I. Definition
The commonly referred to invasive bladder cancer refers to bladder cancer that infiltrates to a depth of the muscular layer of the bladder or above. According to the TNM staging of the AJCC in 2002 includes bladder tumors in stages T2-T4, which account for about 20% of all initially diagnosed bladder tumors, while about 15%-20% of initially diagnosed non-muscular layer invasive bladder cancer will progress to invasive bladder cancer.
II. Diagnosis
1.Signs and symptoms
Intermittent episodes of painless hematuria throughout the whole process is a typical symptom of bladder tumor, but some invasive bladder cancers can have lower urinary tract irritation as the initial manifestation, or even no hematuria, which often indicates that the tumor is growing along the muscular layer and has a higher degree of malignancy.
Patients with advanced stage can have associated metastatic symptoms as well as tumor wasting manifestations. Local pelvic lymph node metastasis can lead to the appearance of lower limb edema, which is more common in patients with invasive bladder cancer. Acute urinary retention due to massive hematuria is the main reason for emergency care in advanced patients.
Physical examination is usually difficult to find positive findings for the primary disease, but some invasive tumors can be detected in the duplex examination, but this examination is usually appropriate after anesthesia.
2.Imaging examination
Routine examinations include ultrasound, urographic x-ray and CT/MRI. Ultrasound and IVU are useful for the diagnosis of concurrent upper urinary tract tumors, but are of little significance for the staging of infiltrative tumors. CTU is currently a more sensitive imaging test for the diagnosis of concurrent upper urinary tract tumors, and enhanced CT of the bladder is useful for differentiating tumors above T3b, but is of limited use for differentiating T1 and T2 stage disease. It is generally believed that the role of conventional MRI examination for diagnosing the stage of invasive bladder tumors is not significantly superior to that of CT examination, but MRI with high field strength can obtain clearer pelvic cross-sectional images than CT, can distinguish bladder wall and peri-vesical fat, and is more sensitive than CT for distinguishing T2 or T3 stage tumors. Enhanced MRI has been reported to obtain more accurate staging image information, but overall, the accuracy of CT or MRI in staging bladder tumors is generally in the range of 60%-70%.
For definite invasive bladder tumors, CT of the lungs, enhanced CT of the upper abdomen, and enhanced CT or MRI of the pelvis should be performed to aid in clinical staging of NM.
PET-CT is clinically relevant for the detection of distant metastases, but is not recommended for the diagnosis of primary tumors because of the influence of urinary excretion tracers.
3.Cytological examination and tumor markers
It is not clinically significant to distinguish whether the disease is infiltrative or not.
4.Cystoscopy and diagnostic TURBT
Cystoscopic biopsy is the classic means of diagnosing bladder tumors, but it is often difficult to distinguish whether the disease is invasive or not, and even some biopsy specimens of submucosal growth tumors are often negative. The best means to confirm invasive bladder cancer is currently considered to be diagnostic TURBT, but because physical damage to the basal tissue during electrodesis often affects the accuracy of histopathologic diagnosis, it is now generally accepted that it is still clinically relevant to perform secondary electrodesis after 4-6 weeks in patients with bladder cancer who have high-risk factors but whose initial TURBT diagnosis is superficial disease.
III. Treatment
Radical total cystectomy
Currently, radical cystectomy is the standard treatment for muscle-invasive bladder cancer, and the indications for surgery include T2-T4a, N0-x, M0, stage bladder tumors, in situ cancer that is ineffective with BCG therapy, mixed pathological types of bladder cancer, and some scholars suggest that T1G3 tumors, non-muscle-invasive bladder cancer with recurrent recurrence after bladder preservation therapy, and other high-risk patients can also be considered for radical cyst resection.
The scope of radical cystectomy includes pelvic lymph node dissection, bladder and surrounding fat, and distal ureter; it also includes the prostate and seminal vesicles in men and the uterus, adnexa, and anterior vaginal wall in women. If the tumor involves the urethra of the prostate in men or the bladder neck in women, urethral aspiration is considered. Transabdominal surgery should begin with exploration of the abdominal lymph nodes. Radical surgery in patients with tumor metastases is not effective. Intraoperative bladder confinement and integrity should be ensured, and intraoperative cryopathology of the ureteral margins can be very helpful in determining the extent of resection.
The standard pelvic lymph node dissection includes all lymphatic adipose tissue from the outer edge of the bladder to the genitofemoral nerve on both sides, proximally to the level of the iliac vessel bifurcation, distally to the pelvic floor fascia, and deeply to the level of the closed lymph nodes. In recent years, it has been suggested that extended lymph node dissection is beneficial for improving postoperative survival of patients up to the level of the abdominal aortic bifurcation and even to the level of the renal artery. It is still controversial whether expanded lymph node dissection should be performed routinely, but it is generally accepted that it is therapeutic for patients with bladder cancer and that expanded lymph node dissection can be considered if local lymph node invasion is present.
Pelvic lymph node dissection can be performed before or after cystectomy, and lymph node dissection is important for tumor treatment and prognosis. The significance of intraoperative pelvic lymph node cryobiopsy remains somewhat controversial. In patients with clearly positive lymph nodes, adjuvant chemotherapy after surgery can help improve the prognosis.