Function and regulation of TRPM7, as well as intracellular magnesium content, are altered in cells expressing ΔF508-CFTR and G551D-CFTR

Cystic fibrosis (CF), one of the most common fatal hereditary disorders, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The CFTR gene product is a multidomain adenosine triphosphate-binding cassette (ABC) protein that functions as a chloride (Cl(-)) channel that is regulated by intracellular magnesium [Mg(2+)]i. The most common mutations in CFTR are a deletion of a phenylalanine residue at position 508 (ΔF508-CFTR, 70-80 % of CF phenotypes) and a Gly551Asp substitution (G551D-CFTR, 4-5 % of alleles), which lead to decreased or almost abolished Cl(-) channel function, respectively. Magnesium ions have to be finely regulated within cells for optimal expression and function of CFTR. Therefore, the melastatin-like transient receptor potential cation channel, subfamily M, member 7 (TRPM7), which is responsible for Mg(2+) entry, was studies and [Mg(2+)]i measured in cells stably expressing wildtype CFTR, and two mutant proteins (ΔF508-CFTR and G551D-CFTR). This study shows for the first time that [Mg(2+)]i is decreased in cells expressing ΔF508-CFTR and G551D-CFTR mutated proteins. It was also observed that the expression of the TRPM7 protein is increased; however, membrane localization was altered for both ΔF508del-CFTR and G551D-CFTR. Furthermore, both the function and regulation of the TRPM7 channel regarding Mg(2+) is decreased in the cells expressing the mutated CFTR. Ca(2+) influx via TRPM7 were also modified in cells expressing a mutated CFTR. Therefore, there appears to be a direct involvement of TRPM7 in CF physiopathology. Finally, we propose that the TRPM7 activator Naltriben is a new potentiator for G551D-CFTR as the function of this mutant increases upon activation of TRPM7 by Naltriben.

[Radiotherapy in cancers of the oesophagus, the gastric cardia and the stomach]

Localized oesophageal and gastric cancers have a poor prognosis. In oesophageal cancer, external radiotherapy combined with concomitant chemotherapy is accepted as part of the therapeutic armamentarium in a curative intent in the preoperative setting for resectable tumours; or without surgery in inoperable patients or non-resectable tumours due to wide local and/or regional extension. Data from the literature show conflicting results with no clinical evidence in favour of either a unique dose protocol or consensual target volume definition in the setting of exclusive chemoradiation. In the preoperative setting, chemoradiotherapy has become the standard in oesophageal cancer, even though there is no evidence that surgery may be beneficial in locally advanced tumours that respond to radiotherapy and chemotherapy. The main cause of failure after exclusive chemoradiotherapy in oesophageal cancer is locoregional relapse suggesting that doses and volumes usually considered may be inadequate. In gastric cancer, radiotherapy may be indicated postoperatively in patients with resected tumours that include less than D2 lymph node dissection or in the absence of perioperative chemotherapy. Preoperative chemoradiotherapy in gastric cancers is still under investigation. The evolving techniques of external radiotherapy, such as image-guided radiotherapy (IMRT) and volumetric modulated arctherapy (VMAT) have reduced the volume of lung and heart exposed to radiation, which seems to have diminished radiotherapy-related morbi-mortality rates. Given this, quality assurance for radiotherapy and protocols for radiotherapy delivery must be better standardized. This article on the indications for radiotherapy and the techniques used in oesophageal and gastric cancers is included in a special issue dedicated to national recommendations from the French society of radiation oncology (SFRO) on radiotherapy indications, planning, dose prescription, and techniques of radiotherapy delivery.

Are fiducial markers useful surrogates when using respiratory gating to reduce motion of gastroesophageal junction tumors?

BACKGROUND

Radiation therapy (RT) is an integral component of the management of gastroesophageal junction (GEJ) tumors. We evaluated the use of implanted radiopaque fiducials as tumor surrogates to allow for more focal delivery of RT to these mobile tumors when using respiratory gating (RG) to reduce motion.

MATERIAL AND METHODS

We analyzed four-dimensional computed tomography scans of 20 GEJ patients treated with RG and assessed correlation between tumor and implanted fiducial motion over the whole respiratory cycle and within a clinically realistic gate around end-exhalation. We evaluated fiducial motion concordance in 11 patients with multiple fiducials.

RESULTS

Gating reduced anterior-posterior (AP) and superior-inferior (SI) mean tumor and fiducial motions by over 50%. Fiducials and primary tumor motions were moderately correlated: R(2) for AP and SI linear fits to the entire group were 0.54 and 0.68, respectively, but the correlation had strong inter-patient variation. For all patients with multiple fiducials, relative in-gate displacements were below 3 mm; results were similar for eight of 11 patients over the whole cycle.

CONCLUSION

Implanted fiducial and gross tumor volume (GTV) motions correlate well but the correlation is patient-specific and may be dependent on the location of the fiducials with respect to the GTV.

Effect of Chemoradiotherapy vs Chemotherapy on Survival in Patients With Locally Advanced Pancreatic Cancer Controlled After 4 Months of Gemcitabine With or Without Erlotinib: The LAP07 Randomized Clinical Trial

IMPORTANCE

In locally advanced pancreatic cancer, the role of chemoradiotherapy is controversial and the efficacy of erlotinib is unknown.

OBJECTIVES

To assess whether chemoradiotherapy improves overall survival of patients with locally advanced pancreatic cancer controlled after 4 months of gemcitabine-based induction chemotherapy and to assess the effect of erlotinib on survival.

DESIGN, SETTING, AND PARTICIPANTS

In LAP07, an international, open-label, phase 3 randomized trial, 449 patients were enrolled between 2008 and 2011. Follow-up ended in February 2013.

INTERVENTIONS

In the first randomization, 223 patients received 1000 mg/m2 weekly of gemcitabine alone and 219 patients received 1000 mg/m2 of gemcitabine plus 100 mg/d of erlotinib. In the second randomization involving patients with progression-free disease after 4 months, 136 patients received 2 months of the same chemotherapy and 133 underwent chemoradiotherapy (54 Gy plus capecitabine).

MAIN OUTCOMES AND MEASURES

The primary outcome was overall survival from the date of the first randomization. Secondary outcomes were the effect of erlotinib and quality assurance of radiotherapy on overall survival, progression-free survival of gemcitabine-erlotinib and erlotinib maintenance with gemcitabine alone at the second randomization, and toxic effects.

RESULTS

A total of 442 of the 449 patients (232 men; median age, 63.3 years) enrolled underwent the first randomization. Of these, 269 underwent the second randomization. Interim analysis was performed when 221 patients died (109 in the chemoradiotherapy group and 112 in the chemotherapy group), reaching the early stopping boundaries for futility. With a median follow-up of 36.7 months, the median overall survival from the date of the first randomization was not significantly different between chemotherapy at 16.5 months (95% CI, 14.5-18.5 months) and chemoradiotherapy at 15.2 months (95% CI, 13.9-17.3 months; hazard ratio [HR], 1.03; 95% CI, 0.79-1.34; P = .83). Median overall survival from the date of the first randomization for the 223 patients receiving gemcitabine was 13.6 months (95% CI, 12.3-15.3 months) and was 11.9 months (95% CI, 10.4-13.5 months) for the 219 patients receiving gemcitabine plus erlotinib (HR, 1.19; 95% CI, 0.97-1.45; P = .09; 188 deaths vs 191 deaths). Chemoradiotherapy was associated with decreased local progression (32% vs 46%, P = .03) and no increase in grade 3 to 4 toxicity, except for nausea.

CONCLUSIONS AND RELEVANCE

In this open-label, randomized trial involving patients with locally advanced pancreatic cancer with disease controlled after 4 months of induction chemotherapy, there was no significant difference in overall survival with chemoradiotherapy compared with chemotherapy alone and there was no significant difference in overall survival with gemcitabine compared with gemcitabine plus erlotinib used as maintenance therapy.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00634725.

Peripheral arterial occlusive disease during ponatinib therapy after failure of imatinib: a case report

WHAT IS KNOWN AND OBJECTIVE

Peripheral vascular adverse events have been reported with ponatinib treatment in chronic myeloid leukaemia (CML) after failure of dasatinib or nilotinib. We here report peripheral arterial occlusive disease (PAOD) in a patient who had previously received only imatinib as tyrosine kinase inhibitor.

CASE DESCRIPTION

The patient was a 70-year-old man with no history of cardiovascular disease. He developed arterial hypertension 5 months after the initiation of ponatinib and PAOD 41 months later.

WHAT IS NEW AND CONCLUSION

Peripheral arterial occlusive disease can occur several years after the initiation of ponatinib in patients who had previously received only imatinib. Long-term surveillance is required for preventing the complications of ponatinib-associated PAOD.

Chemoradiation in rectal squamous cell carcinoma: Bi-institutional case series

BACKGROUND AND PURPOSE

Primary rectal squamous cell carcinoma (SCC) is an uncommon disease. Early reports stated that surgery is the most effective treatment. However, recent publications suggest conservative strategy with chemoradiation provides satisfactory results.

PATIENTS AND METHODS

We have retrospectively studied the medical charts of 23 patients treated for a rectal SCC in two teaching hospitals in France between 1992 and 2013. Twenty-one patients received an exclusive chemoradiotherapy (CRT) and two a pre-operative CRT followed by a planned surgery. Patients received pelvic irradiation with a dose ranging from 36-45 Gy followed by a boost of 15-23 Gy. Twenty-two patients received a concurrent chemotherapy.

RESULTS

After CRT, the rate of clinical complete response was 83%. With a median follow-up of 85 months, 5-year overall survival rate was 86%. Five patients presented with a relapse. The 5-year disease-free survival rate was 81%. The 5-year colostomy-free survival rate was 65%. Three patients (13%) presented with grade III-IV late rectal toxicity.

CONCLUSIONS

Although retrospective, this is the largest cohort of patients treated with CRT for a rectal SCC. Exclusive CRT could result in high local control rate and prolonged survival in rectal SCC patients with a high rate of organ preservation.

Current standards and new innovative approaches for treatment of pancreatic cancer

Pancreatic adenocarcinoma remains a devastating disease with a 5-year survival rate not exceeding 6%. Treatment of this disease remains a major challenge. This article reviews the state-of-the-art in the management of this disease and the new innovative approaches that may help to accelerate progress in treating its victims. After careful pre-therapeutic evaluation, only 15-20% of patients diagnosed with a pancreatic cancer (PC) are eligible for upfront radical surgery. After R0 or R1 resection in such patients, evidence suggests a significantly positive impact on survival of adjuvant chemotherapy comprising 6 months of gemcitabine or fluorouracil/folinic acid. Delayed adjuvant chemoradiation is considered as an option in cases of positive margins. Borderline resectable pancreatic cancer (BRPC) is defined as a tumour involving the mesenteric vasculature to a limited extend. Resection of these tumours is technically feasible, yet runs the high risk of a R1 resection. Neoadjuvant treatment probably offers the best chance of achieving successful R0 resection and long-term survival, but the best treatment options should be determined in prospective randomised studies. Gemcitabine has for 15 years been the only validated therapy for advanced PC. Following decades of negative phase III studies, increasing evidence now suggests that further significant improvements to overall survival can be achieved via either Folfirinox or gemcitabine + nab-paclitaxel regimens. Progress in systemic therapy may improve the chances of resection in borderline resectable pancreatic cancer (BRPC) or locally advanced PC. This requires first enhancing knowledge of the genetic events driving carcinogenesis, which may then be translated into clinical studies.

Clinical applications of circulating tumor DNA and circulating tumor cells in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most frequent pancreatic cancer type and is characterized by a dismal prognosis due to late diagnosis, local tumor invasion, frequent distant metastases and poor sensitivity to current therapy. In this context, circulating tumor cells and circulating tumor DNA constitute easily accessible blood-borne tumor biomarkers that may prove their clinical interest for screening, early diagnosis and metastatic risk assessment of PDAC. Moreover these markers represent a tool to assess PDAC mutational landscape. In this review, together with key biological findings, we summarize the clinical results obtained using "liquid biopsies" at the different stages of the disease, for early and metastatic diagnosis as well as monitoring during therapy.

Intensity modulated radiation therapy reduces gastrointestinal toxicity in locally advanced pancreas cancer

PURPOSE

We compared gastrointestinal (GI) and hematologic toxicity in patients with locally advanced pancreas cancer (LAPC) undergoing definitive chemoradiation using intensity modulated radiation therapy (IMRT) or 3-dimensional conformal radiation therapy (3D-CRT) planning.

METHODS AND MATERIALS

We retrospectively studied 205 patients with LAPC undergoing IMRT (n = 134) and 3D-CRT (n = 71) between May 2003 and March 2012. Patient, tumor, and treatment characteristics and acute GI/hematology toxicity according to the Common Terminology Criteria for Adverse Events, version 3.0, were recorded. Multivariable logistic regression models were used to test association between acute grade 2+ GI and hematologic toxicity outcomes and predictors. Propensity score analysis for grade 2+ GI toxicity was performed to reduce bias for confounding variables: age, gender, radiation dose, field size, and chemotherapy type.

RESULTS

Median follow-up time for survivors was 22 months and was similar between groups. Median RT dose was significantly higher for IMRT versus 3D-CRT (5600 cGy vs 5040 cGy, P < .001); concurrent chemotherapy was mainly gemcitabine (56%) or 5-fluorouracil (38%). Grade 2+ GI toxicity occurred in 34% (n = 24) of 3D-CRT compared with 16% (n = 21) of IMRT patients. Using propensity score analysis, 3D-CRT had significantly higher grade 2+ GI toxicity (odds ratio, 1.26; 95% confidence interval, 1.08-1.45; P = .001). Grade 2+ hematologic toxicity was similar between IMRT and 3D-CRT groups, but was significantly greater in recipients of concurrent gemcitabine than in 5-fluorouracil (62% vs 29%, P < .0001).

CONCLUSIONS

IMRT is associated with significant lower grade 2+ GI toxicity versus 3D-CRT for patients undergoing definitive chemoradiation therapy for LAPC. Because IMRT is better tolerated at higher doses and may allow further dose escalation, potentially improving local control for this aggressive disease. Further prospective studies of dose-escalated chemoradiation using IMRT are warranted.

[Follow-up after radiotherapy of anal canal carcinoma]

Anal canal carcinoma is a rare and curable disease for which the standard of care is radiation therapy with concurrent 5-fluoro-uracil and mitomycine-based chemotherapy. Post-treatment follow-up however is rather poorly defined. This article offers a review of the various post-treatment surveillance options both for early diagnosis of relapse and care for late treatment effects. While follow-up remains mostly clinical, we will discuss morphologic (endorectal echoendoscopy, pelvic magnetic resonance imaging, tomodensitometry and positron emission tomography) and biologic (squamous cell carcinoma antigen and pathology) follow-up so as to determine their diagnostic and prognostic value.

Just how accurate are the major risk stratification systems for early-stage endometrial cancer?

BACKGROUND

To compare the accuracy of five major risk stratification systems (RSS) in classifying the risk of recurrence and nodal metastases in early-stage endometrial cancer (EC).

METHODS

Data of 553 patients with early-stage EC were abstracted from a prospective multicentre database between January 2001 and December 2012. The following RSS were identified in a PubMed literature search and included the Post Operative Radiation Therapy in Endometrial Carcinoma (PORTEC-1), the Gynecologic Oncology Group (GOG)-99, the Survival effect of para-aortic lymphadenectomy (SEPAL), the ESMO and the ESMO-modified classifications. The accuracy of each RSS was evaluated in terms of recurrence-free survival (RFS) and nodal metastases according to discrimination.

RESULTS

Overall, the ESMO -modified RSS provided the highest discrimination for both RFS and for nodal metastases with a concordance index (C-index) of 0.73 (95% CI, 0.70-0.76) and an area under the curve (AUC) of 0.80 (0.78-0.72), respectively. The other RSS performed as follows: the PORTEC1, GOG-99, SEPAL, ESMO classifications gave a C-index of 0.68 (0.66-0.70), 0.65 (0.63-0.67), 0.66 (0.63-0.69), 0.71 (0.68-0.74), respectively, for RFS and an AUC of 0.69 (0.66-0.72), 0.69 (0.67-0.71), 0.68 (0.66-0.70), 0.70 (0.68-0.72), respectively, for node metastases.

CONCLUSIONS

None of the five major RSS showed high accuracy in stratifying the risk of recurrence or nodal metastases in patients with early-stage EC, although the ESMO-modified classification emerged as having the highest power of discrimination for both parameters. Therefore, there is a need to revisit existing RSS using additional tools such as biological markers to better stratify risk for these patients.

Prognosis model for overall survival in locally advanced unresecable pancreatic carcinoma: An ancillary study of the LAP 07 trial

235

Background: The management of locally advanced pancreatic cancer (LAPC) patients remains controversial and complex. Better discrimination for Overall Survival (OS) is needed to improve therapeutic decisions. We address this issue, with the largest Phase III cohort of LAPC, by establishing the first prognosis model for OS with the full spectrum of parameters currently available at diagnosis. Methods: We enrolled 442 LAPC patients recruited in LAP07, an international multicenter randomized phase III trial (NCT00634725). 30 baseline variables among demographic, cancer history, clinical, biological and radiological parameters were evaluated in univariate and multivariate analyses as prognostic factors for OS. The predictive value of the final model was evaluated with Harrell’s C index. This analysis was repeated 1,000 times with the use of bootstrap sample to derive 95%CI for the C. A prognostic score and nomogramm were then developed based on the identified prognostic factors in the final model. Results: Independent prognostic factors identified in multivariate analysis (n=370) for OS were: Age (HR= 1.01; 95%CI 1.00 - 1.03; p=0.0418), Pain (HR= 1.36 ; 95%CI 1.08 - 1.71; p=0.0094), Albumin (HR= 0.96; 95%CI 0.94 - 0.98; p=0.0001), and RECIST size (HR= 1.01; 95%CI 1.00 - 1.02; p=0.0033), Harrell’s C-statistic for the final model was 0.60 (95% bootstrap CI 0.56 0.63). A prognostic score between 0 and 4 was then calculated for each patient, based on the previous model. Three risk-groups for death could be identified: lower risk (n=17; median OS time = 18.8 months; group of reference); intermediate risk (n=166 ;median OS time = 13.4 months; HR=1.7); higher risk (n=187 ; median OS time = 11.8 months; HR=2.1); p = 0.0101 by the global log rank test. A score and nomogramm were also developped with the addition of CA19.9 information. Conclusions: Our results highlighted 4 OS’s independent pronostic factors among a broad spectrum of parameters at time of diagnosis. We identified 3 groups with different OS’s prognosis profile. The determination of this simple prognostic score allows risk stratification that may help guiding clinical management of patients and the design for future clinical trials.