Application of fluorescence in situ hybridization in the detection of transitional cell carcinoma of the bladder: a multi-center clinical study based on the Chinese population

Introduction Bladder cancer (BC) is the second most common malignant tumor of the urinary system.

More than 70% of BC patients have only superficial disease at the time of initial diagnosis, and 30% of patients have progressed to the stage of muscular invasion.

Early diagnosis of BC is essential to prevent Ta and T1 tumors from progressing to the muscular invasion stage.

Although non-muscle infiltrating transitional cell carcinoma can be treated by transurethral resection (TUR), its 5-year and 15-year recurrence rates are 70% and 90%, respectively, and about 15% to 25% of recurrent tumors have advanced tumors.
Grade or muscular invasive disease.

Early diagnosis, proper treatment and proper monitoring are important components of treatment.

Cystoscopy is still the gold standard for diagnosis of suspected BC patients.

However, a considerable number of patients cannot accept this test, which reduces the compliance of monitoring.

Cytology is still the gold standard for non-invasive detection of BC, but its sensitivity is low.

Therefore, new methods are needed to detect BC early.

Early studies have shown that fluorescence in situ hybridization (FISH) analysis of urine or bladder irrigation fluid for aneuploidy at specific chromosomes and sites may help early detection of tumors or recurrence.

Therefore, FISH has been tested and used in Europe and the United States to detect exfoliated urine cells with these genetic changes.

However, the reliability of FISH testing has not been verified in the Chinese population.
When Chinese patients are compared with Western populations, different geographic locations may cause genetic differences.

Therefore, it is necessary to explore the genetic changes of BC in the Chinese population.

This article reports the results of China's first multi-center trial to evaluate the ability of FISH to detect the urine of patients with gross hematuria with or without a history of BC, and then to detect BC.

Results 01.
The FISH and cytology testing procedures provided 4807 patients with gross hematuria with informed consent and included them in this trial.

Among all the subjects, 4688 completed the two tests and 4125 achieved valid results.

Among 4125 patients, patients with suspected upper urinary tract mass or complicated cystoscopy were excluded, and the remaining 3959 patients with valid pathological diagnosis were analyzed.

Among them, 3021 were males and 938 were females, aged 15-97 years (average 63.
04±13.
31 years).

Due to the large number of biopsy specimens, only 979 patients were randomly selected for central analysis staging and grading.

02.
Cohort characteristics of patients with hematuria Among 3959 patients who completed FISH examination, cytological analysis and pathological cystoscopy diagnosis, 3640 cases were diagnosed as transitional cell BC, of ​​which 3011 cases were correctly diagnosed by FISH (true positive), 1217 The case was diagnosed correctly by cytology (true positive).

319 patients were not diagnosed with BC, including inflammation, kidney tumors, benign bladder tumors, and bladder tumors of non-transitional cell origin.

265 cases and 299 cases were correctly diagnosed (true negative) by FISH and cytology.

03.
Comparing the results of FISH and cytology in all patients with transitional cell carcinoma of the bladder, the sensitivity of FISH and cytology was 82.
7% and 33.
4%, respectively (p<0.
001).

The specificities of FISH and cytology were 83.
1% and 93.
7%, respectively (p<0.
001).

Analyze the ROC curve and calculate the AUC value.

The AUC values ​​of FISH and cytology were 0.
829 and 0.
636, respectively (p<0.
001).

The positive predictive values ​​of FISH and cytology were 98.
2% and 98.
4%, respectively.

04.
Characteristics of patients with effective pathological diagnosis Among the 983 patients with analyzable pathological information, 855 were transitional cell BC. In this group of patients, 5 cases were Tis stage tumors, 254 cases were Ta stage tumors, 336 cases were T1 stage tumors, 184 cases were T2 stage tumors, 56 cases were T3 stage tumors, and 20 cases were T4 stage tumors.

Therefore, 595 patients were non-muscular invasive cancer and 260 were invasive cancer.

FISH detection identified 81.
7% of non-muscle invasive cancer and 89.
6% of invasive cancer (p=0.
004), while the ratio of cytological detection was 22.
9% and 39.
6% (p<0.
001).

532 patients had low-grade tumors, and 323 patients had high-grade tumors.

FISH detection identified 82.
5% of low-grade tumors and 90.
1% of high-grade tumors (p=0.
003), and the proportions of cytological detection were 21.
8% and 42.
4%, respectively (p<0.
001).

05.
The detection sensitivity and specificity of FISH and cytology in patients with or without a history of cell carcinoma were 84.
38% and 85.
76%, respectively (p= 0.
655), while the sensitivity of cytological detection was 31.
29% and 28.
18% (p=0.
430).

The specificities of FISH detection were 50% and 77.
5%, and the specificities of cytology detection were 100% and 90%, respectively.

Discussion Traditional urine cytology is still the most commonly used method for diagnosing new BC and its recurrence in combination with cystoscopy; however, the limited sensitivity of this method has prompted the search for new diagnostic techniques.

Various new alternative laboratory methods based on detecting different indicators such as BTA stat, BTA TRAK, NMP22, telomerase and fibrinogen degradation products have been used to diagnose BC.

Compared with urine cytology, the unsatisfactory detection specificity reported so far limits the clinical application of these methods, and may only be used for screening and monitoring.

Other trials have proven that FISH is a more accurate tool in detecting and predicting the recurrence of patients with urothelial cancer.

The study used chromosome 3, 7, and 17 centromeric probes combined with p16 site-specific probes to detect chromosomal abnormalities in urine exfoliated cells.

The results showed that the genetic changes at positions 3, 7, 17, and p16 in cancer patients accounted for 71.
3%, 72.
2%, 67.
4%, and 72.
9%, respectively.

It shows that the combination is consistent with the reported genetic changes in Chinese BC patients.

In general, the sensitivity of FISH detection is 82.
7%, and the AUC value is 0.
829, while the sensitivity of cytology detection is 33.
4%, and the AUC value is 0.
636; there is a significant difference between the sensitivity of FISH and cytology detection and the AUC value.
difference.

Although cytology has better specificity than FISH, this study found that 2 patients had negative cystoscopy results, but the FISH test results at the 4th and 6th months were positive (false positive).

Repeated cystoscopy biopsy confirmed that the patient was BC.

This is consistent with Sarosdy's results.
FISH can detect chromosomal changes before the morphology begins to change.

According to previous studies, FISH has the potential to predict the development of UC.

At the time of initial evaluation, FISH "false" positive patients usually develop UC within 15-22 months, and previous FISH positive results are associated with tumor recurrence in 86% of UC monitored cases, including all high-grade recurrence cases.

But our study did not follow up these false positive patients.

Therefore, it is necessary to closely monitor patients with "false positive" hematuria.

This may be a screening method to identify high-risk patients or monitor BC patients.

For non-muscle infiltrating BC and invasive BC, the sensitivity of FISH was 81.
7% and 89.
6% (p=0.
004), and the sensitivity of cytology was 22.
9% and 39.
6% (p<0.
001).

For more aggressive diseases, both tests show better diagnostic value, and FISH is more sensitive.

For low-grade and high-grade tumors, the sensitivity of FISH detection was 82.
5% and 90.
1% (p=0.
003), and the sensitivity of cytology detection was 21.
8% and 42.
4% (p<0.
001).

Both detection methods have good diagnostic value for high-grade tumors.

The above results indicate that FISH has a positive potential in diagnosing diseases with poor clinical prognosis.

This study found that there was no difference in BC testing for patients with or without a history of BC.

It is recommended to use a monitoring program based on FISH results for BC patients, and patients with positive FISH results must undergo cystoscopy.

Due to the high risk of tumor recurrence, patients with negative endoscopy results need to repeat cystoscopy in the next few months.

For patients with negative FISH results, it is unlikely that invasive BC will not be detected.
Only some superficial to low-grade tumors may not be diagnosed; therefore, it can reduce or even eliminate the need for periodic cystoscopy until FISH positive.

Recent studies have shown that most invasive diseases are unlikely to be missed, but the feasibility of this method remains to be confirmed.

At present, it has been proved that the sensitivity of FISH to detect BC is higher than that of cytology, and the FDA has also approved it as a method to diagnose BC.

Based on these results, the China Food and Drug Administration has adopted and approved FISH for the detection of BC.

Compared with urine cytology testing, FISH testing for BC is more expensive; however, if the cost of FISH testing can be reduced, this technology will be widely accepted by developing countries including China.

This study has certain limitations, including that the sensitivity of cytological detection is lower than previously reported.

In addition, long-term studies are needed to determine the value of FISH in monitoring BC.

Conclusion Compared with cytological examination, FISH has a better diagnostic value for the detection of transitional cell carcinoma of the bladder in patients with or without a history of BC.

The detection sensitivity of FISH for high-grade and muscular invasive diseases is higher than that for low-grade and non-muscular invasive diseases.

Literature link: https://doi.
org/10.
1016/j.
ajur.
2018.
06.
001