CIMETIDINE AND TUMORS
Published on: EOS. EOS. Vol XX - 2000. n° 1, pag. 3-6.
Repeatedly it has been demonstrated that cimetidine (antihistamine anti-H2),
administred in the perioperative period or for 1-2 years after the intervention,
increases the survival of patients affected by gastric or colorectal cancer.
Two questions come out from the works published until now:
Cimetidine benefits have been generally attributed to the block of activator
stimulus that histamine exerts on T-suppressor cells; but this hypothesis
has not been proved by the (contradictory) results achieved in experimental
pathology and, most of all, in the different histological kinds of tumor
(always dramatically negative in melanoma). Analyzing and giving full value
to initial phases of antitumoral defence (that is aspecific), we can answer
to the questions we posed:
- How does cimetidine act ?
- What kinds of tumor can cimetidine be useful against ?
Cimetidine will be effective in all the entodermic tumors (glands of digestive
apparatus, epithelium of digestive tract, epithelium of respiratory tract);
perhaps effective in the ectodermic ones (nervous tissue and epidermis);
non effective in the mesodermic and mesenchymal ones (blood cells, lymphatic vascular sistem, dermis).
- in gastric and colorectal cancers, cimetidine, blocking granulocytes
receptors for histamine:
- “gives back” to granulocytes their chemiotactic sensitivity, opening the way to an adequate aspecific protective reaction;
- permits the formation of the irreversible thrombocytic plug, that mechanically reduces the haematic flux to the tumor;
- permits PLTs to release platelet factor 4, which is an inhibitor of the tumorous neo-angiogenesis.
- cimetidine effectiveness is correlated to the specific metabolism
of the tumor, therefore to its embryonal derivation and to its functional
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