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Ultrasonic Evaluation of the Prostatic Nodule
0022-534 7/78/1201-0086.$02. 00/0 Vol. 120, July
THE JOURNAL OF UROLOGY
Printed in U.SA.
Copyright © 1978 by The Williams & Wilkins Co.
ULTRASONIC EVALUATION OF THE PROSTATIC NODULE MARTIN I. RESNICK,* JAMES W. WILLARD
AND
WILLIAM H. BOYCE
From the Department of Surgery, Section of Urology, Bowman Gray School of Medicine, Winston-Salem, North Carolina
ABSTRACT
Prostatic nodules detected on rectal examination of 50 patients were evaluated by the usual means and by prostatic ultrasonic scanning. Nodules were characterized as being either malignant, benign, inflammatory or stones. Those patients without evidence of calcification on radiography underwent prostatic biopsy and the histological findings were compared to the ultrasonic study. All histologically confirmed malignancies were diagnosed preoperatively and there were no instances of falsely negative ultrasonic studies. attenuation usually are present throughout the gland. Prostatic nodules that represent areas of nodular hyperplasia ultrasonically cannot be distinguished from the remaining portions of the hyperplastic gland (fig. 1). Malignant nodules are viewed at focally dense asymmetric areas that do not fade with increased instrument attenuation. Frequently, sound waves are not transmitted through the tumor, thus resulting in poor definition of that portion of the prostatic capsule lying directly anterior to the involved area (fig. 2). Larger tumors will distort the capsule and with periprostatic extension frequently, seminal vesicle invasion can be detected. At times, areas of chronic prostatitis are difficult to distinguish from malignancy. Frequently, the dense echoes are MATERIALS AND METHODS symmetrical, extend laterally from the urethra and never The study population consists of a group of patients evalu- distort or obscure the prostatic capsule (fig. 3). In addition to ated at the North Carolina Baptist Hospital after detection of the ultrasonic findings the diagnosis usually is suspected on a prostatic nodule by rectal examin,ation. Included in the the basis of symptoms, degree of prostatic tenderness and evaluation of all patients was a complete history and physical induration, characteristics of expressed prostatic fluid and examination, urinalysis, urine culture, sequential multiple other pertinent clinical studies. Ultrasonically, prostatic calculi share several characterisanalytical computer serum chemistry survey, serum acid phosphatase determination and, when indicated, excretory tics typical of carcinomas. They, too, will be viewed as focally urography and cystoscopy. Plain x-rays of the pelvis with dense asymmetric areas that produce sonic shadows anteriorly oblique views were obtained on all patients in an effort to owing to their ability to impair the transmission of sonic impulses (fig. 4). However, they do not cause distortion of the identify and localize prostatic calcifications. The technique of transrectal prostatic ultrasonography has prostatic capsule and their position can be confirmed with been described in detail previously. 4 • 5 Briefly, a rotatable radiographic studies. We studied 50 patients with previously undiagnosed prostransrectal transmitting and receiving ultrasonic probe is passed into the rectum and serial sonograms are obtained of tatic nodules. The mean age of patients was 70.2 years (range the prostate and surrounding structures. The image is dis- 39 to 90) and all but 2 were more than 50 years old at the time played on a scan converter, which displays in 9112 shades of of evaluation. Prostatic calcifications were found in 5 patients gray. Photographic records are obtained of each scan and and the position as determined by ultrasonography and rastored for future reference. Perineal needle biopsies were diography corresponded to the location of the palpable nodule. performed on those patients without evidence of prostatic Perineal needle prostatic biopsies were performed in the calcification or if the location of the nodules did not correspond remaining 45 patients (table 1). Twenty-one patients had ultrasonic scans suggestive of to the site of prostatic calculi, as determined by ultrasonogramalignancy and all were found to have histological evidence phy and radiography. of adenocarcinoma after appropriate biopsy. Needle biopsies from 2 patients revealed only benign tissue. However, because RESULTS Ultrasonic characteristics of benign glands typically reveal of the presence of suspicious scans, open perineal biopsies a symmetrical, triangular echo pattern that represents reflec- were performed in both and adenocarcinoma was diagnosed tions from the prostatic capsule. The capsule usually is contin- correctly. One patient with a nodule in the left lobe of the uous and free of distortion. Numerous fine homogeneous prostate was found to have calcification on the right side. The echoes that can be eliminated with increased instrument sonic findings suggested that the nodule was malignant and, indeed, biopsy confirmed this suspicion. Twenty patients had nodules that ultrasonically appeared Accepted for publication September 16, 1977. Read at annual meeting of Southeastern Section, American Uro- as benign tissue and all biopsies revealed benign hyperplasia. A suspicious ultrasonic area was detected in 1 patient in the logical Association, New Orleans, Louisiana, March 27-31, 1977. This investigation was supported by Grant R26 CA 20118-02 from palpably normal opposite lobe and biopsy confirmed the presthe National Prostatic Cancer Project, National Cancer Institute, ence of clinically undetectable adenocarcinoma. National Institutes of Health, Bethesda, Maryland. Biopsies from 4 patients revealed changes consistent with *Requests for reprints: Section of Urology, Bowman Gray School of Medicine, Winston-Salem, North Carolina 27103. chronic prostatitis. Based on the ultrasonic scan prostatitis 86 Rectal palpation is the single most important step in the physical examination for detecting carcinoma of the prostate and it is well recognized that there is an increased incidence of early disease detection when done routinely. 1 Although small nodular or indurated areas in the prostate may be readily palpable the differentiation between benign and malignant lesions cannot be made by physical examination alone. 2 • 3 Many clinicians follow the dictum "every hard prostate is cancer until proven otherwise" and that the only certain method of establishing the proper diagnosis is with adequate biopsy. We herein describe the use of transrectal prostatic ultrasonography as an adjunct in the evaluation and management of patients with prostatic nodules.
37
FIG. 1. Prostatic scan of 62-year-old man with nodule in left lobe of prostate. Scan is typical of benign hyperplasia. C, capsule
FIG. 2. Prostatic scan of 71-year-old man with 1 cm. nodule confined to right lobe of prostate. Prostatic capsule is not distorted but sonic shadow is present anteriorly secondary to sonically dense mass. T, tumor. C, capsule.
was predicted in 2 of these patients but a differentiation could rectal examination alone. An rm,o,..annn was perrormed on all not be made between carcinoma and inflammation in the patients and pathological stage of the disease at the time of other 2 cases. The clinical history and the detection of white exploration closely corresponded to the ultrasonic findings. blood cells in the expressed prostatic fluid were suggestive of DISCUSSION prostatitis, which was confirmed by biopsy. Transrectal ultrasonography clearly demonstrated the deSmall, early, infiltrating prostatic tumors can be confused gree of tumor involvement in patients with malignancy. Based with a variety of different diseases of the prostate. Several on age and clinical status only 8 patients were believed to be studies have shown that approximately 50 per cent of nodules suitable candidates for radical prostatectomy (table 2). When or indurated areas of the prostate are malignant and most physical examinations are considered alone only 6 of these 8 reports emphasize that there is little or no correlation between patients had what was believed to be disease localized to the the clinical impression as determined by rectal palpation and prostate gland. The remaining 2 patients had tumors located the results of surgical biopsy.';-8 Benign prostatic nodules may along the base of the gland and there was believed to be be secondary to benign nodular hyperplasia, acute prostatitis, minimal extension around the seminal vesicles that was chronic prostatitis (non-specific, tuberculous, granulomatous, amenable to removal by a radical operation. Ultrasonic stud- abscess), calculi, vascular injury (prostatic infarct, periprosies confirmed the presence of seminal vesicle involvement in tatic venous thrombosis) or hormonal influences (squamous these latter 2 patients. However, 2 other patients who were metaplasia). 9 Prostatic malignancies causing nodules include believed to have localized disease were found to have extension adenocarcinoma, squamous cell carcinoma, transitional cell around the seminal vesicles that could not be appreciated by carcinoma, sarcoma, lymphoma and metastatic tumors.
88
RESNICK, WILLARD AND BOYCE
Fm. 3. Prostatic scan of 58-year-old man with area of induration present over left lobe of prostate. Symmetrical dense periurethral echoes present are typical ofprostatitis. U, urethra. C, capsule.
•
'
Fm. 4. Prostatic scan of 56-year-old man with nodular area present in left lobe of prostate. Sonograms characteristic of stones are dense and produce echo shadows anteriorly. S, stone. C, capsule.
Perineal needle biopsy, the usual method of establishing the histological diagnosis of carcinoma of the prostate, has a recognized diagnostic error approaching 30 per cent in localized nodules. 10 Accuracy frequently depends on the expertise of the surgeon and the extent of disease. Usually, the higher the stage the easier it is to establish the proper diagnosis by biopsy. Other than by perineal needle biopsy suspicious areas may be biopsied transrectally (open or needle), transurethrally or by an open perineal procedure. Transrectal biopsy has been reported to be highly accurate but the procedure carries the potential risk of infection because the needle must be passed through the rectal mucosa. 11 Since most carcinomas are located posteriorly and not periurethrally transurethral biopsy generally is considered to be the least accurate technique. Open perineal biopsy is probably the most accurate technique for the detection of prostatic cancer but since it requires anesthesia, an incision and several days of hospitali-
zation it is not performed routinely and is usually reserved for highly suspicious glands that have had negative biopsies by the other methods. Rectal examination is of value not only in the detection of malignancy but also in the clinical assessment of tumor stage. Frequently, extensive lesions are appreciated by the presence of tumor extension in the lateral sulci or around the seminal vesicles. Not infrequently, discrete nodules are found to be quite extensive either at the time of the operation or on pathological examination of the removed specimen and understaging has been reported to occur in approximately 25 per cent of all patients with seemingly localized disease. 2 • 12 Involvement of the seminal vesicles should be suspected if the upper margins of the tumor cannot be palpated and it is more likely to occur if the nodule is located at the base of the gland rather than at the apex. Transrectal ultrasonography appears to be a useful adjunct in the evaluation of patients with prostatic nodules. The
GLTRAS0t~IC E 1/_.t\LlfJAT10f'J OF PROSTATIC NODlJLE
1. Comparison offinclings by prostatic ultrasonography and histologic diagnosis in 45 patients with prostatic nodules
TABLi':
Adenocarcinoma Benign hyperplasia Prostatitis
Ultrasound
Biopsy
21
21 (19)* 20 (22)*
20 4t
4
* Needle biopsy in 2 patients initially benign; repeat open biopsy revealed carcinoma.
t Could not distinguish prostatitis from carcinoma in 2 patients.
TABLE
2. Comparison of rectal examination and ultrasonography in
staging carcinoma of prostate Stage
Clinical examination Ultrasonography Surgical stage
B
C
6 4 4
2 4 4
technique is helpful not only in identifying and localizing nodular lesions but also in the differentiation of malignant and benign lesions. This procedure is of value in selecting those patients who have had negative studies but warrant further diagnostic evaluation either by repeating the needle biopsy or by proceeding to an open biopsy. Finally, ultrasonography is a useful non-invasive staging technique. With increased staging accuracy the surgeon can be forewarned of extensive lesions so that effective therapy may be used properly.
39
REFERENCES
1. Kimbrough, J. C. and Rowe, R. B.: Carcinoma of the prostate. J. Urol., 66: 373, 1951. 2. Jewett, H. J.: Significance of the palpable prostatic nodule. J.A.M.A., 160: 838, 1956. 3. Grabstald, H.: Further experience with transrectal biopsy of the prostate. J. Urol., 74: 211, 1955. 4. Boyce, W. H., McKinney, W. M., Resnick, M. I. and Willard, J. W.: Ultrasonography as an aid in the diagnosis and management of surgical diseases of the pelvis: special emphasis on the genitourinary system. Ann. Surg., 184: 477, 1976. 5. Resnick, M. I., Willard, J. W. and Boyce, W. H.: Recent progress in ultrasonography of the bladder and prostate. J. Urol., 117: 444, 1977. 6. Barnes, R. W. and Okamoto, S.: Diagnosis of prostatic carcinoma: a statistical study. West. J. Surg., 69: 362, 1961. 7. Emmett, J. L., Barber, K. W., Jr. and Jackman, R. J.: Transrectal biopsy to detect prostatic carcinoma: a review and report of 203 cases. J. Urol., 87: 460, 1962. 8. Goldstein, A. E. and Weinberg, T.: The importance of correct pathologic diagnosis of carcinoma of prostate: clinical application. Amer. Surg., 20: 971, 1954. 9. Grabstald, H.: The clinical and laboratory diagnosis of cancer of the prostate. Cancer, 15: 76, 1965. 10. Kaufman, J. J. and Schultz, J. I.: Needle biopsy of the prostate: a re-evaluation. J. Urol., 87: 164, 1962. 11. Zincke, H., Campbell, J. T., Utz, D. C., Farrow, G. M. and Anderson, M. J.: Confidence in the negative transrectal needle biopsy. Surg., Gynec. & Obst., 136: 78, 1973. 12. Jewett, H. J., Eggleston, J. C. and Yawn, D. H.: Radical prostatectomy in the management of carcinoma of the prostate: probable causes of some therapeutic failures. J. Urol., 107: 1034, 1972.
THE JOURNAL OF UROLOGY
Printed in U.SA.
Copyright © 1978 by The Williams & Wilkins Co.
ULTRASONIC EVALUATION OF THE PROSTATIC NODULE MARTIN I. RESNICK,* JAMES W. WILLARD
AND
WILLIAM H. BOYCE
From the Department of Surgery, Section of Urology, Bowman Gray School of Medicine, Winston-Salem, North Carolina
ABSTRACT
Prostatic nodules detected on rectal examination of 50 patients were evaluated by the usual means and by prostatic ultrasonic scanning. Nodules were characterized as being either malignant, benign, inflammatory or stones. Those patients without evidence of calcification on radiography underwent prostatic biopsy and the histological findings were compared to the ultrasonic study. All histologically confirmed malignancies were diagnosed preoperatively and there were no instances of falsely negative ultrasonic studies. attenuation usually are present throughout the gland. Prostatic nodules that represent areas of nodular hyperplasia ultrasonically cannot be distinguished from the remaining portions of the hyperplastic gland (fig. 1). Malignant nodules are viewed at focally dense asymmetric areas that do not fade with increased instrument attenuation. Frequently, sound waves are not transmitted through the tumor, thus resulting in poor definition of that portion of the prostatic capsule lying directly anterior to the involved area (fig. 2). Larger tumors will distort the capsule and with periprostatic extension frequently, seminal vesicle invasion can be detected. At times, areas of chronic prostatitis are difficult to distinguish from malignancy. Frequently, the dense echoes are MATERIALS AND METHODS symmetrical, extend laterally from the urethra and never The study population consists of a group of patients evalu- distort or obscure the prostatic capsule (fig. 3). In addition to ated at the North Carolina Baptist Hospital after detection of the ultrasonic findings the diagnosis usually is suspected on a prostatic nodule by rectal examin,ation. Included in the the basis of symptoms, degree of prostatic tenderness and evaluation of all patients was a complete history and physical induration, characteristics of expressed prostatic fluid and examination, urinalysis, urine culture, sequential multiple other pertinent clinical studies. Ultrasonically, prostatic calculi share several characterisanalytical computer serum chemistry survey, serum acid phosphatase determination and, when indicated, excretory tics typical of carcinomas. They, too, will be viewed as focally urography and cystoscopy. Plain x-rays of the pelvis with dense asymmetric areas that produce sonic shadows anteriorly oblique views were obtained on all patients in an effort to owing to their ability to impair the transmission of sonic impulses (fig. 4). However, they do not cause distortion of the identify and localize prostatic calcifications. The technique of transrectal prostatic ultrasonography has prostatic capsule and their position can be confirmed with been described in detail previously. 4 • 5 Briefly, a rotatable radiographic studies. We studied 50 patients with previously undiagnosed prostransrectal transmitting and receiving ultrasonic probe is passed into the rectum and serial sonograms are obtained of tatic nodules. The mean age of patients was 70.2 years (range the prostate and surrounding structures. The image is dis- 39 to 90) and all but 2 were more than 50 years old at the time played on a scan converter, which displays in 9112 shades of of evaluation. Prostatic calcifications were found in 5 patients gray. Photographic records are obtained of each scan and and the position as determined by ultrasonography and rastored for future reference. Perineal needle biopsies were diography corresponded to the location of the palpable nodule. performed on those patients without evidence of prostatic Perineal needle prostatic biopsies were performed in the calcification or if the location of the nodules did not correspond remaining 45 patients (table 1). Twenty-one patients had ultrasonic scans suggestive of to the site of prostatic calculi, as determined by ultrasonogramalignancy and all were found to have histological evidence phy and radiography. of adenocarcinoma after appropriate biopsy. Needle biopsies from 2 patients revealed only benign tissue. However, because RESULTS Ultrasonic characteristics of benign glands typically reveal of the presence of suspicious scans, open perineal biopsies a symmetrical, triangular echo pattern that represents reflec- were performed in both and adenocarcinoma was diagnosed tions from the prostatic capsule. The capsule usually is contin- correctly. One patient with a nodule in the left lobe of the uous and free of distortion. Numerous fine homogeneous prostate was found to have calcification on the right side. The echoes that can be eliminated with increased instrument sonic findings suggested that the nodule was malignant and, indeed, biopsy confirmed this suspicion. Twenty patients had nodules that ultrasonically appeared Accepted for publication September 16, 1977. Read at annual meeting of Southeastern Section, American Uro- as benign tissue and all biopsies revealed benign hyperplasia. A suspicious ultrasonic area was detected in 1 patient in the logical Association, New Orleans, Louisiana, March 27-31, 1977. This investigation was supported by Grant R26 CA 20118-02 from palpably normal opposite lobe and biopsy confirmed the presthe National Prostatic Cancer Project, National Cancer Institute, ence of clinically undetectable adenocarcinoma. National Institutes of Health, Bethesda, Maryland. Biopsies from 4 patients revealed changes consistent with *Requests for reprints: Section of Urology, Bowman Gray School of Medicine, Winston-Salem, North Carolina 27103. chronic prostatitis. Based on the ultrasonic scan prostatitis 86 Rectal palpation is the single most important step in the physical examination for detecting carcinoma of the prostate and it is well recognized that there is an increased incidence of early disease detection when done routinely. 1 Although small nodular or indurated areas in the prostate may be readily palpable the differentiation between benign and malignant lesions cannot be made by physical examination alone. 2 • 3 Many clinicians follow the dictum "every hard prostate is cancer until proven otherwise" and that the only certain method of establishing the proper diagnosis is with adequate biopsy. We herein describe the use of transrectal prostatic ultrasonography as an adjunct in the evaluation and management of patients with prostatic nodules.
37
FIG. 1. Prostatic scan of 62-year-old man with nodule in left lobe of prostate. Scan is typical of benign hyperplasia. C, capsule
FIG. 2. Prostatic scan of 71-year-old man with 1 cm. nodule confined to right lobe of prostate. Prostatic capsule is not distorted but sonic shadow is present anteriorly secondary to sonically dense mass. T, tumor. C, capsule.
was predicted in 2 of these patients but a differentiation could rectal examination alone. An rm,o,..annn was perrormed on all not be made between carcinoma and inflammation in the patients and pathological stage of the disease at the time of other 2 cases. The clinical history and the detection of white exploration closely corresponded to the ultrasonic findings. blood cells in the expressed prostatic fluid were suggestive of DISCUSSION prostatitis, which was confirmed by biopsy. Transrectal ultrasonography clearly demonstrated the deSmall, early, infiltrating prostatic tumors can be confused gree of tumor involvement in patients with malignancy. Based with a variety of different diseases of the prostate. Several on age and clinical status only 8 patients were believed to be studies have shown that approximately 50 per cent of nodules suitable candidates for radical prostatectomy (table 2). When or indurated areas of the prostate are malignant and most physical examinations are considered alone only 6 of these 8 reports emphasize that there is little or no correlation between patients had what was believed to be disease localized to the the clinical impression as determined by rectal palpation and prostate gland. The remaining 2 patients had tumors located the results of surgical biopsy.';-8 Benign prostatic nodules may along the base of the gland and there was believed to be be secondary to benign nodular hyperplasia, acute prostatitis, minimal extension around the seminal vesicles that was chronic prostatitis (non-specific, tuberculous, granulomatous, amenable to removal by a radical operation. Ultrasonic stud- abscess), calculi, vascular injury (prostatic infarct, periprosies confirmed the presence of seminal vesicle involvement in tatic venous thrombosis) or hormonal influences (squamous these latter 2 patients. However, 2 other patients who were metaplasia). 9 Prostatic malignancies causing nodules include believed to have localized disease were found to have extension adenocarcinoma, squamous cell carcinoma, transitional cell around the seminal vesicles that could not be appreciated by carcinoma, sarcoma, lymphoma and metastatic tumors.
88
RESNICK, WILLARD AND BOYCE
Fm. 3. Prostatic scan of 58-year-old man with area of induration present over left lobe of prostate. Symmetrical dense periurethral echoes present are typical ofprostatitis. U, urethra. C, capsule.
•
'
Fm. 4. Prostatic scan of 56-year-old man with nodular area present in left lobe of prostate. Sonograms characteristic of stones are dense and produce echo shadows anteriorly. S, stone. C, capsule.
Perineal needle biopsy, the usual method of establishing the histological diagnosis of carcinoma of the prostate, has a recognized diagnostic error approaching 30 per cent in localized nodules. 10 Accuracy frequently depends on the expertise of the surgeon and the extent of disease. Usually, the higher the stage the easier it is to establish the proper diagnosis by biopsy. Other than by perineal needle biopsy suspicious areas may be biopsied transrectally (open or needle), transurethrally or by an open perineal procedure. Transrectal biopsy has been reported to be highly accurate but the procedure carries the potential risk of infection because the needle must be passed through the rectal mucosa. 11 Since most carcinomas are located posteriorly and not periurethrally transurethral biopsy generally is considered to be the least accurate technique. Open perineal biopsy is probably the most accurate technique for the detection of prostatic cancer but since it requires anesthesia, an incision and several days of hospitali-
zation it is not performed routinely and is usually reserved for highly suspicious glands that have had negative biopsies by the other methods. Rectal examination is of value not only in the detection of malignancy but also in the clinical assessment of tumor stage. Frequently, extensive lesions are appreciated by the presence of tumor extension in the lateral sulci or around the seminal vesicles. Not infrequently, discrete nodules are found to be quite extensive either at the time of the operation or on pathological examination of the removed specimen and understaging has been reported to occur in approximately 25 per cent of all patients with seemingly localized disease. 2 • 12 Involvement of the seminal vesicles should be suspected if the upper margins of the tumor cannot be palpated and it is more likely to occur if the nodule is located at the base of the gland rather than at the apex. Transrectal ultrasonography appears to be a useful adjunct in the evaluation of patients with prostatic nodules. The
GLTRAS0t~IC E 1/_.t\LlfJAT10f'J OF PROSTATIC NODlJLE
1. Comparison offinclings by prostatic ultrasonography and histologic diagnosis in 45 patients with prostatic nodules
TABLi':
Adenocarcinoma Benign hyperplasia Prostatitis
Ultrasound
Biopsy
21
21 (19)* 20 (22)*
20 4t
4
* Needle biopsy in 2 patients initially benign; repeat open biopsy revealed carcinoma.
t Could not distinguish prostatitis from carcinoma in 2 patients.
TABLE
2. Comparison of rectal examination and ultrasonography in
staging carcinoma of prostate Stage
Clinical examination Ultrasonography Surgical stage
B
C
6 4 4
2 4 4
technique is helpful not only in identifying and localizing nodular lesions but also in the differentiation of malignant and benign lesions. This procedure is of value in selecting those patients who have had negative studies but warrant further diagnostic evaluation either by repeating the needle biopsy or by proceeding to an open biopsy. Finally, ultrasonography is a useful non-invasive staging technique. With increased staging accuracy the surgeon can be forewarned of extensive lesions so that effective therapy may be used properly.
39
REFERENCES
1. Kimbrough, J. C. and Rowe, R. B.: Carcinoma of the prostate. J. Urol., 66: 373, 1951. 2. Jewett, H. J.: Significance of the palpable prostatic nodule. J.A.M.A., 160: 838, 1956. 3. Grabstald, H.: Further experience with transrectal biopsy of the prostate. J. Urol., 74: 211, 1955. 4. Boyce, W. H., McKinney, W. M., Resnick, M. I. and Willard, J. W.: Ultrasonography as an aid in the diagnosis and management of surgical diseases of the pelvis: special emphasis on the genitourinary system. Ann. Surg., 184: 477, 1976. 5. Resnick, M. I., Willard, J. W. and Boyce, W. H.: Recent progress in ultrasonography of the bladder and prostate. J. Urol., 117: 444, 1977. 6. Barnes, R. W. and Okamoto, S.: Diagnosis of prostatic carcinoma: a statistical study. West. J. Surg., 69: 362, 1961. 7. Emmett, J. L., Barber, K. W., Jr. and Jackman, R. J.: Transrectal biopsy to detect prostatic carcinoma: a review and report of 203 cases. J. Urol., 87: 460, 1962. 8. Goldstein, A. E. and Weinberg, T.: The importance of correct pathologic diagnosis of carcinoma of prostate: clinical application. Amer. Surg., 20: 971, 1954. 9. Grabstald, H.: The clinical and laboratory diagnosis of cancer of the prostate. Cancer, 15: 76, 1965. 10. Kaufman, J. J. and Schultz, J. I.: Needle biopsy of the prostate: a re-evaluation. J. Urol., 87: 164, 1962. 11. Zincke, H., Campbell, J. T., Utz, D. C., Farrow, G. M. and Anderson, M. J.: Confidence in the negative transrectal needle biopsy. Surg., Gynec. & Obst., 136: 78, 1973. 12. Jewett, H. J., Eggleston, J. C. and Yawn, D. H.: Radical prostatectomy in the management of carcinoma of the prostate: probable causes of some therapeutic failures. J. Urol., 107: 1034, 1972.