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Editor,—We refer to a recent publication of Poole,1 discussing the incidence of conjunctival squamous carcinoma in Tanzania, notably in HIV affected patients. We have extensively studied a similar condition (bovine ocular squamous carcinoma) with a comparable genesis in veterinary cases, in the Harare area (Zimbabwe).2 We treated such cases with intralesional IL-2 injections of 200 000 U IL-2 (Chiron) over 10 days. A large number of remissions and in 67% of the cases even complete cures (20 month observation period) were obtained. In fact, even tumours of over 6 cm in diameter may regress completely with this therapeutic regimen.3 This form of treatment is cheap, non-toxic, effective, and feasible even in basic situations. It might be worth considering such treatment in human patients, obviously with the appropriate prerequisites.
Editor,—I thank Koten and Den Otter for their interest in my paper. Their experience with intralesional interleukin-2 in the treatment of bovine ocular squamous carcinoma makes very interesting reading. Regional low dose administration of interleukin-2 appears to be safe and is already used in other specialties: systemic toxicity is reduced and a high local concentration is achieved, and most adverse reactions are self limiting and can be managed on an outpatient basis. An appropriate clinical trial would be valuable if their good results in the bovine condition could be replicated in the human one.
It would be hard to justify experimental treatment in an advanced condition where local excision or enucleation might be life saving. A careful trial in the treatment of early conjunctival tumours, however, with vigilant follow up (sometimes difficult in an African setting), might be worthwhile. Another application of their useful work, when attempting to preserve an otherwise normal eye, might be to inject interleukin-2 at the excision margins after tumour resection, to prevent recurrence.
To be of use in Africa any treatment needs to be cost effective. One vial of recombinant interleukin-2 contains 18 million units and costs £140. If this could be used for several patients the cost might not be prohibitive. To put this cost in perspective, many patients I saw in Tanzania could not afford the £15 for cataract surgery.
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