Cut-off Point Of Tumor Size Research Articles

Investigating the impact of tumor location and size on the risk of recurrence for papillary thyroid carcinoma in the isthmus.

The purpose of the study was to investigate the ability of new parameters in distinguishing high-risk patients of recurrence from isthmic papillary thyroid carcinomas (iPTCs). One hundred sixteen iPTC patients who underwent total thyroidectomy were identified from 3461 PTC patients from 2014 to 2019. Tumor margin to trachea midline distance (TTD), maximum tumor size (TS), and transverse diameter of trachea (TD) were measured on CT images. Cox proportional hazard models served to identify risk factors associated with recurrence-free survival (RFS). The iPTC prognostic formula (IPF = TD/(TTD - TS) - TD/TTD) was evaluated to assess the prognosis. RFS was conducted between the different groups using the Kaplan-Meier analysis. The receiver operating characteristic (ROC) curve of each parameter was drawn to predict recurrence. Central lymph node metastasis (CLNM) and extrathyroidal invasion in iPTC were 58.6% and 31.0%, respectively. Regional recurrence occurred in 16 (13.8%) patients, and no patient died or had distant metastasis. The 3- and 5-year RFS of iPTC were 87.5% and 84.5%, respectively. Gender (p = 0.001) and PLNM (prelaryngeal lymph node metastasis) (p = 0.010) in cPTC (center of iPTC located between two imaginary lines perpendicular to the surface of the skin from the most lateral points of the trachea) and non-cPTC (iPTC patients enrolled in this study excluding cPTC) groups differed significantly. A cut-off point of tumor size >1.1 cm and IPF ≤5.57 were established to have significant differences in prognosis (p = 0.032 and p = 0.005, respectively). Multivariate analysis showed that IPF ≤5.57 was independent prognostic factor for RFS (HR: 4.415, 95%CI: 1.118-17.431, p = 0.034). This study indicated the association between IPF and RFS in iPTC patients and established new models to assess risk factors for recurrence pre-operation. IPF ≤5.57 was significantly associated with poor RFS and might be promising parameters for predicting prognosis and surgical decision-making pre-operation.

Tumor size improves the accuracy of the prognostic prediction of T4a stage colon cancer

The aim of this study was to evaluate the potential impact of tumor size on the long-term outcome of colon cancer (CC) patients after curative surgery. A total of 782 curatively resected T4a stage CC patients without distant metastasis were enrolled. Patients were categorized into 2 groups according to the best threshold of tumor size: larger group (LG) and smaller group (SG). Propensity score matching was used to adjust for the differences in baseline characteristics. The ideal cutoff point of tumor size was 5 cm. In the multivariate analysis for the whole study series, tumor size was an independent prognostic factor. Patients in the LG had significant lower 5-year overall survival (OS) and relapse-free survival (RFS) rates (OS: 63.5% versus 75.2%, P < 0.001; RFS: 59.5% versus 72.4%, P < 0.001) than those in the SG. After matching, patients in the LG still demonstrated significant lower 5-year OS and RFS rates than those in the SG. The modified tumor-size-node-metastasis (mTSNM) staging system including tumor size was found to be more appropriate for predicting the OS and RFS of T4a stage CC than TNM stage, and the -2log likelihood of the mTSNM staging system was smaller than the value of TNM stage. In conclusion, tumor size was an independent prognostic factor for OS and RFS. We maintain that tumor size should be incorporated into the staging system to enhance the accuracy of the prognostic prediction of T4a stage CC patients.

Construction, validation and, visualization of a web-based nomogram for predicting the overall survival and cancer-specific survival of leiomyosarcoma patients with lung metastasis.

BackgroundThis study sought to assess the prognostic factors for leiomyosarcoma (LMS) patients with lung metastasis and construct web-based nomograms to predict overall survival (OS) and cancer-specific survival (CSS).MethodPatients diagnosed with LMS combined with lung metastasis between 2010 and 2016 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. The patients were randomly divided into a training set and a testing set. The X-tile analysis provides the best age and tumor size cut-off point, and changes continuous variables into categorical variables. The independent prognostic factors were determined by Cox regression analysis, and 2 nomograms were established. Receiver operating characteristic curves and calibration curves were used to evaluate the nomograms. Based on the nomograms, 2 web-based nomograms were established.ResultsTwo hundred and twenty-eight cases were included in the OS nomogram construction, and were randomly divided into a training set (n=160) and a validation set (n=68). Age, T stage, bone metastasis, surgery, chemotherapy, marital status, tumor size, and tumor site were found to be correlated with OS. One hundred and eighty-three cases were enrolled in the CSS nomogram construction, and randomly divided into a training set (n=129) and a validation set (n=54). Age, bone metastasis, surgery, chemotherapy, tumor size, and tumor site were found to be correlated with CSS. Two nomograms were established to predict OS and CSS. In the training set, the areas under the curve of the nomogram for predicting 1-, 2-, and 3-year OS were 0.783, 0.830, and 0.832, respectively, and those for predicting 1-, 2-, and 3-year CSS were 0.889, 0.777, and 0.884, respectively. Two web-based nomograms were established to predict OS (https://wenn23.shinyapps.io/lmslmosapp/), and CSS (https://wenn23.shinyapps.io/lmslmcssapp/).ConclusionThe developed web-based nomogram is a useful tool for accurately analyzing the prognosis of LMS patients with lung metastasis, and could help clinical doctors to make personalized clinical decisions.

Evaluation of head and neck soft tissue sarcoma 8th edition pathologic staging system and proposal of a novel stage grouping system.

The AJCC 8th edition issued a dedicated staging system for head and neck soft tissue sarcomas (HN-STS) with 2 and 4cm tumor cut-off points, as well as a T4 classification based on invasion of adjacent structures. Stage groupings were not provided due to a paucity of data. We identified HN-STS patients undergoing primary surgery without neoadjuvant therapy patients in the Surveillance, Epidemiology, and End Results (SEER) database. We used multivariable analysis to examine adverse prognosticators. Then, using, recursive partitioning analysis (RPA), we established a stage grouping system that was externally validated in the National Cancer Database (NCDB). Multivariable analysis in the SEER cohort (N=546) demonstrated worsened survival with tumors invading adjacent structures (P<0.001) and increasing de-differentiation (P<0.001). There was no prognostic difference based on size for T1-3 tumors; however, when assessed as a continuous variable, a 5cm tumor size cut-off point was predictive of outcome. RPA generated a stage grouping system with the following five-year overall survival: RPA Stage I (pT1-3N0-1G1-2M0) 71.2%, RPA Stage II (pT4abN0-1G1-2M0/pT1-3N0-1G3-4M0) 53.4%, and RPA Stage III (pT4abN0-1G3-4M0) 17.5%. This was successfully externally validated in the NCDB cohort (P<0.001). We confirm the importance of structural invasion and grade and demonstrate that the currently used size cut-off points are not prognostic. We propose a novel stage grouping system. A 5cm tumor size cut-off point for tumor stage should be further evaluated.

Laparoscopic Splenic Vessels and Spleen Preservation Distal Pancreatectomy Via Inferior-Posterior Splenic Vein Approach.

Preservation of splenic vessels can minimize the risks of splenic infarction and gastric varices in laparoscopic spleen preserving distal pancreatectomy. A well-established procedure would provide high splenic vessels and spleen preservation rate. This study evaluated the outcomes and depending factors of laparoscopic splenic vessels and spleen preservation distal pancreatectomy (LsvspDP) via inferior-posterior splenic vein approach. This retrospective study enrolled patients who underwent LsvspDP via inferior-posterior splenic vein approach in National Cheng-Kung University Hospital from February 2009 to June 2019. The clinic-pathologic data were collected and analyzed. The primary outcome of this study was the learning curve based on the cumulative sum analysis. The secondary outcomes were to evaluate the critical factors for the failure of splenic vessels and spleen preservation. During the study period, a total of 64 patients received LsvspDP attempt. Splenic vessels were successfully preserved in 49 patients and the overall spleen preservation rate was 76.6%. According to cumulative sum analysis, the learning curve of LsvspDP was the 33rd case and several plateaus were observed during the learning curve phase. Old age (P=0.001), tail location (P=0.038), and large tumor (P=0.01) were independent risk factors of failed splenic vessels preservation, whereas the cut-off point of tumor size for prediction of spleen preservation was 5.4 cm. The complication rates were 7.8%, 7.8%, and 12.5% for Clavien grade I, II, and III, respectively, and 0% for Clavien grade IV or V. The rate of postoperative pancreatic fistula-grade B was 14.8%, among which the tail location was lower than the nontail location (0% vs. 24.3%; P=0.008). The mean value of operative time, blood loss, and hospital stay were 198±67 minutes, 139±242 mL, and 8.5±5.6 days, respectively. In LsvspDP, the inferior-posterior splenic vein approach resulted in high splenic vessels and spleen preservation rate. Thirty-three patients were required to overcome the learning curve. Old age, tail location, and large tumor size were independent factors for the failure of splenic vessels preservation, whereas the cut-off value for tumor size was 5.4 cm to predict splenic vessels preservation.

Prognostic Value of Tumor Length for Cause-Specific Death in Resectable Esophageal Cancer

The current esophageal cancer American Joint Committee on Cancer TNM staging system may not capture the full prognostic implications of the primary tumor. A study is needed to explore the prognostic value of tumor size on esophageal cancer-specific death. Patients who underwent surgical resection for non-metastatic esophageal cancer were selected from the Surveillance, Epidemiology and End Results Program database (United States, 1988 to 2014). With the use of statistics methods, maximally selected rank and two hazard models (Cox model and Fine-Gray model), the optimum cutoff point for tumor length in each T classification was estimated and the prognostic value of tumor size on esophageal cancer-specific death was analyzed. A total of 4,447 patients were identified. The median tumor size was significantly correlated with Tclassification, with the correlation coefficient of 0.43 (p<0.001). Patients in the T1 to T3 classifications who hadlarger tumor size showed a larger probability of cancer-specific death. The multivariate Cox model showed that tumor size was significantly associated with an increase in cancer-specific death in T1 (2.15, 95% confidence interval [CI]: 1.72 to 2.69) and T2 (1.31, 95% CI: 1.06 to 1.62) but was marginally significantly associated in T3 (1.12, 95% CI: 1.00 to 1.27) and insignificantly associated in T4 classification (p > 0.1). Similar results were found by using the multivariate Fine-Gray model. We have found that combining T classification with tumor size can increase the precision in identifying the high-risk groups in T1 to T2 classifications. On the basis of esophageal cancer-specific death our study explores the prognostic cutoff point of tumor size by T classification.

Impact of tumor size on survival outcome of pancreatic carcinoma following pancreatic resection: A systematic review and meta-analysis

The aim of the study was to evaluate the influence of tumor size on long-term survival outcome of pancreatic tumors following pancreatic resection and the possibility of implementing another tumor size cut-off point in AJCC pancreatic tumor staging. Literature searches was conducted on electronic database to identify relevant studies on tumor size related survival outcome following pancreatic resection for pancreatic adenocarcinoma. Meta-analysis was done using the effect estimates and the use of 95% confidence intervals (CIs) was done to calculate the pooled risk estimates; heterogeneity among studies was examined using I2 statistic. Total of 18 trials (13 retrospective and 5 prospective studies) including 6230 elderly patients was included in this study. The pooled HR of the tumor size with 2 cm cut-off was 1.43 with 95% CI of [1.27-1.62], I2= 17%, p&lt;0.00001 and was statistically significant. Median survival for tumor size &lt;2, &gt;2, &lt;3, &gt;3, &lt;4 and &gt;4 were 41.02 months, 16.20 months, 19.41 months, 10.79 months, 24.2 months and 15.14 months respectively and the 1-, 3-, and 5-year survival rate decreased with increasing tumor diameter. Importantly, a total of four studies results indicated that 3-year survival rate and a total of five studies results indicated that 5-year survival rate had statistical significance with 3 cm cut-off. Tumor diameter of 2 cm seems to be a reasonable but relatively less comprehensive cut-off point. 3 cm cut-off maybe become a new potential tumor size cut-off point in addition to the current sole 2 cm cut-off point defining tumor stage.Asian Journal of Medical Sciences Vol.9(1) 2018 1-10

CT Features of Colorectal Schwannomas: Differentiation from Gastrointestinal Stromal Tumors.

PurposeTo find differential CT features of colorectal schwannomas from gastrointestinal stromal tumors (GISTs).Materials and MethodsCT features of 13 pathologically proven colorectal schwannomas and 21 GISTs were retrospectively reviewed. The following CT items were analyzed: size, longitudinal and transverse location, shape, margin, homogeneity, necrosis, surface ulceration, calcification, degree of attenuation, the presence of enlarged lymph node (LN), and metastasis. Among the features, significant variables were evaluated using univariate statistical tests. The optimal cut-off point of tumor size was obtained by ROC analysis. Binary logistic regression analysis was used to find the most independent CT variables.ResultsSmall size, non-rectum location, smooth margin, homogeneous high attenuation without necrosis, and the presence of enlarged LNs were found to be significant variables to differentiate schwannomas from GISTs (P<0.05). The optimized cut-off point for tumor size in distinguishing GISTs from schwannomas was 3.9 cm (AUC = 0.808, sensitivity = 66.7%, specificity = 92.3%, P<0.0001). Binary regression analysis revealed that only non-rectum location remained independent predictor for schwannomas differentiated from GISTs (odds ratio = 31.667, P = 0.001).ConclusionColorectal schwannomas usually located in non-rectum and appear as small subepithelial nodules showing homogeneous high attenuation and smooth margin. Schwannomas exclusively accompany with enlarged LNs.

Predictive Factors for Non-Sentinel Lymph Node Metastasis in the Case of Positive Sentinel Lymph Node Metastasis in Two or Fewer Nodes in Breast Cancer.

BackgroundIn breast cancer, recent clinical trials have shown that sentinel lymph node biopsy (SLNB) alone without axillary lymph node dissection results in excellent prognosis if there is sentinel lymph node (SLN) metastasis in two or fewer nodes. The aim of the present study was to investigate the association between non-SLN metastasis and clinicopathological factors in case of SLN metastasis in two or fewer nodes in breast cancer.MethodsPatients who underwent SLNB for invasive breast cancer and were found to have positive SLN in two or fewer nodes were evaluated. The associations between non-SLN metastasis and clinicopahological factors were examined. Statistical analyses were performed using the Mann-Whitney and Chi-square tests, with statistical significance set at P < 0.05.ResultsA total of 358 patients were enrolled during the study period and all of these patients were female and 54 patients had SLN metastasis (15%). Positive SLN in two or fewer nodes was identified in 44 patients (81.5%). Among these patients, 17 (38.6%) were found to have non-SLN metastasis. Non-SLN metastasis was associated with invasive tumor size (P = 0.015) and lymphatic involvement (P = 0.035). Multivariate analysis showed that tumor size (P = 0.011) and lymphatic involvement (P = 0.019) remained significant independent predictors of non-SLN metastasis, and that an invasive tumor size cut-off point of 28 mm was useful for dividing patients with positive SLN in two or fewer nodes into non-SLN-positive and non-SLN-negative groups.ConclusionsNon-SLN metastasis was found in more than 30% of patients with SLN metastasis present in two or fewer nodes. Large tumor size and the presence of lymphatic involvement were significantly associated with non-SLN metastasis.

The Impact of Tumor Size on Early Distal Gastric Cancer of the Lymph Node Metastasis

This article discusses the results of study of the impact of tumor size on the lymph node metastasis of early distal gastric cancer (EDGC). The understanding of such impact will provide the basis for the selection of optimal lymph node dissection and scope. Between April 1995 and August 2006, 146 patients of EDGC underwent primary surgery and were included in the study. We selected the optimal cut-off point of tumor size via ROC curve. We then investigated the relationship between the tumor size and the lymph node metastasis for each group. The optimal cut-off point of the tumor size was 23 mm. Metastasis only occurred in No.1, 3-7 lymph nodes for patients in small-diameter group (SDG) or those in large-diameter group (LDG) with intramucosal carcinoma. For patients in the LDG with submucosal carcinoma, metastasis occurred in No.1, 3-7, 8a, 9 and 12a lymph nodes. For EDGC patients, when tumor was <23 mm or intramucosal cancer was ≥23 mm, metastasis tended to occur only in No.1, 3-7 lymph nodes. But if submucosal cancer was ≥23 mm, metastasis occurred in all of No. 1, 3-7 and No. 8a, 9 and 12a lymph nodes.

Analysis of lymph node metastasis in pancreatic neuroendocrine tumors (PNETs) based on the tumor size and hormonal production

Because of the rarity and variety of pancreatic neuroendocrine tumors (PNETs), there have been few reports regarding the indication for lymph node dissection in patients with these tumors. This study aimed to evaluate the risk of lymph node metastasis of PNETs based on the tumor size and hormonal production. Data for a total of 66 patients who had PNETs resected at our department between 1987 and 2010 were retrospectively studied. The clinicopathological features, including the disease-specific survival rate, were assessed based on the status of lymph node metastasis at the time of initial surgical resection. Then the cut-off point of tumor size to predict lymph node metastasis was estimated. There were 12 patients (18%) with lymph node metastasis. The frequency of lymph node metastasis tended to be higher in gastrinomas than that in other tumors (43 vs. 15%; P = 0.08). The size of PNETs with lymph node metastasis was significantly larger than that of the PNETs without metastasis (P = 0.04). The postoperative survival rate in the PNET patients with lymph node metastasis was significantly lower than that in the patients without metastasis (P < 0.0001). Only 2 (8%) of 26 PNETs with a tumor size of <15 mm had lymph node metastasis, and both of these were gastrinomas. On the other hand, 10 (25%) of the remaining 40 PNETs with a tumor size of ≥15 mm had lymph node metastasis. Notably, there were no PNETs with lymph node metastasis in 22 non-gastrinomas with a tumor size of <15 mm. Non-gastrinomas with a tumor size of ≥15 mm and all gastrinomas would be an indication for pancreatectomy with lymph node dissection.

Is tumor size a reliable predictor of histopathological characteristics of renal cell carcinoma?

Objectives:To determine whether smaller tumor size is associated with less-aggressiveness in renal cell carcinoma (RCC).Materials and Methods:Series records of 505 patients diagnosed with RCC were retrospectively reviewed and the data concerning tumor size and pathological information were extracted and analyzed.Results:Five hundred and eight RCCs were identified. The mean tumor size was 5.02 ± 2.70 cm. No correlation was detected between the size of tumor and the histological subtype. The overall nuclear grade distribution was 57.1% and 42.9% for low-grade and high-grade disease, respectively. Each 1 cm increase in tumor size was associated with a significant increase in the odds ratio of high-grade disease by 1.46. 91.1% were found low-stage lesions and the odds ratio for the association of high-stage disease with each 1 cm increase in tumor size was 1.67. Multinomial models revealed that each 1 cm increase in the tumor size was associated with a 35% increase in renal capsule involvement and 66% renal vascular invasion. The cut-off point of tumor size in renal vascular invasion was 5.6 cm.Conclusion:Tumor size is not an independent predictor for the histological subtype of RCC. However, it is closely correlated to histopathological features, with the indications that the greater the tumor size, the more aggressive potential the RCC is.

Prognostic Stratification of Localized Renal Cell Carcinoma by Tumor Size

Recent retrospective studies have challenged the current TNM classification of 7.0 cm to distinguish between T1 and T2 tumors. We reevaluated the optimal tumor size cutoff point that independently differentiates patient prognosis beyond the other accepted prognostic features. From 1990 to October 2006, 398 patients who underwent radical nephrectomy for localized renal cell carcinoma (T1-T2, N0, M0) were followed prospectively. Median followup was 5.3 years and 37 patients died of tumor related causes. The optimal tumor cutoff point was calculated and multivariate Cox proportional hazards models were used to adjust for the effects of Fuhrman grade, tumor type, sex, age and Karnofsky performance status on cancer specific survival. Sensitivity analysis included all 66 patients with elective nephron sparing surgery. Univariate analysis supported 7 cm as the optimal cutoff point for prognostic stratification (p = 0.002). The 4 cm cutoff point that is used to distinguish between stage T1a and T1b could not be confirmed with analogous statistical significance (p = 0.20). On multivariate analysis tumor size dichotomized at 7 cm was an independent prognostic factor (HR 2.89, 95% CI 1.46-5.73, p = 0.002), as was Fuhrman grade 3 (HR 3.68, 95% CI 1.37-9.83, p = 0.010) and age older than 60 years (HR 3.64, 95% CI 1.63-8.14, p = 0.002). The inclusion of patients with elective nephron sparing surgery confirmed these results. Univariate and multivariate analyses of our patient cohort undergoing radical nephrectomy for localized renal cell carcinoma showed no cutoff point other than 7 cm to be more suitable for distinguishing between T1 and T2 tumors, supporting the current TNM classification. In T1 tumors the analysis did not allow a clear dichotomization of tumor size in this group.

Optimal Size Cutoff Point for Prognostic Stratification of Localized Renal Cell Carcinoma

Purpose: The purpose of this study was to evaluate the validity of the cutoff size for a localized renal cell carcinoma (RCC) by assessing the sur- vival of RCC patients according to a series of alternative size cutoff values. Materials and Methods: The outcomes of 147 patients with localized RCC, treated by radical nephrectomy at our institution, between 1984 and 2004, were retrospectively evaluated. The mean follow-up period was 54.9±32.5 months. The survival of patients with tumors smaller than a specified size cutoff was compared with that of tumors larger than the cutoff, and the most discriminating cutoff identified. Results: 114 and 33 patients were pT1 (77.6%) and pT2 (22.4%), respec- tively. There were 10 recurrences (8.8%) and 6 deaths (5.3%) in the pT1 group, and 8 recurrences (24.2%) and 8 deaths (24.2%) in the pT2 group. The differences in survival were maximized when the tumor size cutoff point was 7cm (cancer-specific survival rate: 92.0% vs. 71.5% p=0.0003, disease- free survival rate: 88.5% vs. 69.1% p=0.0092). The next significant diffe- rence was observed with a cutoff of 4cm (cancer-specific survival rate: 96.0% vs. 83.7% p=0.0467, disease-free survival rate: 96.0% vs. 78.8% p= 0.0121). Conclusions: Tumor size is an important prognostic factor in patients with an organ confined RCC. The established cutoff point of 7cm provided reasonable prognostic differences. A 4cm cutoff point is also feasible for separating groups with different survivals after a nephrectomy. Hence, the T1a/1b/T2 classification system is practical for the division of localized

Noninflammatory breast carcinoma with skin involvement.

According to the TNM Supplement, only breast carcinoma with macroscopic 'classic' skin changes (e.g., edema, peau d'orange, ulceration) should be placed in the T4 category; the classification of tumors with histologically proven skin involvement but no clinical skin changes or only discreet changes should be based on the size of the tumor (T1-3). To the authors' knowledge, no data supporting these recommendations have been reported to date. Seventy-six patients with noninflammatory breast carcinoma and histologically proven skin involvement were classified based on the degree of their skin involvement. Fifty patients (66%) presented with clinically obvious skin involvement (Group A), and 26 patients (34%) had breast carcinoma with histologically proven skin involvement but without clinical skin changes (Group B). Reclassification was undertaken to assess the malignant potential of tumors independent of the morphologic parameter 'skin involvement'. Patients in Group A presented significantly more frequently with extensive disease at regional or distant sites (Stages IIIC and IV; P=0.009). The clinical outcome of patients in Group B was significantly more favorable (P=0.0003). The adjusted 3-year survival rates in Group A and Group B were 46.7% and 92.3%, respectively, and the 5-year rates were 38.1% and 83.7%, respectively. Patients in Group B were found to have significantly better (P=0.036) distant recurrence-free survival (DRFS) rates. The DRFS rate at 3 years was 63.6% in Group A, compared with 91.7% in Group B, and the DRFS rate at 5 years was 56.9% in Group A, compared with 82.0% in Group B. Using a cutoff point of tumor size=3 cm, similar findings were made. Both study groups exhibited distinct clinical entities with significant differences in clinical course and prognosis. Cases with histologic skin involvement, relative to those with classic skin involvement, were found to have much less malignant potential. This corroborates the recommendation that cases with only histologic skin involvement should not be placed in the T4 category of the TNM classification.

REEVALUATION OF THE 1997 TNM CLASSIFICATION FOR RENAL CELL CARCINOMA: T1 AND T2 CUTOFF POINT AT 4.5 RATHER THAN 7 CM. BETTER CORRELATES WITH CLINICAL OUTCOME

We analyzed the effects of the change in TNM classification from the 1987 to the 1997 version and suggest a modified tumor size cutoff point between T stages 1 and 2 for renal cell carcinoma. We evaluated a database containing the records of 661 patients who underwent nephrectomy between 1989 and 1999. The effect of the change in TNM classification on the distribution of patients between stages, the rates of M+ and N+ disease, and the local and distant recurrence rates were outlined for 280 patients with T stages 1 and 2 disease. The Cox model was used to identify the optimal cutoff point between T1 and T2 disease, and the resulting effect of adopting this cutoff was outlined. A total of 174 and 128 cases were down staged from 1987 version stage T2 to 1997 version stage T1 and from 1987 TNM stage II to 1997 TNM stage I, respectively. Survival was not significantly different in patients with 1997 TNM stages I and II disease due to a lack of survival difference during the first 2 years of followup. Stage shift also caused an increase in average tumor size, the proportion of patients with high grade cancer, and M+ and N+ disease at diagnosis in 1997 stages T1 and T2 as well as an increase in the proportion of 1997 stage T2N0M0 cases at diagnosis with systemic failure. Analysis of 11 potential cutoff points between 1 and 10 cm. revealed that 4.5 cm. was most predictive of patients survival (hazards ratio 4.99, p = 0.0001). Using this cutoff resulted in improved discriminatory power of the TNM classification and a moderating effect on the distribution of patients, average tumor size, high grade disease, M+ and N+ disease at diagnosis, and systemic failure between T(14.5) and T(24.5) compared with 1997 T1 and T2. Our data imply that the current cutoff point of 7 cm. between stages T1 and T2 tumors is too high. Lowering the cutoff to 4.5 cm. resulted in better discriminatory power of the TNM classification in our dataset. This observation should be further validated by external data.

THE IMPACT OF A 4 CM. CUTOFF POINT FOR STRATIFICATION OF T1N0M0 RENAL CELL CARCINOMA AFTER RADICAL NEPHRECTOMY

The 1997 TNM classification defines T1 tumors as those smaller than 7 cm. Recently, a cutoff point of 4 cm. has been proposed to create a subclass of T1 tumors. We evaluated the validity of this cutoff point by assessing the pathological findings and prognoses of patients with T1N0M0 renal cell carcinoma following radical nephrectomy. We reviewed the hospital charts of 333 patients with T1N0M0 tumors, followed as long as 282 months (median 63) after radical nephrectomy. The validity of tumor size cutoff point for predicting survival outcome was tested in relation to other prognostic factors, including patient age, tumor position, nuclear grade, tumor histopathology and degree of microscopic venous invasion. During followup 32 patients (9.6%) had tumor recurrence and 21 (6.3%) died of renal cell carcinoma. A 5 cm. cutoff point maximized the differences in cancer specific survival rates and a 4 cm. cutoff point maximized the differences in disease-free survival rates. Tumor size was directly related to microscopic venous invasion and nuclear grade, which are significant prognostic factors, and a 4 cm. cutoff point enhanced these relationships. Tumor size is an important prognostic factor for patients with T1N0M0 renal cell carcinoma. A cutoff point of 4 cm. is practical for dividing the T1N0M0 classification into T1a and T1b subclasses.