(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)
Genitourinary Cancer PART – 18
Question: Thank you Chiragbhai for explaining important points related to bladder cancer. 1. One of the major risk factor for this cancer is tobacco smoking. 2. Many of them are superficial cancers, with fairly different behavior and treatment plan compared to invasive cancer. 3. Painless hematuria is the most common presenting symptom. Even microscopic hematuria in adults should be investigated, especially in absence of obvious infection or stone. 4. Cystoscopy is the gold standard test for evaluation and diagnosis. Now this test is opd based using flexible cystoscope, widely available, convenient. Urine cytology is frequently not as useful. Same way IVP has been replaced by CT scan. 5. Transitional cell carcinoma is the most common histology.
Can you elaborate more on the superficial cancers?
Answer: Yes, bladder cancer has a peculiar behavior. About 70% of them are superficial cancers (now more accurately known as non muscle invasive cancers), with less risk of invasion or metastasis. They can be locally recurrent and multifocal. They can be compared possibly with leukoplakia in oral cavity. These tumors are treated by transurethral resection (TURBT) as much as feasible safely (too aggressive resection carries a risk of bladder perforation), followed by close monitoring by repeated endoscopies.
Based on various factors, decision is taken regarding whether to add any other local therapy. There are number of trials and meta analysis. Many of them now show role for immediate (within 24 hours) intravesical chemotherapy (gemcitabine, mitomycin etc) dose after transurethral resection. Some patients need multiple doses. Most common maintenance agent used for intravesical instillation is BCG vaccine. BCG is the same anti tuberculous vaccine that is widely used for generating immunity against tuberculosis. Apparently it creates an immune response inside bladder epithelium which reduces recurrence of superficial bladder cancers, and even may treat occasional small tumors. Multiple instillations are required at varied intervals, for few years. Generally well tolerated, and safe. Some patients may have severe bladder spasm from inflammation of epithelium. Surveillance cystoscopy is required for several years to ensure no recurrent cancers, especially of invasive type.
Some patients with superficial cancers, having high risk features, or widespread disease may need even cystectomy.
Que: Amazing. Yes this does seem a bit like oral leukoplakia. Tobacco exposure leads to field cancerization of head and neck region, resulting in one or multiple leukoplakia, precancerous lesions. These need close surveillance as some will convert into invasive malignancy. Some of these lesions can be observed and others with certain negative features need to be resected. Whole area of oral cavity, and pharynx is at risk for development of additional lesions, mainly for first 5 years. But difference here is presence of an intervention like BCG vaccine or chemotherapy, given in the bladder which reduces risk of recurrence to some extent. There is no such intervention today for oral cancers, leukoplakia. Now can you tell us more about invasive bladder cancers?
Ans: You have also become good at teaching. Correlation with leukoplakia was explained well.
About 30% of bladder cancers are invasive, which can spread locally or metastasize.
Most important first step in identifying invasive cancer is a proper deep biopsy that includes adequate bladder wall muscle. Definition of invasive cancer depends on identifying invasion of muscle on pathology. Sometimes the biopsy is too superficial out of fear of bladder perforation mainly, especially in hands of urologists not treating bladder cancers. A biopsy that does not include muscle must be repeated. It cannot be reported as non invasive cancer. Even when biopsy involves muscle and is not showing invasion, it can still miss a high number of true muscle invasive cancers. Hence close observation, correlation with good imaging study etc are also important in determining strategy of surveillance versus aggressive local treatment. A good CT scan done before biopsy, with fully distended bladder may pick up area of suspicion by showing thickened wall. A normal wall seen on CT scan is less likely to have invasive cancer. Whereas a thickened wall is very likely to have invasive cancer, even if one biopsy is normal. The discrepancy (as to muscle invasion) between biopsy done by cystoscopy AND what is found at cystecomy is fairly high, in about 40% cases.
Of course, in addition to this, CT scan may show extravesical spread, lymphadenopathy or metastatic disease. PET-CT is also frequently used nowadays for staging. March 16th 2019. Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA), 079 26754001. Diplomate American Board of Oncology and Hematology. Ahmedabad. firstname.lastname@example.org