Qualitative flow metabolic phenotype of pancreatic cancer. A new prognostic biomarker?

BACKGROUND

Retrospective analysis to investigate the relationship between the flow-metabolic phenotype and overall survival (OS) of pancreatic ductal adenocarcinoma (PDAC) and its potential clinical utility.

METHODS

Patients with histopathologically proven PDAC between 2005 and 2014 using tumor attenuation on routine pre-operative CECT as a surrogate for the vascularity and [18F]FDG-uptake as a surrogate for metabolic activity on [18F]FDG-PET.

RESULTS

In total, 93 patients (50 male, 43 female, median age 63) were included. Hypoattenuating PDAC with high [18F]FDG-uptake has the poorest prognosis (median OS 7 ± 1 months), compared to hypoattenuating PDAC with low [18F]FDG-uptake (median OS 11 ± 3 months; p = 0.176), iso- or hyperattenuating PDAC with high [18F]FDG-uptake (median OS 15 ± 5 months; p = 0.004) and iso- or hyperattenuating PDAC with low [18F]FDG-uptake (median OS 23 ± 4 months; p = 0.035). In multivariate analysis, surgery combined with tumor differentiation, tumor stage, systemic therapy and flow metabolic phenotype remained independent predictors for overall survival.

DISCUSSION

The novel qualitative flow-metabolic phenotype of PDAC using a combination of CECT and [18F]FDG-PET features, predicted significantly worse survival for hypoattenuating-high uptake pancreatic cancers compared to the other phenotypes.

Prediction Variability to Identify Reduced AI Performance in Cancer Diagnosis at MRI and CT

Background A priori identification of patients at risk of artificial intelligence (AI) failure in diagnosing cancer would contribute to the safer clinical integration of diagnostic algorithms. Purpose To evaluate AI prediction variability as an uncertainty quantification (UQ) metric for identifying cases at risk of AI failure in diagnosing cancer at MRI and CT across different cancer types, data sets, and algorithms. Materials and Methods Multicenter data sets and publicly available AI algorithms from three previous studies that evaluated detection of pancreatic cancer on contrast-enhanced CT images, detection of prostate cancer on MRI scans, and prediction of pulmonary nodule malignancy on low-dose CT images were analyzed retrospectively. Each task's algorithm was extended to generate an uncertainty score based on ensemble prediction variability. AI accuracy percentage and partial area under the receiver operating characteristic curve (pAUC) were compared between certain and uncertain patient groups in a range of percentile thresholds (10%-90%) for the uncertainty score using permutation tests for statistical significance. The pulmonary nodule malignancy prediction algorithm was compared with 11 clinical readers for the certain group (CG) and uncertain group (UG). Results In total, 18 022 images were used for training and 838 images were used for testing. AI diagnostic accuracy was higher for the cases in the CG across all tasks (P < .001). At an 80% threshold of certain predictions, accuracy in the CG was 21%-29% higher than in the UG and 4%-6% higher than in the overall test data sets. The lesion-level pAUC in the CG was 0.25-0.39 higher than in the UG and 0.05-0.08 higher than in the overall test data sets (P < .001). For pulmonary nodule malignancy prediction, accuracy of AI was on par with clinicians for cases in the CG (AI results vs clinician results, 80% [95% CI: 76, 85] vs 78% [95% CI: 70, 87]; P = .07) but worse for cases in the UG (AI results vs clinician results, 50% [95% CI: 37, 64] vs 68% [95% CI: 60, 76]; P < .001). Conclusion An AI-prediction UQ metric consistently identified reduced performance of AI in cancer diagnosis. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Babyn in this issue.

Setting the Research Agenda for Clinical Artificial Intelligence in Pancreatic Adenocarcinoma Imaging

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers worldwide, associated with a 98% loss of life expectancy and a 30% increase in disability-adjusted life years. Image-based artificial intelligence (AI) can help improve outcomes for PDAC given that current clinical guidelines are non-uniform and lack evidence-based consensus. However, research on image-based AI for PDAC is too scattered and lacking in sufficient quality to be incorporated into clinical workflows. In this review, an international, multi-disciplinary team of the world’s leading experts in pancreatic cancer breaks down the patient pathway and pinpoints the current clinical touchpoints in each stage. The available PDAC imaging AI literature addressing each pathway stage is then rigorously analyzed, and current performance and pitfalls are identified in a comprehensive overview. Finally, the future research agenda for clinically relevant, image-driven AI in PDAC is proposed.

Abstract

Pancreatic ductal adenocarcinoma (PDAC), estimated to become the second leading cause of cancer deaths in western societies by 2030, was flagged as a neglected cancer by the European Commission and the United States Congress. Due to lack of investment in research and development, combined with a complex and aggressive tumour biology, PDAC overall survival has not significantly improved the past decades. Cross-sectional imaging and histopathology play a crucial role throughout the patient pathway. However, current clinical guidelines for diagnostic workup, patient stratification, treatment response assessment, and follow-up are non-uniform and lack evidence-based consensus. Artificial Intelligence (AI) can leverage multimodal data to improve patient outcomes, but PDAC AI research is too scattered and lacking in quality to be incorporated into clinical workflows. This review describes the patient pathway and derives touchpoints for image-based AI research in collaboration with a multi-disciplinary, multi-institutional expert panel. The literature exploring AI to address these touchpoints is thoroughly retrieved and analysed to identify the existing trends and knowledge gaps. The results show absence of multi-institutional, well-curated datasets, an essential building block for robust AI applications. Furthermore, most research is unimodal, does not use state-of-the-art AI techniques, and lacks reliable ground truth. Based on this, the future research agenda for clinically relevant, image-driven AI in PDAC is proposed.

Hereditary Protein C-Deficiency: Laboratory Values in Transmitters and Guidelines for the Diagnostic Procedure Report on a Study of the SSC Subcommittee on Protein C and Protein S

A multicenter study on protein C-antigen and -activity values was carried out in transmitter patients with hereditary protein C deficiency (diagnosis established by pedigree analysis) and in normal controls in order to (1) establish the range of protein C levels in genetically determined heterozygotes and (2) to evaluate the usefulness of statistical procedures to discriminate between protein C deficient patients and controls. In transmitters absolute protein C activity values ranged from 19 to 82% and antigen values from 22 to 88.5%. Most transmitter patients could clearly be differentiated from the control group. However, in some transmitter patients values of protein C were within the range of the control group. The discrimination between transmitters and controls could be improved by statistical procedures. Using tolerance ellipses the overlapping area of the two groups was smallest when (factor II antigen + factor X antigen)/2 was plotted against protein C antigen. To specify the degree of uncertainty likelihood ratios were calculated to obtain the posterior probability for an individual for being deficient or not. In quadratic discriminant analysis the best discrimination between transmitters and controls was obtained using protein C activity versus factor X antigen and protein C antigen versus factor X antigen. Based on these analysis an equation was derived, which allows the calculation of the likelihood ratio favouring deficiency or non-deficiency in an individual.

A Collaborative Calibration Study of Reference Materials for Thromboplastins

In a collaborative study of ten laboratories performed mainly within the framework of the BCR (the European Community Bureau of Reference), five thromboplastins were calibrated against the WHO (World Health Organisation) primary international reference preparation 67/40. Of these five thromboplastins, three were BCR reference materials (BCT/099, OBT/79 and RBT/79) and two were WHO secondary international reference preparations (68/434 and 70/178). Human brain tissue type is represented by 67/40 and BCT/099; bovine type by 68/434 and OBT/79, and rabbit type by 70/178 and RBT/79.

The calibration relations are expressed in terms of a linear relationship between the logarithms of the prothrombin times, measured in seconds.

Interlaboratory Oral Anticoagulant Quality Assessment by the Netherlands Federation of Thrombosis Services

The 50 laboratories of the Netherlands Federation of Thrombosis Services, covering a population of 9 million and responsible for the laboratory control of approximately 150,000 patients under oral anticoagulation, have participated since 1974 in a voluntary external and internal quality control program. The external program comprises a monthly distribution to the member laboratories of a series of artificially prepared control blood samples, two of which are identical. The overall variation of the coagulation times found were 10% (CV) in 1974 and 8% (CV) in 1975. Performance improved rather abruptly at the beginning of 1975, after the application of a tight methodological standardization and improvement by the manufacturer of the thromboplastin preparation (Thrombotest) used by the great majority of the laboratories involved. The main source of variation was found to be random error in the Thrombotest determination, approximating 6%. Interbatch variation of Thrombotest and inter-aliquot variation of control blood samples both do amount to approximately 3% (CV). In terms of rabbit tissue thromboplastins, which have a lower sensitivity than Thrombotest (i. e., a flatter slope of the correlation between the PT and the anticoagulant effect), the total variation in the performance of the Dutch laboratories is 2.2-5.6% (CV), which is unusually low. The main reason for this is the fact that the laboratories can rely not only on the services of the manufacturer but also on a central information office and a reference laboratory responsible for the preparation of the control blood as well as the standardization (calibration) of thromboplastin.

Use of Posterior Probabilities to Evaluate Methods of Discriminant Analysis

By means of a case study the choice between several methods of discriminant analysis is presented. Experimental data of a two-groups problem with one or two variables is analysed. The different methods are compared according to posterior probabilities which can be computed for each subject and which are the basis of discriminant analysis. These posterior probabilities are analysed graphically as well as numerically.

Probabilistic Differential Diagnosis of Auditory Dysfunction on the Basis of Electrocochleography

Bayes’ theorem was used to establish a probabilistic differential diagnosis between four hearing states :normal hearing, conduction hearing loss, Menière’s disease, and hair-cell damage. Measurements were carried out by electrocochleography (ECoG), action potentials being determined in response to short tone-burst stimulation. This method proved to permit differentiation between normal and abnormal cochleas, but the present state of development does not allow a more detailed diagnosis.

Sensitivity and Specificity of Acid Phosphatase to Detect Prostate Cancer Using Data from a Hospital Information System

Indices of diagnostic tests, such as sensitivity and specificity, should be determined using diagnostic test results of patients tested in clinical practice. Hospital information systems that store data on diagnostic tests and diagnoses might be used for sampling the desired study population and in the actual process of collecting the data.

This paper presents, as an example, a study calculating the sensitivity and specificity of the prostate-specific acid phosphatase test. All data needed in the study were obtained from the hospital information system of Leiden University Hospital. The final health status of each patient was assessed by the cancer registry of the system. The reason for ordering the test was deduced from data on histopathological examinations of prostatic tissue. The actual selections made from the central database are described in dataflow diagrams. The sensitivity of the test was found to be 0.34 and the specificity 0.88, using a discrimination value o f 1.00 U/I. The impact of the reason for ordering the test on the specificity is illustrated. Possible biases of these measured values are discussed.

Patterns of practice of regional nodal irradiation in breast cancer: results of the European Organization for Research and Treatment of Cancer (EORTC) NOdal Radiotherapy (NORA) survey

BACKGROUND

Predicting outcome of breast cancer (BC) patients based on sentinel lymph node (SLN) status without axillary lymph node dissection (ALND) is an area of uncertainty. It influences the decision-making for regional nodal irradiation (RNI). The aim of the NORA (NOdal RAdiotherapy) survey was to examine the patterns of RNI.

METHODS

A web-questionnaire, including several clinical scenarios, was distributed to 88 EORTC-affiliated centers. Responses were received between July 2013 and January 2014.

RESULTS

A total of 84 responses were analyzed. While three-dimensional (3D) radiotherapy (RT) planning is carried out in 81 (96%) centers, nodal areas are delineated in only 51 (61%) centers. Only 14 (17%) centers routinely link internal mammary chain (IMC) and supraclavicular node (SCN) RT indications. In patients undergoing total mastectomy (TM) with ALND, SCN-RT is recommend by 5 (6%), 53 (63%) and 51 (61%) centers for patients with pN0(i+), pN(mi) and pN1, respectively. Extra-capsular extension (ECE) is the main factor influencing decision-making RNI after breast conserving surgery (BCS) and TM. After primary systemic therapy (PST), 49 (58%) centers take into account nodal fibrotic changes in ypN0 patients for RNI indications. In ypN0 patients with inner/central tumors, 23 (27%) centers indicate SCN-RT and IMC-RT. In ypN1 patients, SCN-RT is delivered by less than half of the centers in patients with ypN(i+) and ypN(mi). Twenty-one (25%) of the centers recommend ALN-RT in patients with ypN(mi) or 1-2N+ after ALND. Seventy-five (90%) centers state that age is not considered a limiting factor for RNI.

CONCLUSION

The NORA survey is unique in evaluating the impact of SLNB/ALND status on adjuvant RNI decision-making and volumes after BCS/TM with or without PST. ALN-RT is often indicated in pN1 patients, particularly in the case of ECE. Besides the ongoing NSABP-B51/RTOG and ALLIANCE trials, NORA could help to design future specific RNI trials in the SLNB era without ALND in patients receiving or not PST.

Calcium score: a new risk factor for colorectal anastomotic leakage

BACKGROUND

Anastomotic leakage (AL) is the most feared complication of colorectal surgery. Atherosclerosis is suggested to have a detrimental effect on anastomotic healing. This study aimed to analyze the calcium score, a measure for atherosclerosis, as a risk factor for AL.

STUDY DESIGN

The calcium scores of colorectal patients operated on in 2 Dutch university medical centers were determined using a computed tomography scan and calcium scoring software. The aorta, common iliac arteries, internal and external iliac arteries were studied. Additionally, patient- and operation-related factors were scored.

RESULTS

A total of 122 patients were included. In patients with AL, calcium scores were significantly higher in the left common iliac artery (561.4 vs 156.0, P = .028), right common iliac artery (542.0 vs 144.4, P = .041), both common iliac arteries together (1,103.3 vs 301.9, P = .046), and the left internal iliac artery (716.3 vs 35.3, P = .044).

CONCLUSIONS

Patients with higher calcium scores in the iliacal arteries have an increased leakage risk.

Diagnostic value of fibrinopeptide A and beta-thromboglobulin in acute deep venous thrombosis and pulmonary embolism

The purpose of this study was to assess the predictive values of the assays of fibrinopeptide A (FPA), beta-thromboglobulin (BTG) and their combination in patients suspected of having acute deep venous thrombosis (DVT) or pulmonary embolism (PE). In 80 controls the mean (+/- SD) plasma concentrations of FPA and BTG were 0.72 +/- 0.47 and 28.2 +/- 10.1 ng/ml, respectively. In 26 patients in whom DVT was confirmed by phlebography and Doppler ultrasound, clearly raised mean FPA (5.62 ng/ml) and BTG (70.6 ng/ml) concentrations were measured compared to those in 13 patients in whom this disorder was excluded (1.00 and 33.6 ng/ml, respectively). Also in 25 patients, in whom PE was established by perfusion lung scanning, clearly increased mean FPA (6.28 ng/ml) and BTG (82.4 ng/ml) concentrations were measured compared to those in 12 patients without this disease (1.03 and 32.5 ng/ml, respectively). Raised FPA and BTG concentrations were also found in 20 patients with inflammatory disorders and in 10 with various types of malignancy. The mean FPA and BTG concentrations did not differ between patients with renal failure or diabetes mellitus and patients without these diseases. From the predictive values of these assays and their combination it can be concluded that raised FPA and BTG concentrations are not specific for thrombosis. However, when normal FPA and BTG concentrations are present, acute DVT or PE can safely be excluded in symptomatic patients. In the group with confirmed DVT/PE, anticoagulant treatment (heparin and phenprocoumon) brought down the mean FPA concentration to levels within the normal range in less than 1 hour while the mean BTG concentration remained elevated throughout the 10-day study period.

Loss of Ep-CAM (CO17-1A) expression predicts survival in patients with gastric cancer

Preoperative staging of gastric cancer is difficult and not optimal. The TNM stage is an important prognostic factor, but it can only be assessed reliably after surgery. Therefore, there is need for additional, reliable prognostic factors that can be determined preoperatively in order to select patients who might benefit from (neo) adjuvant treatment. Expression of immunohistochemical markers was demonstrated to be associated with tumour progression and metastasis. The expression of p53, CD44 (splice variants v5, v6 and v9), E-cadherin, Ep-CAM (CO17-1A antigen) and c-erB2/neu were investigated in tumour tissues of 300 patients from the Dutch Gastric Cancer Trial, investigating the value of extended lymphadenectomy compared to that of limited lymphadenectomy). The expression of tumour markers was analysed with respect to patient survival. Patients without loss of Ep-CAM-expression of tumour cells (19%) had a significantly better 10-year survival (P<0.0001) compared to patients with any loss: 42% (s.e.=7%) vs 22% (s.e.=3%). Patients with CD44v6 (VFF18) expression in more than 25% of the tumour cells (69% of the patients) also had a significantly better survival (P=0.01) compared to patients with expression in less than 25% of the tumour cells: 10 year survival rate of 29% (s.e.=3%) vs 19% (s.e.=4%). The prognostic value of both markers was stronger in stages I and II, and independent of the TNM stage. Ep-CAM and CD44v6-expression provides prognostic information additional to the TNM stage. Loss of Ep-CAM-expression identifies aggressive tumours especially in patients with stage I and II disease. This information may be helpful in selecting patients suitable for surgery or for additional treatment pre- or postoperatively.

Continuously infused carboplatin used as radiosensitizer in locally unresectable non-small-cell lung cancer: a multicenter phase III study

PURPOSE

To determine the radiosensitizing effect of prolonged exposure of carboplatin in patients with locally unresectable non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Patients with histologically proven NSCLC, performance score <2, weight loss <10%, and normal organ functions were randomized between carboplatin 840 mg/m2 administered continuously during 6 weeks of radiotherapy or thoracic radiotherapy alone (both 60 Gy). Toxicity was evaluated with National Cancer Institute Common Toxicity Criteria (NCI CTC) and the Radiation Therapy Oncology Group (RTOG) criteria. Quality of life was measured with European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30/LC13 questionnaires.

RESULTS

One-hundred and sixty patients were included. Pathologically confirmed persistent tumor was present in 53% of patients in the combination arm versus 58% in the radiotherapy alone arm (P=0.5). Median survival in the combination arm was 11.8 [95% confidence interval (CI) 9.3-14.2] months and in the radiotherapy alone arm 11.7 (95% CI 8.1-15.5) months; progression-free survival was not different between arms [6.8 and 7.5 months, respectively (P=0.28)]. Acute toxicity was mild, late toxicity was radiation-induced cardiomyopathy (three patients) and pulmonary fibrosis (five patients). Quality of life was not different between arms, but in all measured patients cough and dyspnea improved, pain became less, and slight paresthesia developed 3 months after treatment.

CONCLUSION

Addition of continuously administered carboplatin as radiosensitizer for locally unresectable NSCLC does not improve local tumor control or overall survival.

Liver metastases arising from well-differentiated pancreatic endocrine neoplasms demonstrate increased VEGF-C expression

Pancreatic endocrine neoplasms (PENs) are uncommon, generally well-differentiated neoplasms that demonstrate prominent endocrine differentiation. Although the majority of PENs remain localized, malignant spread may occur via lymphatic or hematogenous routes. Angiogenic growth factors, including the vascular endothelial growth factor (VEGF) family, have been implicated in new vessel growth and hematogenous metastases, although this has not been studied in PENs. We therefore examined 19 primary well-differentiated PENs and 7 liver metastases to determine the expression of VEGF-A and its family member VEGF-C by immunolabeling analysis. VEGF-A immunoreactivity was evident only in scattered cells throughout all lesions. VEGF-C, however, demonstrated low-to-moderate expression in primary PENs by semiquantitative histoscore analysis (factor of labeling intensity by percentage of positive cells), with significantly increased expression in liver metastases (mean histoscore indices: primary PEN, 4.7 versus liver metastases, 9.5; Student's t test; P =.002773). Microvascular density of primary PENs and liver metastases did not appear to linearly correlate with VEGF-C expression. Examination of the VEGF-C-specific receptors VEGFR-2/KDR/Flk-1 and VEGFR-3/Flt-4 demonstrated intense endothelial immunoreactivity for VEGFR-2, as well as VEGFR-2 and -3 expression on the majority of neoplastic cells, suggesting a possible role in autocrine/paracrine neoplastic growth regulation. We postulate that the upregulation of VEGF-C may be involved in PEN progression and metastases, although not via a direct proangiogenic mechanism.

Female donors influence transplant-related mortality and relapse incidence in male recipients of sibling blood and marrow transplants

INTRODUCTION

The male H-Y antigen is recognised as a minor histocompatibility antigen with debatable relevance and has not been substantiated thus far in clinical solid organ transplantation. An increase in transplant-related mortality in male recipients of female stem cells has been recognised and attributed to graft vs host effect against H-Y; in contrast, decreased incidence of relapse, a graft vs leukaemia effect has not yet been described.

METHODS

To detect potentially small but significant differences, we performed an analysis in a highly homogeneous group. We have analysed 782 patients, 438 males and 344 females, who were transplanted from HLA-identical female donors for CML in 1st chronic phase between 1989 and 1997. The risk of transplant related mortality (TRM) and relapse incidence (RI) were compared for male and female recipients over three successive time periods, zero to three months, three months to two years and two to five years post-transplant. Both groups were comparable for known risk factors prior to transplant.

RESULTS

The cumulative risk of TRM at five years was significantly higher in males (42%, s.e.=3.6) than in females (27%, s.e.=2.8; P=0.02) with no overall effect on risk of relapse. Within the three specified time intervals post-transplantation, the number of events of TRM and RI in the two groups of recipients diverged over time. There was no difference within the first time interval (zero to three months) for both events. TRM was higher in male recipients as manifested from three months onwards over the whole observation period of five years (P=0.02). Risk of relapse was significantly reduced in male patients; this difference became manifest only beyond two years (P=0.01).

CONCLUSION

These data confirm the importance of male gender for both, TRM and RI: male recipients of female blood or marrow grafts are at risk of enhanced procedure related mortality, eg GvHD, but benefit from reduced incidence of disease recurrence, hence a GvL effect. GvL in this setting needs more time than GvHD. These data give indirect but convincing evidence for a clinical relevance of H-Y as a minor histocompatibility antigen in humans.

Hematopoietic stem cell transplantation in Europe 1998

INTRODUCTION

Transplantation of hematopoietic stem cells from blood or bone marrow has become accepted therapy for many diseases. Numbers of transplants have increased significantly and stem cell source, donor type and indications have changed during this decade. Information on these changes is essential for interpretation of current data, patient counseling and health care planning.

PATIENTS AND METHODS

Since 1990, members of the European Group for Blood and Marrow Transplantation and teams known to perform blood or marrow transplants have been invited annually to report their transplant numbers by indication, donor type and stem cell source. Data from these surveys have been used to present data for 1998, to assess current status and to give numbers of transplants per participating country, coefficients of variation between countries for individual indications and changes in indication, stem cell source and donor type over the past decade.

RESULTS

In 1998, a total of 20 892 transplants were performed by 528 teams in 31 European countries. Of these transplants 18 400 were first transplants, 5308 (29%) were allogenic, and 13 092 (71%) were autologous. Of the autologous transplants, 809 (6%) were bone marrow derived, and 12 283 (94%) were from peripheral blood stems cells. Of the allogeneic transplants, 3372 (64%) were bone marrow derived, and 1936 (36%) were peripheral blood stem cell transplants. In 1990, the respective figures were 2137 allogeneic (50%) and 2097 (50%) autologous transplants, all exclusively bone marrow derived. Main indications in 1998 were leukemias with 6015 transplants (33%), 68% thereof allogeneic transplants; lymphomas with 7492 transplants (41%), 94% thereof autologous transplants; solid tumors with 4025 transplants (22%), 99% thereof autologous transplants; non-malignant disorders with 868 transplants (5%), 80% thereof allogeneic transplants. Absolute numbers of transplants per year did increase from 4234 in 1990 to 20 892 in 1998. Increase is higher for autologous, than for allogeneic transplants. There were differences in absolute or relative increase over time for individual indications. Transplant rates per number of inhabitants varied between countries, ranging from 0 to >500 total transplants per 10 million inhabitants with a clear correlation between number of teams and transplants per 10 million inhabitants (r=0.61, P<0.001). The least variation between countries was observed for acute leukemias, chronic myeloid leukemia and severe aplastic anemia in allogeneic transplants, for Hodgkin's disease and non-Hodgkin's lymphoma in autologous transplants.

CONCLUSION

These data reflect the current status of blood and marrow transplantation in Europe. They show the continuing increase in utilization, highlight the change from bone marrow to blood as stem cell source and give an objective assessment on presence or absence of trends.

BFM-oriented treatment for children with acute lymphoblastic leukemia without cranial irradiation and treatment reduction for standard risk patients: results of DCLSG protocol ALL-8 (1991-1996)

Modern treatment strategies, consisting of intensive chemotherapy and cranial irradiation, have remarkably improved the prognosis for children with acute lymphoblastic leukemia. However, patients with a potential for cure are at risk of severe acute and late adverse effects of treatment. Furthermore, in 25-30% of patients treatment still fails. The objectives of the DCLSG study ALL 8 were to decrease the toxicity and to increase the effectivity of BFM-oriented treatment. Decrease of toxicity was aimed at by confirmation of the results of the previous DCLSG study ALL-7, showing that the majority (94%) of children with ALL can successfully be treated with BFM-oriented therapy without cranial irradiation, and by reduction of treatment for standard risk (SRG) patients. To increase the cure rate in medium risk (MRG) patients the efficacy of high doses of intravenous 6-mercaptopurine (HD-6MP) during protocol M and in SRG patients the efficacy of high doses of L-asparaginase (HD-L-ASP) during maintenance treatment was studied in randomized studies. Patient stratification and treatment were identical to protocol ALL-BFM90, with the following differences: no prophylactic cranial irradiation, SRG patients received only phase 1 of protocol I. Four hundred and sixty-seven patients entered the protocol: 170 SRG, 241 MRG and 56 HRG patients. The 5 years event-free survival rate for all patients was 73% (s.e. 2%); for SRG, MRG and HRG patients 85% (s.e. 3%), 73% (s.e. 3%) and 39% (s.e. 7%), respectively. In patients >1 year of age at diagnosis unfavorable prognostic factors were male sex, >25% blasts in the bone marrow at day 15 and initial white blood cell count (WBC) >50 x 10(9)/l. The cumulative risk of CNS relapse rate was 5% (s.e. 1%) at 5 years. These results confirm that the omission of cranial irradiation in BFM-oriented treatment does not jeopardize the overall good treatment results, nor does early reduction of chemotherapy in SRG patients. No benefit was observed from treatment intensification with HD-L-ASP in SRG patients, nor from HD-6MP in MRG patients.

[Benign diseases in radiotherapy: a practice survey in Belgium. Peer review of radiotherapy in Belgium]

In 1996 and 2000, a survey of radiation practice in Belgium was performed by sending a questionnaire to the different centers asking their opinion and number of patients treated. There was a great similarity between the two surveys both for indications and total number of patients irradiated. For the most common indications (prevention of cheloids, heterotopic bone formation, hyperthyroidy ophthalmopathy), there was a trend to use similar radiation technique following recent publications. In contrast, if the number of cases of macular degeneration is declining, the prevention of vessels restenosis is becoming more and more an indication.

Free energies of protein decoys provide insight into determinants of protein stability

We have calculated the stability of decoy structures of several proteins (from the CASP3 models and the Park and Levitt decoy set) relative to the native structures. The calculations were performed with the force field-consistent ES/IS method, in which an implicit solvent (IS) model is used to calculate the average solvation free energy for snapshots from explicit simulations (ESs). The conformational free energy is obtained by adding the internal energy of the solute from the ESs and an entropic term estimated from the covariance positional fluctuation matrix. The set of atomic Born radii and the cavity-surface free energy coefficient used in the implicit model has been optimized to be consistent with the all-atom force field used in the ESs (cedar/gromos with simple point charge (SPC) water model). The decoys are found to have a consistently higher free energy than that of the native structure; the gap between the native structure and the best decoy varies between 10 and 15 kcal/mole, on the order of the free energy difference that typically separates the native state of a protein from the unfolded state. The correlation between the free energy and the extent to which the decoy structures differ from the native (as root mean square deviation) is very weak; hence, the free energy is not an accurate measure for ranking the structurally most native-like structures from among a set of models. Analysis of the energy components shows that stability is attained as a result of three major driving forces: (1) minimum size of the protein-water surface interface; (2) minimum total electrostatic energy, which includes solvent polarization; and (3) minimum protein packing energy. The detailed fit required to optimize the last term may underlie difficulties encountered in recovering the native fold from an approximate decoy or model structure.

Genotypically nonidentical related donors for transplantation of patients with myelodysplastic syndromes: comparison with unrelated donor transplantation and autologous stem cell transplantation

Transplantation with histocompatible identical siblings is a curative treatment for patients with myelodysplastic syndromes (MDS). Alternative treatments, such as transplantation with other family donors, are an option for patients without HLA-identical siblings. This study evaluated transplantation with genotypically nonidentical family donors and compared the results to those obtained with unrelated donors and autologous stem cell transplantation. Overall 3-year survival was 35% for the 79 patients transplanted using genotypically nonidentical donors, DFS was 31%, relapse risk 16%, and the treatment-related mortality (TRM) 62%. Patients transplanted using phenotypically identical family donors had a significantly superior survival and a lower TRM than patients transplanted with mismatched family donors. Age had no influence on the outcome of transplantation. The DFS of patients transplanted in early stage of the disease was 42% compared to 28% in patients transplanted with more advanced disease (P = 0.03). The results of transplantation with mismatched family donors were comparable to those obtained with unrelated donor transplantation. This suggests that nonidentical family donors may be considered if a fully matched unrelated donor is not available. The TRM of patients transplanted with nonidentical family donors is significantly higher than the TRM of patients transplanted with autologous stem cells. The disease-free survival of ASCT is not inferior to allogeneic transplantation using nonidentical family donors, and the intensity of the treatment is much lower. The choice of ASCT or alternative donor transplantation must be influenced by the age of the patient and the risk of relapse. For patients under the age of 20 years the treatment of choice may indeed be an alternative donor transplantation.

Tumor load and surgical palliation in gastric cancer

BACKGROUND/AIMS

Most patients with gastric cancer will have resection, even if their disease stage is beyond curability. Proper criteria to assess tumor load in patients deemed noncurative are lacking, and therefore, it is not clear which of these patients will benefit from resection.

METHODOLOGY

Of 996 gastric cancer patients who had laparotomy in a national randomized trial of lymphadenectomy for gastric cancer, 285 (29%) were found to be noncurable because of remnant tumor, peritoneal metastases, distant lymph node metastases or liver metastases. They underwent a palliative procedure considered appropriate by the surgeon. Tumor load in this group was analyzed retrospectively by calculating the number of noncurability signs.

RESULTS

The number of signs of noncurability was related to the type of surgical palliation chosen by the surgeon: of those patients with only one sign of noncurability, 68% had a palliative stomach resection but, of patients with two or more positive signs of noncurability only 36% had a stomach resection. Median survival after palliative resection was 253 days compared to 169 days after a nonresective procedure (P = 0.002). This survival advantage for resected patients disappeared when two or more signs of noncurability were found.

CONCLUSIONS

For patients deemed noncurative, survival depends on tumor load. Accurate preoperative assessment of tumor spread may prevent unnecessary high-risk surgical interventions for patients with noncurative gastric cancer.

Prediction of survival in patients with head and neck cancer

BACKGROUND

In patients with head and neck squamous cell carcinoma (HNSCC) the estimated prognosis is usually based on the TNM classification. The relative weight of the three contributing parameters is often not completely clear. Moreover, the impact of other important clinical variables such as age, gender, prior malignancies, etc is very difficult to substantiate in daily clinical practice. The Cox-regression model allows us to estimate the effect of different variables simultaneously. The purpose of this study was to design a model for application in new HNSCC patients. In our historical data-base of patients with HNSCC, patient, treatment, and follow-up data are stored by trained oncological data managers. With these hospital-based data, we developed a statistical model for risk assessment and prediction of overall survival. This model serves in clinical decision making and appropriate counseling of patients with HNSCC.

PATIENTS AND METHODS

All patients with HNSCC of the oral cavity, the pharynx, and the larynx diagnosed in our hospital between 1981 and 1998 were included. In these 1396 patients, the prognostic value of site of the primary tumor, age at diagnosis, gender, T-, N-, and M-stage, and prior malignancies were studied univariately by Kaplan-Meier curves and the log-rank test. The Cox-regression model was used to investigate the effect of these variables simultaneously on overall survival and to develop a prediction model for individual patients.

RESULTS

In the univariate analyses, all variables except gender contributed significantly to overall survival. Their contribution remained significant in the multivariate Cox model. Based on the relative risks and the baseline survival curve, the expected survival for a new HNSCC patient can be calculated.

CONCLUSIONS

It is possible to predict survival probabilities in a new patient with HNSCC based on historical results from a data-set analyzed with the Cox-regression model. The model is supplied with hospital-based data. Our model can be extended by other prognostic factors such as co-morbidity, histological data, molecular biology markers, etc. The results of the Cox-regression may be used in patient counseling, clinical decision making, and quality maintenance.

Mechanisms of oncogenesis in colon versus rectal cancer

Observations support the theory that development of left- and right-sided colorectal cancers may involve different mechanisms. This study investigated different genes involved in oncogenesis of colon and rectal cancers and analysed their prognostic value. The study group comprised 35 colon and 42 rectal cancers. Rectal cancer patients had been treated with standardized surgery performed by an experienced rectal cancer surgeon. Mutation analysis was performed for p53 in eight colon cancers and for APC and p53 in 22 rectal cancers. MLH1, MSH2, Bcl-2, p53, E-cadherin and beta-catenin were investigated by immunohistochemistry in all colorectal tumours. APC mutation analysis of the MCR showed truncating mutations in 18 of 22 rectal tumours (82%), but the presence of an APC mutation was not related to nuclear beta-catenin expression (p=0.75). Rectal cancers showed significantly more nuclear beta-catenin than colon cancers (65% versus 40%, p=0.04). p53 mutation analysis corresponded well with p53 immunohistochemistry (p<0.001). Rectal cancers showed significantly more immunohistochemical expression of p53 than colon cancers (64% versus 29%, p=0.003). In rectal cancers, a significant correlation was found between positive p53 expression and worse disease-free survival (p=0.008), but not in colon cancers. Cox regression showed that p53-expression (p=0.03) was an independent predictor for disease-free survival in rectal cancers. This study concluded that rectal cancer may involve more nuclear beta-catenin in the APC/beta-catenin pathway than colon cancer and/or nuclear beta-catenin may have another role in rectal cancer independently of APC. The p53-pathway seems to be more important in rectal cancer, in which it also has independent prognostic value. When prognostic markers are investigated in larger series, differences in biological behaviour between colon and rectal cancer should be considered.