Original Article: Cutaneous Cryosurgery for Common Skin Conditions

Issue Date: April 1, 2020

See additional reader comments at: https://www.aafp.org/afp/2020/0401/p399.html

To the Editor: In the Strength of Recommendation Taxonomy (SORT) table from their article, Clebak and colleagues gave a SORT Evidence Rating of B (based on inconsistent or limited-quality patient-oriented evidence) to the following recommendation, “Cryosurgery is as effective as daily treatment with salicylic acid in the treatment of plantar warts, with higher reported patient satisfaction.” A randomized controlled trial was cited for this information.¹

In the text of the article, Clebak and colleagues referred to a 2012 Cochrane review² that found “no difference in clearance rates in the treatment of warts comparing repeat cryosurgery with daily salicylic acid”; however, they did not mention the review in their recommendation and seemed to give precedence to the aforementioned single randomized controlled trial over a systematic review, which is an inversion of the Levels of Evidence.

The Cochrane review cited a meta-analysis (generally held to be higher level evidence than randomized controlled trials), as well as the single randomized controlled trial cited by Clebak and colleagues. The authors of the Cochrane review concluded the following: “A meta-analysis of cryotherapy versus placebo for warts at all sites favoured neither intervention nor control…One trial showed cryotherapy to be better than both placebo and [salicylic acid], but only for hand warts.” The trial cited in the Cochrane review was not the randomized controlled trial cited by Clebak and colleagues, but rather an article by Bruggink and colleagues.³

Cryosurgery is not without risks, and high-level evidence suggesting that it is no better than placebo in a disease process that will likely resolve on its own⁴ should make us reconsider whether family physicians should offer cryotherapy for cutaneous warts. I believe that the quoted statement from this article is not supported by current evidence and is misleading at best.

In Reply: Our article attempted to provide a balanced review of the techniques, indications, contraindications, and complications of cryosurgery in common dermatologic applications. We did not specifically review the clinical question of the optimal approach to cutaneous warts.

The authors of the 2012 Cochrane review summarizing topical treatments for cutaneous warts acknowledged that the included studies were of limited quality and were at a high risk of bias.¹ Only one trial showed cryotherapy to be more effective than salicylic acid and placebo; however, this was only for warts of the hand. A Cochrane review without clear recommendation would be a SORT B, similar to a recommendation from a single, good-quality randomized controlled trial based on the SORT taxonomy.²

The “high level evidence” referenced by Dr. Fay represents the 2014 guidelines of the British Association of Dermatologists for the Management of Cutaneous Warts, which includes the 2012 Cochrane review that favors cryotherapy over salicylic acid treatment for warts of the hand.³

We encourage family physicians to include the benefits and risks of all procedures, including cryosurgery, with patients as part of an informed and shared decision-making process.