Enrique Roca

A High Degree of LINE-1 Hypomethylation Is a Unique Feature of Early-Onset Colorectal Cancer

Objective Early-onset colorectal cancer (CRC) represents a clinically distinct form of CRC that is often associated with a poor prognosis. Methylation levels of genomic repeats such as LINE-1 elements have been recognized as independent factors for increased cancer-related mortality. The methylation status of LINE-1 elements in early-onset CRC has not been analyzed previously. Design We analyzed 343 CRC tissues and 32 normal colonic mucosa samples, including 2 independent cohorts of CRC diagnosed ≤50 years old (n = 188), a group of sporadic CRC >50 years (MSS n = 89; MSI n = 46), and a group of Lynch syndrome CRCs (n = 20). Tumor mismatch repair protein expression, microsatellite instability status, LINE-1 and MLH1 methylation, somatic BRAF V600E mutation, and germline MUTYH mutations were evaluated. Results Mean LINE-1 methylation levels (±SD) in the five study groups were early-onset CRC, 56.6% (8.6); sporadic MSI, 67.1% (5.5); sporadic MSS, 65.1% (6.3); Lynch syndrome, 66.3% (4.5) and normal mucosa, 76.5% (1.5). Early-onset CRC had significantly lower LINE-1 methylation than any other group (p<0.0001). Compared to patients with <65% LINE-1 methylation in tumors, those with ≥65% LINE-1 methylation had significantly better overall survival (p = 0.026, log rank test). Conclusions LINE-1 hypomethylation constitutes a potentially important feature of early-onset CRC, and suggests a distinct molecular subtype. Further studies are needed to assess the potential of LINE-1 methylation status as a prognostic biomarker for young people with CRC.

Radiochemotherapy with short daily infusion of low-dose oxaliplatin, leucovorin, and 5-FU in T3–T4 unresectable rectal cancer: a phase II IATTGI study

PURPOSE Oxaliplatin (OXA)/5-fluorouracil (5-FU) have confirmed their preclinical synergy in advanced colorectal cancer patients. Chemoradiotherapy with 5-FU + leucovorin (LV) is considered the standard treatment in unresectable rectal cancer patients. The objective was to evaluate OXA with 5-FU + LV and concurrent radiotherapy in unresectable rectal cancer patients. PATIENTS AND METHODS TREATMENT OXA 25 mg/m(2)/day in 30-min infusions, followed by bolus LV 20 mg/m(2)/day and bolus 5-FU 375 mg/m(2)/day. All drugs were given on 4 days during Weeks 1 and 5 of a standard radiotherapy cycle (50.4 Gy). A single OXA dose (50 mg/m(2)) was also given on the third week of radiotherapy. A cycle of OXA with 5-FU + LV was administered 4 weeks after chemoradiotherapy, with surgery planned 4 weeks later. RESULTS Between March 1998 and April 2000, 22 patients with T3-T4 unresectable rectal cancer were accrued. Patient characteristics included the following: 11 females, 11 males, median age 58 (range: 18-76). Performance status ECOG (PS) 0: 2 patients, PS 1: 7 patients, and PS 2: 13 patients. The following RTOG Grade 3-4 toxicities were reported: diarrhea, 6 patients; cutaneous, 3 patients; neutropenia-leukopenia, 2 patients; and thrombocytopenia, 1 patient; 1 treatment-related death resulted (febrile neutropenia-sepsis after chemoradiotherapy). Only 1 patient had neurosensory Grade 2 (OXA-specific Levis scale) toxicity. Nine patients had PS worsening during treatment. Five patients had chemoradiotherapy delay (median: 6 days). Of 22 patients, 16 underwent surgery (without serious surgical complications); 12/16 had a complete resection (5/12 had sphincter preservation). Pathologic examination revealed 3/12 complete remissions, 2/12 minimal microscopic residual disease, 2/12 T2N0, 1/12 T3N0, and 4/12 positive nodes; 4/16 had unresectable disease. Median follow-up was 15 months (range: 3.0-43.4 months), median time to progression was 15.7 months (CI 95%, 0, 31.7), and median overall survival was 19.5 months (CI 95%, 18.0, 21). CONCLUSIONS Outpatient treatment with low-dose, 30-min daily OXA infusion was feasible and very active, with acceptable toxicity.

Immunohistochemical expression of somatostatin receptors in digestive endocrine tumours

INTRODUCTION Somatostatin receptors are expressed in a large number of human tumours. The somatostatin receptors types 1-5 expression in a series including 100 gastro-entero-pancreatic endocrine tumours were analysed. METHODS From a prospectively built database of patients with gastro-entero-pancreatic endocrine tumours referred from three institutions, 100 cases with clinical and pathological data were selected. Somatostatin receptors expression by immunohistochemistry with somatostatin receptor types 1-5 antibodies in tissue paraffin sections were studied and correlated with the histological diagnosis according to the WHO classification, location and functional status. RESULTS Of the 100 cases, 67 were gastrointestinal tumours, 25 pancreatic and 8 liver metastasis of unknown origin. Thirty-one of them were functioning tumours: 2 insulinomas, 5 gastrinomas, 1 glucagonoma and 23 carcinoids. Somatostatin receptors expression was observed in 94 tumours. The six negative cases were all non-functioning tumours. Somatostatin receptors 2a and 5 were highly expressed (86 and 62%, respectively), and surprisingly found even in poorly differentiated endocrine carcinomas. Somatostatin receptors expression was less frequent in pancreatic than in gastrointestinal tumours. Well-differentiated neoplasms had a higher density of somatostatin receptors. Only SSTR2a showed membrane staining. CONCLUSIONS Immunohistochemistry revealed that somatostatin receptors were highly expressed in both primary and metastatic gastro-entero-pancreatic endocrine tumours with heterogeneous staining distribution. It proved to be a reliable technique even in small tumour samples.

Report of solid cancer in patients (pts) with gastrointestinal stromal tumours (GIST)

9065 Background: GIST are the most common non-epitelial tumour of the gastrointestinal tract with an increasing incidence after molecular discovery ( KIT gene) and clinical- pathological diagnostic tools (CD117). Data regarding association between GIST and other tumors have so far been limited to some reports of families with multiple GIST, Carneys triad (multiple gastric stromal tumors, pulmonary chondroma, paraganglioma) and GIST in neurofibromatosis pts. The objective is to evaluate the incidence of solid tumors (excluding in situ carcinomas and cutaneus neoplasm non melanoma) in pts with GIST. PATIENTS AND METHODS we assessed retrospectively a cohort of pts with histologic (and inmunohistochemistry) diagnosis of GIST from the prospective GATE-D data-base ( period 1999- 2003). Demographic data, characteristics of primary non- GIST tumor and GIST were evaluated. RESULTS from 86 GIST pts, 9 (10,4%) had prior solid cancer history. Any of the pts developed solid cancer after GIST diagnosis. Characteristics of 86 GIST pts: median age 58 (16-81), male/female 58/28, gastric location 60%, median size 10cm (2-39), advanced disease 36 pts and median follow-up 33 months. Prior to GIST, 9 pts had other cancer history: 2 breast cancer (T2N0M0, T2N1M0), 2 colon cancer (T3N1M0, T2N0M0), 2 cutaneus melanoma (Breslow 1,2 and 1,5 mm, both sentinel nodes negative), 1 prostate (score Gleason 6, PSA 8), 1 renal (T1N0M0) and thyroid (2cm medullar) carcinoma in a 42 years old female. Non GIST tumors occurred 9 (4-15) years (median) before GIST. The median age for the non GIST tumor was 52 (37-70). All tumors were resected and any pt relapsed. All of the non-GIST tumors were considered sporadic (no family history in anyone). Characteristics of the 9 GIST pts who had prior cancer: median age 64 (45-81), gastric location 7/9, median size 6 cm, locally advanced or metastatic 5/9, 4 of them with Imatinib ( all of them in partial response +8,+10,+10,+13 months). CONCLUSION in our serie 10,4% of GIST pts had prior cancer history (mainly sporadics). Future studies (clinical and molecular) are going to confirm if GIST are linked to other tumors. No significant financial relationships to disclose.

Non-surgical management of rectal cancer. Series of 68 cases, long follow up in two leading centres in Argentina

BACKGROUND The non-surgical management in a selected group of rectal cancer patients has shown promising results with adequate follow up. AIMS describing the results of the non-surgical management in patients with complete clinical response, with a close follow up. METHODS Between 2006 and 2015, patients with rectal cancer, stages I-III, without metastasis, treated with neoadjuvant CRT/CT, who had clinical complete response were included. CCR was defined through digital palpation, endoscopy-based criteria and MRI. Follow up was set according to institutional guidelines. RESULTS 68 patients were included. Initial stage was assessed with MRI in 55/68 pts and EUS 11/68. Considering the recurrence risk factors 57.6% (29/68) were T2-3ab N0, 3.3% (2/68) were T4N0, 29% (20/68) were T3-4 N1-2, with 39.7% with positive MRC. Mean distance to the anal margin was 3cm. Chemoradiation included radiotherapy at 50.4cGy, and concurrent capecitabine. In 22% a fluoropirimidine and oxaliplatin-based schema was used as induction therapy. Median follow up was 37.5 months and response assessment time 9 weeks (5-19). Eleven patients recurred, 6 endoluminally, 3 developed mesorectal recurrence, and two distant failure. Five years DFS and OS were 76.3% and 93.8%. CONCLUSIONS conservative management was feasible with close follow up in leading cancer centres. In this series, DFS and OS were comparable to the data already reported in the literature.

Pitfalls in the diagnosis of biallelic PMS2 mutations

Constitutional Mismatch Repair Deficiency (CMMR-D) syndrome is an inherited childhood cancer syndrome due to bi-allelic mutations in one of the four DNA mismatch repair genes involved in Lynch syndrome. The tumor spectrum of this syndrome includes hematological, brain and Lynch syndrome associated malignancies, with an increased risk of synchronous and metachronous cancers, and signs of Neurofibromatosis type-1 syndrome such as café-au-lait macules during the first three decades of life. Here, we report the first Argentinian patient with CMMR-D syndrome, focusing on her history of cancer and gastrointestinal manifestations, and the challenging molecular algorithm to finally reach her diagnosis.

Assessment of early response to imatinib 800 mg after 400 mg progression by 18F-fluorodeoxyglucose PET in patients with metastatic gastrointestinal stromal tumors

INTRODUCTION Imatinib is the standard first-line therapy for advanced gastrointestinal stromal tumor. (18)F-fluorodeoxyglucose PET computed tomography (FDG PET/CT) shows a faster response than computed tomography in nonpretreated patients. PATIENTS & METHODS After disease progression on imatinib 400 mg, 16 patients were exposed to 800 mg. Tumor response was evaluated by FDG PET/CT on days 7 and 37. Primary objective was to correlate early metabolic response (EMR) with progression-free survival (PFS). RESULTS EMR by FDG PET/CT scan was not predictive of PFS. Median PFS in these patients was 3 months. Overall survival was influenced by gastric primary site (p = 0.05). CONCLUSION The assessment of EMR by FDG PET/CT in patients with advanced gastrointestinal stromal tumor exposed to imatinib 800 mg was not predictive of PFS or overall survival.

Recomendaciones sobre el manejo del cáncer de páncreas tipo adenocarcinoma en Latinoamérica: Reunión del Consenso del Simposio Latinoamericano de Gastroenterología Oncológica (SLAGO) y de la Asociación Ibero Latinoamericana de Terapia Radiante (ALATRO), Viña del Mar, Chile 2015

Pancreatic cancer is a malignancy of great impact in developed countries and is having an increasing impact in Latin America. Incidence and mortality rates are similar for this cancer. This is an important reason to offer to the patients the best treatments available. During the Latin American Symposium of Gastroenterology Oncology (SLAGO) held in Vina del Mar, Chile, in April 2015, a multidisciplinary group of specialists in the field met to discuss about this disease. The main conclusions of this meeting, where practitioners from most of Latin American countries participated, are listed in this consensus that seek to serve as a guide for better decision making for patients with pancreatic cancer in Latin America.

Is proliferative index (Ki-67) useful to stratify patients (pts) with G2 gastroenteropancreatic neuroendocrine tumors (GEP-NETs)? Clinicopathologic correlation.

255 Background: Grade 2 (G2) Neuroendocrine tumors (NETs), of the digestive tract is a heterogeneous group of tumors. Several treatment options including chemotherapy and target therapy are available, but there is a lack of prospective trials assessing the role of pronostic factors in this population. Aim(s): to analyze prognostic factors and clinical characteristics in a population of patients with G2 GEP-NETs. To determine the role of ki 67 in the stratification of G2 population. Methods: Study population was obtained from our prospective database (Argentum Group). Survival was estimated using the Kaplan-Meier method and compared between Ki-67 quartiles using the log-rank test. Value of Ki-67 to discriminate mortality was assesed with a ROC curve analysis Results: 144 pts were evaluated. Mean age 54.9, 46.7% male. 102 (70.8%) with metastatic disease, mainly hepatic in 97 pts. (67.4%). 67.9 % underwent surgery. 34% received chemotherapy, and 10.9% target therapy. Median Ki-67 value was 6 (IQR 4-10), ROC ...

Assessment of early response to imatinib 800 mg after 400 mg progression by 18f-fluorodeoxyglucose positron emission tomography in patients with metastatic gastrointestinal stromal tumor.

10081 Background: Imatinib is the standard first-line therapy for advanced GIST patients. 18 F- fluorodeoxyglucose positron emission tomography (FDG-PET/CT) shows a faster response than CT in nonpr...