Percentage of tumor and tumor length in prostate biopsy specimens: a study of American veterans

In this study, the tumors of 451 Veterans Affairs patients with prostate cancer were examined. In the biopsy specimens, percentage of tumor and tumor length were observed in addition to Gleason grade. The patients were then followed up until death or for a mean of 4.9 years to see how these measures of the quantity of tumor in the biopsy specimens related to overall survival. Cox proportional hazards model analysis demonstrated that patient age and serum prostate-specific antigen (PSA) level were related significantly to overall survival. After controlling for these 2 variables, percentage of tumor was significantly related to overall survival (P = .0012), and after controlling for age and PSA level, tumor length was significantly related to overall survival (P = .00026). Nevertheless, these 2 measures did not add prognostic information, that is, either one or the other was significant, but not both, probably because they are closely correlated. The results favor including one or the other of these 2 quantitative measures in reports on prostate biopsy specimens with tumor.

Overcoming challenges in designing and implementing a phase II randomized controlled trial using a presurgical model to test a dietary intervention in prostate cancer

BACKGROUND

The time between the diagnosis of cancer and a planned definitive surgical procedure offers a strong and direct approach for assessing the impact of interventions (including lifestyle interventions) on the biology of the target tissue and the tumor. Despite the many strengths of presurgical models, there are practical issues and challenges that arise when using this approach.

PURPOSE/METHODS

We recently completed an NIH-funded phase II trial that utilized a presurgical model in testing the comparative effects of flaxseed supplementation and/or dietary fat restriction on the biology and biomarkers associated with prostatic carcinoma. Herein, we report the rationale for our original design, discuss modifications in strategy, and relay experiences in implementing this trial related to the following topics: (1) subject accrual; (2) subject retention; (3) intervention delivery; and (4) retrieval and completion rates regarding the collection of paraffin-embedded and fresh frozen prostate tissue, blood, urine, ejaculate, anthropometric measures and survey data.

RESULTS

This trial achieved its accrual target, i.e., a racially-representative (70% white, 30% minority) sample of 161 participants, low rates of attrition (7%); and collection rates that exceeded 90% for almost all biospecimens and survey data. While the experience gained from pilot studies was invaluable in designing this trial, the complexity introduced by the collection of several biospecimens, inclusion of a team of pathologists (to provide validated readings), and shifts in practice patterns related to prostatectomy, made it necessary to revise our protocol; lessons from our experiences are offered within this article.

CONCLUSIONS

While our experience specifically relates to the implementation of a presurgical model-based trial in prostate cancer aimed at testing flaxseed-supplemented and fat-restricted diets, many of the lessons learned have broad application to trials that utilize a presurgical model or dietary modification within various cancer populations.

Tumor length in prostate cancer

To evaluate the impact of tumor length and fraction of positive biopsy cores on overall survival, I used the data for 526 patients with prostate cancer. Median follow-up in patients not observed until death was more than 6 years. In a Cox model analysis that included age, serum prostate-specific antigen (PSA) level, grade, and fraction of positive cores, tumor length was the most closely associated with overall survival time (P=6 x 10(-5)); however, the impact of tumor length was mostly for a subset of men with tumors measuring more than 20 mm. Patient age, serum PSA level, Gleason score, fraction of cores with tumor, and tumor length were all significantly codependent variables. For routine cases of prostate cancer, measuring tumor length in the needle cores may be unnecessary. Tumor length may assist studies of long-term outcomes or treatment trials in prostate cancer by reducing baseline variance better than other prognostic variables. For the few patients with unusually large amounts of tumor in biopsy specimens, tumor length may provide a concise indicator for the likelihood of an adverse outcome, especially when the values of other prognostic variables appear by themselves to be less ominous.

Twenty-five years of fiber analysis: what have we learned?

Asbestos exposure has resulted in a variety of diseases, including asbestosis, carcinoma of the lung (LC), pleural plaques, and malignant mesothelioma (MM). We hypothesized that there have been significant changes in the mineral fiber content of lung tissue from individuals with these diseases over the past 25 years. Asbestos content was measured in lung tissue samples from 819 individuals using light microscopy (to measure asbestos body concentrations) and scanning electron microscopy (to measure types and concentrations of mineral fibers). Cases were divided chronologically according to those occurring in the first half (group 1) versus those occurring in the second half (group 2). The study included 419 cases of MM, 206 cases of asbestosis, and 340 cases of LC. The median asbestos body count (in asbestos bodies per gram) decreased from group 1 to group 2 for each disease: MM, 480 to 350; asbestosis, 24700 to 19200; and LC, 1600 to 174 (reference range, 0-20). A similar trend was observed for fiber counts by scanning electron microscopy. Amosite was the most frequently detected asbestos fiber type and decreased in frequency of detection and median concentration from group 1 to group 2. Crocidolite showed an increased detection frequency from group 1 to group 2 across all 3 disease categories. The decrease in asbestos body and amosite concentrations over time is consistent with the banning of asbestos from insulation products in 1972. The source for the increased detection of crocidolite was not identified and needs further investigation.

Obesity-related plasma hemodilution and PSA concentration among men with prostate cancer

CONTEXT

Recent studies have suggested that obese men have lower serum prostate-specific antigen (PSA) concentrations than nonobese men. Because men with higher body mass index (BMI) have greater circulating plasma volumes, lower PSA concentrations among obese men may be due to hemodilution.

OBJECTIVE

To determine the association between hemodilution and PSA concentration in obese men with prostate cancer.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective study of men who underwent radical prostatectomy for prostate adenocarcinoma from 1988 to 2006, using data from the databases of the Shared Equal Access Regional Cancer Hospital (n = 1373), Duke Prostate Center (n = 1974), and Johns Hopkins Hospital (n = 10 287). Multivariate linear regression models adjusting for clinicopathological characteristics were used to analyze the main outcome measures.

MAIN OUTCOME MEASURES

Associations between BMI and mean adjusted PSA concentrations, mean plasma volume, and mean adjusted PSA mass (total circulating PSA protein, calculated as PSA concentration multiplied by plasma volume), assessed by determining P values for trend.

RESULTS

After controlling for clinicopathological characteristics, higher BMI was significantly associated with higher plasma volume (P < .001 for trend) and lower PSA concentrations (P < or = .02 for trend) in all cohorts. In 2 of the 3 cohorts, PSA mass did not change significantly with increasing BMI. In the third cohort, higher BMI was associated with increased PSA mass (P < .001 for trend), but only between BMI category less than 25 and the other categories.

CONCLUSIONS

In men undergoing radical prostatectomy, higher BMI was associated with higher plasma volume; hemodilution may therefore be responsible for the lower serum PSA concentrations among obese men with prostate cancer. Prospective studies are needed to evaluate this association in screened populations.

Information content of five nomograms for outcomes in prostate cancer

In this study, we used 327 cases of localized prostate cancer to determine the information content provided by 5 popular nomograms for predicting outcomes in localized prostate cancer. All study patients underwent radical prostatectomy. For each case and each nomogram, we calculated the estimated probability of outcome, and, from this probability, we calculated the information content as 1-S, where S is the entropy. With this definition, information content is minimized at 0 and maximized at 1. We found that the average information content ranged from 0.16 for the Partin tables to 0.44 for the recent Kattan nomogram for 10-year disease-free survival. Furthermore, the Kattan 10-year nomogram provided information content greater than 0.5 for 50% of study cases, so that among these 5 nomograms, we judged its performance the best. Nevertheless, because even this nomogram provided less than 0.5 information content for 50% of our cases, we believe that it can be improved and that additional measurements or markers observed on the biopsy tissues are likely to produce better nomograms.

Interobserver agreement on what constitutes visceral pleural invasion by non-small cell lung carcinoma: an internet-based assessment of international current practices

Visceral pleural invasion (VPI) increases the T category of non-small cell lung carcinomas (NSCLCs) that otherwise only meet T1 criteria to T2. The American Joint Committee on Cancer provides no guidelines on what constitutes VPI. Penetration beyond the visceral pleural elastic layer (VPEL) has been proposed as the minimum criterion but is not internationally accepted. The purposes of this study were to elucidate current international practices regarding assessment of VPI and identify histologic features pathologists consider necessary for VPI. We examined responses to an online quiz consisting of 15 NSCLCs adjacent to or involving the visceral pleura. Of 103 participants from 22 countries, 84.5% were in academic practice; 42.7% had a subspecialty interest in pulmonary pathology. Interobserver percentage agreement about whether VPI was present, absent, or indeterminate ranged from 36.9% to 93.2% (mean, 73.0%). The K for participants for all quiz cases was 0.35. There was considerable diagnostic variability in cases with extensive pleural elastosis and when tumor cells were intermingled with the VPEL. It seems that the majority of participants consider penetration of the VPEL necessary and also sufficient to categorize VPI as present. However, the formation of internationally recognized guidelines for assessing VPI by NSCLC is likely to improve diagnostic consensus.

Outcome for repeated biopsy of the prostate: roles of serum PSA, small atypical glands, and prostatic intraepithelial neoplasia

We studied the relationships between the outcome in the last follow-up prostate biopsy specimen and serum prostate-specific antigen (PSA), prostatic intraepithelial neoplasia (PIN), and atypical small acinar proliferations (ASAPs) at the occasion of the initial biopsy in 244 cases in which the initial specimen was negative for tumor and at least 1 follow-up biopsy was done. PSA levels and ASAPs were significantly associated with cancer in the follow-up biopsy specimen (<P < .005; logistic regression analysis); however, the presence of PIN in the initial biopsy specimen did not relate to cancer in the follow-up specimen (P > .1). Thus, the probability that a follow-up biopsy demonstrates cancer depends on PSA and ASAPs, and even when ASAPs are present, serum PSA exerts an influence. For example, low PSA values, 5 ng/mL (5 mug/L) or less, are associated with low probabilities of a positive follow-up biopsy result, even when ASAPs were present in the first biopsy specimen. For higher PSA values, the presence of ASAPs dramatically increases the probability of a positive follow-up biopsy result compared with cases with no atypia or PIN in the first biopsy specimen.

Solar elastosis in cutaneous melanoma

By studying more than 1,200 patients with cutaneous melanoma and long-term follow-up, I examined the relationship between solar elastosis and age at diagnosis of melanoma, key features of melanoma, and the outcome of overall survival in melanoma. I found that melanomas with elastosis were diagnosed significantly later than those without elastosis (P approximately 0; log-rank test). This result may be because elastosis is positively related to age. However, I also found that melanomas of head and neck areas, which tend to have more elastosis, were diagnosed at later ages than melanomas of other body sites (P = 1.2 x 10-5; log-rank test). Thus, a second explanation for the results favors a protective effect of elastosis on the development of cutaneous melanoma, possibly related to increased levels of vitamin D. I also found that once melanoma develops, cases with elastosis demonstrated no differences in thickness, mitotic rate, ulceration, or overall survival time from cases without elastosis.

Melanocytic Nevi With Nonsurgical Trauma: A Histopathologic Study

There is a belief among dermatopathologists that benign melanocytic nevi (BMN) may display atypical histologic characteristics when traumatized. However, to our knowledge, a systematic study of nonsurgically traumatized melanocytic nevi (TMN) has not been published. We studied a series of 92 TMN. Cases were analyzed for histologic evidence of architectural and cytologic criteria associated with atypia. Of the patients, 54 were female and 37 were male. The mean age was 38 years old (range 8-74 years old). Nevi were present, in order of frequency, on the extremities, trunk, and head/neck, but there were no acral sites. Histologic findings of trauma were as follows: parakeratosis (92%), dermal telangiectasias (61%), ulceration (51%), dermal inflammation (49%), melanin within stratum corneum (24%), and dermal fibrosis (25%). Pagetoid spread of melanocytes was limited to the site of trauma in 20% of cases and was identified away from areas of trauma in 8% of cases. Melanocytic atypia was seen in three cases. Dermal mitoses were rare (one mitotic figure in three cases). Pagetoid spread under a traumatized epidermis was relatively frequent and, in isolation, is compatible with a benign TMN. Any traumatized melanocytic lesion that displays cytologic atypia, pagetoid spread outside of the area of the traumatized epidermis, or dermal mitoses should be treated with caution because these findings were rarely seen in TMN.

Mitotic rate in melanoma: a reexamination

We reexamined the relationship between mitotic rate and overall survival in more than 1,200 cases of cutaneous melanoma with long-term follow-up. Like others, we found that mitotic rate was significantly associated with survival (P < 4 x 10(-8)) and more prognostic than tumor ulceration but was not an independent prognosticator because it was significantly associated with tumor thickness and ulceration. Thus, all 3 histologic variables are interrelated; among these, tumor thickness is the most important. Although mitotic rate can be effectively categorized in 3 groups (1/mm2, 1/mm2(-4)/mm2, and > 4/mm2), the optimal way to use mitotic rate remains unclear, and even this simplification requires determining the raw number per square millimeter. Because the collective information provided by tumor thickness, mitotic rate, ulceration, patient age, and site of tumor about hard outcomes such as 5-year fatality is limited and because measuring mitotic rate requires extra time, we recommend that mitotic rate need not be part of routine reports on cutaneous melanoma. Nevertheless, mitotic rate should continued to be measured in academic centers and other sites that maintain large prospective databases on melanoma, and it should be included in further studies of prognosis and adjuvant therapies for cutaneous melanoma.

Entropy and information content of laboratory test results

This article introduces the use of information theoretic concepts such as entropy, S, for the evaluation of laboratory tests results, and it offers a new measure of information, 1 - S, which tells us just how far toward certainty a laboratory test result can predict a binary outcome. The derived method is applied to the serum markers troponin I and prostate-specific antigen and to histologic grading of HER-2/neu staining, to cytologic diagnosis of cervical specimens, and to the measurement of tumor thickness in malignant melanoma. Not only do the graphic results provide insight for these tests, they also validate prior conclusions. Thus, this information theoretic approach shows promise for evaluating and understanding laboratory test results.

Pancreatic and bile duct brushing cytology in 1000 cases: review of findings and comparison of preparation methods

BACKGROUND

Duct brushing cytology is an important tool in evaluation of the extrahepatic biliary tract and large pancreatic ducts. The emergence of neoadjuvant therapies underscores the importance of accurate preoperative diagnosis by noninvasive means. Liquid-based preparation methods, such as ThinPrep, have become popular for nongynecologic cytology specimens.

METHODS

Findings from bile and pancreatic duct brushings were reviewed over the 10-year period of 1994-2003. Cytologic material, imaging reports, and clinical data were reviewed and pathologic and clinical follow-up data were obtained. The slides were prepared by direct smear only (18.8%), direct smear plus cytospin (14.4%), or direct smear plus ThinPrep (66.8%).

RESULTS

A total of 1118 specimens were identified (1008 bile duct, 110 pancreatic duct) from 864 patients. The cytologic findings were: 53.5% negative, 16.5% malignant, 18.2% suspicious for malignancy, 11% atypical/inconclusive, 0.8% inadequate. Follow-up in the form of either histology or at least 6 months clinical observation was available for 82.2% of cases (n = 971). Overall operating characteristics were: 52.6% sensitivity, 99.4% specificity, 98.9% positive predictive value, 67.1% negative predictive value, and 75.7% accuracy. Diagnostic agreement between cytology and follow-up was the main variable analyzed. Agreement was significantly affected by characteristics of the sampled lesion, with ductal narrowing having the lowest rate of malignancy. In addition, the ThinPrep method showed superior sensitivity and accuracy compared with other preparation methods (P = .02). Nonsignificant associations were noted for patient age and gender, site of lesion, and the presence of either stones or prior stent.

CONCLUSION

In a large dataset from a single institution, brushing cytology showed modest sensitivity and high specificity. Diagnostic agreement was considerably better for benign cases. The combination of direct smear and the ThinPrep method showed superior sensitivity and accuracy.

Analysis of turnaround times in pathology: an approach using failure time analysis

This article introduces the use of failure time analysis methods for studying turnaround times in pathology. The key to understanding the approach is to view a laboratory specimen like a living patient. When the specimen enters the laboratory, the time is analogous to the time of diagnosis for a patient. When the specimen's analysis is completed, the event is analogous to a patient who has died. To illustrate the approach, I use data previously published and data generated at the Durham, NC, Veterans Affairs Medical Center. I demonstrate that the Kaplan-Meier plotting method, the log-rank test, and the Cox model can all be applied to turnaround times and provide useful results.

Predicting prostate biopsy results: The importance of PSA, age, and race

We studied whether age and race have a significant role in predicting the results of prostate biopsy after consideration of prostate-specific antigen (PSA) alone. We evaluated the results of 884 prostate biopsies performed on 695 men, including 188 black men. We used logistic regression analysis to evaluate relationships between presence of cancer in the biopsy specimen and the key predictor variables of PSA, age and black race. We also evaluated the importance of a Bayes-derived positive predictive value (PPV), which used age- and race-specific values of specificity and sensitivity of PSA and age- and race-specific Surveillance, Epidemiology, and End Results incidences of prostate cancer. In univariate analysis, the Bayes PPV was associated significantly with presence of cancer (chi2 = 216; P approximately .000); however, serum PSA provided more information (chi2 = 248; P approximately .000). With serum PSA in the logistic model, the Bayes PPV provided no further information (P > .08), and as additional variables, neither age nor black race contributed further information (P > .1). Serum PSA provides the most predictive information about the results of biopsy of the prostate, probably because it naturally correlates with age and race. Decisions about whether to biopsy should rest on values of serum PSA and need not consider age and race.

Lymph nodes in colorectal carcinoma. The Poisson probability paradigm

This article introduces use of the Poisson probability density function and Bayes probability rule to understand and analyze lymph nodal metastases in colorectal carcinoma. We apply these models to 370 patients who underwent resection of their tumors. In 213 cases with negative lymph nodes, we found that the Bayes-estimated probability of missed metastases was related significantly to subsequent survival (P = .0006). In 157 cases with lymph nodal metastases, we found that the estimated value of the Poisson parameter a was associated more closely with subsequent survival than pN stage (P = 9 10(-6)). Consequently, we believe that the Poisson model provides insight and useful results in colorectal carcinoma.

Lymph nodes in colorectal carcinoma. The Poisson probability paradigm

This article introduces use of the Poisson probability density function and Bayes probability rule to understand and analyze lymph nodal metastases in colorectal carcinoma. We apply these models to 370 patients who underwent resection of their tumors. In 213 cases with negative lymph nodes, we found that the Bayes-estimated probability of missed metastases was related significantly to subsequent survival (P = .0006). In 157 cases with lymph nodal metastases, we found that the estimated value of the Poisson parameter a was associated more closely with subsequent survival than pN stage (P = 9 10(-6)). Consequently, we believe that the Poisson model provides insight and useful results in colorectal carcinoma.