Probability Of Lymph Node Metastasis Research Articles

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Unfortunately, there are significant flaws in Mr. Promish's interpretation of our results and his Bayesian estimation procedure. First, the data contained in Table 5 of our article1 are observed (descriptive) not estimated (predicted) probabilities of lymph node metastases. To use Mr. Promish's monitory example, Table 5 shows that neither of the 2 women in our sample with ≤ 0.5-cm, nonpalpable tumors with lymphvascular invasion (LVI) had lymph node metastases at presentation. However, we should point out that whether the data contained in Table 5 are observed or estimated probabilities, the practicing clinician should never presume to be “absolutely certain” that a particular patient has any specific probability of lymph node metastases based on the results of published retrospective analyses. This is especially true for women with a relatively unusual or rare pattern of prognostic characteristics such as ≤ 0.5 cm, nonpalpable tumors with LVI. This simply is because one can never be absolutely certain that the prognostic characteristics or features of a particular patient are exactly equivalent to the characteristics or features of the sample on which the analyses were conducted. Furthermore, the practicing clinician also should keep in mind that any statistic has an associated confidence interval within which one reasonably can expect the corresponding population parameter to vary. The confidence interval on a proportion involving two patients is very wide. Mr. Promish also implies that his Bayesian estimation procedure may give a better representation of the risk of lymph node metastases than our logistic regression model. When evaluating the performance of any estimation procedure, the practicing clinician always should consider carefully the agreement between the actual, observed results and the results estimated or predicted by the estimation procedure. When disagreement is large, it is wise to question the validity of the procedure used to generate the estimates. One should be concerned about the validity of the Bayesian procedure used by Mr. Promish simply because it generated estimates that differ markedly from the actual probabilities reported in our Table 5. In contrast, our three variable logistic regression model-generated estimates that differ very little from the actual probabilities given in Table 5. Furthermore, unlike the Bayesian estimates, the monotone relation between tumor size and probability of lymph node metastases that has been observed by other authors2-5 clearly is evident in the estimates generated by our logistic regression procedure. We recently cross-validated our 3-variable model on a second, independent sample of 3108 women and found nearly identical probabilities of lymph node metastases for the risk groups shown in Table 5 in our article.1 Jeremy S. H. Jackson Ph.D.*, Ivo A. Olivotto M.D.*, Donna Mates M.A.*, * British Columbia Cancer Agency, Vancouver and Fraser Valley Clinics, Vancouver and Surrey, British Columbia, Canada

Author reply

Unfortunately, there are significant flaws in Mr. Promish's interpretation of our results and his Bayesian estimation procedure. First, the data contained in Table 5 of our article1 are observed (descriptive) not estimated (predicted) probabilities of lymph node metastases. To use Mr. Promish's monitory example, Table 5 shows that neither of the 2 women in our sample with ≤ 0.5-cm, nonpalpable tumors with lymphvascular invasion (LVI) had lymph node metastases at presentation. However, we should point out that whether the data contained in Table 5 are observed or estimated probabilities, the practicing clinician should never presume to be “absolutely certain” that a particular patient has any specific probability of lymph node metastases based on the results of published retrospective analyses. This is especially true for women with a relatively unusual or rare pattern of prognostic characteristics such as ≤ 0.5 cm, nonpalpable tumors with LVI. This simply is because one can never be absolutely certain that the prognostic characteristics or features of a particular patient are exactly equivalent to the characteristics or features of the sample on which the analyses were conducted. Furthermore, the practicing clinician also should keep in mind that any statistic has an associated confidence interval within which one reasonably can expect the corresponding population parameter to vary. The confidence interval on a proportion involving two patients is very wide. Mr. Promish also implies that his Bayesian estimation procedure may give a better representation of the risk of lymph node metastases than our logistic regression model. When evaluating the performance of any estimation procedure, the practicing clinician always should consider carefully the agreement between the actual, observed results and the results estimated or predicted by the estimation procedure. When disagreement is large, it is wise to question the validity of the procedure used to generate the estimates. One should be concerned about the validity of the Bayesian procedure used by Mr. Promish simply because it generated estimates that differ markedly from the actual probabilities reported in our Table 5. In contrast, our three variable logistic regression model-generated estimates that differ very little from the actual probabilities given in Table 5. Furthermore, unlike the Bayesian estimates, the monotone relation between tumor size and probability of lymph node metastases that has been observed by other authors2-5 clearly is evident in the estimates generated by our logistic regression procedure. We recently cross-validated our 3-variable model on a second, independent sample of 3108 women and found nearly identical probabilities of lymph node metastases for the risk groups shown in Table 5 in our article.1 Jeremy S. H. Jackson Ph.D.*, Ivo A. Olivotto M.D.*, Donna Mates M.A.*, * British Columbia Cancer Agency, Vancouver and Fraser Valley Clinics, Vancouver and Surrey, British Columbia, Canada

SYSTEMATIC SEXTANT BIOPSIES IMPROVE PREOPERATIVE PREDICTION OF PELVIC LYMPH NODE METASTASES IN PATIENTS WITH CLINICALLY LOCALIZED PROSTATIC CARCINOMA

Purpose An algorithm including the results of systematic sextant biopsies was statistically developed and evaluated to predict the probability of pelvic lymph node metastases in patients with clinically localized carcinoma of the prostate. Materials and Methods Clinical stage, serum prostate specific antigen concentration, Gleason score, number of positive biopsies, number of biopsies containing any Gleason grade 4 or 5 cancer and number of biopsies predominated by Gleason grade 4 or 5 cancer were recorded in 345 patients undergoing pelvic lymph node dissection and correlated with the incidence of lymph node metastases. Multivariate logistic regression, and classification and regression trees analyses were performed. Results In univariate analysis all variables had a statistically significant influence on lymph node status. Logistic regression showed that the amount and distribution of undifferentiated Gleason grade 4 and 5 cancer in the biopsies were the best predictors of lymphatic spread followed by serum prostate specific antigen. Classification and regression trees analysis classified 79.9% of patients who had 3 or fewer biopsies with Gleason grade 4 or 5 cancer and no biopsies predominated by undifferentiated cancer as a low risk group. In this group positive lymph nodes occurred in only 2.2% (95% confidence interval 0.8 to 4.7%). Conclusions Including the results of systematic sextant biopsies substantially enhances the predictive accuracy of algorithms that define the probability of lymph node metastases in prostatic cancer. Patients thus defined as having no lymphatic spread could potentially be spared pelvic lymph node dissection before definitive local treatment.

Original Articles: Prostate Cancer: The Use and Accuracy of Cross-Sectional Imaging and Fine Needle Aspiration Cytology for Detection of Pelvic Lymph Node Metastases Before Radical Prostatectomy

The role of cross-sectional pelvic imaging with computerized tomography or magnetic resonance imaging and fine needle aspiration in the assessment of pelvic lymph nodes in patients with prostate cancer is undefined. To address this issue we used formal decision analysis, comparing an imaging arm to a no imaging arm. Patient utility values were calculated, and test parameters and complication rates were extracted from the literature. Imaging was superior to no imaging only when the pretest probability of pelvic lymph node metastases was high. The most important parameter was the sensitivity of cross-sectional imaging for lymphadenopathy. When the sensitivity was 36%, which was the baseline figure derived from the literature, the probability of lymph node metastases required for imaging to be beneficial overall was 32%. We also performed a retrospective review of magnetic resonance imaging examinations at our institution in 174 patients with newly diagnosed prostate cancer and pathological confirmation of nodal status. The sensitivity for detecting nodal metastases was 25%. With this figure, the estimated probability of nodal metastases required to make imaging beneficial would be 45%, which is possible to achieve with highly selective clinical criteria. With a policy of imaging only in select patients the marginal cost is $794 per patient benefited (aborted radical prostatectomy because of nodal metastases detected with fine needle aspiration) compared to $50,661 per patient benefited if all patients are imaged. Thus, cross-sectional pelvic imaging before radical prostatectomy, solely for the purpose of detecting pelvic lymph node metastases, is not justified routinely. However, it is worthwhile on the basis of patient use values and cost-effectiveness in a select group of patients at high risk for nodal metastases.

The pattern of lymph node involvement in carcinoma of the head of the pancreas. A histologic study of the surgical findings in patients undergoing extensive nodal dissections.

To clarify the pattern of lymph node metastasis in carcinoma of the pancreas, lymph node involvement was examined in forty-two patients who underwent extensive nodal dissections, including the paraaortic lymph nodes. The correlation between the spread of the tumor and lymph node involvement was evaluated: The most common site of involved lymph nodes was the retropancreatic region. The prevalence of nodal metastases was 78.6%. Metastases to the paraaortic region were present in seven patients, among whom metastases in the paraaortic region were most common in the median region from the celiac artery to the inferior mesenteric artery and in the space between the aorta and the vena cava. The risk of lymph node metastases tended to increase with tumor size, except in the paraaortic region, where the correlation between the frequency of metastasis and tumor size was poor. The probability of lymph node metastases increased with the degree of lymphatic invasion (ly) and the growth pattern of the tumor (INF) and was high in patients with invasion into the retropancreatic tissue and in tumors with scirrhous histology. These results indicate that even in small cancers, lymph nodes of the paraaortic region frequently harbor metastases and should be dissected en block during radical resections of pancreatic cancer.

Lymphoscintigraphy with (123)I-marked epidermal growth factor in cervix cancer

Several malignant neoplasms express high levels of epidermal growth factor receptors. The aim of this study was to assess whether 123I-labeled epidermal growth factor can concentrate in lymph node metastases of squamous cell carcinomas of the cervix. 14 patients with advanced cervical cancer were selected because of their high probability of lymph node metastases. Planar scintigrams were recorded from the lower and upper abdomen following subcutaneous injection of 123I-labeled epidermal growth factor into the web space of each foot. Scintigraphic images were interpreted without knowledge of computerized tomography scan (n = 13) and ultrasound (n = 9) results from the pelvic lymph nodes. In 2 patients, histological verification was performed by diagnostic biopsy of pelvic lymph nodes. Nodal involvement was confirmed by computerized tomography for 4 of the 11 positive scans and by ultrasound for 2. In 11 out of 14 patients an increased uptake of 123I-labeled epidermal growth factor could also be seen in the primary tumour. Our findings suggest that targeting of cervical cancer lymph node metastases can be achieved by in vivo binding of 123I-labeled epidermal growth factor with receptors on tumour cell surfaces.

Curative local excision in the treatment of carcinoma of the rectum

A safe, simple technique of curative local excision is used for early invasive carcinoma of the rectum. Strict criteria were applied in selecting patients for curative local excision: (1) the tumor was less than 3 cm in diameter; (2) there were no clinically involved pelvic lymph nodes; (3) the tumor had a pedicle or pseudopedicle, and (4) subsequent histopathologic examination showed that the tumor was confined to the mucosa and submucosa of the bowel wall and completely excised. Curative local excision in 16 patients had no operative mortality or morbidity. The five-year cancer specific survival was 100 per cent, which compares favorably with the 88 per cent cancer specific survival rate in 268 patients managed by conventional curative resection for Dukes' stage A tumors. When the 7.1 per cent operative mortality of resection was additionally considered, the five-year survival fell to 81 per cent. The probability of lymph-node metastases in primary rectal tumors confined to the mucosa and submucosa was found to be 6.2 per cent irrespective of their diameter, i.e., slightly less than the mortality of resection.

Indication of mediastinal lymph nodes metastases by radioaerosol inhalation lung scanning in pulmonary neoplasm.

Fifty-three patients with pulmonary neoplasm were studied by radioaerosol inhalation and perfusion lung scans, bronchoscopy and spirometry. The probability of lymph node metastases could be estimated by the amount of inhaled aerosol deposited at the carina. On thoracotomy, actual mediastinal lymphadenopathy was minimum, if any, in 4 patients without carinal aerosol deposition. Application of the aerosol inhalation lung scan to pulmonary neoplasm provides useful diagnostic and prognostic information regarding mediastinal lymph nodes metastases.