Surveillance neuroimaging in childhood intracranial ependymoma: how effective, how often, and for how long?

OBJECT: The authors examined images obtained in 52 children with intracranial ependymomas to determine risk factors for tumor recurrence and to assess the impact of surveillance imaging on patient outcome. METHODS: Data obtained in all children with intracranial ependymomas were prospectively entered into a database from January 1987 to June 2000. The imaging and clinical details in all patients were reviewed. Fifty-two children with histologically proven intracranial ependymomas were treated at the authors' institution; recurrences developed in 28 (54%) of them, with a median time from surgery to first recurrence of 14.5 months (range 3-65 months). Of these tumor recurrences, 43% were asymptomatic and were noted on surveillance imaging. Seventeen children died, all of whom had recurrences. Incomplete excision of the primary tumor was significantly associated with reduced time to recurrence (p = 0.0144) and time to death (p = 0.0472). The age of the patient, location of the primary tumor, histological findings, and the presence or absence of spinal metastases on preoperative imaging were not significantly associated with outcome. The risk of death at any given time was 12-fold greater in patients in whom a recurrence was identified due to symptoms rather than on surveillance images (p = 0.016). CONCLUSIONS: Recurrent childhood ependymoma has a poor prognosis. The extent of the initial local tumor resection is the factor most closely associated with outcome. Surveillance imaging reveals a substantial number of asymptomatic recurrences, and survival appears to be improved in these patients compared with those identified by symptoms. The improvement in survival is thought to be greater than that expected just from earlier diagnosis.     

Use of E mu-PIM-1 transgenic mice short-term in vivo carcinogenicity testing: lymphoma induction by benzo[a]pyrene, but not by TPA

E mu-pim-1 transgenic mice are predisposed to develop lymphomas. Due to their low spontaneous tumour incidence and their increased sensitivity towards the lymphomagen ethylnitrosourea these mice may present an interesting model for short-term carcinogenicity testing. Here, we report on the further exploration of this transgenic mouse model with two additional carcinogens known to have, among others, the lymphohaematopoietic system as target, i.e. benzo[a]pyrene (B[a]P) and 12-O-tetradecanoylphorbol-13-acetate (TPA). B[a]P, given three times a week (by gavage) for 13 weeks at 4.3, 13 or 39 mg/kg body weight, resulted in a dose-related increase in lymphomas up to a 90% incidence in E(mu)-pim-1 mice during the observation period of 40 weeks. B[a]P also induced tumours of the forestomach within this observation period, though at a lower incidence and apparently equally effective in wildtype and transgenic mice. TPA, on the other hand, was unable to induce lymphomas (or tumours in any other organ) in either transgenic or wildtype animals within the observation period of 44 weeks, when applied dermally at the maximum tolerated dose of 3 microg/mouse, twice a week for 35 weeks. Molecular analysis showed that B[a]P-induced lymphomas in transgenic mice were of T-cell origin, 80% of which had elevated levels of c-myc expression. None of the lymphomas had increased N-myc expression and mutation analysis of the ras-gene family revealed a K-ras mutation in only one out of eight tumours investigated. Also, none of the lymphomas showed aberrant expression of p53 as determined by immunohistochemistry. It is concluded that the E mu-pim-1 mouse model will not be very suitable for short-term carcinogenicity testing in general: only genotoxic chemicals that have the lymphohaematopoietic system as target for carcinogenesis in wild- type mice, appear to be efficiently identified.      

Clinical assessment of outcome of prostate cancer (TCP, NTCP)

In the recent past there have been major advances in the management of patients with prostate cancer. New imaging procedures as 3-D CRT and IMRT have played a major role in the tretament of patients with localized prostate cancer. 3-D CRT allows higher doses to be delivered more precisely to the target volume with acceptable organs at risk morbidity. Improved tumor control results in lower incidence of distant metastases and better survival with an enhanced quality of life. This outcome yields a lower cost per treatment of patients over their life time.     

Penile bulb dose and impotence after three-dimensional conformal radiotherapy for prostate cancer on RTOG 9406: findings from a prospective, multi-institutional, phase I/II dose-escalation study

PURPOSE: To assess the relationship between the dose to the bulb of the penis and the risk of impotence in men treated on Radiation Therapy Oncology Group (RTOG) 9406. METHODS AND MATERIALS: Men enrolled on a Phase I/II dose-escalation study, RTOG 9406, who were reported to be potent at entry and evaluable (n = 158) were selected for inclusion. Follow-up evaluations were scheduled every 3, 4, and 6 months for the first, second, and the third through fifth years, then annually. At each follow-up visit an assessment of potency status was made. Penile structures were defined by a single observer blinded to the potency status, using Web-based, on-line software. The dosimetry for penile structures was calculated at the Quality Assurance Center at Washington University and provided to RTOG Statistical Headquarters to determine whether there was a relationship between dose and impotence. RESULTS: Patients whose median penile dose was > or = 52.5 Gy had a greater risk of impotence compared with those receiving <52.5 Gy (p = 0.039). In a multivariate analysis neither age, the dose to the prostate, nor the use of hormonal therapy correlated with the risk of impotence. CONCLUSIONS: Dose to the bulb of the penis seems to be associated with the risk of radiation-induced impotence.     

An embryo-associated fatty acid-binding protein in the filarial nematode Brugia malayi

Brugia malayi is a filarial nematode parasite that causes lymphatic filariasis, a disease that affects millions of people in the tropics. Sexual reproduction of filarial worms occurs within the lymphatic vessels of the human host and is crucial for transmission of the parasite to the mosquito vector. We have previously identified several B. malayi genes that exhibit apparent gender-specific expression. One of these had significant sequence similarity to the Ascaris suum embryo-associated fatty acid binding protein, As-p18. The full length cDNA for the B. malayi female-associated fatty acid binding protein (Bm-FAB-1) encodes a 17.8 kDa protein (excluding a signal peptide) with 70% sequence identity with mature As-p18 and significant similarity to Caenorhabditis elegans and mammalian fatty acid-binding proteins (FABPs). Antibodies raised to Bm-FAB-1 bound to developing embryos within female worms, especially around early embryo cells and the surfaces of immature worms within eggs. Functional studies showed that recombinant Bm-FAB-1 binds to several long chain fatty acids including oleate, but not retinol. Taken together, these results demonstrate that Bm-FAB-1 is a member of an unusual nematode-specific, secreted lipid binding protein family. The existence of a novel class of lipid binding proteins in nematode embryos raises the possibility that drugs targeting these proteins could be developed with broad activity against nematode parasites of medical and veterinary importance.     

Clinical usefulness of <Superscript>99m</Superscript>Tc-EDDA/HYNIC-TOC scintigraphy in oncological diagnostics: a preliminary communication

This study assessed the clinical usefulness of a new technetium-99m labelled somatostatin analogue from the standpoint of oncological diagnostics. The study group comprised 40 patients in whom malignant neoplasms (32 primary and 8 metastatic) had been diagnosed. Among the primary tumours there were 21 cases of lung cancer (2 small cell and 19 non-small cell), seven pituitary adenomas (five hormonally active and two inactive), one liposarcoma, two carcinoids and one breast carcinoma. The metastatic tumours consisted of three malignant melanomas, one phaeochromocytoma, one prostatic cancer, one leiomyosarcoma, one pancreatic carcinoma ectopically secreting ACTH and one carcinoid of the thymus. The radiopharmaceutical ^99mTc-EDDA/HYNIC-Tyr³-octreotide was administered i.v. at an activity of 740–925 MBq. The imaging comprised a whole-body scan and a single-photon emission tomography acquisition. Positive scintigrams were obtained in all cases of small cell and non-small cell lung cancer, four out of five hormonally active pituitary adenomas, one out of two cases of carcinoid, the liposarcoma and the breast cancer. Neoplastic metastases were visualised in two out of three patients with melanoma and in patients with phaeochromocytoma, ACTH-secreting pancreatic carcinoma and thymic carcinoid. Scintigrams were negative in both hormonally inactive pituitary adenomas, in one case of metastatic malignant melanoma, in the leiomyosarcoma and in the case of metastasis from prostatic carcinoma. The results of this pilot study indicate that ^99mTc-EDDA/HYNIC-TOC is a potentially useful radiopharmaceutical for imaging of a wide range of primary and metastatic tumours. Special attention should be paid to the successful imaging of all cases of non-small cell lung cancer .     

Comparison of alternative biochemical failure definitions based on clinical outcome in 4839 prostate cancer patients treated by external beam radiotherapy between 1986 and 1995

PURPOSE: To assess the merit of the American Society for Therapeutic Radiology and Oncology (ASTRO) definition of biochemical failure after external beam radiotherapy for prostate cancer by testing alternative prostate-specific antigen (PSA) failure definitions against the "gold standard" of clinical failure and to study the effect of backdating the time of failure. METHODS AND MATERIALS: Nine participating institutions agreed to submit follow-up results for all patients with clinically localized prostatic cancer (Stage T1b, T1c, T2, N0M0) treated between 1986 and 1995 by external beam radiotherapy only, to doses of >or=60 Gy, with no androgen deprivation before treatment. A total of 4839 men met the study criteria, with a median follow-up time of 6.3 years. The prediction of clinical failure by 102 definitions of biochemical failure was assessed using various quantitative measures. RESULTS: Four definitions were superior as measured by the sensitivity, specificity, positive and negative predictive values, and hazard of clinical failure after biochemical failure: two rises of at least 0.5 ng/mL backdated, PSA level at or greater than the absolute nadir plus 2 ng/mL at the call date, and PSA level at or greater than the current nadir plus 2 or 3 ng/mL at the call date. The absolute nadir was the lowest measured PSA level during all of follow-up, and the current nadir was the lowest PSA measured previous to a particular PSA measurement during follow-up. With the possible exception of patients in the low-risk group, the likelihood of ultimate clinical failure decreased as the time of biochemical failure increased. Failure definitions based on PSA levels >0.2 or 0.5 ng/mL were inferior to other definitions. Backdating the failure time introduced bias into the estimate of freedom from biochemical failure, which was increasingly overestimated at shorter median follow-up times. This bias can be circumvented either by using a failure definition based on the call date or by backdating the censoring times of patients with one or two rises who could potentially have failure at a future (unobserved) time. A short follow-up time as such does not result in bias unless the failures are backdated; in the absence of backdating, it is the precision of failure-free survival that is increasingly compromised as the follow-up time is reduced. CONCLUSION: The ASTRO failure definition ended the confusion resulting from different failure definitions that had been in use, and it did so accurately enough that it is probably not necessary to recalculate previously published results. Nevertheless, for the current pooled analysis of outcome in 4839 men with a 6.3-year median follow-up, other definitions of biochemical failure were superior as assessed by various quantitative measures of concordance of biochemical and ultimate clinical failure. An additional disadvantage of the ASTRO definition is the bias introduced by backdating failures, as well as the necessarily retrospective nature of its application. Some "current" definitions, but not those based on the PSA level rising above a fixed threshold, have significantly higher sensitivity and specificity, do not lead to biased estimations of biochemical disease-free survival, and are directly applicable during patient counseling. These are all issues that would play a role in replacing the ASTRO consensus definition.