Predictors of Long-Term Survival in Patients Treated for Oligometastases

PURPOSE/OBJECTIVE(S)

The purpose of this work is to report the long-term outcomes of patients with oligometastases treated with curative intent radiotherapy in the context of the recently developed ESTRO EORTC classification schema.

MATERIALS/METHODS

This retrospective, single institution study consists of consecutive adult patients with oligometastases from solid tumor malignancy referred to a single high volume radiation oncologist. Oligometastases were defined as 5 or fewer extracranial or intracranial metastatic lesions where all sites of active disease are amenable to treatment. Patients with a history of distant metastases requiring treatment of the primary tumor ± regional lymph nodes were included. Radical local therapies utilized included stereotactic radiotherapy (53% of patients, median dose 27 Gy in 3 fractions), intensity modulated radiotherapy (64% of patients; median dose 50 Gy in 15 fractions), surgery and/or ablation. Overall survival and progression-free survival were estimated using the Kaplan-Meier method. Predictors of survival were assessed using log-rank test for categorical variables and Cox regression for continuous variables for univariable analysis and Cox multivariable analyses.

RESULTS

The study population consists of 130 patients with 207 treated distant metastases referred to radiation oncology between 1/2014 and 12/2021. Key patient characteristics include median age 71, median pre-radiation albumin 3.7 g/dl, 72% ECOG 0-1 performance status, 35% lung primary, 12% prostate primary, median of 1 distant metastasis treated, 31% bone metastases, 30% brain metastases, 47% required treatment to primary tumor ± regional lymph nodes and 71% received systemic therapy after radiation. The most frequent ESTRO EORTC oligometastatic groups were synchronous oligometastases (40%) and metachronous oligorecurrence (29%). At a median follow-up of 28.8 months (IQR 16.0 to 56.3 months), the median overall survival is 37.9 months with a 4-year overall survival of 41.1%. The median progression-free survival was 12.3 months with a 4-year progression-free survival of 22.6%. On multivariable analysis, the strongest predictors of overall survival are age (HR 1.05 [1.02-1.08]; CI: 95%; p<0.001), ECOG performance status (HR 1.69 [1.15-2.47]; CI: 95%; p = 0.007), primary prostate, breast or kidney tumor (HR 2.79 [1.29-6.03]; CI: 95%; p = 0.009) and pre-radiation serum albumin (HR 0.55 [0.35-0.87]; CI: 95%; p = 0.01). The strongest predictors of progression free survival on multivariable analysis are albumin (HR 0.59 [0.39-0.88]; CI: 95%; p = 0.009) and primary prostate, breast or kidney tumor (HR 1.90 [1.06-3.38]; CI: 95%; p = 0.03).

CONCLUSION

Long-term overall survival is not uncommon after radical treatment for oligometastases. The ESTRO EORTC classification provides an enriched nomenclature for oligometastases but is not independently predictive of survival.

Postoperative Drip-Infusion of Remifentanil Reduces Postoperative Pain-A Retrospective Observative Study

Development of remifentanil-induced hyperalgesia (RIH) postoperatively is an unpleasant experience that requires further treatment. This study assessed the effects of gradual withdrawal combined with drip infusion of remifentanil on postoperative pain and the requirement for rescue analgesics. A total of 559 patients receiving total intravenous anesthesia with propofol and remifentanil were enrolled. All patients either underwent gradual withdrawal of remifentanil (GWR) or gradual withdrawal combined with drip infusion (GWDR) with a dose of 1 mcg·kg⁻¹ for 30 min after extubation. The numeric rating scale (NRS) and the requirement of rescue analgesics were assessed. The requirement for rescue analgesics was significantly lower in the GWDR group than in the GWR group (13.2% vs. 35.7%; p < 0.001). At the post-anesthetic care unit (PACU), patients in the GWDR group had a lower NRS pain score (p < 0.001). In addition, in the postoperative 2nd hour, patients in the GWDR group had a significantly lower NRS than the GWR group (beta, −0.31; p = 0.003). No remifentanil-related adverse effects were observed. We found that gradual withdrawal combined with drip infusion of remifentanil required less rescue analgesics and reduced pain scores. The new way of remifentanil administration may be effective to prevent RIH.

Immune profiling of lupus miliaris disseminatus faciei and successful management with anti-tumour necrosis factor therapy

Lupus miliaris disseminatus faciei (LMDF) is a chronic inflammatory dermatosis of unknown aetiology, most often seen in young adults. Although many treatments for LMDF exist, treatment guidelines have not been developed, and response to therapy is generally unpredictable. We present the results of transcriptomic analysis of LMDF lesional skin, which revealed a variety of differentially expressed genes linking LMDF to alterations in innate and adaptive T helper 1 immunity. Immunohistochemical analysis was also performed, identifying similar changes in T-cell immune responses. Given evidence for increased tumour necrosis factor (TNF) pathway activity, our patient, who had previously been refractory to multiple treatments, was initiated on TNF inhibitor therapy with excellent response. This characterization of the LMDF immune response may lead to improved treatment of this condition.

Clinical Use of Acid Suppressants and Risk of Dementia in the Elderly: A Pharmaco-Epidemiological Cohort Study

BACKGROUND

Results of studies regarding the potential link between acid suppressant use and dementia risk are inconsistent. This study aimed to evaluate the association of cumulative exposure to histamine 2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) with dementia risk in an Asian older cohort aged ≥65 years.

METHODS

Patients initiating H2RA (the H2RA user cohort, n = 21,449) or PPI (the PPI user cohort, n = 6584) and those without prescription for H2RA (the H2RA non-user cohort, n = 21,449) or PPI (the PPI non-user cohort, n = 6584) between 1 January 2000 and 31 December 2005 without a prior history of dementia were identified from Taiwan's National Health Insurance Research Database (NHIRD). The outcome of interest was all-cause dementia. Patients' exposure to H2RAs or PPIs was followed-up from dates of initial prescription to the earliest outcome of incident dementia, death, or the end of 2013. Potential associations between acid suppressant use and dementia risk were analyzed using time-dependent Cox regression estimated hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

After mutual adjustment for H2RA and PPI use and other potential confounders, patients with H2RA use had significantly higher risk of developing dementia as compared to those not treated with H2RAs (adjusted HR, 1.84; 95% CI, 1.49-2.20). Likewise, PPI users had significantly elevated risk of dementia compared to PPI non-users (adjusted HR, 1.42; 95% CI, 1.07-1.84).

CONCLUSIONS

Our results indicate that exposures to H2RAs and PPIs are associated with increased dementia risk.

Whole-genome sequencing of two North American Drosophila melanogaster populations reveals genetic differentiation and positive selection

The prevailing demographic model for Drosophila melanogaster suggests that the colonization of North America occurred very recently from a subset of European flies that rapidly expanded across the continent. This model implies a sudden population growth and range expansion consistent with very low or no population subdivision. As flies adapt to new environments, local adaptation events may be expected. To describe demographic and selective events during North American colonization, we have generated a data set of 35 individual whole-genome sequences from inbred lines of D. melanogaster from a west coast US population (Winters, California, USA) and compared them with a public genome data set from Raleigh (Raleigh, North Carolina, USA). We analysed nuclear and mitochondrial genomes and described levels of variation and divergence within and between these two North American D. melanogaster populations. Both populations exhibit negative values of Tajima's D across the genome, a common signature of demographic expansion. We also detected a low but significant level of genome-wide differentiation between the two populations, as well as multiple allele surfing events, which can be the result of gene drift in local subpopulations on the edge of an expansion wave. In contrast to this genome-wide pattern, we uncovered a 50-kilobase segment in chromosome arm 3L that showed all the hallmarks of a soft selective sweep in both populations. A comparison of allele frequencies within this divergent region among six populations from three continents allowed us to cluster these populations in two differentiated groups, providing evidence for the action of natural selection on a global scale.

Phase I/II trial of concurrent sunitinib (SU) and image-guided radiotherapy (IGRT) followed by maintenance systemic therapy for patients with oligometastases

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Background: Preclinical data suggest that SU enhances the efficacy of radiotherapy. We tested the combination of SU and hypofractionated IGRT in a cohort of patients with historically incurable distant metastases.

Methods: Eligible patients had 1 to 5 sites of metastatic solid tumors measuring ≤ 6 cm. The most common tumor types treated were head and neck, liver, lung, kidney, and prostate cancers. Patients were treated with concurrent SU (25 to 50 qd d 1–28) and IGRT (40 to 50 Gy in 10 fractions d 8–19). Following IGRT, patients could either receive maintenance SU (50 mg daily, 4 weeks on/2 weeks off starting on d 43) or alternate forms of systemic therapy. Most patients were treated with the recommended phase II dose of SU 37.5 mg and IGRT 50 Gy. Maintenance SU was used in 40% of patients.

Results: Between 2/07 and 6/08, 43 patients with 81 metastatic lesions were enrolled with a median follow up for surviving patients was 20.1 months (range, 5–37 months). The incidence of acute grade ≥ 3 toxicities was 33%, most commonly myelosuppression, bleeding and abnormal liver function tests. The 2-year estimates for local control and distant control were 74% and 43%, respectively. The 2-year estimates for progression- free survival and overall survival were 39% and 46%, respectively. To date, 15 (35%) patients were alive without evidence of disease, 6 (14%) were alive with distant metastases, 13 (30%) were dead from distant metastases, 1 (2%) was dead from local progression, 6 (14%) were dead from comorbid illness, and 2 (5%) were dead from treatment-related toxicities. Predictors of improved progression-free survival were genitourinary primary tumor (HR 0.18; p=0.04), IGRT dose > 40 Gy (HR 0.21; p=0.005), number of metastases (HR 2.22; p=0.006) and maintenance SU (HR 0.31; p=0.06). Flow cytometry demonstrates a significant reduction in immune suppressive myeloid derived suppressor cells and T regulatory cells in SU treated patients.

Conclusions: Concurrent SU and IGRT achieves durable local and distant control in a significant subset of patients with oligometastases, particularly patients with genitourinary primary tumors with ≤ 2 distant metastases.

[Table: see text]

Preliminary evidence suggesting caution in the use of psychiatric self-report measures with adolescents with high-functioning autism spectrum disorders

This study investigated the utility of self-report measures to screen for psychiatric comorbidities in autism spectrum disorders (ASDs). Thirty-eight 10-17 year olds with an ASD and without mental retardation completed: the Children's Depression Inventory-Short version (CDI-S), Revised Children's Manifest Anxiety Scale (RCMAS), Conners-Wells Adolescent Self-report Scale-Short edition (CASS-S), and Short Leyton Obsessional Inventory-Child Version (SLOI-CV). Their parents were interviewed with the Autism Comorbidity Interview-Present and Lifetime (ACI-PL) to establish psychiatric diagnoses. Sensitivity, specificity, positive and negative predictive values, and reliability coefficients were calculated for each self-report and compared to values from literature. The CDI-S and CASS-S yielded a high number of false negatives, with lower sensitivities and specificities in the sample than the literature. There was a nearly significant difference in total mean RCMAS scores between participants with and without anxiety, though again the means for both groups were below the threshold of concern. The SLOI-CV yielded a high false positive rate. All four instruments had reliability coefficients comparable to literature values. Results must be considered preliminary due to sample size. However, the findings suggest that although self-report instruments may provide useful information in the diagnosis of psychiatric comorbidities in ASD, caution must be exercised in their interpretation.

Genomic and functional analysis identifies CRKL as an oncogene amplified in lung cancer

DNA amplifications, leading to the overexpression of oncogenes, are a cardinal feature of lung cancer and directly contribute to its pathogenesis. To uncover novel such alterations, we performed an array-based comparative genomic hybridization survey of 128 non-small cell lung cancer cell lines and tumors. Prominent among our findings, we identified recurrent high-level amplification at cytoband 22q11.21 in 3% of lung cancer specimens, with another 11% of specimens exhibiting low-level gain spanning that locus. The 22q11.21 amplicon core contained eight named genes, only four of which were overexpressed (by transcript profiling) when amplified. Among these, CRKL encodes an adaptor protein functioning in signal transduction, best known as a substrate of the BCR-ABL kinase in chronic myelogenous leukemia. RNA interference-mediated knockdown of CRKL in lung cancer cell lines with (but not without) amplification led to significantly decreased cell proliferation, cell-cycle progression, cell survival, and cell motility and invasion. In addition, overexpression of CRKL in immortalized human bronchial epithelial cells led to EGF-independent cell growth. Our findings indicate that amplification and resultant overexpression of CRKL contributes to diverse oncogenic phenotypes in lung cancer, with implications for targeted therapy, and highlighting a role of adapter proteins as primary genetic drivers of tumorigenesis.

Focal amplification and oncogene dependency of GAB2 in breast cancer

DNA amplifications in breast cancer are frequent on chromosome 11q, in which multiple driver oncogenes likely reside in addition to cyclin D1 (CCND1). One such candidate, the scaffolding adapter protein, GRB2-associated binding protein 2 (GAB2), functions in ErbB signaling and was recently shown to enhance mammary epithelial cell proliferation, and metastasis of ERBB2 (HER2/neu)-driven murine breast cancer. However, the amplification status and function of GAB2 in the context of amplification remain undefined. In this study, by genomic profiling of 172 breast tumors, and fluorescence in situ hybridization validation in an independent set of 210 scorable cases, we observed focal amplification spanning GAB2 (11q14.1) independent of CCND1 (11q13.2) amplification, consistent with a driver role. Further, small interfering RNA (siRNA)-mediated knockdown of GAB2 in breast cancer lines (SUM52, SUM44PE and MDA468) with GAB2 amplification revealed a dependency on GAB2 for cell proliferation, cell-cycle progression, survival and invasion, likely mediated through altered phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling. GAB2 knockdown also reduced proliferation and survival in a cell line (BT474) with ERBB2 amplification, consistent with the possibility that GAB2 can function downstream of ERBB2. Our studies implicate focal amplification of GAB2 in breast carcinogenesis, and underscore an oncogenic role of scaffolding adapter proteins, and a potential new point of therapeutic intervention.

Phase II trial of concurrent 5-fluorouracil, hydroxyurea, cetuximab, and intensity moduled radiation therapy (IMRT) for locally advanced head and neck cancer

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Background: This phase II study was conducted to evaluate the tolerability and efficacy of incorporating cetuximab and simultaneous integrated boost intensity modulated radiation (SIB-IMRT) into a well-described 5-fluorouracil (5-FU) and hydroxyurea (HU)-based chemoradiation regimen. Endpoints included overall survival (OS), locoregional (LRC) and (DC), quality of life and toxicity. Methods: Patients with stage IVa-IVb or high-risk stage III squamous cell carcinomas were enrolled on a phase II trial. Prior organ-conserving surgical therapy or induction chemotherapy was allowed off protocol. SIB-IMRT was prescribed to low (43.2 to 48 Gy) and intermediate (54 to 63 Gy) risk volumes. A separate IMRT conedown plan was targeted to gross disease (72 Gy). The median radiation dose was 72 Gy (range 60 to 72 Gy) administered in 1.5 Gy fractions BID on weeks 1, 3, 5, 7 ± 9. Concurrent systemic therapy consisted of 5-FU (600 mg/m2), HU (500 mg BID) and cetuximab (250 mg/m2). Results: From January 2007 to April 2008, 33 subjects enrolled. Characteristics included 24 males; median age 59; ECOG performance status was 0 in 12. Disease was stage IVa-b disease in 31 (94%), T3–4 in 16 (48%), N2–3 in 23 (70%), and oropharynx primary in 15 (45%). Median follow-up in surviving patients is 15 months (range 6 to 22 months). The 1 year LRC, DC and OS is 91%, 82%, and 92%, respectively. Grade 3 toxicity consisted of mucositis (33%), radiation dermatitis (15%), anemia (15%), and leukopenia (15%), and neutropenia (9%). There were no grade 4–5 events. The majority of patients (64%) were able to tolerate treatment without a feeding tube. Median patient reported University of Washington QOL-R scores before, immediately after, 3 months and 8 months after chemoradiation were 85.5 (±14), 65 (±13), 76.5 (±15), and 84.5 (±9), respectively. Conclusions: Concurrent 5-FU, HU, cetuximab, and SIB-IMRT is a promising and reasonably well tolerated approach to incorporating molecularly targeted therapy in the curative therapy of locally advanced head and neck cancer.

[Table: see text]

Genomic profiling identifies TITF1 as a lineage-specific oncogene amplified in lung cancer

Lung cancer is a leading cause of cancer death, where the amplification of oncogenes contributes to tumorigenesis. Genomic profiling of 128 lung cancer cell lines and tumors revealed frequent focal DNA amplification at cytoband 14q13.3, a locus not amplified in other tumor types. The smallest region of recurrent amplification spanned the homeobox transcription factor TITF1 (thyroid transcription factor 1; also called NKX2-1), previously linked to normal lung development and function. When amplified, TITF1 exhibited increased expression at both the RNA and protein levels. Small interfering RNA (siRNA)-mediated knockdown of TITF1 in lung cancer cell lines with amplification led to reduced cell proliferation, manifested by both decreased cell-cycle progression and increased apoptosis. Our findings indicate that TITF1 amplification and overexpression contribute to lung cancer cell proliferation rates and survival and implicate TITF1 as a lineage-specific oncogene in lung cancer.

Effect of adjuvant radiotherapy (RT) on overall survival (OS) for node positive head and neck squamous cell carcinoma (HNSCC)

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Background: Although adjuvant RT is often recommended for locally advanced HNSCC, its effect on OS or cancer-specific survival (CSS) has not been clearly demonstrated. Methods: Within the Surveillance, Epidemiology, and End Results (SEER) Database, we selected patients with locally invasive but node negative (SEER stage 2) or node positive HNSCC (SEER stage 3–4) treated either with surgery alone (S) or surgery and radiation (S+RT). This analysis included 13,145 patients from the SEER 17 database diagnosed between 1988 and 2001. Exclusion criteria included distant metastases, no RT records or death within 3 months of surgery. The median follow-up was 4.7 years. Results: Adjuvant RT was utilized in 55% of patients with stage 2 and 84% of stage 3–4 HNSCC. For Stage 2 HNSCC, adjuvant RT was associated with lower 5 year OS on univariate analysis (46.32% for S+RT vs. 49.76% for S, p=0.016) but not on multivariate analysis (HR 1.00, p=0.93). For Stage 3 HNSCC, RT improved 5 year OS associated with RT on univariate analysis (52% for S + RT vs. 41% for S, p<0.001) and multivariate analysis (HR 0.80, p=0.002). For Stage 4 HNSCC, RT significantly improved 5 year OS on univariate analysis (35% for S + RT vs. 25% for S, p<0.001) and multivariate analysis (HR 0.75, p<0.001). The addition of RT improved 5 year CSS for both stage 3 (59.7% vs. 51.4%) and stage 4 HNSCC (42.1% vs. 32.8%). Conclusions: In the largest reported analysis of adjuvant RT in locally advanced HNSCC, adjuvant RT results in an approximately 10% absolute increase in 5-year CSS and OS for node-positive HNSCC compared to S alone. The absolute benefit of RT is underestimated on univariate analysis because patients with poor prognostic factors are more frequently selected for adjuvant RT. Outcomes in this high-risk population remain suboptimal, emphasizing the need for continued investigation of innovative treatment approaches.

No significant financial relationships to disclose.

Diagnosis of renal tumors on needle biopsy specimens by histological and molecular analysis

PURPOSE

We diagnosed the subtypes of renal cell carcinoma on needle core biopsies using a combination of histopathology and a molecular diagnostic algorithm.

MATERIALS AND METHODS

Core biopsies were taken of renal tumors following nephrectomy. RNA was extracted and quantitative real-time polymerase chain reaction was performed for 4 gene products to differentiate among renal cell carcinoma subtypes. Histopathological diagnosis was achieved on a second core before and after obtaining the molecular diagnostic algorithm results.

RESULTS

Based on the nephrectomy diagnosis 6 of 77 renal masses were nonneoplastic and 71 were tumors, including 65 renal cell carcinoma/oncocytomas. The overall diagnostic accuracy using histology and our molecular diagnostic algorithm combined was 90.0% (70 of 77). Side by side comparison of histology vs molecular diagnostic algorithm was feasible for 60 classifiable renal cell carcinoma/oncocytomas (31 clear cell, 14 papillary renal cell carcinoma, 6 chromophobe renal cell carcinoma, 2 mucinous tubular and spindle cell carcinoma, and 7 oncocytoma). In this group histology correctly predicted the final histological subtype in 83.3% (50 of 60) of cores. Addition of the molecular diagnostic algorithm to histology improved the subtyping accuracy to 95% (57 of 60), whereas the molecular diagnostic algorithm alone was accurate in 50 of 60 cases (83.3%). Dividing these 60 specimens into clear cell and nonclear cell neoplasms, the addition of the molecular diagnostic algorithm improved the sensitivity for the diagnosis of clear cell carcinoma from 87.1% (27 of 31) to 100% and the negative predictive value from 87.5% to 100%.

CONCLUSIONS

Core biopsies of renal tumors provide adequate material for diagnosing and subtyping renal cell carcinoma. The addition of our molecular diagnostic algorithm to histology improved the diagnostic accuracy of core biopsies of renal masses.

gamma-H2AX as a therapeutic target for improving the efficacy of radiation therapy

Exposure to ionizing radiation (IR) results in the formation of DNA double strand breaks, resulting in the activation of phosphatidylinositol 3'-kinase-like kinases ATM, ATR and DNK-PKcs. A physiologically important downstream target is the minor histone H2A variant, H2AX, which is rapidly phosphorylated on Ser 139 of the carboxyl tail after IR. Recent work suggests that phosphorylated H2AX (gamma-H2AX) plays an important role in the recruitment and/or retention of DNA repair and checkpoint proteins such as BRCA1, MRE11/RAD50/NBS1 complex, MDC1 and 53BP1. H2AX-/- mouse embryonic fibroblasts are radiation sensitive and demonstrate deficits in repairing DNA damage compared to their wildtype counterparts. Cells treated with peptide inhibitors of gamma-H2AX demonstrate increased radiosensitivity following radiation compared with untreated irradiated cells. Analysis of the kinetics of gamma-H2AX clearance after IR or other DNA damaging agents reveals a correlation between increased gamma-H2AX persistence and unrepaired DNA damage and cell death. These data highlight the potential of post-translational modifications of chromatin as a therapeutic target for enhancing the efficacy of radiotherapy. Therapies that either block gamma-H2AX foci formation by inhibiting upstream kinase activity or that directly inhibit H2AX function may interfere with DNA damage repair processes and warrant further investigation as potential radiosensitizing agents. Agents that increase persistence of gamma-H2AX after IR are likely to increase unrepaired DNA damage.

Use of canalicular membrane vesicles (CMVs) from rats, dogs, monkeys and humans to assess drug transport across the canalicular membrane

INTRODUCTION

A novel application of a Ultrafree filter cartridge/centrifugation method was evaluated to determine uptake in canalicular membrane vesicles (CMVs) from SD rats, beagle dogs, cynomolgus monkeys (common safety species in the pharmaceutical industry) and humans to assess biliary transport.

METHODS

CMVs prepared from fresh livers of rats, dogs, monkeys and humans (four donors) were characterized for enrichment, basolateral and Golgi contamination and orientation. The presence of MRP2 and p-glycoprotein (P-gp) were confirmed by Western blots. Uptake of [3H]-leukotriene C4 (LTC4) and [3H]-estradiol-17beta-d-glucuronide (E2-Gluc) was determined at a low substrate concentration and/or by kinetic measurements (K(m) and V(max)). Correlation of in vitro data with in vivo findings was achieved by determining the biliary clearance of E2-Gluc in rats after a single i.v. dose and with literature in vivo data for LTC4.

RESULTS

CMVs were highly enriched and minimally contaminated based on marker enzyme activities. Uptake clearance among different species varied by approximately ten-fold (rat > dog = human > monkey) for LTC4 and less than two-fold for E2-Gluc. The lower uptake of LTC4 by human than rat CMVs may be attributed to a higher Km value for human than rat CMVs. Uptake of LTC4 or E2-Gluc by human CMVs showed little inter-subject variability (2-5-fold). Differences in in vitro uptake clearance (10-fold) between LTC4 and E2-Gluc in rat CMVs seemed to correlate with differences in their biliary clearance (4-fold) in rats, consistent with LTC4 and E2-Gluc being a high and a low clearance substrate, respectively.

DISCUSSION

A novel application of a Ultrafree filter cartridge/centrifugation method was developed to determine uptake in CMVs from different preclinical animal safety species and humans, and may represent a useful approach to study the mechanism of biliary excretion during drug discovery and development.

Sparing of the penile bulb and proximal penile structures with intensity-modulated radiation therapy for prostate cancer

Quality of life is an important consideration in the treatment of early prostate cancer. Laboratory and clinical data suggest that higher radiation doses delivered to the bulb of penis and proximal penile structures correlates with higher rates of post-radiation impotence. The goal of this investigation was to determine if intensity-modulated radiation therapy (IMRT) spares dose to the penile bulb while maintaining coverage of the prostate. 10 consecutive patients with clinically organ confined prostate cancer were planned with 3D conformal radiation therapy (3D-CRT) or IMRT to give a dose of 74 Gy without specifically constraining the plans to spare the penile bulb. All 10 patients were ultimately treated with IMRT. Dose-volume histograms were evaluated and the doses to prostate, rectum, bladder and penile bulb were compared. IMRT reduced the mean penile bulb doses compared with 3D-CRT (33.2 Gy vs 48.9 Gy, p<0.001), the percentage of penile bulb receiving over 40 Gy (37.7% vs 67.2%, p<0.001) and the dose received by >95% of penile bulb (5.3 Gy vs 11.7 Gy, p=0.003). Maximum penile bulb doses were higher with IMRT (81.2 Gy vs 73.1 Gy, p<0.001) although the volume of this high dose region was small. Both methods resulted in similar coverage of the prostate. The volume of rectum receiving 70 Gy was significantly reduced with IMRT (18.4% vs 21.9%, p=0.003) but the volumes of bladder receiving 70 Gy were similar (p=0.3). IMRT may potentially reduce long term sexual morbidity by reducing the dose to the majority of the penile bulb.

Clinical management of prostatic intraepithelial neoplasia as diagnosed by extended needle biopsies

OBJECTIVE

To examine the results of the clinical management of patients with high-grade prostatic intraepithelial neoplasia (PIN), as diagnosed by extended needle biopsies.

PATIENTS AND METHODS

The clinical data were reviewed from a cohort of 387 men who underwent > or = 10 core prostate needle biopsies between 1 January 1996 and 31 December 1997 by one urologist (W.C.D.). Two study groups were identified; the first comprised 47 patients with only high-grade PIN and the second was a control group of 137 patients with only benign findings on their biopsies. Those patients with cancer, atypia or a prostatic biopsy with fewer than 10 cores were excluded. The clinical and histological data were evaluated. The criteria for re-biopsy were two successive increases in prostate specific antigen (PSA) level or any change in the findings on digital rectal examination (DRE). All patients were monitored at 6-12 month intervals.

RESULTS

Of the 387 patients, 46% had normal findings, 5.2% had atypia, 12.6% had PIN alone, 15 (3.9%) had PIN plus atypia, 6.7% had PIN plus cancer and 32.3% had cancer. There was no significant difference between the PIN and control groups in age, DRE, PSA level, prostate size (by ultrasonography), free testosterone level, number of the cores and time of follow-up (median 34.8 and 36.6 months for the PIN and control groups, respectively). Of the PIN and control groups, 21 (45%) and 43 (31%) respectively had at least one re-biopsy. Five patients (24%) in the PIN and one (2.3%) in the control group developed cancer (P = 0.0124). All these patients had organ-confined disease and were found to have either Gleason scores 3 + 3 or 3 + 4 on surgical specimens. There was no correlation between the original location of PIN and the location of subsequent malignancy.

CONCLUSIONS

Patients with one set of extended needle biopsies with high-grade PIN should be followed clinically every 6-12 months, and it may be safe to reserve repeat biopsy for those with changes in PSA level and/or in the DRE.

Metabolism of zaleplon by human liver: evidence for involvement of aldehyde oxidase

1. The metabolism of Zaleplon (CL-284,846; ZAL) has been studied in precision-cut human liver slices and liver cytosol preparations. 2. Human liver slices metabolized ZAL to a number of products including 5-oxo-ZAL (M2), N-desethyl-5-oxo-ZAL (M1) and N-desethyl-ZAL (DZAL), the latter metabolite being known to be formed by CYP3A forms. 3. Human liver cytosol preparations catalysed the metabolism of ZAL to M2. Kinetic analysis of three cytosol preparations revealed mean (+/- SEM) K(m) and V(max) of 93 +/- 18 mm and 317 +/- 241 pmol/min/mg protein, respectively. 4. Using 16 individual human liver cytosol preparations a 33-fold variability in the metabolism of 80 micro M ZAL to M2 was observed. Correlations were observed between M2 formation and the metabolism of the aldehyde oxidase substrates phenanthridine (r(2) = 0.774) and phthalazine (r(2) = 0.460). 5. The metabolism of 80 micro M ZAL to M2 in liver cytosol preparations was markedly inhibited by the aldehyde oxidase inhibitors chlorpromazine, promethazine, hydralazine and menadione. Additional kinetic analysis suggested that chlorpromazine and promethazine were non-competitive inhibitors of M2 formation with K(i) of 2.3 and 1.9 micro M, respectively. ZAL metabolism to M2 was also inhibited by cimetidine. 6. Incubations conducted with human liver cytosol and H(2)(18)O demonstrated that the oxygen atom incorporated into ZAL and DZAL to form M2 and M1, respectively, was derived from water and not from molecular oxygen. 7. In summary, by correlation analysis, chemical inhibition and H(2)(18)O incorporation studies, ZAL metabolism to M2 in human liver appears to be catalysed by aldehyde oxidase. With human liver slices, ZAL was metabolized to products dependent on both aldehyde oxidase and CYP3A forms.

Inhibition of zaleplon metabolism by cimetidine in the human liver: in vitro studies with subcellular fractions and precision-cut liver slices

1. The effect of cimetidine on the metabolism of zaleplon (ZAL) in human liver subcellular fractions and precision-cut liver slices was investigated. 2. ZAL was metabolized to a number of products including 5-oxo-ZAL (M2), which is known to be formed by aldehyde oxidase, N-desethyl-ZAL (DZAL), which is known to be formed by CYP3A forms, and N-desethyl-5-oxo-ZAL (M1). 3. Human liver microsomes catalysed the NADPH-dependent metabolism of ZAL to DZAL. Kinetic analysis of three microsomal preparations revealed mean (+/-SEM) S(50) and V(max) of 310 +/- 24 micro M and 920 +/- 274 pmol/min/mg protein, respectively. 4. Human liver cytosol preparations catalysed the metabolism of ZAL to M2. Kinetic analysis of three cytosol preparations revealed mean (+/-SEM), K(m) and V(max) of 124 +/- 14 micro M and 564 +/- 143 pmol/min/mg protein, respectively. 5. Cimetidine inhibited ZAL metabolism to DZAL in liver microsomes and to M2 in the liver cytosol. With a ZAL substrate concentration of 62 micro M, the calculated mean (+/-SEM, n = 3) IC50 were 596 +/- 103 and 231 +/- 23 micro M for DZAL and M2 formation, respectively. Kinetic analysis revealed that cimetidine was a competitive inhibitor of M2 formation in liver cytosol with a mean (+/-SEM, n = 3) K(i) of 155 +/- 16 micro M. 6. Freshly cut human liver slices metabolized ZAL to a number of products including 1, M2 and DZAL. 7. Cimetidine inhibited ZAL metabolism in liver slices to M1 and M2, but not to DZAL. Kinetic analysis revealed that cimetidine was a competitive inhibitor of M2 formation in liver slices with an average (n = 2 preparations) K(i) of 506 micro M. 8. The results demonstrate that cimetidine can inhibit both the CYP3A and aldehyde oxidase pathways of ZAL metabolism in the human liver. Cimetidine appears to be a more potent inhibitor of aldehyde oxidase than of CYP3A forms and hence in vivo is likely to have a more marked effect on ZAL metabolism to M2 than on DZAL formation. 9. The results also demonstrate that precision-cut liver slices may be a useful model system for in vitro drug-interaction studies.

Use of a quantitative real-time reverse transcription-polymerase chain reaction method to study the induction of CYP1A, CYP2B and CYP4A forms in precision-cut rat liver slices

1. The aim was to employ real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) technology (TaqMan to examine the induction of some selected cytochrome P450 (CYP) forms in precision-cut rat liver slices. 2. Taqman primers and probe sets were developed for rat CYP1A1, CYP1A2, CYP2B1 and CYP4A1 forms. 3. Rat liver slices were cultured in control medium or medium containing either 10 micro g ml(-1) Aroclor 1254 (ARO), 500 micro M sodium phenobarbitone (NaPB) or 50 micro M Wy-14643 (WY) for 3, 6 and 24 h. 4. Compared with control liver slices, treatment with ARO for 3 and 6 h produced 24- and 184-fold increases, respectively, in CYP1A1 mRNA levels, and after 24h produced an 85-fold increase in CYP1A2 mRNA levels. Levels of CYP1A1 and CYP1A2 mRNA were not markedly affected by NaPB and WY. 5. Treatment with ARO and PB for 24 h produced 10.6- and 23.8-fold increases, respectively, in CYP2B1 mRNA. Levels of CYP2B1 mRNA were not markedly affected by WY. 6. Treatment with WY, but not ARO and NaPB, for 24h produced a 20.4-fold increase in levels of CYP4A1 mRNA. 7. These results demonstrate that cultured liver slices may be used to evaluate the effect of xenobiotics on CYP form mRNA levels.

X-ray crystallographic structure of ABT-378 (lopinavir) bound to HIV-1 protease

The crystal structure of ABT-378 (lopinavir), bound to the active site of HIV-1 protease is described. A comparison with crystal structures of ritonavir, A-78791, and BILA-2450 shows some analogous features with previous reported compounds. A cyclic urea unit in the P(2) position of ABT-378 is novel and makes two bidentate hydrogen bonds with Asp 29 of HIV-1 protease. In addition, a previously unreported shift in the Gly 48 carbonyl position is observed. A discussion of the structural features responsible for its high potency against wild-type HIV protease is given along with an analysis of the effect of active site mutations on potency in in vitro assays.