I NSTGCT to provide information that will allow a rational selection of the most appropriate management option.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1999

Recurrent, multiple, calcified soft tissue metastases from osteogenic sarcoma without pulmonary involvement.

Osteosarcoma (osteogenic sarcoma) metastasizes primarily to the lung. With the introduction of neoadjuvant chemotherapy as part of the treatment, the overall and disease-free survival rates have dramatically improved. In this case report, a young man with multiple soft tissue and bone metastases, including a rare large bone-forming retroperitoneal metastasis, is described. Despite the extensive extrapulmonary metastases, the patient did not develop pulmonary metastases in the 4 years following initial presentation of the primary tumour.

Adult↗

PubMed1999

Long-term results of preoperative intra-arterial doxorubicin combined with neoadjuvant radiotherapy, followed by extensive surgical resection for locally advanced soft tissue sarcomas of the extremities.

BACKGROUND AND PURPOSE: In the 1980s a combined modality therapy of intraarterial doxorubicin, neoadjuvant radiotherapy and surgery was initiated at the Groningen University Hospital as a limb-saving treatment for locally advanced, primarily irresectable high-grade soft tissue sarcomas (STS) of the extremities. This study presents the short- and long-term results. PATIENTS AND METHODS: Between 1983 and 1987, 11 patients were treated with intraarterial doxorubicin, preoperative radiotherapy (10 x 3.5 Gy) and surgical resection. Non-radical resections received additional postoperative radiotherapy of 20-30 Gy. RESULTS: The limb-salvage rate was 91%, without local recurrences during a median follow-up of 84 months. Six patients died (55%); five from metastatic disease (45%). There were five long-term survivors with a median follow-up of 10 years. Three patients (60%) suffered serious late complications, resulting in disabilitating limb function. CONCLUSION: Although this approach is feasible as a limb-saving treatment for these unfavorable STS, long-term morbidity is high.

Adult↗

PubMed1999

Sentinel node biopsy as a surgical staging method for solid cancers.

The sentinel node is the first lymph node that drains a primary tumour. If this lymphatic drainage occurs in a step-wise fashion, this lymph node reflects the pathological status of the remaining lymph node basin. The day before the operation, a total dose of 60 MBq 99mTc nanocolloid is injected around the primary tumour for lymphoscintigraphy. On the day of surgery, 1 ml of blue dye is injected around the primary tumour to facilitate sentinel lymph node detection. After making a small incision over the regional lymph node region, the sentinel node can be detected using a hand-held gamma ray detection probe; the sentinel lymph node and the afferent lymphatic vessels will be stained blue. Sentinel node biopsy has proved useful for malignant melanoma, breast cancer, penile cancer, vulvar cancer, Merkel cell carcinoma and thyroid cancer. New studies are described on breast cancer and malignant melanoma. Gamma-probe-guided localization of radiolabelled lymph nodes can direct the surgeon non-invasively to the exact location of the sentinel node. Once localized with a gamma probe, it is quick and easy to remove the sentinel node through a small incision. Discriminating the node from other tissue can be aided by blue dye which stains the lymph node. It appears that both radioactivity and blue dye are complementary for locating the sentinel node.

Biopsy↗

PubMed1999

Familial testicular cancer in a single-centre population.

Familial occurrence of testicular cancer suggests a genetic predisposition to the disease. A genetic susceptibility may also be reflected by the occurrence of bilateral testicular neoplasms and the high rates of urogenital developmental anomalies in families prone to testicular cancer. In this study, the proportion of familial testicular cancer cases was analyzed retrospectively in a single-centre population of 693 testicular cancer patients treated between 1977 and 1997 and the relative risk (RR) for first-degree relatives of patients was estimated. In addition, the existence of bilateral testicular neoplasms and urogenital developmental anomalies in familial testicular cancer patients was evaluated. 24 of the 693 patients (3.5%) had a first-degree relative with testicular cancer. These 24 cases belonged to 17 families; in 7 of these 17 families both affected first-degree family members were part of the study population of 693 patients. Consequently, the 693 studied patients belonged to a total of 686 families. Thus, the actual proportion of familial testicular cancer was 2.5% (17 of 686 families). The familial cases consisted of 11 brother pairs, including 2 pairs of identical twins and 1 pair which also had two affected cousins, and 6 father-son pairs (in total 36 cases, 12 treated elsewhere). Estimates of the RR to first-degree relatives showed a 9- to 13-fold increased RR to brothers (P < 0.001) and a 2-fold increased RR to fathers (P = non-significant (n.s)) of testicular cancer patients. Among the 36 patients with familial testicular cancer, 2 (5.6%) had bilateral testicular cancer, 4 (11.1%) had undescended testis, 3 (8.3%) had inguinal hernia, and 1 (2.8%) showed renal hypoplasia. The present data on familial occurrence of testicular cancer may lend support to a role of genetic factors in the aetiology of testicular cancer.

Adult↗

PubMed1999

Epidemiological aspects of soft tissue sarcomas (STS)--consequences for the design of clinical STS trials.

The purpose of the study was to gain insight into epidemiological aspects of soft tissue sarcomas (STS), based on the population-based cancer registry of the Comprehensive Cancer Center North-Netherlands (CCCN), and to provide data for the development of future STS clinical trials. 456 primary STS (Kaposi, urogenital and gastro-intestinal STS excluded), registered from 1989 to 1995 by the cancer registration of the Comprehensive Cancer Center North-Netherlands (CCCN), were analysed. The annual, age-adjusted, STS incidence was 3.6 per 100,000. Incidence increased with age. Half of the patients were over the age of 65 years. Malignant fibrous histiocytomas and liposarcomas were most frequently encountered. At presentation, nodal involvement was rare (3-8%). Distant metastases were more frequently encountered (9-14%), and appeared to be related to tumour size and site. Above 70 years of age, 16% of patients received no treatment at all, especially for metastatic disease.

Adult↗

PubMed1999

Geographic clustering of testicular cancer incidence in the northern part of The Netherlands.

Geographic variations in testicular cancer incidence may be caused by differences in environmental factors, genetic factors, or both. In the present study, geographic patterns of age-adjusted testicular cancer incidence rates (IRs) in 12 provinces in The Netherlands in the period 1989-1995 were analysed. In addition, the age-adjusted IR of testicular cancer by degree of urbanization was evaluated. Cancer incidence data were obtained from the Netherlands Cancer Registry. The overall annual age-adjusted IR of testicular cancer in The Netherlands in the period 1989-1995 was 4.4 per 100000 men. The province Groningen in the north of the country showed the highest annual IR with 5.8 per 100000 men, which was higher (P < 0.05) than the overall IR in The Netherlands (incidence rate ratio (IRR) 1.3, 95% confidence interval (CI) 1.1-1.6). The highest IR in Groningen was seen for both seminomas and non-seminomas. In addition, Groningen showed the highest age-specific IRs in all relevant younger age groups (15-29, 30-44 and 45-59 years), illustrating the consistency of data. The province Friesland, also situated in the northern part of the country, showed the second highest IR of testicular cancer with 5.3 cases per 100000 men per year (IRR 1.2, 95% CI 1.0-1.5, not significant). This mainly resulted from the high IR of seminoma in Friesland. Analysis of age-adjusted IRs of testicular cancer by degree of urbanization in The Netherlands showed no urban-rural differences at analysis of all histological types combined, or at separate analyses of seminomas and non-seminomas. Geographic clustering of testicular cancer seems to be present in the rural north of The Netherlands with some stable founder populations, which are likely to share a relatively high frequency of genes from common ancestors including genes possibly related to testicular cancer. Although this finding does not exclude the involvement of shared environmental factors in the aetiology of testicular cancer, it may also lend support to a genetic susceptibility to testicular cancer development. Testicular cancer cases in stable founder populations seem particularly suitable for searching for testicular cancer susceptibility genes because such genes are likely to be more frequent among affected men in such populations.

Adolescent↗

PubMed1999

The changing distribution of stage in nonseminomatous testicular germ cell tumours, from 1977 to 1996.

OBJECTIVE: To determine the changes between 1977 and 1996 in the distribution of stages of testicular cancer (TC). PATIENTS AND METHODS: The stage distribution was assessed, using various classifications, i.e. the Royal Marsden (RM), Indiana, European Organization for Research and Treatment of Cancer (EORTC), International Germ Cell Cancer Collaborative Group (IGCCCG) and the Medical Research Council (MRC), in 517 patients with nonseminomatous testicular germ cell tumours (NSTGCTs) diagnosed at a single institution between 1977 and 1996. RESULTS: The number of patients in four consecutive 5-year periods (1977-81, 1982-86, 1987-91, 1992-96) was 119, 141, 141, and 116, respectively. Frequency analyses showed a significant increase of RM stage I, in proportion to stage II-IV, in 1982-86 (55%, odds ratio, OR, 2.54), 1987-91 (53%, OR 2.33) and 1992-96 (61%, OR 3.24) compared to the period 1977-81 (33%). A separate analysis of patients with disseminated disease showed a proportionate significant decrease of RM stage II in 1992-96 (29%, OR 0.43) compared with 1977-81 (49%). There was also a relative decrease of good-prognosis patients with disseminated disease in 1992-96 compared with 1977-81, using analyses of the Indiana (from 56% to 33%, OR 0.39) and EORTC classification (from 78% to 56%, OR 0.36). Analyses of the IGCCCG and MRC classification showed a significant decrease of good-prognosis patients in the 1982-86 compared with the first 5-year period (for IGCCCG, from 54% to 35%, OR 0.46, and for MRC, from 43% to 24%, OR 0.42). CONCLUSION: The stage distribution of NSTGCT over the past two decades has changed. The proportion of stage I patients has increased since the early 1980s, apparently resulting from a shift of low-extent disseminated disease to stage I disease. This finding is relevant in reducing the treatment required in a higher proportion of patients and the subsequent reduction of long-term risk from treatment.

Adolescent↗

PubMed1999

Objective and subjective effects of treatment for testicular cancer on sexual function.

OBJECTIVE: To determine whether the treatment of patients with testicular cancer, using cisplatin combined with etoposide and bleomycin (BEP) after orchidectomy in those with disseminated disease, causes changes in sex hormones and penile vascularization, possibly related to sexual dysfunction. PATIENTS AND METHODS: Ten patients treated with BEP were compared with 11 undergoing orchidectomy alone followed by surveillance. Sex hormone levels were analysed and cavernosal artery duplex ultrasonography performed before orchidectomy and at 6 and 12 months afterward. Patients were questioned about their sexual function. After 1 year, a visual erotic stimulation (VES) test was performed to assess penile rigidity. RESULTS: In contrast to the surveillance group, BEP-treated patients had higher follicle-stimulating hormone (4.6 vs 26.5 U/L) and luteinizing hormone (1.4 vs 8.2 U/L) levels, and lower testosterone levels (21.1 vs 14.7 nmol/L) at 6 months than at baseline. At 1 year, most patients had compensated hypergonadotrophic eugonadism, but Leydig cell function had recovered. Changes in cavernosal artery peak flow velocities induced by local injection with papaverine/phentolamine showed no difference between the groups before and 6 months after orchidectomy. Loss of libido and erectile dysfunction were reported more frequently by BEP-treated patients. However, 1 year after treatment, most reported a satisfying sex life and VES resulted in a rigid erection in nearly all patients. The reported erectile dysfunction could not be explained by changes in plasma testosterone levels or diminished blood flow velocities. CONCLUSIONS: After being diagnosed with testicular cancer, sexual morbidity is considerable, but within 1 year some improvement may be expected. BEP induces transient testicular dysfunction but this recovers. Although BEP is related to symptoms of angiopathy, cavernosal blood flow seems to be unaffected. These findings and the normal VES-evoked penile rigidity suggest that sexual dysfunction is more psychological than organically induced by BEP.

Adult↗

PubMed1999

The effect of surgical wounding on tumour development.

For more than a century, a role for wound healing in the outgrowth of tumours has been implied based on observations in both experimental and clinical studies. Wound healing can be divided into stages of inflammatory, proliferative, repair and remodelling processes. Through proper regulation of activation of epithelial, endothelial and inflammatory cells, platelets and fibroblasts, and the production of growth factors, wounds heal and the various cell types resume their normal function. In tumour growth, similar processes of cell activation and growth factor production are observed. These processes are, however, differently regulated leading to ongoing cellular activation. In recent years, growth factors such as EGF, TGF-alpha and TGF-beta, bFGF, IGF I and II, and PDGF have been identified to play a role in the different stages of wound healing. In addition, some of these factors have now been identified as also being involved in the outgrowth of tumours. In this review, cell types involved in wound healing and tumour growth, as well as the growth factors and cytokines they produce and the role of the extracellular matrix, extensively present in both conditions, are being discussed. A better understanding of the time interval during which the sequelae of events in wound healing occur in relation to the time interval of tumour recurrence may be the basis for defining new therapeutic strategies that can interfere with tumour outgrowth without affecting wound healing processes. These new therapeutic approaches may be of importance especially after surgery or other invasive (diagnostic) procedures in cancer patients.

Animals↗

PubMed1999

Current treatment for colorectal cancer metastatic to the liver.

Surgery is currently the only available treatment option which offers the potential for cure for patients with liver metastases from colorectal cancer. Of those who undergo a potentially curative operation for their primary tumour but subsequently recur, almost 80% will develop evidence of metastatic disease within the liver. Greater experience and improvements in technique in liver surgery, with an increasingly aggressive surgical approach to metastatic colorectal cancer to the liver, has resulted in prolonged disease-free survival with 5-year rates varying from 21% to 48%. In order to increase these numbers further and to treat patients not eligible for surgical therapy, new treatment modalities and strategies have been developed. This review presents an update of the current treatment for colorectal disease metastatic to the liver.

Chemotherapy, Adjuvant↗

PubMed1999

Short- and long-term histopathological changes in the canine liver following single high-dose intraoperative radiation therapy (IORT).

PURPOSE: The histopathological changes in the canine liver following single high-dose intraoperative radiation therapy (IORT) were investigated in order to establish the tolerance of liver tissue to IORT, thus providing a framework for clinical IORT treatment of patients with metastatic disease to the liver. MATERIALS AND METHODS: Following partial resection of the liver, IORT in doses of 10, 20, 25, or 30 Gy was applied to the resection plane and a non-surgically manipulated part of the liver of 25 beagles. RESULTS: There were no postoperative complications, and no morbidity or mortality during a maximal follow-up of 5 years. Dogs were killed at 3 months, and 1, 2, 3 and 5 years following IORT. Light microscopic examination revealed capsular thickening, severe parenchymal fibrosis, liver cell atrophy, and bile duct proliferation at the irradiated area 1 2 years following IORT. At 3-5 years, however, only mild parenchymal changes were found that consisted of slight periportal fibrosis, an incidental portal-central fibrous septum and vascular changes with endothelial proliferation and focal arteriolar hyalinosis. CONCLUSIONS: This study demonstrated that following partial hepatic resection, IORT to the liver in the canine model can be applied safely, without short- or long-term treatment morbidity. Although doses up to 30Gy resulted in severe local tissue damage 1-2 years following IORT, these changes were largely reversible due to hepatic regeneration.

Animals↗

PubMed1999

L-[1-11C]-tyrosine PET to evaluate response to hyperthermic isolated limb perfusion for locally advanced soft-tissue sarcoma and skin cancer.

UNLABELLED: PET with L-[1-11C]-tyrosine (TYR) was investigated in patients undergoing hyperthermic isolated limb perfusion (HILP) with recombinant tumor necrosis factor alpha (rTNF-alpha) and melphalan for locally advanced soft-tissue sarcoma and skin cancer of the lower limb. METHODS: Seventeen patients (5 women, 12 men; age range 24-75 y; mean age 52 y) were studied. TYR PET studies were performed before HILP and 2 and 8 wk afterwards. The protein synthesis rates (PSRs) in nanomoles per milliliter per minute were calculated. After final PET studies, tumors were resected and pathologically examined. Patients with pathologically complete responses (pCR) showed no viable tumors after treatment. Those with pathologically partial responses (pPR) showed various amounts of viable tumors in the resected tumor specimens. RESULTS: Six patients (35%) showed a pCR and 11 patients (65%) showed a pPR. All tumors were depicted as hot spots on PET studies before HILP. The PSR in the pCR group at 2 and 8 wk after perfusion had decreased significantly (P < 0.05) in comparison to the PSR before HILP. A significant difference was found in PSR between the pCR and pPR groups at 2 and at 8 wk (P < 0.05). Median PSR in nonviable tumor tissue was 0.62 and ranged from 0.22 to 0.91. With a threshold PSR of 0.91, sensitivity and specificity of TYR PET were 82% and 100%, respectively. The predictive value of a PSR > 0.91 for having viable tumor after HILP was 100%, whereas the predictive value of a PSR < or = 0.91 for having nonviable tumor tissue after HILP was 75%. The 2 patients in the pPR groups with a PSR < 0.91 showed microscopic islets of tumor cells surrounded by extensive necrosis on pathological examination. CONCLUSION: Based on the calculated PSR after HILP, TYR PET gave a good indication of the pathological outcome. Inflammatory tissue after treatment did not interfere with viable tumor on the images, suggesting that it may be worthwhile to pursue TYR PET in other therapy evaluation settings.

Adult↗

PubMed1999

FDG and L-[1-11C]-tyrosine imaging of soft-tissue tumors before and after therapy.

UNLABELLED: This study was undertaken to investigate the relationship of PET using fluorodeoxyglucose (FDG) or L-[1-11C]-tyrosine (TYR) with histopathologic findings in soft-tissue tumors, before and after therapy. Histopathologic parameters that were studied were tumor grade, mitotic rate, proliferation activity and amount of necrosis. METHODS: PET with either FDG or TYR was performed in 55 patients with a lesion suspected to be a malignant soft-tissue tumor. In 28 patients, a second PET study was performed after therapy. Metabolic rate of glucose consumption (MRglc) and protein synthesis rate (PSR) were calculated. Histologic parameters were obtained from a biopsy specimen that was taken just after the first PET study and from the tumor remnant that was resected after therapy. RESULTS: MRglc correlated with tumor grade (r = 0.71) and mitotic rate (r = 0.68) but not with proliferation or necrosis. After therapy, there was no longer a correlation with mitotic rate. PSR correlated with tumor grade (r = 0.53), mitotic rate (r = 0.73) and proliferation (r = 0.66). After therapy, correlation with mitosis and proliferation had improved, and a negative correlation was found between PSR and necrosis (r = -0.74). CONCLUSION: These results validate the use of both FDG and TYR to give an in vivo indication of histologic tumor parameters. However, FDG gives a better indication of tumor grade, whereas TYR is more accurate in predicting mitotic rate and proliferation, especially after therapy. FDG may therefore not be the most suited tracer for monitoring therapy. TYR might be more appropriate for that purpose.

Adolescent↗