Sunday, 9 October 2011
Transitional cell carcinomas
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Transitional cell carcinomas can be caused by —
a) Napthylamine
b) Smoking
c) Bilharziasis
d) Betel nut
Ans. Three options are correct i.e., ‘a, b & c’ {Ref : Robbin’s 7″/e p. 1029 & 6th/e p. 1007]
A number of factors have been implicated in the causation of transitional cell carcinoma. Some of the more important contributors include the following:
Cigarette smoking is clearly the most important influence, increasing the risk threefold to sevenfold, depending on the pack-years and smoking habits. Fifty per cent to 80% of all bladder cancers among men are associated with the use of cigarettes. Cigars, pipes, and smokeless tobacco invoke a much smaller risk.
Industrial exposure to arylamines, particularly 2-naphthylamine as well as related compounds, as pointed out in the earlier discussion of chemical carcinogenesis (Chapter
. The cancers appear 15 to 40 years after the first exposure.
Schistosoma haematobium infections in areas where these are endemic (Egypt, Sudan) are an established risk. The ova are deposited in the bladder wall and incite a brisk chronic inflammatory response that induces progressive mucosal squamous metaplasia and dysplasia and, in some instances, neoplasia. Seventy per cent of the cancers are squamous, the remainder being transitional cell carcinoma.
Long-term use of analgesics, implicated also in analgesic nephropathy (Chapter 21) .
Heavy long-term exposure to cyclophosphamide, an immunosuppressive agent, induces as noted hemorrhagic cystitis and increases the risk of bladder cancer.
How these influences induce cancer is unclear, but a number of genetic alterations have been observed in transitional cell carcinoma. The cytogenetic and molecular alterations are heterogeneous. Particularly common (occurring in 30% to 60% of tumors studied) are chromosome 9 monosomy or deletions of 9p and 9q as well as deletions of 17p, 13q, 11p, and 14q. [8] The chromosome 9 deletions are the only genetic changes present frequently in superficial papillary tumors and occasionally in noninvasive flat tumors.
a) Napthylamine
b) Smoking
c) Bilharziasis
d) Betel nut
Ans. Three options are correct i.e., ‘a, b & c’ {Ref : Robbin’s 7″/e p. 1029 & 6th/e p. 1007]
A number of factors have been implicated in the causation of transitional cell carcinoma. Some of the more important contributors include the following:
Cigarette smoking is clearly the most important influence, increasing the risk threefold to sevenfold, depending on the pack-years and smoking habits. Fifty per cent to 80% of all bladder cancers among men are associated with the use of cigarettes. Cigars, pipes, and smokeless tobacco invoke a much smaller risk.
Industrial exposure to arylamines, particularly 2-naphthylamine as well as related compounds, as pointed out in the earlier discussion of chemical carcinogenesis (Chapter
. The cancers appear 15 to 40 years after the first exposure. Schistosoma haematobium infections in areas where these are endemic (Egypt, Sudan) are an established risk. The ova are deposited in the bladder wall and incite a brisk chronic inflammatory response that induces progressive mucosal squamous metaplasia and dysplasia and, in some instances, neoplasia. Seventy per cent of the cancers are squamous, the remainder being transitional cell carcinoma.
Long-term use of analgesics, implicated also in analgesic nephropathy (Chapter 21) .
Heavy long-term exposure to cyclophosphamide, an immunosuppressive agent, induces as noted hemorrhagic cystitis and increases the risk of bladder cancer.
How these influences induce cancer is unclear, but a number of genetic alterations have been observed in transitional cell carcinoma. The cytogenetic and molecular alterations are heterogeneous. Particularly common (occurring in 30% to 60% of tumors studied) are chromosome 9 monosomy or deletions of 9p and 9q as well as deletions of 17p, 13q, 11p, and 14q. [8] The chromosome 9 deletions are the only genetic changes present frequently in superficial papillary tumors and occasionally in noninvasive flat tumors.
IMPORTANT POINT IN TREATMENT OF TRANSITIONAL CELL CARCINOMA OF BLADDER:–Intravesical therapies are used in two general contexts: as an adjuvant to
a complete endoscopic resection to prevent recurrence or, less commonly,
to eliminate disease that cannot be controlled by endoscopic resection
alone. Intravesical treatments are advised for patients with recurrent disease,
>40% involvement of the bladder surface by tumor, diffuse CIS, or T1
disease. The standard intravesical therapy, based on randomized comparisons,
is bacillus Calmette-Guerin (BCG) in six weekly instillations, followed
by monthly maintenance administrations for ≥1 year
a complete endoscopic resection to prevent recurrence or, less commonly,
to eliminate disease that cannot be controlled by endoscopic resection
alone. Intravesical treatments are advised for patients with recurrent disease,
>40% involvement of the bladder surface by tumor, diffuse CIS, or T1
disease. The standard intravesical therapy, based on randomized comparisons,
is bacillus Calmette-Guerin (BCG) in six weekly instillations, followed
by monthly maintenance administrations for ≥1 year
At least 95% of cancers of the oral cavity (including the tongue) are squamous cell carcinomas.A major regional predisposing influence is the chewing of betel nuts and pan in India and parts of Asia.
SO BETEL NUT IS RELATED TO SQUAMOUS CELL CARCINOMA NOT TRANSITIONAL CELL.
Though smoking is related to both types.
SO BETEL NUT IS RELATED TO SQUAMOUS CELL CARCINOMA NOT TRANSITIONAL CELL.
Though smoking is related to both types.
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