Predictive probability of serum prostate-specific antigen for prostate cancer: an approach using Bayes rule

This article introduces the use of Bayes probability rule to calculate age and serum prostate-specific antigen (PSA)-specific positive predictive values (PPVs) for prostate cancer. The PPV is the conditional probability of having prostate cancer, given a value of PSA and a particular age group. The formulation uses values of sensitivity obtained from previously reported studies of more than 2,700 men with prostate cancer, and it uses values of specificity obtained from previously reported studies of more than 99,000 men without prostate cancer. The formulation also introduces the use of a population-based and age-specific probability of prostate cancer, and for this it relies on the National Cancer Institute-sponsored Surveillance, Epidemiology and End Results data. The Bayes PPV suggests that in younger men, cut points defining an elevated PSA level should be raised rather than lowered. The Bayes formulation also provides estimates of the PPV for narrow intervals of PSA, and these tabulated results may provide useful guidelines for the implications of serum PSA levels at specific age groups.

Expression of HIF-1alpha, CA IX, VEGF, and MMP-9 in surgically resected non-small cell lung cancer

Endogenous hypoxia markers have been studied as prognostic indicators because they appear to be associated with tumor aggressiveness. This study was undertaken to compare the expression of two endogenous hypoxia markers, Hypoxia-inducible factor-1alpha (HIF-1alpha) and carbonic anhydrase IX (CA IX), with regard to their prognostic significance. We also compared spatial distribution of HIF-1alpha and CA IX and examined their relationship with expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-9, which may be regulated by hypoxia. We studied 74 resected stage I/II non-small cell lung cancers (NSCLCs) for expression of HIF-1alpha, CA IX, VEGF, and MMP-9 by immunohistochemistry, and the extent of tumor necrosis. Univariate and multivariate analyses were performed to assess prognostic implications of these markers for disease free survival. HIF-1alpha expression was strongly correlated with CA IX (r=0.667, p<0.001) and was co-localized with CA IX in corresponding areas. HIF-1alpha and CA IX expression were higher in areas with moderate to severe tumor necrosis relative to areas with minimal necrosis, suggesting their relationship with hypoxia. VEGF expression also showed a modest relationship with HIF-1alpha (p=0.07); however, there was no relationship between HIF-1alpha and MMP-9 expression (p>0.99). Expression of HIF-1alpha and CA IX above the median value was significantly associated with shorter disease free survival in univariate analysis (p<0.05). However, only high CA IX expression and pathologic stage were independent prognostic indicators in a multivariate analysis. Of the markers considered in this study, CA IX expression status was the most reliable hypoxia marker for predicting tumor aggressiveness.

The importance of total number of sentinel lymph nodes in patients with stage N0 cutaneous melanoma

Staging of malignant melanoma now relies routinely on the sentinel node (SN) technique. On average, 2.1 SNs are removed per patient. Nevertheless, despite the success of the SN technique, approximately 10% of patients with negative SNs experience metastatic recurrence. Because a prior theoretical analysis using Poisson and Bayes probability models suggested that limited sampling of SNs could cause false-negative results, we undertook this study to see whether the subset of patients with negative SN and only 1 or 2 nodes examined have a shorter time to recurrence than patients with 3 or more nodes examined and found to be negative. Our study cases comprised 178 melanoma cases with SN biopsy: positive SN, 47; negative SN and fewer than 3 nodes examined, 68; and negative SN and more than 2 nodes examined, 63. Patients with negative SNs and fewer than 3 examined had disease-free survival intermediate between patients with positive SNs and those with negative SNs and more than 2 examined (P = .013). These results suggest that among patients with negative SNs, those with fewer than 3 nodes examined have greater risk for recurrence.

Pancreatic FNA in 1000 cases: a comparison of imaging modalities

BACKGROUND

Image-guided FNA is a popular method for evaluating pancreatic lesions, but few large studies on pancreatic FNA exist.

METHODS

Cytologic material, imaging reports, and clinical follow-up information were reviewed from pancreatic FNA cases performed over a 5-year period.

RESULTS

A total of 1050 pancreatic FNAs were obtained by EUS (n = 843), US (n = 140), and CT (n = 67). On-site assessment was performed in 89.2% (n = 937) of cases. Findings were as follows: positive for neoplasm 48.9% (n = 503), negative 29.1% (n = 306), descriptive 10% (n = 105), suspicious 5.9% (n = 62), atypical/inconclusive 4.6% (n = 48), and nondiagnostic/inadequate 1.5% (n = 26). Follow-up in the form of histology or at least 6 months of clinical observation was available for 61.2% (n = 643). There was an overall false-positive rate of 0.3% and a false-negative rate of 14.3%. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were as follows: 79.4, 99.0, 99.4, 67.9, 84.5 for the total series, respectively; 79.9, 98.8, 99.2, 72.5, 86.5 for EUS, respectively; 77.9, 100, 100, 48.6, 81.7 for US, respectively; and 78.6, 100, 100, 47.1, 82.0 for CT, respectively. In general, accuracy was not influenced by lesion size or site, number of FNA passes, or number of procedures per patient. After controlling for lesion size, EUS resulted in greater accuracy than US or CT when evaluating lesions <3 cm ( p = 0.015).

CONCLUSIONS

All imaging modalities showed moderate to high sensitivity, specificity, and accuracy. Logistic regression analysis showed that for lesions <3 cm, the EUS method had higher accuracy than US or CT. No statistically significant difference was seen for larger lesions or for the number of FNA passes.

Analysis of lymph nodal metastases in malignant melanoma using the poisson probability paradigm and Bayes rule

This article deals with and formalizes 2 notions common to the practice of pathology. The first is that the number of lymph nodes found positive for metastasis relates directly to the total number of lymph nodes examined. The second is that for any patient, there is a chance that the absence of lymph node metastases is a false-negative result. I introduce the Poisson probability density function to deal with the first notion and the Bayes probability rule to deal with the second. To illustrate the insight these 2 models provide, I apply them to data regarding lymph nodal metastases in malignant melanoma. In this preliminary study, the results of these 2 models correlate well with observed survival probabilities in patients with stage N0 melanoma and with observed rates of false-negative results in sentinel lymph node biopsy technology. With further development, the combination of these models should provide a way to estimate the probability of nodal metastasis when, in fact, none have been observed. Thus, these models might provide useful tools for evaluating patients with stage N0 malignant neoplasms.

Erythropoietin and erythropoietin receptor expression in human prostate cancer

Erythropoietin is a hematopoietic cytokine that regulates the production of red blood cells. Erythropoietin is normally produced in the adult kidney in a hypoxia-inducible manner. The recombinant form of human erythropoietin is in clinical use for the prevention and treatment of anemia that is associated with cancer and its treatment with chemoradiation therapy. A series of recent studies from our laboratory and others have reported the expression of receptors for erythropoietin in several different types of human cancer cells. In the present study, we investigated the expression of erythropoietin receptor and its ligand erythropoietin in human prostate cancer. In clinical specimens of prostate cancer, we found abundant expression of erythropoietin receptor protein in all primary tumors examined using immunohistochemistry. Furthermore, we observed erythropoietin coexpression in prostate cancer cells by immunohistochemical analysis. To determine whether monolayer cultures of continuous cell lines derived from prostate cancer also express erythropoietin receptor and erythropoietin, we studied well-characterized hormone-responsive (LNCaP) and hormone-refractory (PC-3) prostate cancer cell lines. We performed reverse-transcription and polymerase chain reaction assays to detect erythropoietin receptor and erythropoietin mRNA transcripts, and also immunoprecipitation and immunoblotting to detect erythropoietin receptor protein expression in prostate cancer cells. These experiments revealed the expression of both erythropoietin receptor and erythropoietin in LNCaP and PC-3 cells suggesting that these prostate cancer cell lines may serve as useful experimental models for further studies of erythropoietin and erythropoietin receptor function in prostate cancer. The coexpression of erythropoietin receptor and its ligand erythropoietin in human prostate cancer cells suggests the potential for growth regulation by erythropoietin-erythropoietin receptor in an autocrine or paracrine manner.

Diagnostic impact of core-needle biopsy on fine-needle aspiration of non-Hodgkin lymphoma

We retrospectively reviewed 74 fine-needle aspiration (FNA) cases of presumptive non-Hodgkin lymphoma (NHL). All the cases had cytology and core-needle biopsy and 53 cases had concurrent flow cytometric analysis. FNA (cytology and flow cytometry) and core-needle biopsy were evaluated independently. FNA was diagnostic of diffuse large B-cell lymphoma (DLBL) in 25% (13/53) of cases and small B-cell NHL in 15% (8/53) of cases, whereas core-needle biopsy was diagnostic of DLBL in 37% (27/74) of cases and small B-cell NHL in 8% (6/74) of cases. Subclassification of small B-cell NHL was reached in 3/6 cases by core-needle biopsy. Insufficient cases were observed in both FNA (47%; 25/53) and core-needle biopsy (28%; 21/74) groups. With the combination of FNA and core-needle biopsy, diagnostic cases of DLBL increased to 43% (32/74) and insufficient samples were reduced to 16% (12/74). There was no clear advantage in the diagnosis and classification of small B-cell NHL by adding core-needle biopsy to FNA (14%; 10/74). We conclude that core-needle biopsy is a useful adjunct to FNA in the diagnosis of DLBL and shall be encouraged. In small B-cell NHL, core-needle biopsy does not add to the diagnostic ability of FNA. Cases insufficient for diagnosis may be seen in both core-needle biopsy and FNA. A combined approach reduces the number of insufficient cases and is recommended in routine FNA practice.

Carbonic Anhydrase IX in Early-Stage Non–Small Cell Lung Cancer

PURPOSE

Tumor hypoxia is associated with poor prognosis and increased tumor aggressiveness. Carbonic anhydrase (CA) IX, an endogenous marker for tumor hypoxia, catalyzes the hydration of carbon dioxide into carbonic acid and contributes to the pH regulation of tumor cells. Therefore, CA IX might allow tumors to acclimate to a hypoxic microenvironment, promoting tumor cell proliferation. We hypothesized that CA IX expression is related to tumor cell proliferation and poor disease-free survival in patients with early-stage non-small-cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

CA IX expression was measured in 75 resected NSCLC tumors to assess prognostic implications for disease-free survival. The relationship of CA IX expression with microvessel density (MVD) and proliferation (Ki-67) index was assessed via colocalization analysis.

RESULTS

All patients had operable NSCLC (stage I, 58; stage II, 17). CA IX expression was present in 54 (72%) of 75 patients and was associated with tumor necrosis (P < 0.05). CA IX-positive tumor areas showed greater cell proliferation as measured by Ki-67 index (P < 0.05) and less MVD (P < 0.05) than did CA IX-negative areas in colocalization analysis. The percentage of CA IX-positive tumor cells was significantly related to postoperative recurrence and poor disease-free survival (P < 0.05). Ki-67 index and pathologic stage were also independent prognostic factors for worse disease-free survival (P < 0.05).

CONCLUSIONS

CA IX expression of tumor cells may be an indicator for poor disease-free survival in early-stage NSCLC.

The impact of pathology review on treatment recommendations for patients with adenocarcinoma of the prostate

This study was designed to estimate the frequency with which changes in Gleason score because of a genitourinary pathologist's review changed prostate cancer treatment recommendations. The study cohort consisted of 602 patients who presented to a genitourinary oncologist for a second opinion after being diagnosed with prostate cancer based on a needle biopsy at a nonacademic institution from 1989 through 2001. Each of the prostate biopsy specimens was sent for review by a genitourinary pathologist. Applying the rule that low-risk patients would receive monotherapy, and intermediate or high-risk patients would receive combined modality therapy, the frequency with which treatment recommendations were changed by pathology review was calculated. Pathology review by a genitourinary pathologist changed the Gleason score by at least 1 point in 44% of cases. Upgrades were more common than downgrades and accounted for 81% [95% confidence interval: 76-86%] of the changes. Patients' risk category was increased in 10.8% of cases and was decreased in 3.4%. Risk category was changed from low risk to intermediate or high risk in 8.2%, but was changed from intermediate or high risk to low risk in only 0.9%. Genitourinary pathology review would have changed management in approximately 10% of men, mainly in the direction of combined therapy over monotherapy.

Use of Bayes rule and MIB-1 proliferation index to discriminate Spitz nevus from malignant melanoma

Differentiating Spitz nevus from malignant melanoma is difficult and controversial. Despite helpful lists of differential diagnostic features, uncertainty about the diagnosis often provokes some to stain the tumor for MIB-1 antibody to Ki-67 and measure the proliferation index (PI) of the tumor. Of the many reports about MIB-1 PI in Spitz nevi and melanoma, none have consolidated the information to provide guidelines for the predictive probability that a lesion is a Spitz nevus, given that the MIB-1 PI falls into a certain interval. The present study used previously published data and exponential and gamma probability density functions to model statistical distributions of PI, respectively, in Spitz nevi and melanomas and Bayes rule to estimate the predictive probability that a lesion is a Spitz nevus, given an observed PI. Results indicate that PIs more than 10% favor a melanoma diagnosis and PIs less than 2%, Spitz nevus. PI values between 2% and 10% yield various predictive values for Spitz nevus, depending on the a priori probability that the lesion is a Spitz nevus. The algorithm tabulates guidelines for the predictive probabilities of Spitz nevus given an observed PI.

Pilot study to explore effects of low-fat, flaxseed-supplemented diet on proliferation of benign prostatic epithelium and prostate-specific antigen

OBJECTIVES

Dietary factors may influence the prostate and have an impact on prostatic growth and disease. A small number of studies have suggested that flaxseed-supplemented, fat-restricted diets may thwart prostate cancer growth in both animals and humans. Unknown, however, is the potential effect of such a diet on benign prostatic epithelium.

METHODS

We undertook a pilot study to explore whether a flaxseed-supplemented, fat-restricted diet affects the proliferation rates in benign epithelium. We also explored the effects on circulating levels of prostate-specific antigen (PSA), total testosterone, and cholesterol. Fifteen men who were scheduled to undergo repeat prostate biopsy were instructed to follow a low-fat (less than 20% kcal), flaxseed-supplemented (30 g/day) diet and were provided with a supply of flaxseed to last throughout the 6-month intervention period. The PSA, total testosterone, and cholesterol levels were determined at baseline and at 6 months of follow-up. Reports from the original and repeat biopsies were compared, and proliferation (MIB-1) rates were quantified in the benign prostatic epithelium.

RESULTS

Statistically significant decreases in PSA (8.47 +/- 3.82 to 5.72 +/- 3.16 ng/mL; P = 0.0002) and cholesterol (241.1 +/- 30.8 to 213.3 +/- 51.2 mg/dL; P = 0.012) were observed. No statistically significant change was seen in total testosterone (434.5 +/- 143.6 to 428.3 +/- 92.5 ng/dL). Although 6-month repeat biopsies were not performed in 2 cases because of PSA normalization, of the 13 men who underwent repeat biopsy, the proliferation rates in the benign epithelium decreased significantly from 0.022 +/- 0.027 at baseline to 0.007 +/- 0.014 at 6 months of follow-up (P = 0.0168).

CONCLUSIONS

These pilot data suggest that a flaxseed-supplemented, fat-restricted diet may affect the biology of the prostate and associated biomarkers. A randomized controlled trial is needed to determine whether flaxseed supplementation, a low-fat diet, or a combination of the two regimens may be of use in controlling overall prostatic growth.

Race and the linkage between serum prostate-specific antigen and prostate cancer: a study of American veterans

Many aspects of prostate cancer differ between black men and white men, including incidence, stage, grade, sensitivities and specificities of serum prostate-specific antigen (PSA) levels, and survival. In general, the level of serum PSA reflects the mass of the prostate and the amount of tumor present, but the question to consider is whether this relationship is the same for blacks as for whites. If it is the same, then the ways we use serum PSA to screen, stage, and follow up white men with cancer should work equally for black men. If it is not, then we need alternative strategies for using serum PSA levels in blacks. I used regression analysis to study how the serum PSA level depends on prostate mass and the amount of tumor in 194 American veterans, including 87 black men. I found that black men produced higher levels of serum PSA for any given amount of tumor compared with whites, and I demonstrated that this difference can significantly affect the assessment of risk for outcomes in blacks.

An abnormal cervicovaginal cytology smear in uterine carcinosarcoma is an adverse prognostic sign: analysis of 25 cases

Carcinosarcoma of the uterus has been poorly characterized on cervicovaginal (Pap) smears, and we examine whether they effectively screen for carcinosarcoma and whether an abnormal Pap smear result has any clinical importance. Twenty-five patients with histologically confirmed carcinosarcoma had a conventional Pap smear shortly before diagnosis. Eleven smears (44%) originally were read as abnormal (malignant or atypical), and 4 additional cases were read as abnormal on retrospective review (15/25 [60%]). All malignant elements were epithelial, and 2 cases (8%) had atypical spindle cells, but no diagnostic sarcoma. Cervical involvement was the only histologic parameter correlating with an abnormal Pap smear result (P = .04). Univariate analysis found stage III or IV disease was an adverse prognostic sign compared with stage I or II disease (mean survival, 8 vs 36 months, respectively; P = .001), and multivariate analysis indicated that an abnormal Pap smear result correlated with worse survival (P = .023). The conventional Pap smear is insensitive (60%) for detecting carcinosarcoma, but when the result is abnormal, the Pap is an important stage-independent adverse prognosticator.

Patient age in Spitz nevus and malignant melanoma: implication of Bayes rule for differential diagnosis

In the differential diagnosis of Spitz nevus vs malignant melanoma, patient age provides a critical piece of clinical information, because Spitz nevi occur mostly in children and melanomas occur mostly in adults. Nevertheless, there is overlap in the age distributions of Spitz nevus and melanoma. The issue to consider is how these age distributions and their governing probability densities can impact the a priori probability that a lesion is a Spitz nevus vs a melanoma. Herein I introduce a quantitative approach that uses Bayes rule together with previous published data on the age distributions in Spitz nevi and melanoma. The resulting algorithm yields plots and a table of predictive a priori probabilities of Spitz nevus, given patient age occurring within narrow intervals, and I believe these provide useful guidelines for using age in the differential diagnosis of Spitz nevus and malignant melanoma.

Immunohistochemical detection of occult lymph node metastases in non-small cell lung cancer: anatomical pathology results from Cancer and Leukemia Group B Trial 9761

PURPOSE

Our purpose was to study the detection of occult metastases (OM) in regional lymph nodes using immunohistochemical stain for cytokeratin, and for this study we targeted clinical stage I patients with non-small cell lung cancer.

EXPERIMENTAL DESIGN

The study comprised the first 193 patients entered onto Cancer and Leukemia Group B protocol 9761. All had clinically staged T(1-2)N(0)M(0) non-small cell lung cancer, and all underwent curative resections of their primary tumors. Samples of the primary tumor and lymph nodes were taken from lymph node stations 2-12 and shipped to a central laboratory, where each lymph node was histologically processed and stained with H&E as well as with immunohistochemical stain using antibodies to cytokeratin (AE1/3).

RESULTS

Altogether, we examined 825 lymph nodes. Whereas routine H&E staining allowed us to detect 18 positive lymph nodes, immunohistochemical staining allowed us to detect 45 positive lymph nodes (P < 0.0001). There were 28 OM [i.e., those detectable only by immunohistochemistry (IHC)], and there was 1 metastasis detected only by H&E staining. The OM included 9 OM in N1 stations and 19 OM in N2 stations. Twelve patients with OM had skip metastases. Routine H&E staining upstaged six patients to N1, and IHC added another five. Routine H&E upstaged 9 patients to N2, and IHC added another 11. We also uncovered new details about the way in which H&E detection depends on metastatic tumor burden. Specifically, for the probability of detecting metastases by H&E to exceed 0.50, the maximum diameter of the metastasis must be greater than 0.23 mm.

CONCLUSIONS

IHC detects greater than twice as many positive regional lymph nodes as does H&E staining, and the foci of tumor it detects are significantly smaller than those detected by H&E staining.

Morphometric evaluation of tumor matrix metalloproteinase 9 predicts survival after surgical resection of adenocarcinoma of the lung

PURPOSE

Recently, several matrix metalloproteinases (MMPs) have shown promise as prognosticators in non-small cell lung cancer. In this study, we sought to validate the importance of MMP-9 and to study the relationships between MMP-9 and several other tumor or stromal markers.

EXPERIMENTAL DESIGN

We examined MMP-9 and several other markers in tumor tissues from 152 patients with surgically excised adenocarcinomas of the lung. Their preoperative clinical stages were T(1-4)N(0)M(0); however, pathological exam of their resected tissues demonstrated that 33 were stage II, and 64 were stage III. We used immunohistochemistry and morphometry to evaluate the amount of tumor staining for MMP-9, and the outcome for our study was survival time until death from recurrent lung cancer.

RESULTS

Multivariate Cox model analysis demonstrated that pathological stage was significantly related to survival time (P < 0.01), but quantitative staining of the tumor for MMP-9 added prognostic information (P < 3.0 x10(-16)) and was more strongly prognostic than pathological stage. In the subset of pathological stage I patients, staining for MMP-9 was also significantly associated with survival (P < 1.0 x10(-6)), and a cutpoint at the median staining of 11.2% for MMP-9 divided them into two groups with distinctive survival times. Those with MMP-9 > 11.2% had a median survival time of just 11 months. Those with MMP-9 < 11.2% had not reached a median survival and had a mean survival time of >62 months.

CONCLUSIONS

Tumor staining for MMP-9 in resected adenocarcinoma of the lung is strongly related to survival. Patients with >11.2% staining in their tumors comprise a subset with a high hazard for dying of lung cancer and may be an appropriate target for prospective studies of adjuvant chemotherapy after surgical resection.

Basal cell hyperplasia in the peripheral zone of the prostate

Basal cell hyperplasia in the prostate is often viewed as a transition zone proliferation, related to usual, nodular glandular, and stromal hyperplasia. Basal cell hyperplasia in the prostatic peripheral zone, the most common site for development of prostatic intraepithelial neoplasia and carcinoma, has not been previously characterized. We characterized the incidence and histomorphological attributes of basal cell hyperplasia in a series of 500 consecutive sextant needle core biopsy samples and in 26 completely embedded prostate glands from radical prostatectomy specimens. Comparative proliferation indices (by MIB-1 staining) and apoptotic indices (by TUNEL labeling) were quantitated for peripheral zone versus transition zone basal cell hyperplasia versus normal basal cells. The incidence of basal cell hyperplasia in prostate needle biopsy tissue was 10.2% (51 of 500 cases). Usual basal cell hyperplasia was detected in 8.2% of the 500 cases, and basal cell hyperplasia with prominent nucleoli, in 2.0% of cases. Basal cell hyperplasia in needle biopsy tissue was typically focal and associated with inflammation, which was usually lymphocytic, in 84% of cases. Peripheral zone basal cell hyperplasia was found in 23% of whole prostate glands. Peripheral zone basal cell hyperplasia was not observed to be in direct physical continuity with intraepithelial or invasive neoplasia. Peripheral zone and transition zone basal cell hyperplasia exhibited similar mean proliferation and apoptotic indices, at 1% and 0.07%, respectively. This proliferation index was elevated, and apoptotic index was decreased, relative to normal basal cells (P = 1 x 10(-7)). Basal cell hyperplasia in the peripheral zone is present in a significant minority of prostate needle biopsy samples and whole prostate glands. The presence of prominent nucleoli in basal cell hyperplasia may cause diagnostic concern for a neoplastic proliferation. The increase in cell number in basal cell hyperplasia appears to be due to a coordinate increase in proliferation index coupled with a diminished apoptotic index. The presence of inflammation in the majority of basal cell hyperplasia foci suggests that peripheral zone basal cell hyperplasia in untreated patients may represent a stereotyped response to injury such as that sustained because of inflammation.