Practice Patterns In Early Stage Hodgkin Lymphoma: Analysis Of The National Cancer Database

Treatment for early stage Hodgkin lymphoma (HL) involves radiation therapy (RT), chemotherapy (CT) or combined modality therapy (CMT). Previous studies demonstrated declining use of RT and increasing use of CT alone. We assessed rates of RT vs. CMT among HL patients receiving RT. Among those receiving CMT, we studied the distribution of RT dose, particularly the use of 20 Gy (per HD10) and factors that affect the dose used. The National Cancer Database (2004-2015) was queried for patients with Stage I and II HL treated with RT and divided those treated with RT alone vs. CMT. Demographics, disease characteristics, and treatment details were analyzed. Logistic regression was used to identify variables associated with receiving RT alone. Among patients receiving CMT, multinomial regression was used to identify factors correlating with RT doses. Significance was defined at p <0.05. Of 27,912 patients that met study criteria, 24% were Stage I and 76% were Stage II. Of these, 12% received RT alone and 88% received CMT. Factors associated with receiving RT alone were nodular lymphocyte predominant histology (NLPHL, odds ratio (OR) 26.4 vs. classical HL), increasing age (OR 5.3 for age >65 vs <21), black race (OR 2.1 vs. white race), axilla/arm (OR 1.3) or groin/leg (OR 1.9) site (vs. head and neck (HN)), and the use of doses ≥ 40 Gy (OR 15.9 vs. <30 Gy). Conversely, patients with stage II disease (OR 0.35), B symptoms (OR 0.33) and thorax (OR 0.44) or multiregional primary site (OR 0.66 vs. HN) were less likely to receive RT alone. Among patients treated with CMT, the majority (64.6%) received ≥30 to ≤36 Gy, while 19.1% received >20 to <30 Gy, 7.3% received exactly 20 Gy, 4.6% received >36 Gy, and 4.4% received <20 Gy. The use of 20 Gy was more common at academic facilities (11% vs. 7-9% at other facilities) and increased significantly after 2010, with rates of 1-9% in 2004-2009 and 9-17% in 2010-2015. Adjusting for competing variables, use of 20 Gy (vs. ≥30 to ≤36 Gy) was less common for thorax site (OR 0.43 vs. HN), stage II disease (OR 0.41), B symptoms (OR 0.33), and Medicaid or uninsured patients (OR 0.70 and 0.52, respectively vs. private insurance). 20 Gy dosing was more common with increasing distance from treatment center (OR 2.9 for >100 miles) and later year of diagnosis (OR 6.3 for 2010-2015 vs 2004-2009). Use of dose >36 Gy decreased over time (4-9% in 2004-2009 vs 2-4% in 2010-2015). Of patients receiving RT for early stage HL, 12% receive RT alone. Adjusting for co-variates, RT alone (vs. CMT) is more common among patients with NLPHL, older age, black race, and axilla or groin disease, but less common in those with B symptoms, stage II disease, and thoracic disease. Of those treated with CMT, there is a wide variability in RT dose. The use of 20 Gy is increasing since 2010 and is more common in patients with stage I disease, no B symptoms, HN site, academic facility, and greater distance from facility.