Adjuvant Radiotherapy After Radical Cystectomy for Patients with High-risk Muscle-invasive Bladder Cancer: Results of a Multicentric Phase II Trial

BACKGROUND

High-risk muscle-invasive bladder cancer (MIBC) has a poor prognosis. Old trials showed that external beam radiotherapy (EBRT) after radical cystectomy (RC) decreases the incidence of local recurrences but induces severe toxicity.

OBJECTIVE

To evaluate the toxicity and local control rate after adjuvant EBRT after RC delivered with volumetric arc radiotherapy.

DESIGN, SETTING, AND PARTICIPANTS

This is a multicentric phase 2 trial. From August 2014 till October 2020, we treated 72 high-risk MIBC patients with adjuvant EBRT after RC. High-risk MIBC is defined as ≥pT3-MIBC ± lymphovascular invasion, fewer than ten lymph nodes removed, pathological positive lymph nodes, or positive surgical margins.

INTERVENTION

Patients received 50 Gy in 25 fractions with intensity-modulated radiotherapy to the pelvic lymph nodes ± cystectomy bed.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome is acute toxicity. We report on local relapse-free rate (LRFR), clinical relapse-free survival (CRFS), overall survival (OS), and bladder cancer-specific survival (BCSS).

RESULTS AND LIMITATIONS

The median follow-up is 18 mo. Forty-two patients (61%) developed acute grade 2 gastrointestinal (GI) toxicity. Four patients (6%) had acute grade 3 GI toxicity. One patient had grade 5 diarrhea and vomiting due to obstruction at 1 mo. Two-year probabilities of developing grade ≥3 and ≥2 GI toxicity were 17% and 76%, respectively. Urinary toxicity, assessed in 17 patients with a neobladder, was acceptable with acute grade 2 and 3 urinary toxicity reported in 53% (N = 9) and 18% (N = 3) of the patients, respectively. The 2-yr LRFR is 83% ± 5% and the 2-yr CRFS rate is 43% with a median CRFS time of 12 mo (95% confidence interval: 3-21 mo). Two-year OS and BCSS are 52% ± 7% and 62% ± 7%, respectively. Shortcomings are the nonrandomized study design and limited follow-up.

CONCLUSIONS

Adjuvant EBRT after RC can be administered without excessive severe toxicity.

PATIENT SUMMARY

In this report, we looked at the incidence of toxicity and local control after adjuvant external beam radiotherapy (EBRT) following radical cystectomy (RC) in high-risk muscle-invasive bladder cancer patients. We found that adjuvant EBRT was feasible and resulted in good local control. We conclude that these data support further enrollment of patients in ongoing trials to evaluate the place of adjuvant EBRT after RC.

Abstract P4-12-06: Quality of life, fatigue, and subjective cognitive functioning immediately and 6 months after adjuvant chemotherapy in breast cancer patients

Background

The aim of this study was to examine quality of life (QoL), fatigue, and subjective cognitive functioning (SCF) after chemotherapy in breast cancer (BC) patients.

Methods

BC patients were recruited before chemotherapy (3 FEC+3 Tax, BC-Chemo) and compared with disease-specific controls (i.e., BC patients not receiving chemotherapy, BC-Controls) and healthy controls (HC) matched for age and education.

All participants completed questionnaires assessing QoL (using the Functional Assessment of Cancer Therapy – General Population), fatigue (using the Functional Assessment of Chronic Illness Therapy-Fatigue), and SCF (with the Cognitive Failure Questionnaire) at recruitment and 6 months later (i.e., one month after the end of chemotherapy). Follow-up data (1 year after recruitment) were available for BC-Chemo and HC only.

Difference scores were computed for each participant (i.e., score after 6 months/ 1 year minus score at baseline) and transformed when necessary so that negative scores would reflect decline over time (i.e., decreased QOL, increased fatigue, and increased cognitive complaints). These difference scores were analysed using independent t-tests (BC-Chemo vs BC-Controls on one hand, and BC-Chemo vs HC on the other hand).

Results

Eighteen BC- Chemo, 19 BC-Controls, and 20 HC completed the study (mean age = 49, 58, and 44 years, resp., p = 0.001, BC-Controls being significantly older).

Statistical analyses showed that, after chemotherapy, BC- Chemo patients showed significantly lower QoL, more fatigue, and declined SCF than both groups of controls (see Table 1).

However, 6 months later, no statistically significant differences were found between BC- Chemo and HC with respect to QoL and fatigue. Only SCF remained significantly lower in BC- Chemo.

Table 1.Mean Scores (standard deviations) for Quality of Life (QoL), Fatigue, and Subjective Cognitive Functioning (SCF) in Breast Cancer Patients treated with Chemotherapy (BC-Chemo) or not (BC-Controls) and Healthy Controls 6 months and 1 Year After Baseline BC-ChemoBC-ControlsHealthy ControlsQoL (FACT-GP)   6 months after baseline-5.8 (8)1.1 (8.7)*-0.3 (4.7)*1 year after baseline-5.3 (11.8) 0.2 (9.4)Fatigue (FACIT-F)   6 months after baseline-6.1 (11.1)0 (7.3)*-0.1 (3.8)*1 year after baseline-3.6 (10.3) -2.1 (6.5)SCF (CFQ)   6 months after baseline-7.4 (9.4)0.3 (10.9)*1 (5)*1 year after baseline-10.4 (13) 1.2 (6)**p < 0.05 (two-tailed independent t-tests vs BC-Chemo). Note. FACT-GP: Functional Assessment of Cancer Therapy – General Population (higher scores = greater QoL). FACIT-F: Functional Assessment of Chronic Illness Therapy-Fatigue Scale (higher scores = low fatigue). CFQ: Cognitive Failure Questionnaire (higher scores = greater subjective cognitive problems). All difference scores reflect decline over time.

Conclusions

Shortly after chemotherapy (i.e., 6 months after baseline), breast cancer patients experienced diminished QoL and increased fatigue compared to both disease-specific and healthy controls, but these differences were no longer significant 6 months later. In contrast, group differences in SCF were significant at both timepoints, suggesting long-lasting cognitive decline for patients receiving chemotherapy.

Citation Format: Mebis J, Censabella S, Engels S, Van Marsenille C, Orye G, Marquette S, Vansteelant L, Luyten D, Maes A, Noé L, Bulens P. Quality of life, fatigue, and subjective cognitive functioning immediately and 6 months after adjuvant chemotherapy in breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-12-06.

Regulators of platelet cAMP levels: clinical and therapeutic implications

Platelets are indispensable for primary haemostasis, but their function needs to be tightly regulated to prevent excessive platelet activity, possibly leading to atherothrombotic events. An important mediator of the platelet activity is cyclic AMP (cAMP), which inhibits platelet aggregation. Intracellular cAMP levels are regulated via the Gs and Gi alpha subunits of heterotrimeric G proteins, which couple to adenylyl cyclase to respectively stimulate or inhibit cAMP production. Binding of a ligand to its G protein-coupled seven-transmembrane receptor activates these G proteins. In this review, we discuss a Gs-coupled receptor on platelets, VPAC1, and 2 important Gi-coupled receptors, the ADP receptor P2Y(12) and the prostaglandin E(2) receptor EP3. The regulation of platelet cAMP levels at the level of the receptors themselves or the G proteins coupled to them is analyzed. Alterations in Gsα and Giα function are associated with altered platelet reactivity. An increase in Gs function, or alternatively a defective Gi signaling, can be a risk factor for bleeding, while a loss of Gs function can result in a prothrombotic state. Regulator of G protein signaling (RGS) proteins accelerate the rate of inactivation of G protein-mediated signaling. One of the RGS proteins, RGS2, inhibits Gs signaling by interacting directly with adenylyl cyclase. The thienopyridine class of antiplatelet agents is based on cAMP-mediated regulation of platelet function through modification of the P2Y(12) receptor. Clopidogrel and some other novel cAMP regulators are discussed. Secondly, we review the use of prostacyclin derivatives to treat pulmonary arterial hypertension.

Platelet Gs hypofunction and abnormal morphology resulting from a heterozygous RGS2 mutation

SUMMARY BACKGROUND

Regulator of G-protein signaling (RGS) 2 negatively regulates Gs signaling by inhibiting the activation of adenylyl cyclase (AC). RGS2 mRNA contains four translation initiation sites, leading to four isoforms with different abilities to inhibit AC activity; the largest isoform is the most pronounced inhibitor. A role for RGS2 in platelets is not known.

OBJECTIVE

To describe a heterozygous RGS2 mutation (G23D) in three related patients, leading to Gs hypofunction in their platelets, and to study the mechanism behind the effect of the RGS2 mutation on platelet function and morphology.

METHODS

Gs signaling was studied ex vivo in platelets and in vitro in transfected cells. Translation initiation was evaluated in vitro, and the interaction of wild-type and G23D RGS2 with AC was unraveled via immunoprecipitation. Platelet granule content was analyzed with proteomics.

RESULTS

The mutation leads to reduced cAMP production after stimulation of Gs-coupled receptors. The largest RGS2 isoforms, with strong AC inhibitor activity, are enriched when the mutation is present, as compared with wild-type RGS2. Moreover, the mutation results in a stronger interaction of RGS2 with AC. G23D RGS2 carriers have enlarged, round platelets with abnormal alpha-granules. Proteomics of the platelet releasate revealed altered expression of some proteins involved in actin assembly, and carriers seemed to have a reduced platelet shape change.

CONCLUSIONS

We present the first platelet Gs signaling defect caused by a heterozygous RGS2 variant that results in a unique mutational mechanism, such as the differential use of translation initiation sites resulting in different functional RGS2 isoforms.

Substantial improvement of nanotube processability by freeze-drying

As-produced carbon nanotubes often contain a fraction of impurities such as metal catalysts, inorganic supports, and carbon by-products. These impurities can be partially removed by using acidic dissolution. The resulting nanotube materials have to be dried to form a powder. The processability of nanotubes subjected to regular (thermal vaporisation) drying is particularly difficult because capillary forces pack and stick the nanotubes irreversibly, which limits their dispersability in polymeric matrices or solvents. We show that this dramatic limitation can be circumvented by using freeze-drying instead of regular-drying during nanotube purification process. In this case, the nanotubes are trapped in frozen water which is then sublimated. As a result the final powder is significantly less compact and, more important, the nanotubes can be easily dispersed with no apparent aggregates, thereby greatly enhancing their processability, e.g., they can be used to make homogeneous composites and fibers. Results from coagulation spinning from water-based dispersions of regularly-dried and freeze-dried nanotubes are compared. We also show that freeze-dried materials, in contrast to regularly-dried materials, can be dissolved in organic polar solvents using alkali-doped nanotubes. High resolution TEM and XRD analysis demonstrate that the nanotube structure and quality are not affected at the nanoscale by freeze-drying treatments.

Cloning, sequencing and structural analysis of 976 base pairs of the promoter sequence for the rat lipoprotein lipase gene. Comparison with the mouse and human sequences

We cloned and sequenced the -976bp promoter of the rat lipoprotein lipase LPL gene. The sequence was compared with the mouse and human sequences. The homology between the rat and mouse LPL nucleotide sequences was not quite as strong in the promoter sequence as in the coding sequence. Among the 976nt promoter there were 118 divergences, i.e. 11.8%, compared to only 5.6% for the LPL coding region. However, within the 200nt immediately 5' to the transcriptional start site (proximal promoter), the divergence was only 4%. New potential cis-elements (such as CACCC, GATA, GC and GA boxes, IRS, Krox, MEF 2, E-box, CCArGG and 1/2 VDRE) were identified in the rat, mouse or human LPL gene.

Human lipoprotein lipase last exon is not translated, in contrast to lower vertebrates

We have sequenced the first fish (zebrafish, Brachydanio rerio) lipoprotein lipase (LPL) cDNA clone. Similarities were found in mammalian LPL cDNA, but the codon spanning the last two exons (which is thus split by the last intron) is AGA (Arg) as opposed to TGA in mammals. Exon 10 is thus partially translated. These results were confirmed with rainbow trout (Oncorhynchus mykiss). We also investigated whether mammal TGA coded for selenocystein (SeCys), the 21st amino acid, but found that this was not the case: TGA does not encode SeCys but is a stop codon. It thus appears that the sense codon AGA (fish) has been transformed into a stop codon TGA (human) during the course of evolution. It remains to be determined if the "loss" of the C-terminal end of mammalian LPL protein has conferred an advantage in terms of LPL activity or, on the contrary, a disadvantage (e.g., susceptibility to diabetes or atherosclerosis).

Comparison of the cDNA and amino acid sequences of lipoprotein lipase in eight species

By aligning nucleotide and amino acid sequences of lipoprotein lipase in eight species (man, pig, cow, sheep, mouse, rat, guinea-pig and chicken), we found that the main domains (catalytic, N-glycosylation and putative heparin binding sites) are well conserved. The longest identical amino acid chain was encoded by a sequence between the end of exon 2 and the beginning of exon 3, emphasizing the importance of this region which encodes the beta 5-loop of the active site, among other domains. Exon 10 is entirely untranslated in the seven mammals studied here and contains species-characteristic deletions, insertions or elements rich in A or A + T. In chicken, the beginning of exon 10 is translated. These eight previously unreported alignments could be a useful tool for further studies on LPL function.

Homozygous deletion of exon 9 causes lipoprotein lipase deficiency: possible intron-Alu recombination

We studied a homozygous deletion in the lipoprotein lipase gene at the molecular level. Comprising the end of intron 8, the whole of exon 9, and about two-thirds of intron 9, this 2.136-kb deletion caused complete lipoprotein lipase deficiency and severe hypertriglyceridemia (type I hyperlipoproteinemia). Intron 9 of a normal control subject was also sequenced in order to define the exact borders of the deletion. Up to now, only the first 0.721 kb of intron 9 had been sequenced. Thus the complete sequence of intron 9 (3.090 kb) is now available. Three Alu sequences were characterized in the normal intron 9, while the proband had only the third complete Alu sequence. The first Alu sequence was located in the deleted region, and only the left arm of the second was present, as the deletion began near its center. A stem-loop structure involving a 14-nt region towards the end of intron 8 and an Alu sequence in intron 9 might have led to the deletion. Sequence analysis showed that the three Alu sequences belonged to the 40-million-year-old Alu-Sa subclass.

Fentanyl pre-treatment does not affect the pharmacokinetic profile of an induction dose of propofol in adults

The initial disposition of propofol was reported to change when the administration was preceded by fentanyl. The pharmacokinetic profile of the induction dose of propofol (2 mg kg-1 body weight) was studied in 20 ASA I patients randomly allocated to receive fentanyl 1.5 microgram kg-1 (n = 12) or not (n = 8). Anaesthesia was maintained with isoflurane in N2O/O2. Venous blood drawn from the contralateral arm was used to determine whole blood propofol concentrations. The mean propofol blood concentrations were comparable in the two groups and were best fitted by a three exponential equation in all the patients, conforming to a three-compartment open mammillary model. Distributions (T1/2 alpha) redistribution (T1/2(7)) and elimination (T1/2 beta half-lives were comparable in the groups, without significant differences in the total body clearance in the area under the time-concentration curve (zero-infinity) in the volume of distribution at steady-state, in the volume of distribution during the elimination phase or in the mean resident time. Our data support the conclusion that pretreatment with fentanyl does not affect the pharmacokinetic profile of the induction dose of propofol in ASA I patients.

Sequence of rat lipoprotein lipase-encoding cDNA

A rat lipoprotein lipase (LPL)-encoding cDNA (LPL) has been entirely sequenced and compared to the sequences of all the LPL cDNAs reported in other species. As expected, high homology was found between the coding exons. The putative catalytic triad, Ser132, Asp156, His241, according to human numbering, is conserved in rat. As is the case in mouse, an Asn444 present in human LPL is also missing. The major divergences between human, mouse and rat LPLs were observed in the untranslated exon 10, where (i) the rat cDNA exhibits a 157-bp insertion and an 81-bp deletion relative to human; (ii) neither the B1 repeat nor the homopurine stretch reported in mouse can be recognized, and (iii) the rat cDNA displays several A+T-rich stretches.

Effect of magnesium deficiency on post-heparin lipase activity and tissue lipoprotein lipase in the rat

Previous studies have provided evidence that Mg deficiency affects lipid metabolism. The present experiments were designed to assess whether the hypertriglyceridemia associated with Mg deficiency was related to alterations in post-heparin lipase activity (PHLA). Mg-deficient and control diets were pair-fed to weanling Wistar rats for eight days and plasma lipoproteins were separated into various density classes by sequential preparative ultracentrifugation. Triglycerides were significantly increased in chylomicrons and in the very low density lipoprotein, low density lipoprotein and high density lipoprotein (HDL) fractions. Cholesterol and phospholipid levels were significantly lower in the HDL fraction. PHLA in deficient rat was substantially lower than in control rats. The inverse correlation between plasma triglyceride concentration and PHLA strongly suggests that hypertriglyceridemia is the result of defective lipolysis of plasma triglycerides in Mg-deficient rats. Further examination of the PHLA was carried out by salt-mediated inhibition of lipoprotein lipase (LPL) and by heparin sepharose affinity chromatography and purified rat LPL antiserum. The results indicate that hepatic lipase is significantly decreased in Mg-deficient rats but the low PHLA is due mainly to a decline in LPL. However, total LPL activity, that is, both the intracellular and the extracellular pools of LPL in adipose tissue, heart and diaphragm, were unaffected by Mg deficiency. The results suggest that the decrease of LPL activity in the plasma of Mg-deficient rats may be due to a selective decrease in the heparin-releasable pool of enzyme.

Antibody against human lipoprotein lipase

A polyclonal antibody against human lipoprotein lipase (LPL) was prepared. LPL from post-heparin plasma was first purified by heparin Sepharose 4B affinity chromatography. Protein impurities co-eluted with LPL were then eliminated by electrophoresis in the presence of ampholytes. Antithrombin III was identified in this fraction of protein impurities by immunodiffusion against a human antithrombin antiserum, while no antithrombin III could be detected in the purified LPL fraction. Immunodiffusion revealed a single line of precipitation between this antibody and human post-heparin plasma LPL. When pre-incubated with a constant activity of highly purified post-heparin plasma LPL (2.7 mU/75 microliters), an equal volume of the anti-LPL antiserum, either pure or diluted to 1/32 caused complete inhibition of the enzyme activity. Half maximal inhibition was observed at a dilution of approximately 1/200. By using a secondary antibody, it was shown that antiserum inhibited LPL activity by means of its immunoglobulins. This antibody was able to inhibit LPL from human adipose tissue, indicating that human LPL released from endothelial cell membranes has common antigenic determinants with adipose tissue LPL.

Antibody against rat adipose tissue lipoprotein lipase

To facilitate detailed studies of rat adipose tissue lipoprotein lipase regulation, a high titre polyclonal antibody was raised against purified rat adipose tissue lipoprotein lipase (in a goat). The first stage of the purification of the lipoprotein lipase was carried out with heparin-Sepharose affinity chromatography. In the second stage we took advantage of the binding property of lipoprotein lipase to ampholytes. These ampholytes, used during this second step, do not have to be eliminated prior to injecting the enzyme preparation into the animal. They have neither toxic nor antigenic effects on the animal; moreover, their presence does not affect the antigenic potency of the lipoprotein lipase. When pre-incubated with a constant amount of adipose tissue lipoprotein lipase (8 mU/75 microliter), an equal volume of the antiserum raised either pure or diluted up to 1/50 resulted in complete inhibition of enzyme activity, and half maximal inhibition was observed at a dilution of 1/800. The antibody was effective in inhibiting rat heart lipoprotein lipase but not salt-resistant hepatic lipase. Immunodiffusion revealed a single line of precipitation between this antibody and the adipose tissue lipoprotein lipase.

Post-heparin lipolytic activity with no hepatic triacylglycerol lipase involved in a mammalian species

It was found that lipolytic activity in bovine post-heparin plasma differed from that of other mammalian species by the fact that intravenous heparin induced the release of lipoprotein lipase but not hepatic triacylglycerol lipase. Initially, this fact was strongly suspected when no remaining lipolytic activity could be found after whole bovine post-heparin plasma had been tested with either 1 M NaCl or antiserum against lipoprotein lipase. This was further confirmed by using heparin-Sepharose affinity chromatography when the entire lipolytic activity was eluted with 1.5 M NaCl but none with 0.4 or 0.7 M NaCl. The active fraction had lipoprotein lipase characteristics, i.e. it required serum activators to produce optimum activity and was fully inhibited by NaCl of high molarity and by anti-lipoprotein lipase antiserum. Neither the different doses of heparin nor the various times of sampling altered the results. This raises the question whether hepatic triacylglycerol lipase is absent from the bovine liver or whether this enzyme is present but cannot be released by heparin.