Estudio de las lesiones neoplásicas metacrónicas en el carcinoma colorrectal

Fundamento. Analizar la frecuencia y las características de las lesiones neoplásicas metacrónicas, carcinomas y adenomas, tras la resección de un cáncer colo-rectal (CCR). Pacientes y métodos. Revisamos 382 CCR operados y seguidos mediante colonoscopias completas en dos hospitales de nuestra comunidad. Analizamos las lesiones metacrónicas registradas valorando su localización, momento del diagnóstico, histología, número y tamaño. Estudiamos la frecuencia de adenomas de aparición precoz (12 meses), comparando su tamaño con respecto al resto de lesiones. Resultados. La mediana de seguimiento fue de 48 meses (12-112), con 2,74±1,47 colonoscopias/caso. Diagnosticamos 7 cánceres metacrónicos (1,8%), 4 de ellos en estadio I. La mediana de tiempo hasta su diagnóstico fue de 24 meses (13-54). Registramos adenomas metacrónicos en 162 casos (42,4%), sin diferencias entre los dos hospitales: 42,1% vs. 43,8% (p=0,88). Un 6,3% de los pacientes presentaron adenomas avanzados. En 164 casos en que el primer control se efectuó a los 12 meses, la incidencia de adenomas fue del 24%. Los adenomas fueron mayoritariamente únicos (60,8%) y menores de 5 mm (68,5%). En un 55,5% de los casos con pólipos, alguno tenía una localización proximal. El diagnóstico se realizó en la 1ª exploración (56,2%), 2ª (27,8%) ó 3ª (9%). La mediana de tiempo hasta el diagnóstico fue de 21 meses (12-112) para el adenoma simple y de 35 (12-112) para el avanzado. Conclusiones. Nuestro seguimiento permitió aplicar un tratamiento teóricamente curativo en la mayoría de los carcinomas metacrónicos diagnosticados. La alta incidencia de adenomas y su frecuente localización proximal hacen necesario un seguimiento con colonoscopias completas, que debería iniciarse al año de la operación y podría pasar a ser menos estricto tras tres exploraciones consecutivas sin pólipos

Assisted hopping and interaction effects in impurity models

We study, using Numerical Renormalization Group methods, the generalization of the Anderson impurity model where the hopping depends on the filling of the impurity. We show that the model, for sufficiently large values of the assisted hopping term, shows a regime where local pairing correlations are enhanced. These correlations involve pairs fluctuating between on site and nearest neighbor positions

Estudio de la frecuencia, distribución y rendimiento diagnóstico en las lesiones neoplásicas sincrónicas del carcinoma colo-rectal

ABSTRACT To analyse the frequency, characteristics and diagnosis of synchronic neoplastic lesions in colorectal cancer. A review was carried out of 384 colorectal cancers, diagnosed through complete colonoscopy and resected. The synchronic cancers and the characteristics of the adenomas were determined: number, size, histological type, dysplasia, as well as their localisation in the colon and with respect to the carcinoma. Twenty-eight synchronic cancers were found (7.3% of the total); 8 developed tumours and 20 malignant polyps. In 54.4% of the cases there was a synchronic adenoma. In patients with synchronic lesions, 43% showed an advanced adenoma. Twenty percent of the synchronic polyps found were proximal to the splenic flexure; 41% were distal and 38% had both localisations. Fifty-nine point one percent of the patients had some adenoma proximal to the cancer, with criteria of advanced adenoma in 13.9%. The distribution of the adenomas was more uniformly spread in the cancers with a proximal localisation (p = 0.038). Seventeen percent of the distal cancers presented synchronic lesions with a proximal colon localisation exclusively. Partial endoscopies would diagnose the distal cancers, but would omit a synchronic adenoma in 42.3% of the sigmoidoscopies and 40% of the short colonoscopies. High rates of carcinoma and synchronic adenomas were registered. We underline the high index of advanced adenomas and the frequency of synchronic lesions proximal to the cancer, which is why incomplete colonoscopies, although allowing the diagnosis of the distal cancer, omit a high percentage of synchronic adenomas, including advanced lesions. All of this confirms the need to perform a complete pre- , intra- and post operational colonoscopy in resectable colorectal cancer

Synchronous neoplastic lesions in colorectal cancer. An analysis of possible risk factors favouring presentation

Aim: few data have been published regarding the causes of synchronous lesions in patients with colorectal cancer. The aim of our study was to identify potential factors that might be implicated in the development of multicentric lesions, since this knowledge could be useful for tailored follow-up once initial synchronous lesions have been removed. Methods: we retrospectively reviewed 382 colorectal cancer cases diagnosed by total colonoscopy and histological study of surgical specimens. We divided our population into 2 groups, based on whether they had synchronous lesions or otherwise. Several data related to personal and family history, habits, symptoms, and tumor characteristics were assessed. Univariate and multivariate statistical analyses were performed. Results: 208 (54.5%) patients had synchronous adenomas and 28 (7.3%) had synchronous cancer. A multivariate analysis showed that the following parameters were consistently related to the presence of multicentric lesions –male gender: OR = 1.97; CI = 1.13-3.45; p = 0.017; age ≥ 59 years: OR = 2.57; CI = 1.54-4.29; p < 0.001; personal history of colonic adenomas: OR = 3.04; CI = 1.04-8.85; p = 0.042; and obstructive tumors: OR = 0.48; CI = 0.27-0.85; p = 0.012. Conclusion: our results show that several parameters that are easy to measure could be considered risk factors for the development of multicentric lesions. These factors need to be confirmed with follow-up studies analyzing their role in patients with and without metachronic lesions once all synchronous lesions have been removed

Análisis de la posible influencia de las lesiones sincrónicas en el pronóstico del cáncer colorrectal resecado

Aim: To analyze the relationship between synchronous lesions in patients with colorectal cancer and their prognostic value. Patients and methods: We have retrospectively reviewed 369 patients with resected colorectal cancer. We compared the rate of apparently curative surgery, progression and tumoral relapse, development of extracolonic cancer and mortality between patients with and without synchronous cancer. Afterwards, we analyzed the same parameters in colorectal cancer with and without synchronous adenomas. Finally, we repeated the analysis after stratification of cancers in 2 groups according to pTNM staging: 0-I-II stage vs III-IV. Results: We found synchronous adenomas in 54.7% of our patients and synchronous cancers in 7.6%. Follow-up period of groups with and without synchronous lesions were: 70.8 ± 22.9 and 67.2 ± 24.5 months (p = 0.55) respectivelly. Synchronous cancers showed higher mortality: 35.7 vs. 14.4%: p = 0.006; OR = 3.31 (1.33-8.13), higher tumoral progression : 39.3 vs. 19.1%: p = 0.011; OR = 2.75 (1.14-6.56) and higher relapse rate: 10.7 vs. 3.5%: p = 0.096. Stratifying according to stage, patients with stage 0-I-II and synchronous cancer showed worse prognosis: mortality = 27.7 vs. 8.1%, p = 0.019; OR = 4.45 (1.2-15.1), tumoral progression = 27.8 vs. 8.5%, p = 0.02; OR = 4.12 (1.14-14.19), and extracolonic cancer = 16.7 vs. 6.4% p = 0.095. There were no statistical differences between cases with and without synchronous adenomas. Conclusions: Synchronous cancers showed worse prognosis after resection, with higher rate of tumoral progression and mortality. This difference is focused on the cases diagnosed in stage 0-I-II, not being found in III-IV. The presence of synchronous adenomas doesn’t influence prognosis

Phase diagram of the dissipative quantum particle in a box

We analyze the phase diagram of a quantum particle confined to a finite chain, subject to a dissipative environment described by an Ohmic spectral function. Analytical and numerical techniques are employed to explore both the perturbative and non-perturbative regime of the model. For small dissipation the coupling to the environment leads to a narrowing of the density distribution, and to a displacement towards the center of the array of accessible sites. For large values of the dissipation, we find a phase transition to a doubly degenerate phase which reflects the formation of an inhomogeneous effective potential within the array.Comment: 9 pages, 7 figures. Typos correcte

Proposals for evaluating the regularity of a scientist'sresearch output

Evaluating the career of individual scientists according to their scientific output is a common bibliometric problem. Two aspects are classically taken into account: overall productivity and overall diffusion/impact, which can be measured by a plethora of indicators that consider publications and/or citations separately or synthesise these two quantities into a single number (e.g. h-index). A secondary aspect, which is sometimes mentioned in the rules of competitive examinations for research position/promotion, is time regularity of one researcher's scientific output. Despite the fact that it is sometimes invoked, a clear definition of regularity is still lacking. We define it as the ability of generating an active and stable research output over time, in terms of both publications/ quantity and citations/diffusion. The goal of this paper is introducing three analysis tools to perform qualitative/quantitative evaluations on the regularity of one scientist's output in a simple and organic way. These tools are respectively (1) the PY/CY diagram, (2) the publication/citation Ferrers diagram and (3) a simplified procedure for comparing the research output of several scientists according to their publication and citation temporal distributions (Borda's ranking). Description of these tools is supported by several examples