After a patterns-of-care study (PCS) in 2003/2004 addressing benign disorders in general, the German Cooperative Group on Radiotherapy for Benign Diseases (GCG-BD) conducted several multicenter cohort studies including the use of radiotherapy (RT) in painful gonarthrosis (GNA).
From 2006 to 2008, a PCS for GNA was conducted in all German RT institutions using a standardized structured questionnaire. Patient accrual, patient number, pretreatment, pain record, treatment indications, RT technique, and target volume concepts for painful GNA were assessed. In addition, the long-term functional and subjective outcomes were evaluated.
238/248 institutions (95.9%) returned the questionnaire: 50 (21%) reported no clinical experience with RT in GNA, while 188 (79%) institutions treated 4,544 patients annually (median 15; range one to 846 cases per institution). Indications for treatment were acute pain symptoms in 18.9%, chronic pain in 95.3%, and treatment-refractory pain in 81.1%. The median total dose was 6 Gy (range 3-12 Gy), with a median single dose of 1 Gy (0.25-3 Gy). 40.4% of the institutions applied two fractions and 51.4% three fractions weekly. RT was delivered with orthovoltage units (25%), linear accelerators (79.6%), and cobalt-60 units (8.3%). 42 institutions evaluated the long-term clinical outcome in a total of 5,069 cases. Median pain reduction for at least 3 months was reported in 60% (5-100%), median pain reduction for at least 12 months in 40% (10-100%), and median persistent pain reduction in 27.8% (10-85%) of the treated patients. In 30% of patients (7-100%), a second RT series was applied for inadequate pain response or early pain recurrence. No radiogenic acute or chronic side effects were observed.
This PCS comprises the largest number of cases reported for RT in painful and refractory GNA. Despite variations in daily RT practice, high response and low toxicity for this treatment in a very large number of painful and refractory GNA cases renders low-dose RT an effective conservative therapy which can be applied prior to surgical procedures.