[Cancer Research 60, 2152-2154, April 15, 2000]
© 2000 American Association for Cancer Research
Prognosis of Primary Testicular Seminoma: A Report on 57 New Cases1
Keita Fujikawa2,
Yoshiyuki Matsui,
Hiroya Oka,
Shigeki Fukuzawa,
Miharu Sasaki and
Hideo Takeuchi
Department of Urology, Kobe City General Hospital, Kobe City [K. F., Y. M., H. O., S. F., H. T.], and Department of Urology, Shizuoka City Hospital, Shizuoka City 420 [M. S.], Japan
 |
ABSTRACT
|
|---|
Most urologists perform adjuvant radiation therapy for stage 1
(TxN0M0) testicular seminoma after
orchiectomy, although the majority of patients with clinical stage 1
seminoma do not have occult metastases and therefore do not require
elective nodal irradiation. However, there are currently no clinical or
histological parameters that can be used to distinguish patients who
need radiation therapy from those who do not. We reported previously
that estimates of volume-weighted mean nuclear volume (MNV) were a
better predictor of the prognosis of prostate cancer and renal cell
carcinoma than subjective histological grading. Here, we examined the
usefulness of estimation of MNV for predicting the prognosis of primary
testicular seminoma. A retrospective study of 57 patients with
testicular seminoma diagnosed between April 1981 and March 1997 at Kobe
City General Hospital was performed. Unbiased estimates of MNV data
were compared for prognostic value with the level of ß-human
chorionic gonadotropin (ß-HCG), 
-fetoprotein (AFP), alkaline
phosphatase (ALP), and lactate dehydrogenase (LDH). Fifty patients were
stage 1 (TxN0M0), and 7 patients
were stage 2 (TxN1–2M0). All
patients received orchiectomy, followed by radiation therapy. Estimates
of MNV of stage 2 patients were significantly larger than that of stage
1 patients (P = 0.0142). Although the LDH level
was also significantly higher in stage 2 (P = 0.001), there were no significant differences between stages 1 and 2
with respect to ß-HCG (P = 0.997), ALP
(P = 0.226), and AFP (P = 0.467). Multivariate logistic regression analysis revealed that the
estimate of MNV was the only variable predicting lymph node metastasis
(P = 0.0315). In stage 1 patients, only the
estimate of MNV was significantly correlated with progression-free
survival (P = 0.0118). These findings indicate
that the estimate of MNV may be an important prognostic indicator for
testicular seminoma. Estimates of MNV may also be useful for excluding
patients from surveillance protocols.
|
INTRODUCTION
|
|---|
Remarkable improvement in the prognosis of testicular tumors has
recently been achieved. Metastatic disease can be cured in the majority
of patients by multiagent systemic chemotherapy after orchiectomy
(1
, 2)
. Patients with clinical stage 1 seminoma are
treated by orchiectomy plus external radiation to the retroperitoneal
lymph nodes at risk of harboring subclinical micrometastases (the
ipsilateral pelvic and para-aortic nodes), and this approach has
achieved long-term cure rates of greater than 90–95% (3
, 4)
. It is generally accepted that approximately 10–20% of
clinical stage 1 seminoma patients have occult disease in the abdomen
(5)
. Therefore, this policy of elective adjuvant regional
nodal irradiation means that 
85% of patients are being treated
unnecessarily (6)
. If it were possible to more accurately
stage seminoma, many patients could avoid the side effects of radiation
therapy, and medical costs would also be decreased. However,
conventional histopathological findings cannot be used to identify
patients with occult retroperitoneal metastases (7)
.
Calculation of the volume-weighted
MNV3
is the only method by which an unbiased estimate of a three-dimensional
parameter can be obtained from single two-dimensional sections
(8)
. The MNV was developed by Gunderson and Jensen
(9
, 10)
, based on a stereological method. We have reported
previously that this parameter is prognostically important for prostate
cancer (11, 12, 13, 14)
, renal cell carcinoma (15)
,
and bladder cancer (16)
. However, the relationship between
MNV and the prognosis of seminoma has not been investigated thus far.
In an effort to identify the subset of patients with clinical stage 1
seminoma who may be monitored after orchiectomy rather than requiring
elective regional nodal irradiation, we examined the clinical and
pathological features of 57 patients, including calculation of their
MNV values.
|
PATIENTS AND METHODS
|
|---|
Patients.
Ninety-seven patients with primary testicular tumors were diagnosed at
Kobe City General Hospital between 1981 and 1997. All patients
underwent orchiectomy, and 57 patients had a final diagnosis of primary
pure seminoma after examination of orchiectomy specimens (classic in
53, spermatocytic in 1, and anaplastic in 3). Pretreatment staging was
done with physical examination, excretory urography, chest X-ray, bone
scan, and computerized tomography of the retroperitoneum. Fifty
patients were classified as clinical stage 1
(TxN0M0), and 7 patients were
classified as stage 2 (TxN1–2M0).
All patients received radiation therapy to the ipsilateral pelvic and
para-aortic nodes. Four patients who had residual retroperitoneal
masses after irradiation were treated with platinum-based chemotherapy
and retroperitoneal lymph node dissection. Patients were followed up
every 1–3 months. Routine tests included physical examination, chest
X-rays, skeletal survey, ultrasonography, or computerized tomography of
the abdomen and serum tumor markers. In this study, unbiased estimates
of MNV were compared with the levels of ß-HCG, AFP, ALP, and LDH to
assess their relative prognostic value. At the time of study
completion, 52 patients were still alive, and 5 had died. The mean
follow-up period for the surviving patients was 61.1 months (range,
24–192 months).
MNV.
The slides used for histological tumor grading were used for the
stereological calculation of MNV. An Olympus BHS microscope (Olympus,
Tokyo, Japan), with a projection attachment and a x100 oil immersion
lens (numerical aperture, 1.4), was used to obtain the quantitative
histopathological variables. The final calibrated magnification was
x1600. A section from each seminoma was projected onto the used test
system. In each specimen, the three-dimensional nuclei were first
sampled in proportion to height by the histological slide. The nuclei
were then resampled in proportion to the sectional area with a
point-grid, and only nuclear profiles hit by points were sampled for
the estimation of MNV, i.e., nuclei are sampled proportional
to height x sectional area = volume
(8)
. On the point-sampled nuclear profiles, nuclear
intercepts were measured from nuclear boundary to nuclear boundary
through the sampling point in one direction, as indicated by the test
system. A minimum of four visual fields and a minimum of 50 nuclei are
needed to calculate MNV (9
, 10)
; thus, 4–10 fields of
vision (average, 6.3) obtained at random and 60–120 intercepts
(average, 85.1) were examined in each patient. An unbiased estimate of
MNV was obtained by multiplying the mean of the cubed intercept length
by 
/3. A detailed description of the techniques used, including the
formulae and calculations, has been published previously
(8, 9, 10)
.
Statistics.
Progression-free survival was estimated from Kaplan-Meier plots, and
differences between groups were assessed with the log-rank test.
Multivariate logistic regression analysis was performed using SPSS
software (Statistical Package for the Social Sciences; SPSS, Inc.,
Chicago, IL) to determine the variables that were correlated
independently with the prognosis. Comparisons between group means were
done using the Mann-Whitney U test. More than two groups
were analyzed by the nonparametric Kruskal-Wallis test. The limit of
significance for all tests was P < 0.05.
|
RESULTS
|
|---|
Lymph Node Metastasis.
The mean estimate of MNV calculated for stage 2 patients was 891.4
µm3, whereas that of stage 1 patients was 626.2
µm3. Therefore, the MNV was significantly larger in stage
2 (P = 0.0142, Table 1
). Although the LDH level was significantly higher in stage 2 than in
stage 1 (P = 0.001), there were no
significant differences between the two stages with regard to the
levels of ß-HCG (P = 0.997), ALP
(P = 0.226), and AFP (P = 0.467, Table 1
). Multivariate logistic regression analysis
revealed that estimates of MNV were the only prognostic factor
predicting lymph node metastasis (P = 0.0315,
Table 2
).
View this table:
[in this window]
[in a new window]
|
Table 1 Significance of each prognostic factor with regard to the presence of
lymph node metastasis in 57 patients with testicular seminoma
|
|
View this table:
[in this window]
[in a new window]
|
Table 2 Multivariate logistic regression analysis of the possible predictors of
lymph node metastasis in 57 patients with testicular seminoma
|
|
Progression-free Survival.
Factors predicting disease progression were analyzed for the stage 1
patients. Five stage 1 patients showed progression during the follow-up
period, with four developing mediastinal lymph node metastasis and one
developing inguinal lymph node metastasis. Fifty stage 1 patients were
classified by their MNV values, which ranged from 259.4 to 1066.7
µm3, with a median of 620 µm3.
Progression-free survival curves are shown in Fig. 1
. The prognosis of the MNV 
620 µm3 group
was significantly worse than that of the MNV < 620
µm3 group (P = 0.0118). LDH
(P = 0.3274), ß-HCG (P = 0.3424), ALP (P = 0.1210), and AFP
(P = 0.9870) were of no prognostic value.
View larger version (13K):
[in this window]
[in a new window]
|
Fig. 1. Kaplan-Meier progression-free survival curves for 50
patients with stage 1 (TxN0M0)
testicular seminoma stratified according to the MNV. ———,
MNV 620 µm3; —-, MNV < 620 µm3.
|
|
|
DISCUSSION
|
|---|
The prognosis of testicular tumors has improved remarkably with
the development of techniques for imaging the retroperitoneum, as well
as introduction of new chemotherapy agents and identification of
sensitive tumor markers (7)
. Many seminoma patients can be
cured by radiation therapy and platinum-based chemotherapy, even when
they have distant metastases (1, 2, 3, 4)
. On the other hand,
most urologists irradiate the retroperitoneal lymph nodes after
orchiectomy for clinically localized (stage 1) seminoma. In fact, the
majority of stage 1 seminomas can be cured by orchiectomy alone;
therefore it would be desirable to spare patients the unpleasant side
effects of irradiation, such as gastrointestinal disturbance, reduced
fertility, a risk of secondary retroperitoneal tumors, and anxiety. In
a recent study performed in England, 7 of 52 patients (13%) with
clinical stage 1 seminoma managed by surveillance after orchiectomy
developed recurrence during a follow-up period of 12–41 months
(5)
. Unfortunately, computed tomographic scans cannot
identify micrometastases, and conventional histopathological findings
cannot identify the patients who have occult retroperitoneal metastases
(6
, 7) . Pathological assessment remains difficult and is
subject to interobserver variation. Nativ et al.
(7)
reported on the importance of the nuclear DNA ploidy
pattern in seminoma, whereas Hittmair et al.
(17)
stated that a diploid seminoma on flow cytometry is
most likely associated with extensive lymphatic infiltration. The
present study focused on whether accurate prediction of the malignant
potential of seminoma was possible by using ordinary histological
slides.
An estimate of MNV is the only method by which an unbiased estimate of
three-dimensional parameters can be obtained from a single
two-dimensional histological section (8)
. This parameter
was developed by Gunderson and Jensen (9
, 10)
and is based
on a stereological method. It has been proven by Sørensen et
al. (18)
, Baak et al. (19)
,
Nielsen et al. (20)
, and ourselves
(21)
to be highly reproducible. Since Weibel
(22)
discussed the application of stereology to cancer
research, the value of MNV as a prognostic factor has been demonstrated
for several tumors (11, 12, 13, 14, 15, 16
, 23, 24, 25)
. We reported
previously that MNV was a better predictor of the prognosis of prostate
cancer (11, 12, 13, 14)
and renal cell carcinoma (15)
than subjective histological grading. Sørensen and Muller
(26)
reported that the MNV of testicular carcinoma
in situ was significantly larger than that of
morphologically normal spermatogonia, but no previous study has
assessed the relationship between estimates of MNV and the prognosis of
seminoma.
When we analyzed the relationship between lymph node metastasis and
several prognostic factors, multivariate analysis showed that the
estimate of MNV was the only factor predicting lymph node metastasis.
It would have been better to study a group of pathologically staged
cancer patients, but unfortunately, this is not possible in clinical
practice. Despite this limitation, our findings revealed a clear trend.
Furthermore, no stage 1 patient with a small estimate of MNV showed
disease progression during the follow-up period. These findings suggest
that patients with a small MNV and no apparent lymph node metastasis on
computed tomographic scans may be candidates for surveillance rather
than radiotherapy.
Several problems remain to be solved before clinical use of estimates
of MNV will become possible. The cut-off value that best reflects the
biological characteristics of seminoma needs to be determined. Although
we used the median as the cut-off value in the present study, further
investigation of a larger number of patients at multiple institutions
will be required to provide a more definitive answer. There have been
no objective criteria for predicting the outcome of patients with
seminoma. However, the present study suggested the possibility that MNV
might be one such criterion; therefore, additional studies must be
performed to assess the reproducibility of this finding.
In conclusion, estimates of MNV may be prognostically important for
seminoma. No special training is needed to measure MNV; only a
projector and microscope are required, and evaluation can be performed
in 10–15 min with excellent reproducibility. Taking this into account,
we recommend MNV estimation for predicting the outcome of patients with
seminoma. MNV may also be a useful criterion for excluding patients
from surveillance.
|
ACKNOWLEDGMENTS
|
|---|
We thank Dr. Sørensen, Stereological Research Laboratory, and
University Institute of Pathology, Aarhus Kommunehospital, University
of Aarhus, Denmark, for technical assistance.
|
FOOTNOTES
|
|---|
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
1 This study was partly supported by the Kobe City
Foundation for Medical Research. 
2 To whom requests for reprints should be
addressed, at Department of Urology, Kobe City General Hospital,
Minatojima-nakamachi 4-6, Chuo-ku, Kobe City 650, Japan. Phone:
81-78-302-4321; Fax: 81-78-302-2487; E-mail: PS5K-FJKW{at}asahi-net.or.jp
3 The abbreviations used are: MNV, mean nuclear
volume; ß-HCG, ß-human chorionic gonadotropin; AFP,
-fetoprotein; ALP, alkaline phosphatase; LDH, lactate
dehydrogenase.
Received 9/23/99.
Accepted 2/16/00.
|
REFERENCES
|
|---|
-
Fossa S. D., Borge L., Aass N., Johannessen N. B., Stenwig A. E., Kaalhus O. The treatment of advanced metastatic seminoma: experience in 55 cases. J. Clin. Oncol., 5: 1071-1078, 1987.[Abstract/Free Full Text]
-
Loehrer P. J., Sr., Birch R., Williams S. D., Greco F. A., Einhorn L. H. Chemotherapy of metastatic seminoma: the Southeastern Cancer Study Group experience. J. Clin. Oncol., 5: 1212-1220, 1987.[Abstract/Free Full Text]
-
Epstein B. E. W., Order S. E., Zinreich E. S. Staging, treatment and results in testicular seminoma: a 12 year report. Cancer (Phila.), 65: 405-411, 1990.[Medline]
-
Bayems Y. C., Hellc P. A., Van Patten W. I. J., Mali S. P. M. Orchiectomy followed by radiotherapy in 176 stage 1 and 2 testicular seminoma patients: benefits of a 10 year follow-up study. Radiat. Oncol., 25: 97-102, 1992.
-
Peckman M. J., Hamilton C. R., Horwich A., Hendry W. F. Surveillance after orchiectomy for stage 1 seminoma of the testis. Br. J. Urol., 59: 343-351, 1987.[Medline]
-
Marks L. B., Rutgers J. L., Shipley W. U., Walker T. G., Stracher M. S., Waltman A. C., Geller S. C. Testicular seminoma: clinical and pathological features that may predict para-aortic lymph node metastasis. J. Urol., 143: 524-527, 1990.[Medline]
-
Nativ O., Winkler H. Z., Reiman H. R. J., Earle J. D., Lieber M. M. Primary testicular seminoma: prognostic significance of nuclear DNA ploidy pattern. Eur. Urol., 31: 401-404, 1997.[Medline]
-
Sørensen F. B. Biology of disease. : Quantitative analysis of nuclear size for objective malignancy grading: a review with emphasis on new, unbiased stereologic methods.. Lab. Investig., 66: 4-23, 1992.[Medline]
-
Gunderson H. J. G., Jensen E. B. Particle sizes and their distributions estimated from line- and point-sampled intercepts. Including graphical unfolding. J. Microsc., 131: 291-310, 1983.
-
Gunderson H. J. G., Jensen E. B. Stereological estimation of the volume-weighted mean volume of arbitrary particles observed on random sections. J. Microsc., 138: 127-142, 1985.[Medline]
-
Fujikawa K., Sasaki M., Aoyama T., Itoh T., Yoshida O. Prognostic criteria in patients with prostate cancer: correlation with volume weighted mean nuclear volume. J. Urol., 154: 2123-2127, 1995.[Medline]
-
Fujikawa K., Sasaki M., Arai Y., Yamabe H., Ogawa O., Yoshida O. Prognostic criteria in patients with prostate cancer: Gleason score versus volume-weighted mean nuclear volume. Clin. Cancer Res., 3: 613-618, 1997.[Abstract]
-
Fujikawa K., Sasaki M., Itoh T., Arai Y., Ogawa O., Yoshida O. Combining volume-weighted mean nuclear volume with Gleason score and clinical stage to predict more reliably disease outcome of the patients with prostate cancer. Prostate, 37: 63-69, 1998.[Medline]
-
Fujikawa K., Aoyama T., Itoh T., Nishio Y., Miyakawa M., Sasaki M. The role of volume-weighted mean nuclear volume for predicting disease outcome in patients with stage M1 prostate cancer. Acta Pathol. Microbiol. Immunol. Scand., 107: 395-400, 1999.
-
Fujikawa K., Sasaki M., Aoyama T., Itoh T. The role of volume-weighted mean nuclear volume for predicting disease outcome in patients with renal cell carcinoma. J. Urol., 157: 1237-1241, 1997.[Medline]
-
Sasaki M., Sørensen F. B., Fukuzawa S., Yamabe H., Olsen S., Yoshida O. Quantitative histopathology in the prognostic evaluation of patients with transitional cell carcinoma of the urinary bladder. Cancer (Phila.), 72: 2470-2483, 1993.[Medline]
-
Hittmair A., Rogatsch H., Feichtinger H., Hobisch A., Mikuz G. Testicular seminomas are aneuploid tumors. Lab. Investig., 72: 70-74, 1995.[Medline]
-
Sørensen F. B., Sasaki M., Fukuzawa S., Yamabe H., Olsen S., Yoshida O. Qualitative and quantitative histopathology in transitional cell carcinoma of the urinary bladder. Lab. Investig., 70: 242-254, 1994.[Medline]
-
Baak J. P. A., Ladekarl M., Sørensen F. B. Reproducibility of mean nuclear volume and correlation with mean nuclear area in breast cancer: an investigation of various sampling schemes. Hum. Pathol., 25: 80-85, 1994.[Medline]
-
Nielsen K., Berlid G. H., Bruun E., Jorgensen P. E., Weis N. Stereological estimates of mean nuclear volume in prostatic cancer, the reproducibility and the possible value of estimations on repeated biopsies in the course of disease. J. Microsc., 154: 63-69, 1989.[Medline]
-
Fujikawa K., Aoyama T., Itoh T., Nishio Y., Miyakawa M., Sasaki M. Is new prognosticator "volume-weighted mean nuclear volume" comparable in multiple institutions?. Anal. Quant. Cytol. Histol., 22: 55-61, 2000.[Medline]
-
Weibel E. R. The value of stereology in analyzing structure and function of cells and organs. J. Microsc., 95: 3-10, 1972.[Medline]
-
Sørensen F. B., Kristensen I. B., Grymer F., Jakobsen A. DNA level, tumor thickness and stereological estimates of nuclear volume in stage 1 cutaneous malignant melanoma. Am. J. Dermatol., 13: 11-18, 1991.
-
Nielsen K., Orntoft T., Wolf H. Stereological estimates of nuclear volume in noninvasive bladder tumors (Ta) correlated with the recurrence pattern. Cancer (Phila.), 64: 2269-2275, 1989.[Medline]
-
Madsen C., Schroder H. D. Stereological estimation of nuclear mean volume in invasive meningioma. Acta Pathol. Microbiol. Immunol. Scand., 104: 103-107, 1996.
-
Sørensen F. B., Muller J. Stereological estimates of nuclear volume in normal germ cells and carcinoma in situ of the human testis. Histopathology, 17: 327-334, 1990.[Medline]
Top
ABSTRACT
INTRODUCTION
