Increased risk of second lung cancer in Hodgkin's lymphoma survivors: a meta-analysis

Patients treated for Hodgkin's lymphoma (HL) have a higher risk of developing second lung cancer (SLC) compared with the general population. The aim of this meta-analysis was to quantify such risk and to analyze contributing risk factors in HL survivors.

According to predefined selection criteria, a literature search identified 21 studies that were included in the analysis.

After eliminating overlapping or duplicate data, 793 (76 % males) incidences of SLC were encountered in 74,831 patients (58 % males) with HL over a median follow-up of 11.5 years. The median age at HL diagnosis and the median age at SLC diagnosis were 33.0 and 45.9, respectively. The mean latency between treatment of HL and development of SLC was 11.5 years. The pooled relative risk (RR) of SLC was 4.62 (95 % confidence interval [CI], 3.18-6.70], I (2) = 98 %), with a median absolute excess rate of 10.4 per 10,000 person-years. RR was positively related to study size, male-to-female ratio, institutional versus population-based data sets, and the use of any radiotherapy (RT) or combined modality therapy (CMT), while age at diagnosis of HL was not significant. The highest risk was shown among patients aged 15-24 years (RR = 8.76 [95 % CI, 4.55-16.89]), while the lowest risk occurred in patients ≥55 years at primary treatment (RR = 2.88 [95 % CI, 2.33-3.56]). RR increased by increasing duration of follow-up, reaching the highest value at 10-14 years (RR = 4.17 [95 % CI, 3.62-8.81]), but did not increase after ≥15 years (RR = 4.01 [95 % CI, 2.68-5.98]). RT only, CMT, or chemotherapy only was associated with RR (95 % CI) of 4.88 (3.14-7.60), 5.15 (4.08-6.50), and 2.39 (1.60-3.55), respectively. Patients with SLC demonstrated poor prognosis.

The current meta-analysis provided a detailed estimate of the risk of SLC among HL survivors. The obtained results may provide guidelines concerning lung cancer screening for this population.