Dermatology Online Journal

Comparison of podophyllotoxin and imiquimod as anal condyloma acuminata therapy
Sreedhar Krishna
Dermatology Online Journal 15 (1): 14

Faculty of Medicine, Imperial College London, United Kingdom. sreedhar.krishna@imperial.ac.uk

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Abstract

Herein we revisit the published evidence for comparison of the efficacy of imiquimod and podophyllotoxin for anal condyloma acuminata

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Comment:

I read the case presentation in December 2008 on intra-anal condylomas with great interest [1]. Dianzani et al. should be applauded for taking a holistic approach to this gentleman's care; in their recognition of the patient's individual psychosocial profile topical therapy was favored over more radical alternatives. Considering these issues, I suggest that in today's era of evidence-based practice, podophyllotoxin may have been more suitable than imiquimod.

Podophyllotoxin, an extract of the American Mayapple plant (Podophyllum peltatum), binds to cellular microtubules and inhibits mitotic division, thereby inducing necrosis of condylomas. Necrosis is maximal between 3-5 days; the erosions that occur during this process are shallow and heal within a few days [2, 3].

Each course of podophyllotoxin comprises twice daily application for three days, followed by a rest period of 4-7 days. Podophyllotoxin is conventionally dispensed as 0.5 percent podophyllotoxin solution. However anal warts are more feasibly and efficiently treated with 0.15 percent podophyllotoxin cream. Clearance rates of anal warts with the use of 0.15 percent podophyllotoxin cream lie between 60-80 percent when patients treat themselves for 1-4 courses [4, 5, 6]. This is somewhat superior to the 40 percent clearance rate reported by males on imiquimod [7]. Moreover, due to the contrasting mechanisms of action, whereas podophyllotoxin commonly effects resolution within 1-4 weeks, the median time to clearance with imiquimod is around 3 months in males [7]. Furthermore, the side effects of podophyllotoxin tend to be mild and restricted to only the first course of treatment [8, 9]; those of imiquimod can be more pronounced, necessitating temporary drug-free periods and even complete withdrawal from treatment in 29 percent and 6 percent, respectively [10]. Intra-anal condyloma have been safely and successfully treated with podophyllotoxin in the past; a recent prospective study reports an 86 percent clearance rate after 4 cycles in this cohort [11]. This is not to say podophyllotoxin is to be universally preferred over imiquimod for anal condyloma acuminata. It is also important to note that the use of podophyllotoxin is contraindicated during pregnancy and women of child-bearing age must be advised to avoid becoming pregnant during therapy.

Incidentally, although this gentleman was noted to have a low-risk HPV genotype, studies have shown that HPV genotyping is not a useful adjunct to cytological screening [12].

References

1. Dianzani C, Pierangeli A, Avola A, et al. Intra-anal condyloma: Surgical or topical treatment? Dermatology Online Journal 14 (12): 8

2. Von Krogh G. Podophyllotoxin for condylomata acuminata eradication. Clinical and experimental comparative studies on Podophyllum lignans, colchicine and 5-fluorouracil. Thesis. Acta Dermatovenereol Suppl 1981; 98:1-48 [PubMed]]

3. Von Krogh G. Penile condylomata acuminata: an experimental model for evaluation of topical treatment with 0.5-1.0% ethanolic preparations of podophyllotoxin for three days. Sex Transm Dis 1981;8:179-84. [PubMed]

4. Claesson U, Lassus A, Happonen H, et al. Topical treatment of venereal warts: a comparative open study of podophyllotoxin cream versus solution. Int J STD AIDS 1996;7:429-34 [PubMed]

5. Strand A, Brinkeborn R-M, Siboulet A. Topical treatment of genital warts in men, an open study of podophyllotoxin cream compared with solution. Genitourin Med 1995;7:387-90 [PubMed]

6. Sand Peterson C, Agner T, Ottevanger V, et al. A single-blind study of podophyllotoxin cream 0.5% and podophyllotoxin solution 0.5% in male patients with genital warts. Genitourin Med 1995;71:391-2. [PubMed]

7. Edwards L, Ferenczy A, Eron L, et al. Self-administered topical 5% imiquimod cream for external anogenital warts. Arch Dermatol 1998;134:25-30. [PubMed]

8. Von Krogh G. Penile condylomata acuminata: an experimental model for evaluation of topical treatment with 0.5-1.0% ethanolic preparations of podophyllotoxin for three days. Sex Transm Dis 1981;8:179-84. [PubMed]

9. Von Krogh G, Szpak E, Andersson M, et al. Self-treatment using 0.25%-0.5% podophyllotoxin ethanol solutions against penile condylomata acuminata-a placebo-controlled comparative study. Genitourin Med 1994;70:105-9. [PubMed]

10. Gollnick H, Barasso R, Benninghoff B, et al. Safety and efficacy of imiquimod 5% cream in uncircumcised males with foreskin-associated genital warts. Poster No P711 at the 8th Congress of the European Academy of Dermatology and Venereology (EADV), 29 September-3 October 1999.

11. Tzatha C, Stavrianeas NG, Triantafyllou K, et al. Long-term follow-up of endoscopic therapy of anal canal condylomata acuminata with podophyllotoxin. J Eur Acad Dermatol Venereol. 2007;21(3):364-7. [PubMed]

12. Fox PA, Seet JE, Stebbing J, et al. The value of anal cytology and human papillomavirus typing in the detection of anal intraepithelial neoplasia: a review of cases from an anoscopy clinic. Sex Transm Infect. 2005 Apr;81(2):142-6. [PubMed]

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