THE USE OF 4% FORMALIN SOLUTION FOR THE TREATMENT OF HEMORRHAGIC ACTINIC PROCTITIS: EXPERIENCE OF THE SERVICE

Introduction Actinic proctitis due to radiation therapy for pelvic neoplasms is a common complication. Among therapeutic options, the use of formalin solution is an effective and low-cost alternative.

Objective To report the service’s experience in treating hemorrhagic actinic proctitis post-prostate neoplasia with intra-rectal 4% formalin application. Case 1: FA, an 88-year-old male, underwent radiotherapy 24 months ago and was admitted for acute exacerbation of chronic rectal bleeding and symptomatic anemia (Hb=5.5). In a previous hospitalization, a colonoscopy with argon plasma coagulation and rectal sucralfate was performed. A subsequent examination revealed submucosal telangiectasias with active bleeding and ulcerations on the anterior rectal wall due to prior argon use. The treatment of choice was the intra-rectal 4% formalin application, following the Teixeira method: rectal instillation via a catheter inserted into the colonoscope over the affected area. A total of 500 ml of 4% formalin was used in aliquots of 50 ml, with each aliquot remaining in contact with the mucosa for 1 minute, followed by washing with 100 ml of saline solution, aspiration of the residual liquid, and repeated application (10 times). Between applications, cleaning of the anal border was performed to prevent skin lesions. There was remission of bleeding during follow-up, without the need for further procedures. Case 2: FBP, an 80-year-old male, underwent radiotherapy 19 months ago and was admitted with rectal bleeding and anemia (Hb=7). He was hospitalized for hemorrhagic actinic proctitis and experienced recurrence of bleeding weeks after the use of argon. The decision was made to use 4% formalin under the previously described technique. He evolved with remission of bleeding and hematimetric stability, leading to hospital discharge. Two weeks later, he reported sporadic bleeding, and a new rectosigmoidoscopy showed circumferential fibrinous ulceration (eschar from previous formalin instillation), without active bleeding.

Conclusion Among various therapies for hemorrhagic actinic proctitis, argon plasma coagulation is the most effective, although it is less available, more costly, and carries the risk of complications. Evidence shows positive results with intra-rectal 4% formalin, and our experience has been satisfactory. This method offers low cost and wide availability, making it an effective option for refractory cases and a first-choice treatment in hospitals lacking other therapeutic resources.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
25 April 2025