Here is the design of a clinical trial:

Official Title: Ductal Lavage Versus Corticosteroids Therapy for Idiopathic Granulomatous Mastitis: a Multicenter, Randomized, Open-labelled, Non-inferior Trial.

Included conditions:
- Granulomatous Mastitis

Study Armgroups:
- {'label': 'Ductal lavage', 'type': 'EXPERIMENTAL', 'description': 'Ductal lavage and breast massage for two weeks.', 'interventionNames': ['Procedure: Ductal lavage']}
- {'label': 'Corticosteroids therapy', 'type': 'ACTIVE_COMPARATOR', 'description': 'Oral corticosteroids therapy for 6 months.', 'interventionNames': ['Drug: Corticosteroid therapy']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Ductal lavage', 'description': 'The patients received ductal lavage and breast massage every other day for two weeks. We used lidocaine (1%) for local anesthesia around the nipple. We used a lacrimal probe to identify 4-5 openings in the lactiferous ducts on the nipple and inserted the infusion cannula (21-23G). A total of 25ml of irrigation solution (5 ml of 2% lidocaine, 40 mg of triamcinolone acetonide, 20 ml of 0.9% saline and 1.0 g of ceftriaxone) was pumped into the ducts over 20-25 minutes. The patient returned to the clinic the next day for breast massage, and the cycle was repeated for two weeks.', 'armGroupLabels': ['Ductal lavage']}
- {'type': 'DRUG', 'name': 'Corticosteroid therapy', 'description': 'Methylprednisolone(Common brand names: Medrol) or prednisone 20-40mg, qd for two weeks, then temper the dose gradually, and then 20mg qd for maintenance (The total duration of the treatment is 6 months).', 'armGroupLabels': ['Corticosteroids therapy']}

Primary Outcomes:
- {'measure': 'Complete Clinical Response(cCR)', 'description': 'The proportion of patients that achieve M-score \\<=1 at 1 year after the treatment.', 'timeFrame': '1 year since randomization'}

Please estimate the sample size based on the assumption: 
A significance level of α=0.025 and power of β=0.80 were considered. A loss to follow-up rate of 10% was also assumed.
Sample size and statistical analysis
        We will report the continuous and categorical variables as the medians (ranges) and counts (percentages), respectively, for the descriptive analysis. The Mann-Whitney U test and ÏÂ²-square test will be used to compare the clinicopathological features between the two groups. The primary and secondary endpoints will be compared by intention-to-treat analysis. We will determine whether there are missing data, and we will use multiple imputation and sensitivity analyses to explore the impact of the missing data.
        We hypothesise that the 1-year cCR rate of oral corticosteroid treatment will be 90%. This trial was designed to assess the non-inferiority of ductal lavage compared with oral corticosteroids, and the clinically acceptable non-inferiority margin for the ductal lavage group was defined as a 1-year cCR rate equal to or better than 15%. This non-inferiority margin was decided before the initiation of the study during a consensus meeting with a panel of experts. A loss to follow-up rate of 10% was considered, and it was calculated that 70 participants (total of 140 participants) were needed in each group, with a significance level of a=0.025âand power of b=0.80. If non-inferiority is confirmed and the lower border of the 95% CI is >0, the superiority effects of ductal lavage vs oral steroids can be suggested.
        An exploratory analysis will be performed to investigate the potential interaction between treatment benefits and the baseline clinicopathological factors, for example, M-score (â¥5âor <5). Subgroup analysis will be performed for significant interactions. Longitudinal data analysis will be performed using marginal generalised estimating equations for the cCR, as well as the random effects/mixed models for the M-scores. All of the statistical analyses will be conducted using STATA V.13 statistical software (StataCorp, College Station, Texas, USA).