DETECTION AND STAGING [published 1995]
ERVIN B. SHAW, M. D., BEVERLY W. DANIEL, M. D., ELIZABETH D.
WOFFORD, M. D., JOHN B. CARTER, M. D. [agar
embedding process explained & photos]
|The importance of early diagnosis of prostate cancer has recently
received much attention both in the medical literature1,2 and
lay media.3 While some calculate that the cost to screen
and then manage every diagnosable prostate cancer would be too burdensome,
our impression is that a great majority of individual patients desire
early diagnosis; and more treatment options are available at early
diagnosis. In view of such possible conflicting motivations, we determined
to do a systematic study of the effectiveness of a maximal-detection
prostate biopsy processing system devised by one of us (EBS) in late
|The frequency and comprehensiveness of needle biopsies of the prostate
gland has increased significantly since 1990 following the introduction
of PSA screening and the availability of a reliable, automated biopsy
gun technique.3 While the surgical pathology evaluation
of these needle biopsies is definitive in the diagnosis of prostatic
cancer, there is significant variation in surgical pathology laboratories
as to the methods and thoroughness with which these biopsies are
studied. The majority of prostate biopsies are done in doctors' offices,
and biopsy specimens are often processed by remote commercial laboratories.
In many urology practices, the multiple biopsies are submitted in
a single container (or possibly divided into right-side and left-side
containers) and processed as a cluster of tissue fragments, most
often with two to three levels of microscopic sections studied. We
introduced a system to separately identify each needle biopsy specimen
whether dealing with lesser or greater numbers of specimens, but
geared toward the sextant technique of prostate gland biopsies. This
sextant approach (three spaced biopsies ... apex, mid, base ... per
each side of the gland, six biopsies in all for each case) is used
in cases of an elevated PSA without a definite palpable lesion or
definite target lesion by ultrasound.5
|Effectiveness of the surgical pathology process was addressed in
the form of two questions: (1) How much surgical pathology work was
necessary to detect all cancers contained in the biopsy specimens?4 (2)
Did the sextant pattern plus this thorough process produce the highest
diagnostic yield of cancers?
SURGICAL PATHOLOGY THOROUGHNESS
Traditionally and by common practice, surgical pathology processing
of needle biopsies has involved sectioning of a single core biopsy
at two levels of section on two slides. With the advent of multiple
(often sextant) needle biopsies of the prostate gland, surgical
pathology processing remained relatively unchanged. Multiple biopsies
not separately identified with lateralizing labels are often processed
altogether in a single cluster of needle biopsy cores. Increasingly,
right and left-sided biopsies are segregated into separate bottles,
each of the multiple biopsies processed in a non-oriented cluster
in a single block cut at two levels of section on two slides. An
informal verbal survey of surgical pathology departments in early
1993 indicated that most departments reviewed multiple frames of
section on two or three slides. The bundle or wad of needle biopsy
cores precluded the ability to view an entire plane of section
of each needle biopsy. Rarely was there any attempt to spatially
orient the sections.
|In an effort to systematize and optimize the information to be
gained from prostatic needle biopsies, we developed a technique for
specimen orientation of transrectal ultrasound-guided (TRUS) needle
biopsies using disposable biopsy guns.4 Labeling and orientation
of each biopsy is maintained from the biopsy needle to the pathology
slide by use of directional orientation blot papers (Fig.
1) and agar pre-embedding of formalin fixed biopsy cores. Blot
papers are made from hand-towel paper, the best being paper which
is quick-absorbing yet firm enough to maintain its shape when wet.
We prefer Kimberly Clark's Surpass hand towels. Even a fragmented
biopsy maintains perfect orientation on a labeled blot paper. Keeping
the blot paper label in mind, the blot paper is mildly firmly touched
by the operator or an assistant onto the biopsy gun needle containing
the tissue core, the core instantly absorbing to the paper (Fig.
2), the paper then folded into the labeled specimen container
holding the 10 percent neutral buffered formalin fixative (we recommend
against any other type of fixative). With careful attention to maintaining
this orientation, the cores are removed onto the metal surgical pathology
dissecting table and arranged in relation to pre-cut, colored-agar
orientation markers. Biopsies and markers are then pre-embedded in
clear, melted agar which rapidly hardens (Fig.
3).6 At least three biopsy cores can be agar pre-embedded
in the same plane of sectioning in one paraffin block.4 Orientation
is maintained within the paraffin block (and thereafter on the histological
slides [Fig. 4]) by the presence of
the colored-agar markers, enabling precise determination as to the
localization (that is, capsular end vs. deep end of the tissue core)
and measured extent of any neoplasia identified. Location and inferred
estimate of tumor extent or volume may facilitate planning and clinico-pathologic
correlation of such procedures as endorectal coil MRI staging studies
or therapeutic options. Interval paraffin ribbons can be saved for
ancillary studies, including immuno-microscopy and DNA profiles [error:
we later found that DNA profiles require much thicker sections].
|We performed a look-back review of our entire experience of 540
consecutive unselected patient cases processed during a 12-month
period (1993) to determine the optimum number of levels of section
per block necessary for detection of all neoplasia actually contained
in the sum of the 18 gauge biopsy cores.4 Prior to and
during the study, an average of 10 slides representing evenly spaced
step-cut sections through the full thickness of the needle biopsy
core was made for each case with a range of seven to 16 slides per
block, two or three frames of tissue on each microscopic slide. This
original processing effort entailed exhaustive review of the 540
patient cases; hence, we assumed that all carcinomas actually contained
in biopsy cores had been detected... that none were missed, there
being no significant amount of tissue remaining in the paraffin blocks.
Using from one to eight biopsies per case, 105 (19 percent) cases
were carcinomatous. 29 of the malignant cases (28 percent) had only
a single, minute (3mm or less) focus of neoplasia in only one of
the biopsy cores.
|Our look-back analysis of this exhaustive processing technique
determined that all of the observed cancers would have been detect
ed by the study of five slides (15 frames of section) of level-plane,
spatially oriented needle biopsy sections. So, how much work is necessary
on a sextant series? To provide a margin of safety, we determined
as policy to prepare six step-sectioned slides (two to three frames
of section per slide) from each paraffin block, step-sectioning the
needle biopsy cores completely through (six slides, each at a separate
plane of section) and saving intervening ribbons until the case interpretation
was completed. Paraffin ribbons from unusual cases could be saved
|A clinical records review of the 29 cases with a single minute
focus of carcinoma revealed that 11 underwent radical prostatectomy.
Complete surgical pathology examination of all 11 surgically resected
prostate glands confirmed the diagnosis of adenocarcinoma, all tumors
being greater than 9mm in diameter or multi-focal in their involvement
of the prostate gland. Very importantly, three of the eleven cases
showed tumor extending to the surgical resection margins. Thus, in
agreement with others,7 the detection of a single minute
tumor focus using multiple (sextant) needle biopsies cannot be assumed
to reflect insignificant carcinoma as such may well represent a small
sampling of a much larger tumor that may be clinically significant. So-called "minute
carcinoma" in a sextant biopsy series has a very significant
chance of not being minute carcinoma in the resected prostate gland!
THOROUGHNESS PLUS SEXTANT PATTERN
Others8 have indicated a higher detection rate of cancer
when using a sextant or systematic patterned biopsy approach to
cases with PSA elevation but without evidence of a target nodule.
A review of 355 consecutive, unselected patients from three area
urology office general practices biopsied with 18 gauge needles
during 1995 indicated a significantly increased yield (39 to 43
percent) if from three to seven biopsies were taken, as opposed
to two or less (24 percent) (Table 1). Our review could not distinguish
cases as being with or without clinical target lesions. 12.8 percent
of the 196 patients undergoing sextant biopsies contained cancer
in only one of the six biopsies (Table 1).
While one might intuitively expect more biopsies to have a greater
diagnostic yield, we saw about a 40 percent yield so long as one
utilized at least three biopsies, a result probably attributable
to the heterogeneous mixture of biopsy indications in our unselected
series. If the utility of screening and early biopsy diagnosis
of prostate cancer is accepted as a mark of medical effectiveness,
our data suggests that there is a significant potential of a false-negative
biopsy study if less than a three-biopsy series is performed.
|In summary it is important to emphasize that minute carcinoma in
a needle biopsy may not be minute clinically. It only requires a
measured zone of cancer 4 mm in length in one biopsy core to define "clinically
significant" (volume > 0.5cc) cancer.7 Hence,
optimally sensitive processing of prostate needle biopsies done according
to the method of highest yield is essential to maximized detection.
Experience related to the 540 patient series indicates that six slides
carrying six spaced levels through the full thickness of the spatially
oriented, single-plane biopsy cores will detect all diagnosable neoplasia
within these biopsies. A less thorough examination hazards the possibility
of missing an important malignancy. A sextant series requires only
two paraffin blocks.
|The spatial orientation of the needle biopsies offers the ability
to roughly locate the tumor site as to the base, mid, and apical
portions of the right or left prostate lobes and to very roughly
estimate tumor size (at least as to a determination of clinically
significant size).7 The biopsy often contains the capsular
boundary, and our process allows one to portray the relationship
of a cancerous segment to the capsule. The capsular end of a biopsy
core may sometimes be discerned grossly by the presence of a thin,
elastic tail of periprostatic areolar tissue stringing from that
end of the biopsy core. The "capsule" of the gland is often
visible microscopically as a slightly increased peripheral loosening
of fibromuscular tissue, usually in contact with some microscopic
adipose tissue. Capsular involvement by tumor on a needle biopsy
most likely is, thereby, a true positive sign reflecting the real
status of tumor within the prostate gland. The presence of ganglion
cells is another indicator of "capsular" area. Of course,
absence of such as capsular or perineural tumor involvement on needle
biopsy cannot be assumed to be a true rule-out result as the amount
of sampling is so small.
|Though not the focus of this paper, it has not escaped our notice
that pre-analytical (prior to specimen receipt in the lab) factors
are crucial to maximized cancer detection and interpretation. These
include: quality PSA determinations, the urologist's choice of the
number of biopsies, biopsying of the most cancer-prevalent plane
(in the absence of a target lesion, para-peripheral rather than paramedial),7 and
snug positioning of the biopsy gun needle tip at the glandular-periglandular
interface (not pre-penetrated into the gland) prior to triggering
the biopsy. Such positioning accomplishes two important objectives.
Firstly, the capsular region is, thereby, likely to be contained
in the biopsy sample and be recognizable histologically. Secondly,
each biopsy thereby consists predominately of a maximized length
of actual prostate gland tissue, a longer cumulative length of multiple
biopsy cores being intuitively expected to detect more cancer than
shorter cumulative lengths. Concern for cancer location misinterpretation
due to the relatively tangential direction of the biopsy plane could
be allayed were a modification to be invented in the biopsy gun for
an angled biopsy path more directly ... less tangentially ... into
the gland. Finally, this fully oriented biopsy approach allows both
a focused approach to the surgical pathology processing of any subsequent
radical prostatectomy specimen, especially in cases of pre-operative
neo-adjuvant total androgen blockade where documentation of the residual
cancer can sometimes be so problematic.9 And a radiologico-pathological
correlation of findings is possible for a more optimized endorectal
coil MRI interpretation as we are providing in our hospital. Though
the reader may infer that our process is overly compulsive and too
time consuming, once set into place, it is actually a smoothly repetitious,
relatively easy approach to a significantly demanding area of surgical
pathology in view of the advantages gained.
- citation for the above = Shaw, EB; Daniel, BW; Wofford, ED; Carter, JB; "Prostate Biopsies: Optimized Cancer Detection and Staging", The Journal of the South Carolina Medical Association, 9/2 (6):261-266; June 1996.
- Optenberg SA, Thompson IM; "Economics of screening for carcinoma
of the prostate." Urol Clin North Am. 17:719-737, 1990.
- Slawin KM; Ohori M, Dillioglugil 0, Scardino, PT; "Screening
for prostate cancer: An analysis of the early experience." CA-A
Ca J Clin. 45(3):134-147, 1995.
- Kolata G. "Advances in detection create dilemma on prostate
cancer." The New York Times; Al, 1993.
- Letter: Shaw EB, Carter JB, Daniel, BW, Wofford, ED; "Adequate Tissue Sampling of Prostate Core Needle Biopsies." Am J Clin Pathol.
108(3):359-360, 1997, HERE.
- Hodge KK, McNeal JE, Terris MK, Stamey TA; "Random systematic
versus directed ultrasound guided transrectal core biopsies of
the prostate." J. Urol. 142:71-74,1989.
- Watson CG, Johnson JM, Shaw EB; "Correct
orientation of specimens for histologic processing - Preliminary
embedding in agar"; Am J Derm Path. 5:165-167, 1983.
- Stamey TA. "Making the most out of six systematic sextant biopsies."
Urol. 45:2-12, 1995.
- Terris MK, McNeal JE, Stamey TA. "Detection of clinically significant
prostate cancer by transrectal ultrasound-guided systematic biopsies."
J. Urol. 148:829-832, 1992.
- Armas OA, Aprikian AG, Reuter VE, et al.; "Clinical
and pathobiological effects of neoadjuvant total androgen ablation
therapy on clinically localized prostatic adenocarcinoma." Am J
Surg Pathol. 18:979-991, 1994.
(posted on-line by lead author April 8, 2001...copyright is with
JSCMA; adjusted 11/20/2016)