Effects of Radiotherapy on the Risk of Developing Secondary Malignant Neoplasms in Hodgkin's Lymphoma Survivors

The Impact of Radiotherapy on the Incidence of Secondary Malignancies: A Pan-Cancer Study in the US SEER Cancer Registries

The population of cancer patients with second primary malignancies (SPMs) is rapidly growing. The relationship between radiotherapy and SPMs for some types of tumors is unknown or debated. In this study, we identify 24 types of first primary malignancies (FPMs) between 2004 and 2015 in the Surveillance, Epidemiology, and End Results (SEER) database. Patients in the radiotherapy group were matched to those in the no radiotherapy group with a matching ratio of 1:1. After propensity-score matching (PSM), additional competing risk regression analyses were performed to calculate the efficacy of radiotherapy to SPMs in the PSM-adjusted population. In addition, the Fine and Gray model was utilized in the primary cohorts, and stratified analyses were performed based on surgery. This study includes a total of 2,831,789 eligible patients with tumors diagnosed from 2004 to 2015 in the SEER 18 database, amongst whom 100,194 (3.5%) patients developed SPMs. We observe higher risks of SPMs associated with radiotherapy in several types of tumors in the PSM-adjusted populations (small bowel adenocarcinoma, small cell lung carcinoma, prostate adenocarcinoma, urinary bladder transitional cell carcinoma, invasive ductal breast carcinoma, invasive lobular breast carcinoma, and Hodgkin lymphoma). The results in the PSM-adjusted populations were consistent with outcomes in the multivariable competing risk models. Meanwhile, in subgroup analyses stratified by surgery, some other types of tumor (except for those with positive results in the PSM-adjusted cohorts) with radiotherapy were also associated with a higher prevalence of SPMs in the subgroups of surgical treatment (pancreatic adenocarcinoma, rectal adenocarcinoma, lung adenocarcinoma and follicular thyroid carcinoma in the surgery subgroups). The impact of radiotherapy on the incidence of secondary malignancies is distinct in different types of cancer. These findings merit further investigation and may ultimately impact treatment decision-making for tumor management.

Survival Pattern of Hodgkin Lymphoma Patients in the Last 25 Years in Lebanon

CONTEXT

After the emergence of combination chemotherapy in 1960s, survival of patients with Hodgkin lymphoma (HL) has dramatically improved worldwide. We lack studies that document the favorable evolution of survival regarding this disease in Lebanon.

OBJECTIVE

To compare the overall survival in HL over 3 different decades in Lebanon.

METHODS

We retrospectively reviewed the charts of 196 patients diagnosed with HL, treated and followed from 1990 to 2015 in our center. Patients were divided into 3 groups according to period of analysis: group A (1990-1999), group B (2000-2009), and group C (2010-2015). We studied the characteristics and survival patterns of patients in each group.

RESULTS

The male-to-female sex ratio was 1.06. The median age at diagnosis was 33 years in group A, 30.4 in group B, and 33.12 in group C (P = .6). Results showed variations in the subtypes of the disease according to the following: nodular-sclerosis HL 59.5% in group A, 76.2% in group B, and 85.4% in group C. Mixed cellularity HL 21.6% in group A, 2.4% in group B, and 73.7% in group C (P = .0001). Patients presented with localized disease in 58.6%, 73.7%, and 56.4% in groups A, B, and C, respectively (P = .173). Complete remission was achieved in 76.5% in group A, 85.3% in group B, and 69.5% in group C (P = .007). The survival rate at 5 years in group A was 91%, 94% in group B, and 100% in group C.

CONCLUSION

The survival of patients with HL has dramatically improved over the past 25 years in Lebanon. These results resemble those achieved in Western countries due to the fast adoption of new molecular imaging technologies at diagnosis and follow-up and the rapid approval of new drugs for relapse in the Lebanese market.