North African dust intrusions and increased risk of respiratory diseases in Southern Portugal

The study of dust intrusions in Portugal is still a subject on which little investigation has been made, especially in terms of their effects. Thus, this work aims to achieve two goals: firstly, to characterize the dust intrusions in the study area; and secondly, to evaluate the possible statistical association between the dust intrusion days and hospital admissions due to respiratory diseases. Dust intrusions in Portugal are prevalent during the summer season. During this season, the dust plumes tend to cover broader areas than in the other seasons and they have origin in the North African countries. In the study area for the period between 2005 and 2015, the relative risk of urgent hospitalizations due to respiratory diseases was 12.6% higher during dust intrusion days. In order to obtain this statistical association, a Distributed Lag Nonlinear Model was developed. With this work, we expect to help the development of further studies regarding North African dust intrusions in Portugal, more precisely their effects on human health.

Variations in the management of adolescents with blunt splenic trauma in England and Wales: are we preserving enough?

INTRODUCTION

Management of blunt splenic injury has changed drastically with non-operative management increasingly used in paediatric and adult patients. Studies from America and Australia demonstrate disparities in care of patients treated at paediatric and adult centres. This study assessed management of splenic injuries in UK adolescents.

MATERIALS AND METHODS

Data were acquired from the Trauma Audit and Research Network on isolated blunt splenic injuries reported 2006-2015. Adolescents were divided into age groups of 11-15 years and 16-20 years, and injuries classified as minor (grades 1/2) or major (3+). Primary outcomes were needed for splenectomy and blood transfusion.

RESULTS

A total of 445 adolescents suffered isolated blunt splenic injuries. Road traffic collisions were the most common mechanism. There were no deaths as a result of isolated blunt splenic injuries, but 49 (11%) adolescents needed transfusions and 105 (23.6%) underwent splenectomies. There was no significant difference observed in the management of adolescents with minor trauma. In major trauma, 11-15-year-olds were more likely to have splenectomies when managed at local trauma units compared with major trauma centres (31% vs 4%, odds ratio 11.5; 95% confidence interval 3.82-34.38, p < 0.0001). Within major trauma centres, older adolescents were more likely to have splenectomies than younger adolescents (35.5% vs 3.8%, odds ratio 14; 95% confidence interval 4.55-43.26, p < 0.0001). There were no significant differences in haemodynamic status, transfusion requirement or embolisation rates.

CONCLUSIONS

There appears to be a large variation in the management of isolated blunt splenic injuries in the UK. The reasons for this remain unclear however non-operative management is safe and should be first line management in the haemodynamically stable adolescent, even with major splenic injuries.

[Opioids for Cancer Pain and its Use under Particular Conditions: A Narrative Review]

INTRODUCTION

All health professionals should be aware of the importance of evaluating pain - fifth vital sign- in cancer patients. Peripheral and central acting analgesics are widely used to treat moderate to severe pain, particularly cancer pain. Many guidelines have addressed this issue. However, real life patients' have other problems and comorbidities that may raise doubts when prescribing.

MATERIAL AND METHODS

Authors made a literature search, trying to clarify same specific situations: loss of oral route, renal impairment (hemodialysis), hepatic impairment, frequent opiod interactions and the availability of short-acting formulations.

RESULTS

The following medicines were included in this analysis: the natural opiates (morphine and codeine), their synthetic and semisynthetic derivatives (hydromorphone, oxycodone, and fentanyl), the partial agonist buprenorphine and finally tramadol and tapentadol. Transdermal systems are only available for buprenorphine and fentanyl. In hepatic impairment, fentanyl is safe, but with the exception of codeine and tramadol; other opioids should be used with caution. In renal failure: fentanyl, hydromorphone, and tapentadol are safe. Morphine should be avoided; other opioids should be used with caution. In hemodialysis, buprenorphine, fentanyl, hydromorphone and tramadol (at doses up to 200 mg/day) may be used.

DISCUSSION

Failure to recognize the impact of various situations described throughout this work, including the bioavailability due to loss of oral route, due to pharmacokinetics and pharmacodynamics of the various drugs, either in the context of the impaired metabolism or excretion, or in due to pharmacological interactions, conditions a serious risk of subtreatment of pain and consequent impact in terms of quality of life.

CONCLUSION

Opioid prescription is safe and effective, even in moderate to severe comorbidities such as renal and hepatic impairment and in patients with no oral route available. In this case, as when considering pharmacological interactions, an individualized therapeutic plan is the best solution and the patient should be assessed regularly. Unadjusted doses may relate to bad pain control and a higher prevalence of adverse events.

SUN-382 Heterogeneous Clinical Presentation In Familial Cases Of Primary Macronodular Adrenal Hyperplasia (PMAH): The Influence Of Somatic Event Of ARMC5

Background: PMAH is a cause of adrenal hypercortisolism and it is a genetic disease linked to ARMC5 gene in most cases. Heterogenous phenotypes due to cortisol secretion and also due to different germline mutations in the ARMC5 have been described in around the world. The diversity of the molecular second hits in adrenal nodules may be able to justify different clinical outcome in the same family. We report two sisters with the same germline mutation and different clinical outcome. Case: A 45-year-old female patient presented with clinical evidence of hypercortisolism. Metabolic syndrome has been evidenced since the age of 35. Hormonal data confirmed an autonomous cortisol secretion. Abdominal CT revealed a bilateral enlargement of adrenal glands with multiples nodules (up to 2 cm, with 10 Housfield Units). ¹⁸F-FDG-PET/CT identified a slight SUV (left SUV 3.4 and right SUV 2.7). A heterozygous germline pathogenic variant of ARMC5 was identified at exon 1: c.165_166insG, p.Ile58Asnfs*45 at BTB (POZ) domain associated with a somatic LOH of the germline mutation. In 2013, the patient underwent Adrenal Sparing Surgery (ASS). She presented an excellent control of metabolic syndrome associated with adrenal insufficiency (AI) for 12 months. After 2 years a clinical recurrence of hypercortisolism was observed and confirmed by laboratory data. A new abdominal ¹⁸F-FDG-PET/CT and CT showed an increase of SUV and enlargement of the right residual adrenal gland (SUV - 3.4). The patient was submitted to a partial right adrenalectomy. Interesting, she did not present total or partial AI after the second surgical procedure. Inversely, her sister (46 years of age), with classical Cushing´s syndrome and carrier of same germline mutation (with similar hormonal data and SUV of ¹⁸F-FDG-PET/CT), presented a long-term remission of hypercortisolism after ASS. The analysis of somatic mutation of ARMC5 revealed a new event c.2082_2088delCCCGCTC, p.Pro695Serfs*20 in heterozygous status at exon 6. Analysis of PMAH sections HE stained showed a different pattern in the proportion and distribution of clusters of compact cells (60%) relative to clear spongiocytic cells. Her sister presented 13% of compact cells, similar to the PMAH pattern. Discussion: The macronodules of PMAH are composed of clear spongiocytic cells which preferentially express 3βHSD steroidogenic enzyme, and small or compact cells, which differentially express CYP17A1 steroidogenic enzyme and are located in dispersed clusters among the clear cells. CYP17A1 has both 17α-hydroxylase activity and 17,20-lyase activity. Conclusion: The somatic events of ARMC5 should be considered and could be involved in heterogeneous cortisol secretion and clinical presentation in familial cases with different outcome. Further familial cohorts and functional studies should increase our understanding of this challenged adrenal disorder.

SAT-320 A Synonymous Pathogenic Variant (p.l180=) in SDHB Gene Identified in a Young Patient with Abdominal Paraganglioma

Background: Pheochromocytomas and paragangliomas (PPGLs) are neuroendocrine tumors derived from chromaffin cells. More than 30% of patients with PPGL have a hereditary predisposition. To date, at least 14 tumor susceptibility genes have been described. Mutations in the succinate dehydrogenase complex iron sulfur subunit B gene (SDHB) are more associated with paragangliomas and metastatic disease. Patients who are young, with larger tumors (>6 cm), positive genetic testing (especially SDHB) or paraganglioma have a higher risk of metastasis development. Case Report: A 14-yr-old boy was referred to investigate severe hypertension and paroxysmal headache, pallor and tachycardia. Biochemical testing for catecholamine-secreting PPGLs showed: 24h urine metanephrines 1.9 µg (normal range, 0.05 to 1.2), plasma normetanephrine 13.3 nmol/L (<0.9 nmol/L), plasma metanephrine <0.2 nmol/L (<0.5 nmol/L), 24h urine norepinephrine 987 µg (14 to 80), 24h urine epinephrine 0 (0.5 to 20 µg) and 24h urine dopamine 391 µg (65 to 400). Magnetic resonance imaging (MRI) revealed a 6.5 cm heterogenous and high-vascular mass in right adrenal gland topography. A strong positive uptake was evidenced in the metaiodobenzylguanidine (MIBG) scintigraphy. A selective α₁-receptor blocker (prazosin) was started to control blood pressure and adrenergic symptoms. The patient underwent laparoscopic surgery and anatomopathological analysis revealed a 5.5 cm paraganglioma (PASS criteria= 3). The normal right adrenal gland was identified in the histopathology and there was no continuity between normal adrenal gland and neoplasia. After one year of follow-up, the patient is in complete remission. Genetic analysis by Sanger automated sequencing revealed no pathogenic variants in VHL and SDHD genes. We identified a heterozygous germline synonymous variant c.540 G>A (p.L180=), involving a G>A transition in the last nucleotide of SDHB exon 5. This synonymous variant results in alternative splicing of the SDHB primary transcript. This germline variant was previously reported in a 12-yr-old patient with isolated jugulotympanic paraganglioma, but it has not been associated with catecolamine-secreting paraganglioma. Neck MRI revealed no abnormalities in our patient. Conclusion: We report here a synonymous pathogenic variant in SDHB exon 5 associated with an abdominal functioning paraganglioma. Annual screening for multifocal disease (abdominal and neck PPGLs) and malignancy should be performed.

SAT-070 Clinical and Imaging Characteristics of Primary Unilateral Adrenal Hyperplasia in Primary Aldosteronism

Primary aldosteronism (PA) is the most common cause of endocrine hypertension (HT) with an estimated prevalence of 10% in referred populations and 15–20% in patients with resistant HT. Aldosterone-producing adenomas are the most common cause of unilateral PA. Primary unilateral adrenal hyperplasia (PUH) is a rare cause of PA, but is probably underestimated. PUH can be diffuse or nodular, with poorly capsulated micronodules. To date, there is a paucity of data characterizing this condition. In this study, our aim was to report the clinical and imaging features of patients with PA caused by PUH. We retrospectively evaluated clinical, imaging and histopathological data of 183 PA patients. PUH was diagnosed in 9 out of 183 patients (5%). All patients had biochemical cure of PA after unilateral adrenalectomy and anatomopathological analysis showed micronodular adrenal hyperplasia in all cases. At the diagnosis, median age was 52 yrs, ranging from 33 and 74 yrs (6 men and 3 women). Hypokalemia was reported in 63% of the cases. Aldosterone/plasmatic renin activity ratio was 123.6 (range, 52 to 379). The median duration of HT was 18 yrs (range, 1 to 52). Because of HT duration before diagnosis, only a patient had HT cure after adrenalectomy. The median follow-up was 46 months (7 to 117 months). Computed tomography (CT) accuracy to determine the lateralization was 67%. The adrenal CT findings were: normal adrenals (n= 1), bilateral hyperplasia (n= 1; right incidentaloma 1.9 cm and left PUH 1.4 cm), unilateral hyperplasia (n= 1), bilateral nodules (n= 1) and unilateral nodules (n= 5; median 1.3 cm, from 0.9 to 1.5). Adrenal venous sampling was performed in 5 patients (successful rate 80%). In the remaining cases, surgery was guided by CT. PUH was in the left adrenal in 7 out of 9 cases (78%). Hot spot somatic mutations in aldosterone-driver genes (KCNJ5, ATP1A1, ATP2B3 and CTNNB1) were excluded by Sanger automated sequencing and the presence of chimeric CYP11B1/CYP11B2 gene was ruled out by long-PCR in all cases. In conclusion, PUH prevalence in our cohort was higher than previously reported. PUH was more frequent in men and in the left adrenal. The most common CT finding was a unilateral nodule smaller than 1.5 cm. However, CT accuracy was low and AVS should be the gold standard to define lateralization. Support: CNPq (403256/2016-0) to MQA; FAPESP (2017/13394-8) to MRC.

OR04-6 Predictors of Clinical Outcome after Adrenalectomy for Unilateral Primary Aldosteronism

Primary aldosteronism (PA) is the most common cause of endocrine hypertension (HT) with an estimated prevalence of 10% in referred populations and 15-20% in patients with resistant hypertension. The most common cause of unilateral PA is aldosterone-producing adenomas (APAs). HT and hypokalemia improve in nearly 100% of patients with unilateral PA after unilateral adrenalectomy. However, complete clinical success (defined as blood pressure ≤130x80 mmHg without anti-hypertensive drugs) has been reported in about 50% (range, 35-80%) of patients with unilateral PA after surgery. HT duration and severity have been associated with clinical outcome after adrenalectomy, but few reports with a limited number of cases evaluated the prognostic role of somatic KCNJ5 mutations. In this study, our aim was to determine clinical and molecular features associated with complete clinical success after unilateral adrenalectomy in unilateral PA patients. We retrospectively evaluated 103 PA patients (42 males; median age 49 yrs, 20-74) with a median follow-up of 25 months. Hypokalemia was present in 78% of the cases. Anatomopathological analysis revealed 94 APAs and 9 unilateral adrenal hyperplasias. All patients had biochemical cure after unilateral adrenalectomy. KCNJ5 mutations were identified in 27 out of 67 (40%) tumors: p.Gly151Arg (n= 13), p.Leu168Arg (n= 13) and p.Glu145Gln (n= 1). Complete clinical success was reported in 32 out of 103 (31%) patients. In univariate analysis, HT duration, body mass index (BMI kg/m²), female sex and somatic KCNJ5mutations were associated with HT resolution after adrenalectomy. Complete clinical success was reported in 50% of patients with HT duration ≤5 yrs (vs. 24% with HT duration >5 yrs; p= 0.011), in 40% of patients with BMI <25 (vs. 22% with BMI ≥25; p= 0.042), in 38% of women (vs. 21% of men; p= 0.079) and in 70% of the patients with tumors harboring KCNJ5 somatic mutations (vs. 30% with WT tumors; p= 0.003). According to a stepwise multivariate logistic regression analysis, only the presence of a somatic KCNJ5 mutation was an independent predictor of complete success after adrenalectomy (relative risk 4.8, 95% confidence interval 1.24 to 19.21; p= 0.023). In conclusion, the presence of a somatic KCNJ5 mutation was an independent predictor of complete clinical success after unilateral adrenalectomy in patients with unilateral PA.

SUN-350 Sterol-O-Acyl Transferase 1 Protein Expression Alone Is Not Sufficient to Predict Response to Mitotane Treatment in Adrenocortical Carcinoma

Background: Objective response rate to mitotane in advanced ACC is only ~20% and adverse drug effects are frequent and potentially serious. Markers of treatment response are not established. We have previously discovered that mitotane is an inhibitor of sterol-O-Acyl transferase 1 (SOAT1) which leads to depletion of cholesterol esters, endoplasmic reticulum stress and cell death in the ACC cell line NCI-H295. Data from a small cohort of patients with advanced ACC treated with mitotane monotherapy suggested longer progression-free survival in patients with high SOAT1 expression in ACC tissue. Aim: To investigate SOAT1 protein expression as a marker of treatment response to mitotane. Methods: SOAT1 protein expression was semiquantitatively determined by immunohistochemistry in full sections of 223 ACC treated with mitotane monotherapy in an adjuvant (n=151) and palliative setting (n=72) from eleven ENSAT centers. Expression was classified as high (H-score ≥2) and low (H-score <2) and correlated with recurrence-free (RFS) and progression-free survival (PFS), overall survival (OS), and mitotane levels after three and six months. Results: After multivariate adjustment for sex, ENSAT stage and Ki67 index, RFS (HR=1.3, log rank p=0.09) and OS (HR=1.6, log rank p=0.14) in adjuvantly treated ACC patients did not differ significantly between tumours with high and low SOAT1 expression. Similarly in the palliative setting, OS (HR=1.0, p=0.47) and PFS (HR=0.6, p=0.66) were not different. In line, high SOAT1 expression did not predict if patients reach the therapeutic window of mitotane. Conclusion: SOAT1 expression alone was not correlated with clinically significantly RFS, PFS, and OS in ACC patients neither in the adjuvant nor in the palliative setting.

OR29-3 Targeted Assessment of G0S2 Methylation Identifies a Rapidly Recurrent, Routinely Fatal Molecular Subtype of Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare malignancy with frequently dismal prognosis and few therapies. Patients with locoregional ACC routinely receive surgery and adjuvant mitotane, but >50% recur with metastases even after complete resection. Histological grade (Ki67>10% or >20 mitoses/50 HPF) is the strongest clinical predictor of recurrence, but time to recurrence in patients with high grade disease is variable and patients with low grade disease frequently recur. Recent molecular profiling studies suggest risk stratification by DNA methylation may better identify patients with homogenously dismal outcomes; in The Cancer Genome Atlas study on ACC (ACC-TCGA), we similarly identified that patients with tumors bearing CpG island hypermethylation (CIMP-high) exhibit rapid recurrence and early death. However, clinical translation of this complex molecular signature remains challenging. Here, we reanalyzed ACC-TCGA data and show that CIMP-high ACC is characterized by upregulation of cell cycle and DNA damage response programs, and identify that hypermethylation and silencing of G0S2 distinguishes this subgroup. We evaluated G0S2 methylation in a multi-institutional retrospective cohort of treatment-naive primary ACC (n=80) and adrenocortical adenomas (n=22) using a straightforward, overnight restriction digest/qPCR-based assay, validated by targeted bisulfite sequencing. We identified that G0S2 hypermethylation is exclusive to a subset of ACC (40%). G0S2 hypermethylation is associated with decreased disease-free survival (median DFS=14 mo., HR=6.91, p<0.0001; Cox regression) and overall survival (median OS=17 mo., HR=2.65, p<0.005; Cox regression). These observations remain significant in multivariate analyses, demonstrating that G0S2 hypermethylation independently predicts rapidly recurrent and fatal ACC. Our data suggests that prospective targeted assessment of G0S2 methylation may enable clinicians to identify patients with CIMP-high ACC, unlikely to exhibit durable response to standard of care. Ultimately, we hope that improved identification of this subgroup will facilitate the evaluation of more aggressive adjuvant therapies for these patients, and increase patient survival in the face of this devastating disease.

MON-407 Tumor Control after Radiotherapy and Temozolomide in a Cushing's Disease Patient with Giant Aggressive Pituitary Tumor

Introduction: Typical ACTH-producing pituitary adenomas are benign tumors, microadenomas, successfully treated by neurosurgery. However, 10-20% of Cushing’s disease (CD) patients have macroadenomas, sometimes invasive and aggressive cases with poorer surgical prognosis needing additional approaches. Temozolomide (TMZ), second generation alkylating agent, has been used alone or in combination to other medications/radiotherapy (RTX) for tumor control of aggressive pituitary adenomas and carcinomas. We report one patient with giant aggressive corticotropinoma that presented control tumor with RTX and TMZ after four pituitary surgeries unable to uncontroll tumor growth. Clinical Case: A 18-year-old female patient presented with weight gain, red moon face, supraclavicular fullness, dorsal hump, large purple striae, acanthosis nigricans, secondary amenorrhea, frontotemporal headache, visual impairment and right palpebral ptosis. Hormonal analysis confirmed ACTH-dependent Cushing's syndrome. Pituitary MRI showed the presence of a large selar and suprasellar expansive lesion of 5.2X5.1X4.0 cm with displacement of third ventricle, hypothalamus and lateral ventricles. The patient was submitted to the first neurosurgery (transsphenoidal route) with partial resection. Pathological analyses confirmed pituitary adenoma positive for ACTH, Ki-67 8%, negative p53 and 7 mitoses/10 field of great increase. Subsequent surgery was done by craniotomy with partial resection. Cabergoline 2 mg/week was started but the tumor keeps growing with worsening of visual complaints and increase of cortisol levels. At admission in our center, we planned new surgeries do remove the maximal tumor possible (debulking) and subsequent RTX and TMZ. She was submitted to third surgery by transsphenoidal route and the last surgical procedure by craniotomy. MRI pre-RTX done three months after the 4^th surgery showed remnant tumor of 3.5X3.0X3.0 cm. Fractioned stereotaxic radiotherapy was done with linear accelerator in a total of 54 Gy divided in 30 sessions. TMZ was initiated in a dose of 150 m²/day, cycles of five days/month, using for 14 months. Pituitary MRI 3, 6 and 10 months after TMZ showed a small reduction of tumor with increase of intratumor cystic areas. Conclusion: The combined use of TMZ and radiotherapy is an important approach for the treatment of rapidly growing, aggressive pituitary ACTH-secreting tumors resistant to conventional treatment.

MON-404 Reversible Dilated Cardiomyopathy in a Severe Case of Cushing’s Disease

Introduction: Patients with Cushing’s syndrome (CS) present a higher mortality compared with the general population mainly due to cardiovascular and infectious diseases. Major forms of cardiac involvement include left ventricular hypertrophy, myocardial ischemia, and, more rarely, reversible dilated cardiomyopathy. This last condition is not fully understood, but it seems to be related to the direct action of cortisol, promoting increase of myocardial responsiveness to several factors involved in myocardial remodeling. Case report: A 18 yrs-old, male, was admitted with a four years clinical picture of progressive weight gain, moon face with plethora, proximal weakness with muscular atrophy, diffuse cutaneous violaceous striae, depressive symptoms and fragility fractures. Arterial hypertension started three years after. Two months before admission, he presented dyspnea, orthopnea and anasarca. At admission, tachycardia, tachypnea, arterial pressure of 170X100 mmHg, oxygen saturation of 83%, bilateral thoracic crackling, diffuse edema reaching inguinal region and BMI of 38.3 kg/m². Hormonal analyses confirmed severe ACTH-dependent CS and pituitary MRI disclosed an expansible lesion of 1.6 cm suggestive of macroadenoma. Initial transthoracic echocardiography showed dilated left cavities, normal myocardial thickness but with moderate systolic dysfunction due to diffuse hypokinesia with ejection fraction (EF) of 45%. Patient was submitted to pharmacological approach to treat heart failure (HF) with furosemide, carvedilol, enalapril and spironolactone. Other etiologies for myocardiopathy such as infectious, autoimmune and metabolic diseases were excluded. Successful pituitary surgery was done in November 2016. The patient presented progressive improve of cardiac symptoms after all the treatments but mainly after pituitary surgery. Subsequent echocardiography 15 months after showed normal cardiac cavities, normal left ventricle and myocardial thickness and preserved global and segmental systolic function, EF of 56%. In the last evaluation (two years after surgery), the patient was using oral hydrocortisone twice/day and losartan Conclusion: Dilated cardiomyopathy is an uncommon clinical morbidity of CS. However, the immediate recognition of this condition and its effective treatment including control of hypercortisolism may reverse this life-threatening clinical condition

SAT-LB058 Effect of a Genetic Modifier of Cancer Risk in TP53 Mutation Carriers

Individuals harboring a germline TP53 mutation have a high lifetime risk of a broad spectrum of cancers, but the age of onset, tumor types and penetrance vary among carriers. The TP53-R337H variant is common in South and Southeastern Brazil due to founder effect and detected in 0.3% of the general population. TP53-R337H predisposes children to adrenocortical tumors (ACTs) and adults to various other Li-Fraumeni syndrome (LFS)-associated core cancers. Assessment of the family history of cancer in TP53-R337H carriers has revealed families fulfilling the classic criteria for LFS as well as those showing an apparently sporadic pattern of cancer presentation, suggesting that genetic and/or environmental factors modulate cancer penetrance in TP53-R337H carriers. Given the incomplete penetrance and heterogeneous familial cancer pattern in TP53-R337H carriers, we hypothesized that additional allelic variants in cis could act as modifiers of TP53-R337H activity and contribute to cancer risk. We used whole genome sequencing for fine mapping analysis of 2-Mb region flanking TP53 locus in ACT samples. Selected common and rare variants were genotyped in 204 unrelated TP53-R337H cancer patients and a control group of 67,359 newborns. Segregation analysis was performed by analyzing 682 family members. Cancer risk was ascertained, and in-vitro functional analysis was performed. We identified a common shared haplotype containing the E134* variant in the XAF1 gene in a subset (42%) of ACT patients harboring the TP53-R337H mutation. This rare variant (minor allele frequency worldwide= 0.004) was identified in 70% of TP53-R337H carrying chromosomes. Co-segregation of both variants was observed in 79% of cancer patients, however, it was significantly enriched in individuals with sarcoma (odds ratio, 5.6; 95% CI, 1.3 to 50.8; P=0.010) and multiple primary malignancies (odds ratio, 3.1; 95% CI, 1.0 to 12.9; P=0.033). Breast cancer patients harboring the extended haplotype developed multiple primary tumors three times more frequently than patients with the TP53-R337H-only haplotype. In vitro studies demonstrated that wild-type XAF1 enhances wild-type and p53-R337H transactivation whereas XAF1-E134* markedly attenuated this activity, thereby establishing a functional interaction between p53 and XAF1. These findings demonstrate that a tolerated and common polymorphism (XAF1-E134*) cooperates with the low-penetrance TP53-R337H variant to modulate cancer phenotype and highlights the potential biological contribution of additional variants that act in cis to influence the cancer phenotype conferred by low-penetrance TP53 alleles. Understanding the nature of the germline TP53 mutation and the contribution of other modifiers that influence its function, such as XAF1-E134*, will have implications for genetic counseling, surveillance and clinical management of these patients. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

SUN-354 Quality of Life in Patients with Primary Macronodular Adrenal Hyperplasia

Background: The majority of patients with Cushing’s syndrome (CS) have physical and psychological symptoms that may lead to impaired quality of life (QoL). QoL improving with treatment but remaining significantly impaired compared with the general population despite long-term remission. Aim of this study: To demonstrate that patients with PMAH can present cognitive and psychopathological impairment and show the outcomes after treatment. Methods and Material: The following tools were applied in 14 patients with PMAH: Mini-Mental State Examination (MMSE), Hospital Anxiety and Depression Scale (HADS), Factorial Personality Battery (FPB) and EQ-5D. Results: Eleven patients (78,5%) were females, median age 51 years (40-70) and males median age was 53 years (37-62). According to dexamethasone suppression test (DST), 35,7% were classified as possibly autonomous cortisol secretion (DST 1,8 - 5,0 mcg/dl), and 64,3% were autonomous cortisol secretion (DST > 5,0 mcg/dl). The median BMI was 29,6 kg/m² in female and 32,4 kg/m² in males. 85,7% presented arterial hypertension. 64,2% had DM or intolerance to glucose and 78,5% had dyslipidemia. Eight patients presented ARMC5 mutation and 2 patients were familial cases, all mutations were in exon 1. Only one patient had a Meningioma. Ten patients responded to MMSE (40% presented low cognitive evaluation). The HADS was answered by 14 patients. In the anxiety scale 71,5% had moderate to severe symptoms and 7,1% had mild symptoms. In the depression scale 57,2% presented moderate to severe symptoms and 21,4% had mild symptoms. The FPB show that the patients had exacerbated characteristics in their personality (57% in the neuroticism factor, 21% in extroversion factor, 43% in the sociability factor, 7% in the realization factor and 14% in the openness factor. The EQ-5D demonstrated that 71,4% measured their health status as moderate or severe. The median quality-adjusted life years (QALY) was 0,363 (range -0,07-0,704). Three patients repeated the analyzes after Sparing Adrenal Surgery. One patient presented normal cortisol secretion and two patients’ latent adrenal insufficiency. Two patients responded to the MMSE, with normalization of their cognition. Two patients had improvement in HADS, mainly on the depression scale. Two patients had passed from severe to mild health status on the EQ-5D, and the median QALY increased to 0,704 in both patients. Discussion: The present study clearly demonstrated reduced quality of life in the patients with PMAH. Despite the small number of patients evaluated after the improvement of hypercortisolism, an improvement in the quality of life was demonstrated in these patients. Conclusion: Adrenal surgery is used to control PMAH hypercortisolism and reduce cardiovascular events, but the patient’s quality of life should also be taken into account when considering treatment options.

SUN-351 Are We Underestimating The Role Of Systemic Chemotherapy In The Treatment Of Localized And Advanced Adrenocortical Carcinoma?

Background: Adrenocortical carcinoma (ACC) is a rare and, in the vast majority of cases, aggressive neoplasia. Even in cases of localized disease at the diagnosis in which complete surgical resection of the tumor is performed, rates of local and distant recurrence are very high. Aim: To retrospectively analyze the management and outcomes of cases that presented localized disease (Group 1) and metastatic disease at diagnosis (Group 2) followed in a single Institution. Results: Group 1 was formed by 23 cases and group 2 by 7 cases. In group 1, adjuvant treatment was initiated in 17 patients: 9 received adjuvant radiotherapy (ARDT) associated with mitotane and 8 patients received mitotane alone; six patients have been followed expectantly. Recurrence of the disease was observed in 70% of the cases (n=16). All had distant metastasis and 6 out of 16 also had local recurrence. Most frequent sites of metastasis were lung, liver and peritoneum, including a rare case of heart metastasis. All patients with recurrence received systemic chemotherapy. No patient who was followed without adjuvant treatment has recurred so far. The median recurrence free survival (RFS) and overall survival (OS) were 13 and 30 months, respectively. In group 2, 5 patients had only one site of metastasis at diagnosis (all of them presented lung metastases) and the remaining cases had two (lung and liver) or three sites (lung, liver and bone). In only one case neoadjuvant chemotherapy was the treatment of choice. In the remaining patients, primary tumor was resected and systemic chemotherapy and mitotane started after surgery. The number of chemotherapy regimens ranged from one to four. Median progression free survival (PFS) was 2 months (range, 0.9 to 11 months) and OS was 11 months (range, 0.9 to 30 months). Patients who had more than one metastatic site at diagnosis had a lower survival rate and the patient who underwent neoadjuvant chemotherapy presented the longest PFS (11 months). Conclusions: Group 1 cases analysis reinforces the high rate of disease recurrence in patients with localized disease despite adjuvant treatment with ARDT and mitotane. These findings support the need for multicenter clinical trials to investigate the benefit of systemic chemotherapy in an adjuvant setting in patients at high risk of recurrence. Regarding the metastatic patients at diagnosis, we emphasize the importance of a greater experience with neoadjuvant chemotherapy.

Pain prevalence and treatment in patients with metastatic bone disease

The accomplishment of successful pain treatment requires evaluation, characterization and quantification. The present study characterized pain and survival in a cohort of patients with cancer with bone metastasis who were treated with intravenous bisphosphonates. A total of 84 patients self-completed the Brief Pain Inventory (BPI) and 36-Item Short Form Survey (SF-36), between November 2010 and March 2011 with a 5-year survival follow-up as a surrogate marker of cancer burden. The median age was 62 years old (34–85), 64% of patients were female and 58% of these females had breast cancer. In the population, self-reported pain was 91.6%, with 29 patients (34.5%) reporting severe pain (score 7–10). Among these patients, only 13 (44.8%) presented a similar report to that of their clinical files and 5 were undergoing treatment with strong opioids (17.2%). A total of 45 patients (46%) had not been prescribed analgesic drugs, of these patients, 32 were treated with a weak opioid, and 13 with a strong opioid. An association was observed between pain records and the prescribed analgesic (P=0.031). BPI maximum pain and overall survival data were analyzed, and a significant association was identified between male patients presenting severe pain and decreased survival (P=0.004). Male survival was associated with severe pain, which is consistent with other data. The results revealed a skeletal-related events (SRE)-free survival (time elapsed from diagnosis of the first bone metastasis to the first SRE) of 9 months (4.39–13.73, 95% CI) with a statistically significant difference between subgroups of time since diagnosis of bone metastasis (P=0.005). The added value of the present study is the suggestion that complete and accurate pain narratives are mandatory and may contribute to the optimization of analgesia, and may help to increase survival rates. Optimal pain management for patients with cancer remains an urgent requirement.

The history of cancer pain and bone-targeted agents: 10 most commonly asked questions

The prevalence of pain and skeletal complications of metastatic bone disease is high and an important factor, which contributes to decreased quality of life and low survival rate. Bone-targeted agents are well-established therapies to reduce the skeletal-related events in patients with bone metastasis. However, the analgesic effect of these medications is still controversial. The objective of this review is to summarize the existing evidence about the use of bone-targeted agents in the treatment of metastatic bone pain, trying to answer to the 10 most commonly asked questions in this matter. To achieve this goal, authors did a research of reviews published between January 2001 and January 2018, using the terms MeSH: “cancer pain” and bisphosphonates. The source used was the PubMed (NLM) database. The search yielded 36 reviews, but only 16 met the inclusion criteria. Even with the introduction of a new class of drugs, bisphosphonates and specially zoledronic acid are the most commonly used drugs in most oncology centers. Bisphosphonates and denosumab appear to be beneficial in preventing skeletal morbidity but their analgesic role and impact on quality of life and survival are not so well established.

Neuropathic Pain After Breast Cancer Treatment: Characterization and Risk Factors

CONTEXT

Neuropathic pain (NP) may be an important contributor to the morbidity burden of breast cancer.

OBJECTIVES

We aimed to quantify the incidence of NP in the first year after diagnosis of breast cancer and to identify its main determinants.

METHODS

We performed a prospective cohort study including 506 patients with incident breast cancer, recruited at the Portuguese Institute of Oncology of Porto, and followed for one year; patients with incident NP were additionally evaluated when this condition was diagnosed and after six months, to identify chronic NP.

RESULTS

During the first year, 156 patients were diagnosed with NP (30.8%, 95% CI 27.0-35.0). Anxiety (relative risk [RR] 1.50; 95% CI 1.06-2.13), arm symptoms (RR 1.44; 95% CI 1.02-2.05), cancer Stage III/IV (RR 2.47; 95% CI 1.66-3.66), breast-conserving surgery with axillary lymph node dissection (RR 3.13; 95% CI 1.51-6.48), mastectomy with axillary lymph node dissection (RR 2.52; 95% CI 1.25-5.11), and damaging of the intercostobrachial nerve (RR 2.05; 95% CI 1.25-3.37) were predictors of a higher risk of NP. A total of 97 patients (62.2%, 95% CI 54.4-69.4) diagnosed with NP remained symptomatic after six months.

CONCLUSION

NP and chronic NP were frequent in this population, being associated with anxiety and arm symptoms before breast cancer treatments and type of surgical management. These results highlight the need for monitoring the occurrence of this neurologic side effect of treatments and to develop strategies for reducing the morbidity burden of breast cancer.

[Single Centre Prospective Study of Systematic Pain Evaluation in Portuguese Patients with Metastatic Prostate Cancer]

INTRODUCTION

Pain is one of the most common symptoms reported by cancer patients and is associated with decreased quality of life. Assessment of pain with standardized questionnaires reduces variability in its interpretation and may increase effectiveness of medical interventions. Prostate cancer is the most frequent male neoplasm in Portugal. We designed this study to evaluate the impact of a standardized pain questionnaire on pain management in patients with metastatic prostate cancer.

MATERIAL AND METHODS

Single centre prospective observational study of patients with metastatic prostate cancer. The study was designed to evaluate the benefit of systematically evaluating pain with Brief Pain Inventory-Short Form prior to a scheduled medical oncology consult. Patients reporting pain were reassessed one week later by telephone. To assess the benefit two consecutive cohorts were established based on communication of questionnaire results to the treating physician.

RESULTS

We recruited 207 patients of which 60% reported pain. Statistically significant decrease in mean pain intensity one week after the scheduled appointment was noted (3.95 vs 3.01; p < 0.001). Patients whose Brief Pain Inventory-Short Form was provided to their oncologist experienced greater reduction in pain, which was non-significant (p = 0.227). Using Brief Pain Inventory-Short Form assessment resulted in a higher probability of pain control (43.5% vs 30.9%; p = 0.193).

DISCUSSION

The prevalence of pain founded was higher than described in the literature, probably because our sample was less selected than the published in clinical trials. After the scheduled appointment, there was a statistically significant reduction in mean pain intensity, but the explicit use of this questionnaire was not associated with a statistically significant reduction of pain.

CONCLUSION

Patients with metastatic prostate cancer have a high prevalence of pain. Evaluation and treatment by medical oncologists is associated with a reduction of mean pain intensity. The use of Brief Pain Inventory-Short Form was associated with a non-significant increased reduction of pain.

Chemotherapy-induced peripheral neuropathy after neoadjuvant or adjuvant treatment of breast cancer: a prospective cohort study

PURPOSE

The purposes of this study were to estimate the incidence of chemotherapy-induced peripheral neuropathy (CIPN) and to identify its main determinants and impact in patient-reported outcomes.

METHODS

We performed a prospective cohort study including 296 patients with incident breast cancer submitted to chemotherapy, followed for 1 year. Patients with incident CIPN were reevaluated 6 months after this diagnosis. Relative risks (RR) with 95 % confidence intervals (95 % CI) were computed to quantify the relation between different clinical characteristics and the occurrence of CIPN, using Poisson regression. The variation of patient-reported outcomes between baseline and 1-year follow-up assessments was compared between patients with and without CIPN.

RESULTS

The cumulative incidence of CIPN in the first year after diagnosis was 28.7 % (95 % CI 23.8-34.1), and more than 80 % of the patients were still symptomatic after 6 months. Among the latter, there was a significant decrease in the median total neuropathy score, clinical version (7 versus 4) between the two periods. In multivariable analysis, the risk of CIPN was higher for treatment with docetaxel (cumulative doses ≤300 mg/m(2), RR = 6.96, 95 % CI 2.53-19.10; >300 mg/m(2), RR = 13.32; 95 % CI 4.11-43.14). Alcohol consumption and diabetes were not significantly associated with CIPN. There were no significant differences in the variation of patient-reported outcomes between the baseline and 1-year follow-up evaluations.

CONCLUSIONS

CIPN was frequent in this contemporary cohort of early-stage breast cancer patients and was strongly associated with docetaxel-based regimens. Symptoms persisted for at least 6 months in most patients, but severity was low and CIPN had no impact on patient-reported outcomes.

Neurological complications of breast cancer: study protocol of a prospective cohort study

INTRODUCTION

The improvement in breast cancer survival rates, along with the expected overdiagnosis and overtreatment associated with breast cancer screening, requires a comprehensive assessment of its burden. Neurological complications can have a devastating impact on these patients; neuropathic pain and chemotherapy-induced peripheral neuropathy are among the most frequently reported. This project aims to understand the burden of neurological complications of breast cancer treatment in Northern Portugal, and their role as mediator of the impact of the treatment in different dimensions of the patients' quality of life.

METHODS AND ANALYSIS

A prospective cohort study was designed to include 500 patients with breast cancer, to be followed for 3 years. The patients were recruited at the Portuguese Oncology Institute of Porto and evaluations were planned at different stages: pretreatment, after surgery, after chemotherapy (whenever applicable) and at 1 and 3 years after enrolment. Patients diagnosed with neuropathic pain or chemotherapy-induced peripheral neuropathy (subcohorts), were also evaluated at the moment of confirmation of clinical diagnosis of the neurological complication and 6 months later. In each of the follow-up periods, a neurological examination has been performed by a neurologist. Data were collected on sociodemographic and clinical characteristics, quality of life, sleep quality, and anxiety and depression. Between January and December 2012, we recruited and conducted the baseline evaluation of 506 participants. The end of the follow-up period is scheduled for December 2015.

ETHICS AND DISSEMINATION

The study protocol was approved by the Ethics Committee of the Portuguese Oncology Institute of Porto and all patients provided written informed consent. All study procedures were developed in order to assure data protection and confidentiality. Results from this project will be disseminated in international peer-reviewed journals and presented in relevant conferences.

High resolution melting analysis of KRAS, BRAF and PIK3CA in KRAS exon 2 wild-type metastatic colorectal cancer

BACKGROUND

KRAS is an EGFR effector in the RAS/RAF/ERK cascade that is mutated in about 40% of metastatic colorectal cancer (mCRC). Activating mutations in codons 12 and 13 of the KRAS gene are the only established negative predictors of response to anti-EGFR therapy and patients whose tumors harbor such mutations are not candidates for therapy. However, 40 to 60% of wild-type cases do not respond to anti-EGFR therapy, suggesting the involvement of other genes that act downstream of EGFR in the RAS-RAF-MAPK and PI3K-AKT pathways or activating KRAS mutations at other locations of the gene.

METHODS

DNA was obtained from a consecutive series of 201 mCRC cases (FFPE tissue), wild-type for KRAS exon 2 (codons 12 and 13). Mutational analysis of KRAS (exons 3 and 4), BRAF (exons 11 and 15), and PIK3CA (exons 9 and 20) was performed by high resolution melting (HRM) and positive cases were then sequenced.

RESULTS

One mutation was present in 23.4% (47/201) of the cases and 3.0% additional cases (6/201) had two concomitant mutations. A total of 53 cases showed 59 mutations, with the following distribution: 44.1% (26/59) in KRAS (13 in exon 3 and 13 in exon 4), 18.6% (11/59) in BRAF (two in exon 11 and nine in exon 15) and 37.3% (22/59) in PIK3CA (16 in exon 9 and six in exon 20). In total, 26.4% (53/201) of the cases had at least one mutation and the remaining 73.6% (148/201) were wild-type for all regions studied. Five of the mutations we report, four in KRAS and one in BRAF, have not previously been described in CRC. BRAF and PIK3CA mutations were more frequent in the colon than in the sigmoid or rectum: 20.8% vs. 1.6% vs. 0.0% (P=0.000) for BRAF and 23.4% vs. 12.1% vs. 5.4% (P=0.011) for PIK3CA mutations.

CONCLUSIONS

About one fourth of mCRC cases wild-type for KRAS codons 12 and 13 present other mutations either in KRAS, BRAF, or PIK3CA, many of which may explain the lack of response to anti-EGFR therapy observed in a significant proportion of these patients.

The MSH2 c.388_389del mutation shows a founder effect in Portuguese Lynch syndrome families

The MSH2 c.388_389del mutation has occasionally been described in Lynch families worldwide. At the Portuguese Oncology Institute in Porto, Portugal, we have identified 16 seemingly unrelated families with this germline mutation. To evaluate if this alteration is a founder or a recurrent mutation we performed haplotype analysis in the 16 Portuguese index cases and 55 relatives, as well as in four index cases and 13 relatives reported from Germany, Scotland, England, and Argentina. In the Portuguese families we observed a shared haplotype of approximately 10 Mb and all were originated from the north of Portugal. These results suggest that this alteration is a founder mutation in Portugal with a relatively recent origin. In the reported families outside Portugal with this mutation different haplotype backgrounds were observed, supporting the hypothesis that it occurred de novo on multiple occasions. We also conclude that the high proportion of families with the MSH2 c.388_389del mutation indicates that screening for this alteration as a first step may be cost-effective in the genetic testing of Lynch syndrome suspects of Portuguese ancestry, especially those originating from the north of Portugal.

Metoclopramide as an analgesic in severe migraine attacks: an open, single-blind, parallel control study

Metoclopramide is a well-known anti-emetic drug with central and peripheral pharmacological effects. Some authors have reported metoclopramide as an adjunct therapy to other analgesics in patients with migraine attacks. Treatment of migraine headache using a mix of metoclopramide and an NSAID has been patented (European Patent EP1014961) as well as a short series showing great efficacy and tolerability of metoclopramide in patients wtih migraine attacks. We decided to conduct an open, single-blind, parallel control study in the emergency department to evaluate the efficacy and tolerability of metoclopramide in patients with severe migraine attacks. 93 consecutive patients with severe migraine attacks were randomized into two groups (groups A and B). Patients in group A received 10mg of intravenous metoclopramide and patients in group B received 1 g of intravenous paracetamol. Patients were evaluated 5 minutes before (baseline), 15, 30, 60 and 120 minutes after drug delivery, and before being discharged from the emergency department They were then contacted by phone 48 hours after being discharged from the hospital (phone questionnaire). Patients treated with either metoclopramide or paracetamol showed a significant reduction in the intensity of pain at the 120 minute time point, with an 86% and 82% improvement respectively. However, patients treated with metoclopramide showed a more rapid improvement at the 15 and 30 minute evaluations. Patients with severe migraine attacks treated with metoclopramide as monotherapy showed a significant improvement in terms of pain relief and a faster improvement in pain intensity compared to those treated with paracetamol. Metoclopramide and other dopamine antagonistic drugs should be considered a therapeutic option in severe migraine headache attacks.

Cross-transfusion of postshock mesenteric lymph provokes acute lung injury

OBJECTIVE

Substantial investigation has implicated mesenteric lymph as the mechanistic link between gut ischemia/reperfusion (I/R) and distant organ injury. Specifically, lymph diversion prevents acute lung injury (ALI) in vitro, and bioactive lipids and proteins isolated from postshock mesenteric lymph (PSML) maintain bioactivity in vitro. However, Koch's postulates remain to be satisfied via direct cross-transfusion into a naïve animal. We therefore hypothesized that real time cross-transfusion of postshock mesenteric lymph provokes acute lung injury.

METHODS

One set of Sprague-Dawley rats (lymph donors) was anesthetized, with the mesenteric lymph ducts cannulated and exteriorized to drain freely into a siliconates plastic cup; concurrently, a second group of rats ( lymph recipients) was anesthetized, with a cannula inserted into the animal's right internal jugular vein. Blood was removed from the donor rats to induce hemorrhagic shock (MAP of 35 mmHg × 45 min). The recipient rats were positioned 10 cm below the plastic cup, which emptied into the jugular vein cannula. Thus, mesenteric lymph from the shocked donor rat was delivered to the recipient rat at the rate generated during shock and the subsequent 3 h of resuscitation.

RESULTS

Neutrophil (PMN) accumulation in the lungs was substantially elevated in the postshock lymph cross-transfusion group compared to both sham lymph cross-transfusion and instrumented control (MPO: 9.42 ± 1.55 versus 2.81 ± 0.82 U/mg lung tissue in postshock versus sham lymph cross-transfusion, n = 6 in each group, P = 0.02). Additionally, cross-transfusion of PSML induced oxidative stress in the lung (0.21 ± 0.03 versus 0.10 ± 0.01 micromoles MDA per mg lung tissue in lymph cross-transfusion versus instrumented control, n = 6 in each group, P = 0.046). Furthermore, transfusion of PSML provoked lung injury (BAL protein 0.77 ± 0.18 versus 0.15 ± 0.02 mg/mL protein in BALF, postshock versus sham lymph cross-transfusion, n = 6 in each group, P = 0.004).

CONCLUSION

Cross-transfusion of PSML into a naïve animal leads to PMN accumulation and provokes ALI. These data provide evidence that postshock agents released into mesenteric lymph are capable of provoking distant organ injury.

Association between EGF +61A/G polymorphism and gastric cancer in Caucasians

AIM: To investigate the association between epidermal growth factor (EGF) +61A/G polymorphism and susceptibility to gastric cancer, through a cross-sectional study.

METHODS: Polymerase chain reaction resctriction fragment lenght polymorphism analyses were used to genotype EGF +61 in 207 patients with gastric lesions (162 patients with gastric adenocarcinomas, 45 with atrophy or intestinal metaplasia) and 984 controls. All subjects were Caucasian.

RESULTS: Genotype distribution was 23.5% for GG and 76.5% for GA/AA in the control group, 18.4% for GG and 68.6% for GA/AA in the entire group with gastric lesions and 17.9% for GG and 82.1% for GA/AA in the group with gastric adenocarcinoma. No statistically significant associations were found between EGF +61 variants and risk for developing gastric cancer [odds ratios (OR) = 1.41, 95% confidence intervals (CI): 0.90-2.21, P = 0.116]. However, the stratification of individuals by gender revealed that males carrying A alleles (EGF +61A/G or AA) had an increased risk for developing gastric cancer as compared to GG homozygous males (OR = 1.55, 95% CI: 1.05-2.28, P = 0.021).

CONCLUSION: In summary, we found that males who were A carriers for EGF +61 had an increased risk for developing gastric cancer. This result may be explained by the suggestion that women secrete less gastric acid than men.

Colorectal carcinomas with microsatellite instability display a different pattern of target gene mutations according to large bowel site of origin

Background

Only a few studies have addressed the molecular pathways specifically involved in carcinogenesis of the distal colon and rectum. We aimed to identify potential differences among genetic alterations in distal colon and rectal carcinomas as compared to cancers arising elsewhere in the large bowel.

Methods

Constitutional and tumor DNA from a test series of 37 patients with rectal and 25 patients with sigmoid carcinomas, previously analyzed for microsatellite instability (MSI), was studied for BAX, IGF2R, TGFBR2, MSH3, and MSH6 microsatellite sequence alterations, BRAF and KRAS mutations, and MLH1 promoter methylation. The findings were then compared with those of an independent validation series consisting of 36 MSI-H carcinomas with origin from each of the large bowel regions. Immunohistochemical and germline mutation analyses of the mismatch repair system were performed when appropriate.

Results

In the test series, IGFR2 and BAX mutations were present in one and two out of the six distal MSI-H carcinomas, respectively, and no mutations were detected in TGFBR2, MSH3, and MSH6. We confirmed these findings in the validation series, with TGFBR2 and MSH3 microsatellite mutations occurring less frequently in MSI-H rectal and sigmoid carcinomas than in MSI-H colon carcinomas elsewhere (P = 0.00005 and P = 0.0000005, respectively, when considering all MSI-carcinomas of both series). No MLH1 promoter methylation was observed in the MSI-H rectal and sigmoid carcinomas of both series, as compared to 53% found in MSI-H carcinomas from other locations (P = 0.004). KRAS and BRAF mutational frequencies were 19% and 43% in proximal carcinomas and 25% and 17% in rectal/sigmoid carcinomas, respectively.

Conclusion

The mechanism and the pattern of genetic changes driving MSI-H carcinogenesis in distal colon and rectum appears to differ from that occurring elsewhere in the colon and further investigation is warranted both in patients with sporadic or hereditary disease.