Genetic susceptibility to radiation-induced breast cancer after Hodgkin lymphoma.

Female Hodgkin lymphoma (HL) patients treated with chest radiotherapy (RT) have a very high risk of breast cancer. The contribution of genetic factors to this risk is unclear. We therefore examined 211 155 germline single-nucleotide polymorphisms (SNPs) for gene-radiation interaction on breast cancer risk in a case-only analysis including 327 breast cancer patients after chest RT for HL and 4671 first primary breast cancer patients. Nine SNPs showed statistically significant interaction with RT on breast cancer risk (false discovery rate, <20%), of which 1 SNP in the PVT1 oncogene attained the Bonferroni threshold for statistical significance. A polygenic risk score (PRS) composed of these SNPs (RT-interaction-PRS) and a previously published breast cancer PRS (BC-PRS) derived in the general population were evaluated in a case-control analysis comprising the 327 chest-irradiated HL patients with breast cancer and 491 chest-irradiated HL patients without breast cancer. Patients in the highest tertile of the RT-interaction-PRS had a 1.6-fold higher breast cancer risk than those in the lowest tertile. Remarkably, we observed a fourfold increased RT-induced breast cancer risk in the highest compared with the lowest decile of the BC-PRS. On a continuous scale, breast cancer risk increased 1.4-fold per standard deviation of the BC-PRS, similar to the effect size found in the general population. This study demonstrates that genetic factors influence breast cancer risk after chest RT for HL. Given the high absolute breast cancer risk in radiation-exposed women, these results can have important implications for the management of current HL survivors and future patients.

Second Cancer Risk Up to 40 Years after Treatment for Hodgkin's Lymphoma.

BACKGROUND: Survivors of Hodgkin's lymphoma are at increased risk for treatment-related subsequent malignant neoplasms. The effect of less toxic treatments, introduced in the late 1980s, on the long-term risk of a second cancer remains unknown. METHODS: We enrolled 3905 persons in the Netherlands who had survived for at least 5 years after the initiation of treatment for Hodgkin's lymphoma. Patients had received treatment between 1965 and 2000, when they were 15 to 50 years of age. We compared the risk of a second cancer among these patients with the risk that was expected on the basis of cancer incidence in the general population. Treatment-specific risks were compared within the cohort. RESULTS: With a median follow-up of 19.1 years, 1055 second cancers were diagnosed in 908 patients, resulting in a standardized incidence ratio (SIR) of 4.6 (95% confidence interval [CI], 4.3 to 4.9) in the study cohort as compared with the general population. The risk was still elevated 35 years or more after treatment (SIR, 3.9; 95% CI, 2.8 to 5.4), and the cumulative incidence of a second cancer in the study cohort at 40 years was 48.5% (95% CI, 45.4 to 51.5). The cumulative incidence of second solid cancers did not differ according to study period (1965-1976, 1977-1988, or 1989-2000) (P=0.71 for heterogeneity). Although the risk of breast cancer was lower among patients who were treated with supradiaphragmatic-field radiotherapy not including the axilla than among those who were exposed to mantle-field irradiation (hazard ratio, 0.37; 95% CI, 0.19 to 0.72), the risk of breast cancer was not lower among patients treated in the 1989-2000 study period than among those treated in the two earlier periods. A cumulative procarbazine dose of 4.3 g or more per square meter of body-surface area (which has been associated with premature menopause) was associated with a significantly lower risk of breast cancer (hazard ratio for the comparison with no chemotherapy, 0.57; 95% CI, 0.39 to 0.84) but a higher risk of gastrointestinal cancer (hazard ratio, 2.70; 95% CI, 1.69 to 4.30). CONCLUSIONS: The risk of second solid cancers did not appear to be lower among patients treated in the most recent calendar period studied (1989-2000) than among those treated in earlier periods. The awareness of an increased risk of second cancer remains crucial for survivors of Hodgkin's lymphoma. (Funded by the Dutch Cancer Society.).

Infradiaphragmatic irradiation and high procarbazine doses increase colorectal cancer risk in Hodgkin lymphoma survivors.

BACKGROUND: Hodgkin lymphoma (HL) survivors are at increased risk of second malignancies, but few studies have assessed colorectal cancer (CRC) risk after HL treatment. We assessed long-term, subsite-specific CRC risk associated with specific radiation fields and chemotherapy regimens. METHODS: In a Dutch cohort of 3121 5-year HL survivors treated between 1965 and 1995, subsite-specific CRC incidence was compared with general population rates. Treatment effects were quantified by Cox regression analyses. RESULTS: After a median follow-up of 22.9 years, 55 patients developed CRC. The standardized incidence ratios (SIR) was 2.4-fold increased (95% confidence interval (95%CI) 1.8-3.2), leading to 5.7 excess cases per 10 000 patient-years. Risk was still increased 30 years after HL treatment (SIR: 2.8; 95%CI: 1.6-4.6). The highest (SIR: 6.5, 95%CI: 3.3-11.3) was seen for transverse colon cancer (15.0 (95%CI: 4.3-40.8) after inverted-Y irradiation). A prescribed cumulative procarbazine dose >4.2 g m-2 was associated with a 3.3-fold higher CRC risk (95%CI: 1.8-6.1) compared to treatment without procarbazine. Patients receiving >4.2 g m-2 procarbazine and infradiaphragmatic radiotherapy had a hazard ratio of 6.8 (95%CI: 3.0-15.6) compared with patients receiving neither treatment, which is significantly higher than an additive joint effect (Padditivity=0.004). CONCLUSIONS: Colorectal cancer surveillance should be considered for HL survivors who received Infradiaphragmatic radiotherapy and a high cumulative procarbazine dose.

Risk of multiple primary malignancies following treatment of Hodgkin lymphoma.

We assessed risk, localization, and timing of third malignancies in Hodgkin lymphoma (HL) survivors. In a cohort of 3122 5-year HL survivors diagnosed before the age of 51 years and treated between 1965 and 1995, we examined whether risk factors for second and third malignancies differ and whether the occurrence of a second malignancy affects the risk of subsequent malignancies, using recurrent event analyses. After a median follow-up of 22.6 years, 832 patients developed a second malignancy and 126 patients a third one. The risk of a second malignancy was 4.7-fold increased (95% confidence interval [CI], 4.4-5.1) compared with risk in the general population; the risk for a third malignancy after a second malignancy was 5.4-fold (95% CI, 4.4-6.5) increased. The 10-year cumulative incidence of any third malignancy was 13.3%. Compared with patients still free of a second malignancy, patients with a second malignancy had a higher risk of developing subsequent malignancies. This risk depended on age, with hazard ratios of 2.2, 1.6, and 1.1 for patients aged <25, 25 to 34, and 35 to 50 years at HL treatment, respectively. In HL survivors who had a second malignancy, treating physicians should be aware of the increased risk of subsequent malignancies.

Long-Term Cause-Specific Mortality in Hodgkin Lymphoma Patients.

BACKGROUND: Few studies have examined the impact of treatment-related morbidity on long-term, cause-specific mortality in Hodgkin lymphoma (HL) patients. METHODS: This multicenter cohort included 4919 HL patients, treated before age 51 years between 1965 and 2000, with a median follow-up of 20.2 years. Standardized mortality ratios, absolute excess mortality (AEM) per 10 000 person-years, and cause-specific cumulative mortality by stage and primary treatment, accounting for competing risks, were calculated. RESULTS: HL patients experienced a 5.1-fold (AEM = 123 excess deaths per 10 000 person-years) higher risk of death due to causes other than HL. This risk remained increased in 40-year survivors (standardized mortality ratio = 5.2, 95% confidence interval [CI] = 4.2 to 6.5, AEM = 619). At age 54 years, HL survivors experienced similar cumulative mortality (20.0%) from causes other than HL to 71-year-old individuals from the general population. Whereas HL mortality statistically significantly decreased over the calendar period (P < .001), solid tumor mortality did not change in the most recent treatment era. Patients treated in 1989-2000 had lower 25-year cardiovascular disease mortality than patients treated in 1965-1976 (4.3% vs 5.7%; subdistribution hazard ratio = 0.65, 95% CI = 0.46 to 0.93). Infectious disease mortality was not only increased after splenectomy but also after spleen irradiation (hazard ratio = 2.81, 95% CI = 1.55 to 5.07). For stage I-II, primary treatment with chemotherapy (CT) alone was associated with statistically significantly higher HL mortality (P < .001 for CT vs radiotherapy [RT]; P = .04 for CT vs RT+CT) but lower 30-year mortality from causes other than HL (15.8%, 95% CI = 9.7% to 23.3%) compared with RT alone (36.9%, 95% CI = 34.0% to 39.8%, P = .001) and RT and CT combined (29.8%, 95% CI = 26.8% to 32.9%, P = .02). CONCLUSIONS: Compared with the general population, HL survivors have a substantially reduced life expectancy. Optimal selection of patients for primary CT is crucial, weighing risks of HL relapse and long-term toxicity.

Overall and disease-specific survival of Hodgkin lymphoma survivors who subsequently developed gastrointestinal cancer.

BACKGROUND: Hodgkin lymphoma (HL) survivors have an increased risk of gastrointestinal (GI) cancer. This study aims to evaluate whether survival of patients who survived HL and developed GI cancer differs from survival of first primary GI cancer patients. METHODS: Overall and cause-specific survival of GI cancer patients in a HL survivor cohort (GI-HL, N = 104, including esophageal, gastric, small intestinal, and colorectal cancer) was compared with survival of a first primary GI cancer patient cohort (GI-1, N = 1025, generated by case matching based on tumor site, gender, age, and year of diagnosis). Cox proportional hazards regression was used for survival analyses. Multivariable analyses were adjusted for GI cancer stage, grade of differentiation, surgery, radiotherapy, and chemotherapy. RESULTS: GI-HL cancers were diagnosed at a median age of 54 years (interquartile range 45-60). No differences in tumor stage or frequency of surgery were found. GI-HL patients less often received radiotherapy (8% vs 23% in GI-1 patients, P < 0.001) and chemotherapy (28% vs 41%, P = 0.01) for their GI tumor. Compared with GI-1 patients, overall and disease-specific survival of GI-HL patients was worse (univariable hazard ratio (HR) 1.30, 95% confidence interval (CI) 1.03-1.65, P = 0.03; and HR 1.29, 95% CI 1.00-1.67, P = 0.049, respectively; multivariable HR 1.33, 95% CI 1.05-1.68, P = 0.02; and HR 1.33, 95% CI 1.03-1.72, P = 0.03, respectively). CONCLUSIONS: Long-term overall and disease-specific survival of GI cancer in HL survivors is worse compared with first primary GI cancer patients. Differences in tumor stage, grade of differentiation, or treatment could not explain this worse survival.

Retrospective methods to estimate radiation dose at the site of breast cancer development after Hodgkin lymphoma radiotherapy.

BACKGROUND: An increased risk of breast cancer following radiotherapy for Hodgkin lymphoma (HL) has now been robustly established. In order to estimate the dose-response relationship more accurately, and to aid clinical decision making, a retrospective estimation of the radiation dose delivered to the site of the subsequent breast cancer is required. METHODS: For 174 Dutch and 170 UK female patients with breast cancer following HL treatment, the 3-dimensional position of the breast cancer in the affected breast was determined and transferred onto a CT-based anthropomorphic phantom. Using a radiotherapy treatment planning system the dose distribution on the CT-based phantom was calculated for the 46 different radiation treatment field set-ups used in the study population. The estimated dose at the centre of the breast cancer, and a margin to reflect dose uncertainty were determined on the basis of the location of the tumour and the isodose lines from the treatment planning. We assessed inter-observer variation and for 47 patients we compared the results with a previously applied dosimetry method. RESULTS: The estimated median point dose at the centre of the breast cancer location was 29.75 Gy (IQR 5.8-37.2), or about 75% of the prescribed radiotherapy dose. The median dose uncertainty range was 5.97 Gy. We observed an excellent inter-observer variation (ICC 0.89 (95% CI: 0.74-0.95)). The absolute agreement intra-class correlation coefficient (ICC) for inter-method variation was 0.59 (95% CI: 0.37-0.75), indicating (nearly) good agreement. There were no systematic differences in the dose estimates between observers or methods. CONCLUSION: Estimates of the dose at the point of a subsequent breast cancer show good correlation between methods, but the retrospective nature of the estimates means that there is always some uncertainty to be accounted for.

Breast Cancer Risk After Radiation Therapy for Hodgkin Lymphoma: Influence of Gonadal Hormone Exposure.

BACKGROUND: Young women treated with chest radiation therapy (RT) for Hodgkin lymphoma (HL) experience a strongly increased risk of breast cancer (BC). It is unknown whether endogenous and exogenous gonadal hormones affect RT-associated BC risk. METHODS: We conducted a nested case-control study among female 5-year HL survivors treated before age 41. Hormone exposure and HL treatment data were collected through medical records and questionnaires for 174 BC case patients and 466 control patients. Radiation dose to breast tumor location was estimated based on RT charts, simulation films, and mammography reports. RESULTS: We observed a linear radiation dose-response curve with an adjusted excess odds ratio (EOR) of 6.1%/Gy (95% confidence interval [CI]: 2.1%-15.4%). Women with menopause <30 years (caused by high-dose procarbazine or pelvic RT) had a lower BC risk (OR, 0.13; 95% CI, 0.03-0.51) than did women with menopause ≥50 years. BC risk increased by 6.4% per additional year of post-RT intact ovarian function (P<.001). Among women with early menopause (<45 years), hormone replacement therapy (HRT) use for ≥2 years did not increase BC risk (OR, 0.86; 95% CI, 0.32-2.32), whereas this risk was nonsignificantly increased among women without early menopause (OR, 3.69; 95% CI, 0.97-14.0; P for interaction: .06). Stratification by duration of post-RT intact ovarian function or HRT use did not statistically significantly modify the radiation dose-response curve. CONCLUSIONS: BC risk in female HL survivors increases linearly with radiation dose. HRT does not appear to increase BC risk for HL survivors with therapy-induced early menopause. There are no indications that endogenous and exogenous gonadal hormones affect the radiation dose-response relationship.

Pretravel preparation and travel-related morbidity in patients with inflammatory bowel disease.

BACKGROUND: There are no published data on health preparation and travel-related morbidity in patients with inflammatory bowel disease (IBD). METHODS: A retrospective web-based questionnaire study on past travel experiences with more detailed questions concerning the most recent journey. Participants were recruited from the IBD outpatient clinic and via the website of the Dutch patient organization. RESULTS: In all, 277 patients who had traveled abroad during the past 5 years (172 Crohn's disease, 105 ulcerative colitis) filled out the questionnaire. The majority (62%) answered that IBD limited their choice of travel destinations. Forty-three percent traveled to resource-limited destinations and 76% thereof obtained pretravel advice. Only 48% were prescribed an antibiotic for self-treatment in case of infectious diarrhea, and 23% were not protected against hepatitis A. Fecal urgency and incontinence were the main IBD-related inconveniences. Thirty-two percent reported a new episode of diarrhea and 28% thereof attributed it to an enteric infection. In total, 15/277 (5%) consulted a foreign physician, of whom five were admitted to hospital. Fifty-four (19%) had a self-reported exacerbation of IBD within 2 months following travel and 24% thereof attributed it to the recent travel. The Mantel-Haenszel odds ratio for an exacerbation within a 2-month period after travel was 1.1 (95% confidence interval [CI] 0.7-1.8) when the number of self-reported exacerbations in a 5-year period was used as reference and 1.5 (95% CI 0.9-2.6) when the year 2008 was used as reference. CONCLUSIONS: Pretravel advice for IBD patients was often deficient. There was a considerable amount of travel-related morbidity and inconvenience.