Häufigkeit und Verteilungsmuster des Carcinoma in situ in tumorbefallenen Hoden

Diagnosis of Contralateral Testicular Intraepithelial Neoplasia (TIN) in Patients with Testicular Germ Cell Cancer: Systematic Two-Site Biopsies Are More Sensitive Than a Single Random Biopsy

OBJECTIVES

Searching for testicular intraepithelial neoplasia (TIN; carcinoma in situ) in the contralateral testis of patients with germ cell tumour (GCT) may early disclose contralateral GCT. A single biopsy of the testis is thought to accurately detect TIN. Reports on false-negative biopsies have challenged this view. We investigated whether systematic two-site biopsies are more sensitive than single biopsies. We also studied the prevalence of contralateral TIN in a large patient sample.

METHODS

A total of 2318 patients with testicular GCT underwent contralateral double biopsy. All of the biopsy pairs were examined histologically for spermatogenesis and for presence of TIN. Statistical analysis involved first, overall prevalence of contralateral TIN; second, associations of clinical factors with TIN; third, frequency of discordant findings regarding TIN among biopsy pairs; and finally, associations of discordance with clinical factors.

RESULTS

A total of 119 patients (5.13%; 95% confidence interval [CI], 4.27-6.11) had contralateral TIN. TIN is associated with poor spermatogenesis (relative risk [RR] 15.74; 95%CI, 10.38-23.86) and with testicular atrophy (RR 3.78). According to TIN, 31.1% of biopsy pairs were discordant. Discordance was significantly less frequent in atrophic testes and in patients with poor spermatogenesis.

CONCLUSIONS

We confirmed the prevalence of contralateral TIN to be about 5%. TIN is significantly associated with poor spermatogenesis and with testicular atrophy. The diagnostic extra yield imparted by double biopsies is 18%. Discordant results regarding TIN are predominantly encountered in normal-sized testicles. The new standard in diagnosing TIN is two-site biopsy.

False-negative biopsies for the diagnosis of testicular intraepithelial neoplasia (TIN)--an update

PURPOSE

Testicular intraepithelial neoplasia (TIN; or carcinoma in situ of the testis) is the precursor of testicular germ-cell tumours (GCT). It is detected by conventional surgical biopsy of the testis. To date, only little information is available in regard to the accuracy of the biopsy. False-negative biopsies have been reported only sporadically.

PATIENTS AND METHODS

Twenty-one patients who developed a testicular GCT despite a testicular biopsy negative for TIN were analysed clinically and histologically. The median age of the patients is 34 years. The median interval from biopsy to the clinical appearance of GCT is 39 months. Four of the 21 patients had their biopsy done within a previously reported multicentric study (n=1859 cases with negative biopsy including five cases with false-negative biopsy hitherto known). All of the biopsy specimens were re-examined immunohistologically. In 15 cases, the orchiectomy specimens were re-examined for the presence of TIN in the tumour-surrounding tissue.

RESULTS

In five cases, TIN was found in the biopsy specimen upon re-examination. In all of the 15 orchiectomy specimens there was evidence of TIN in the tissue adjacent to the tumour. In three biopsy specimens there were microcalcifications in the seminiferous tubules. Severe impairment of the spermatogenesis was observed histologically in only 3 of the 21 patients. The relative proportion of false-negative biopsies is 0.5% (95% confidence intervals (CI): 0.22%; 0.92%). The sensitivity of the biopsy to detect TIN is 0.914 (95% CI: 0.842; 0.959) and the overall accuracy is 0.995 (95% CI: 0.991; 0.9979). A total of 44 false-negative biopsies are reported to date.

CONCLUSIONS

False-negative biopsies for TIN do occur but the proportion is only 0.5%. There is no clear-cut clinical nor histological feature associated with false-negative biopsies. However, young age (i.e. <18 years) and intratubular microcalcifications should increase the clinician's and pathologist's vigilance. The majority of false-negative biopsies are caused by the non-random distribution of TIN in the testis while some few cases are caused by technical problems. Two-site biopsies would probably increase the accuracy of the biopsy in high risk cases.

Update on the diagnostic safety for detection of testicular intraepithelial neoplasia (TIN)

Testicular intraepithelial neoplasia (TIN) of the testis is the noninvasive precursor of testicular germ cell tumours (GCT) and can be detected by a single random biopsy in 5% of patients with GCT in the contralateral testes. Although it is generally presumed that TIN is dispersed throughout the testis, we realize in about 60% of TIN bearing tissue close to testis tumours that its distribution is not homogenously diffuse, but may be focal. Thus we tested whether we can improve diagnostic safety in detecting TIN by increasing the number of biopsies. We could finally evaluate 295 men with proven testicular tumours. Three biopsies of contralateral testes were taken (each 5 mm length) from one surgical incision site and fixed in Bouin's solution or glutaraldehyde. TIN cells were histologically identified by their typical morphological characteristics and additionally by placental alkaline phophatase (PlAP) immunohistochemistry. Patients revealed testicular tumour without contralateral TIN in 271 cases and with contralateral TIN in 24 cases (8.1%). In 6 of these 24 men with contralateral TIN the cells could be detected in only one (n=5) or two (n=1) of the three specimen investigated. That means in these six patients TIN could have been missed if only one single random biopsy was taken. By increasing the number of biopsies (=increasing the number of investigated seminiferous tubules) the detection rate of contralateral TIN may be increased up to 8.1%. Thus we recommend multiple testicular biopsies to increase the diagnostic safety in detection of TIN. Biopsies may be taken from one randomly chosen surgical incision site.

Diagnosis and management of testicular intraepithelial neoplasia (carcinoma in situ)--surgical aspects

Germ cell tumours (CT) are no true carcinomas; therefore the term testicular intraepithelial neoplasia (IN) is probably more appropriate than "CIS". The diagnostic accuracy of a single-site biopsy is an open question. We experienced 9 false-negative biopsies among 1859 cases. Thus, the proportion of a failed diagnosis is 0.5%. The main reason for diagnostic failure is the non-random distribution of TIN within the testicle. Currently we are investigating whether a two-site biopsy is more accurate than a single biopsy. In the ongoing trial, the over-all prevalence of TIN is around 5.3%, so far. In one quarter of the positive cases the lesion was found in only one of the two specimens. Thus, a double biopsy appears to be more favourable than the traditional single biopsy. Surgical complications amount to 2.5% in that double biopsy study. Only one surgical re-intervention was required among 983 patients. Serial imaging studies with scrotal sonography and magnetic resonance imaging (MRI) disclosed a transient intratesticular haematoma/oedema postoperatively. So, testicular biopsy, even when performed at two sites is in fact a low-complication procedure. Low dose radiotherapy to the testis is the treatment of choice for TIN. However, more than one quarter of patients require testosterone supplementation secondary to androgen-deficiency. Two dose-reduction studies (Denmark and Germany) had to be terminated prematurely because unexpected relapse of TIN was encountered at 14 Gy and 16 Gy. Possibly, hyperfragmentation schedules can overcome the antagonism of androgenic compromise and oncological safety. In a nation-wide survey, it was shown that contralateral biopsies were routinely performed in 66% of the urological departments in Germany. Another 19% offered the biopsy to particular "risk-cases"; only 15% never did a biopsy. Among those refusing biopsies, there was a higher proportion of small hospitals and a significantly lower annual case-number of GCT, when compared to those doing the biopsy. Thus, the contralateral biopsy is a well-established procedure among German urologists; those with a high caseload of GCT particularly appreciate it.

Carcinoma in situ in the testis

Carcinoma in situ (CIS) of the testis is a common precursor of germ-cell tumours in adults and adolescents, with the exception of spermatocytic seminoma. This article reviews existing knowledge on the pathobiology, genetic aspects and epidemiology of CIS, discusses current hypotheses concerning pathogenesis and invasive progression of germ-cell neoplasms and provides guidelines for diagnosis and clinical management of CIS.

False-negative biopsy for testicular intraepithelial neoplasia and high-risk features for testicular cancer

The purpose of this report is to emphasize the possibility of false-negative biopsies for testicular intraepithelial neoplasia (TIN) in men with high-risk features of testicular cancer and to review the relevant literature. At the Norwegian Radium Hospital patients in this category are offered the chance to undergo a testicular biopsy. A patient is described who had a normal testicular biopsy a decade before presenting with an invasive testicular cancer. Furthermore, this patient is the first case reported with a false-negative biopsy for TIN and a family history of testicular cancer. The evaluation of the biopsies included immunohistochemical staining for c-kit and PIAP (placental-like alkaline phosphatase) in order to diagnose early TIN. Though multifocal or diffuse extension seems to be the most frequent pattern of distribution of TIN, the presented case and another 14 cases from the literature review indicate that the focality of TIN may be a reason for a TIN-negative biopsy.

The value of the biopsy of the contralateral testis in patients with testicular germ cell cancer: the recent German experience

PURPOSE

Testicular intraepithelial neoplasia (TIN; so-called carcinoma in situ of the testis), the precursor of testicular germ cell neoplasms can be detected by testicular biopsy many years before the clinical manifestation of the tumour. This study looked at the prevalence of contralateral TIN in patients with testicular germ cell cancer. The purpose was to evaluate this new approach of early detection of testicular cancer and to evaluate the current management strategies.

PATIENTS, METHODS

1954 consecutive patients with unilateral testicular germ cell tumour underwent contralateral biopsy. All specimens were examined immunohistologically with staining for placental alkaline phosphatase. Patients with TIN were usually submitted to low-dose radiotherapy of the testis. A rebiopsy was performed after 3 months. Endocrinological evaluations were done before, during and after treatment.

RESULTS

TIN was observed in 4.9% (95% confidence intervals 3.95%-5.91%). Testicular atrophy constitutes a 4.3 fold increased risk of having contralateral TIN. 64% of the cases with TIN were found in clinically normal testes. Patients with TIN were significantly younger than those without (p < 0.017). No case with TIN was found in patients older than 50 years. Three patients developed a second testicular tumour during follow-up despite a negative biopsy. After radiotherapy, all of 23 patients had complete disappearance of TIN in the rebiopsy. After chemotherapy, 3 of 10 patients had persistent TIN histologically. After radiotherapy, 12 of 41 patients required testosterone replacement.

CONCLUSION

The prevalence of contralateral TIN accords well with the known prevalence of bilateral testicular tumours. Testicular atrophy is a strong indicator for the presence of TIN but about 60% of TIN-cases occur without atrophy. Local radiotherapy to the testis with 18-20 Gy is efficaceous in eradicating TIN, but it causes significant damage to almost one quarter of these patients. Chemotherapy is an unsafe treatment for TIN. This study shows the feasibility of early detection of testicular cancer in a high-risk population by means of searching for TIN. Although the management of the condition still needs refinement, the TIN-concept offers an avenue for the early detection of testicular cancer and early conservative management.