Abstract
Dear Editor:
We unfortunately have discontinued a prospective multicenter trial of Mohs' paste (MP) for gynecological cancer because of a “New clinical research law” to be issued in Japan in April 2019, so we are reporting the outlines and a potential of this trial. Although recent advances in new cancer treatments appear remarkable, treatments available for local recurrence in the uterine cervix or vaginal stump are limited. Regarding genital bleeding, gauze tamponade and artery embolization are sometimes insufficient, reduce quality of life (QOL), and can be fatal. We had proposed successful hemostasis by applying MP for recurring wounds as a new hemostatic option.1,2 MP is made of a commonly used mixture of zinc chloride (50 g), distilled water (25 mL), zinc starch (19 g), and glycerol (15 mL). All seven patients achieved hemostasis and avoided death from genital bleeding. Other unpleasant symptoms such as foul odor and exudates also could be reduced.
However, some improvements were required for gynecological use: (1) MP could not be preserved; (2) MP infiltrated a three- to fivefold depth, and fistula formations may form in surrounding organs; (3) although glycerin is mixed to improve viscosity, MP was easily soluble under the body temperature in the vagina and may have caused vaginitis and pain. So, we created a modified MP that improved these points as detailed information indicated in Ref. 3 : A simple zinc oxide ointment was mixed with MP in a 1:1 ratio, and a small amount of glycerin was added just before treatment.
“Prospective study of the efficacy and feasibility using modified MP in gynecologic cancer” was started for establishing the generalizability of MP application after the Institutional Review Board's approval for four institutes in Kagoshima prefecture, Japan. The details were created referring to the previous guidance, 4 and our protocols were as follows: the purpose is to evaluate the efficacy and feasibility of modified MP for genital symptoms of gynecological cancer, including metastatic tumors. Eligibility criteria: (1) local discomfort symptoms are found; (2) resistant to administer anticancer treatment. Primary outcomes: procedure completion rate and symptom amelioration rates. Secondary outcomes: survival times and acute and chronic complications. Procedures (repeated several times if necessary): direct application to the tumor using a large pledget and soft pressure was applied, and removed 12–24 hours later. Expected complications and countermeasures: (1) pain (frequency: 80%); the pain associated with the surrounding organs stimulation is prophylactically administered with an analgesic agent; (2) dermatitis/mucositis (frequency: 20%); wash and apply ointment if necessary; (3) fistula (frequency: <5%); considered for surgery as needed.
Although the registration was performed for about one year, this trial was categorized as “Specific Clinical Research” and strict provision of the law did not permit continuation. Possible causes of not progressing the trial include small eligible populations, a short duration of registration, and a lack of participation from palliative care facilities. We are convinced that MP is the important modality to improve the QOL of advanced gynecological cancer patients. Further extensive studies are necessary and warranted to establish the treatment strategy.