Is total mesorectal excision always necessary for T1-T2 lower rectal cancer?
ABSTRACT The goal of this multicenter study was to clarify the determinants of local excision for patients with T1-T2 lower rectal cancer.
Data from 567 consecutive patients who underwent radical resection for T1-T2 lower rectal cancer at 12 institutions between 1991 and 1998 were reviewed. Rates of lymph node metastasis were investigated using a tree analysis, which was hierarchized using independent risk factors for nodal involvement.
The independent risk factors for lymph node metastasis were female gender, depth of tumor invasion, histology other than well-differentiated adenocarcinoma, and lymphatic invasion. According to the first three parameters that can be obtained preoperatively, only 0.99% of the patients without risk factors had lymph node metastasis. On the other hand, even if the lower rectal cancer was at stage T1, women with histological types other than well-differentiated adenocarcinoma had an approximately 30% probability of having lymph node metastasis. Lymphatic invasion was most useful to predict nodal involvement among patients with T2 lower rectal cancer. The rates of lymph node metastasis in T2 patients with and without lymphatic invasion were 32.9% and 9.1%, respectively.
Gender is one of the most important predictors for lymph node metastasis in patients with early distal rectal cancer. Three parameters, including depth of tumor invasion, histology, and gender, are useful determinants for local excision. Additional studies are required to establish the minimum optimal treatment for T2 lower rectal cancer.
Conference Paper: Triple step-down DC-DC converters[Show abstract] [Hide abstract]
ABSTRACT: Triple DC-DC power converters appear as a development of the double (quadratic) power converters. Compared to double DC-DC power converters, triple convertors make it possible to use much higher switching frequencies for the same minimum switch-conduction time. DC output/input, AC input-to-output and AC control-to-output small-signal transfer functions of the triple-buck (or double-buck+forward) power converter have been deduced and plotted against load current and frequency, in the operating mode with continuous currents in all inductors, for different values of the circuit components and parameters, taking into account circuit losses. Triple DC-DC power converters have large transfer function phase shifts, but, with properly staggered resonant frequencies of the three LC cells and using additional AC feedback loops, stable SMPSs may still be constructed from them, without drastically limiting error amplifier bandwidthPower Electronics Specialists Conference, 1996. PESC '96 Record., 27th Annual IEEE; 07/1996
Conference Paper: A 2.2 V 300 /spl mu/A RDS pager baseband decoder[Show abstract] [Hide abstract]
ABSTRACT: Compared with more advanced wireless telecommunication systems such as GSM, the pager offers the advantages of a lower cost, a smaller size and a longer battery autonomy. Furthermore, the RDS pager system allows reuse of the existing network of FM radio broadcasting stations, reducing the cost of introduction of the pager network and allowing immediately a large geographical coverage. The realization ofthe RDS baseband decoder described is a first step of an attempt to increase the pager battery autonomy from a few weeks to more than a half year.Solid-State Circuits Conference, 1997. Digest of Technical Papers. 43rd ISSCC., 1997 IEEE International; 01/1997
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ABSTRACT: The aim of this study was to identify risk factors of lymph node metastasis (LNM) for T2 rectal cancer. From a prospectively maintained single-institution database, we identified 346 consecutive pT2 rectal cancers treated with total mesorectal excision from 1998 to 2009. Univariate and multivariate analyses were performed to identify risk factors associated with overall and intermediate/apical LNM. The incidence of overall and intermediate/apical LNM was analyzed by tree analysis. Age, tumor location, pathological features, and depth of invasion were independent predictors for overall LNM. Tumor location, pathological features, and depth of invasion were independent predictors for intermediate/apical LNM. Tree analysis showed that the incidence of LNM was 7.7% for upper rectal cancer with favorable pathological features, and 3.4% for mid/lower rectal cancer without other identified risk factors. The incidence of intermediate/apical LNM was 5.7% for superficial T2 rectal cancer with favorable pathological features, and 3.1% for deep T2 rectal cancer locating in upper rectum with favorable pathological features. Depth of invasion is an independent predictor for LNM in T2 rectal cancer. Using tree analysis, we identified a subset of patients with low risk of LNM who may be candidates of local excision.Journal of Gastrointestinal Surgery 10/2010; 15(1):130-6. DOI:10.1007/s11605-010-1353-1 · 2.39 Impact Factor