A study of soft tissue sarcomas after childhood cancer in Britain

Subsequent Primary Neoplasms: Risks, Risk Factors, Surveillance, and Future Research

The authors' objective is to provide a brief update on recent advances in knowledge relating to subsequent primary neoplasms developing in survivors of childhood cancer. This includes a summary of established large-scale cohorts, risks reported, and contrasts with results from recently established large-scale cohorts of survivors of adolescent and young adult cancer. Recent evidence is summarized concerning the role of radiotherapy and chemotherapy for childhood cancer and survivor genomics in determining the risk of subsequent primary neoplasms. Progress with surveillance, screening, and clinical follow-up guidelines is addressed. Finally, priorities for future research are outlined.

Craniofacial second primary tumors in patients with germline retinoblastoma previously treated with external beam radiotherapy: A retrospective institutional analysis

BACKGROUND

The long-term survival of germline retinoblastoma patients is decreased due to the risk of second primary tumors (SPTs) that occur years after the diagnosis of retinoblastoma. This risk is related to genetic predisposition and other factors, such as the treatment of retinoblastoma by external beam radiotherapy (EBRT).

PROCEDURE

We studied the incidence, risk factors, and prognosis of specific craniofacial SPTs developed within the margins of radiation field in a cohort of 209 patients with germline retinoblastoma treated with EBRT at our institution between 1977 and 2010. Clinical characteristics, survival, incidence, and histology of craniofacial SPTs were recorded.

RESULTS

Fifty-three of the 209 patients developed 60 distinct craniofacial SPTs in irradiated field with a median time from EBRT of 16.9 years (4-35) and a median follow-up of 24.8 years (5.3-40). Osteosarcoma (33.3%) and undifferentiated sarcoma (23.3%) were the more prevalent histological entities. Benign tumors (16.7%) also occurred. The cumulative incidence of craniofacial SPTs reached 32.6% at 35 years after EBRT, and the median survival after diagnosis was five years. In our series, irradiation under 12 months of age, bilateral EBRT, or previous treatment of retinoblastoma with chemotherapy did not significantly increase the risk of craniofacial SPTs.

CONCLUSIONS

This work presents a strong argument to avoid EBRT in the management of retinoblastoma and emphasizes the high risk and poor prognosis of specific craniofacial SPTs. This study also points to the question of the need and benefits of special programs for early detection of craniofacial SPTs in survivors of irradiated germline retinoblastoma.

Solid and Hematologic Neoplasms After Testicular Cancer: A US Population-Based Study of 24 900 Survivors

Background

No large US population-based study focusing on recent decades, to our knowledge, has comprehensively examined risks of second malignant solid and hematological neoplasms (solid-SMN and heme-SMN) after testicular cancer (TC), taking into account initial therapy and histological type.

Methods

Standardized incidence ratios (SIR) vs the general population and 95% confidence intervals (CI) for solid-SMN and heme-SMN were calculated for 24 900 TC survivors (TCS) reported to the National Cancer Institute’s Surveillance, Epidemiology, and End Results registries (1973–2014). All statistical tests were two-sided.

Results

The median age at TC diagnosis was 33 years. Initial management comprised chemotherapy (n = 6340), radiotherapy (n = 9058), or surgery alone (n = 8995). During 372 709 person-years of follow-up (mean = 15 years), 1625 TCS developed solid-SMN and 228 (107 lymphomas, 92 leukemias, 29 plasma cell dyscrasias) developed heme-SMN. Solid-SMN risk was increased 1.06-fold (95% CI = 1.01 to 1.12), with elevated risks following radiotherapy (SIR = 1.13, 95% CI = 1.06 to 1.21) and chemotherapy (SIR = 1.36, 95% CI = 1.12 to 1.41) but not surgery alone (SIR = 0.83, 95% CI = 0.75 to 0.92). Corresponding risks for seminoma were 1.13 (95% CI = 1.06 to 1.21), 1.28 (95% CI = 1.02 to 1.58), and 0.87 (95% CI = 0.74 to 1.01) and for nonseminoma were 1.05 (95% CI = 0.67 to 1.56), 1.25 (95% CI = 1.08 to 1.43), and 0.80 (95% CI = 0.70 to 0.92), respectively. Thirty-year cumulative incidences of solid-SMN after radiotherapy, chemotherapy, and surgery alone were 16.9% (95% CI = 15.7% to 18.1%), 10.1% (95% CI = 8.8% to 11.5%), and 8.8% (95% CI = 7.8% to 9.9%), respectively (P < .0001). Increased leukemia risks after chemotherapy (SIR = 2.68, 95% CI = 1.70 to 4.01) were driven by statistically significant sevenfold excesses of acute myeloid leukemia 1 to 10 years after TC diagnosis. Risks for lymphoma and plasma cell dyscrasias were not elevated.

Conclusions

We report statistically significant excesses of solid-SMN affecting 1 in 6 TCS 30 years after radiotherapy, and 2.7-fold risks of leukemias after chemotherapy, mostly acute myeloid leukemia. Efforts to minimize chemotherapy and radiotherapy exposures for TC should continue. TCS should be counseled about cancer prevention and screening.

Adaptations to a Generalized Radiation Dose Reconstruction Methodology for Use in Epidemiologic Studies: An Update from the MD Anderson Late Effect Group

Epidemiologic studies that include patients who underwent radiation therapy for the treatment of cancer aim to quantify the relationship between radiotherapy and the risk of subsequent late effects. Because of the long follow-up period required to observe late effects, these studies are conducted retrospectively. The studies routinely include patients treated across numerous institutions using a wide range of technologies and represent treatments over several decades. As a result, determining the dose throughout the patient's body is uniquely challenging. Therefore, estimating doses throughout the patient's body for epidemiologic studies requires special methodologies that are generally applied to a wide range of radiotherapy techniques. Over ten years ago, the MD Anderson Late Effects Group described various dose reconstruction methods for therapeutic and diagnostic radiation exposure for epidemiologic studies. Here we provide an update to the most widely used dose reconstruction methodology for epidemiologic studies, analytical model calculations combined with a 3D age-specific computational phantom. In particular, we describe the various adaptations (and enhancements) of that methodology, as well as how they have been used in radiation epidemiology studies and may be used in future studies.

Risk of Second Primary Bone and Soft-Tissue Sarcomas Among Young Adulthood Cancer Survivors

Excess sarcoma risks after childhood cancer are well established, but risks among young adulthood cancer survivors are poorly understood. Using US population-based cancer registry data, we compared bone and soft-tissue sarcoma risk vs the general population among 186 351 individuals who were diagnosed with nonsarcoma first primary malignancies at ages 20-39 years from 1975 to 2014 (follow-up through 2015) and survived at least 1 year. Bone sarcomas were rare (n = 50), but risk was statistically significantly elevated overall (2.9-fold) and greater than fivefold after Hodgkin lymphoma, non-Hodgkin lymphoma, and central nervous system tumors. Soft-tissue sarcomas were more common (n = 284) and risks were statistically significantly elevated approximately twofold overall and after melanoma and carcinomas of the breast, thyroid, and testis, and greater than fourfold after Hodgkin lymphoma and central nervous system tumors. Risks varied markedly by subtype, with the highest risks (greater than fourfold) for osteosarcoma and the soft-tissue subtypes of rhabdomyosarcoma and blood vessel and nerve sheath sarcomas. These data demonstrate elevated risk for sarcoma after a range of young adulthood cancers.

Risk of Soft-Tissue Sarcoma Among 69 460 Five-Year Survivors of Childhood Cancer in Europe

Background

Childhood cancer survivors are at risk of subsequent primary soft-tissue sarcomas (STS), but the risks of specific STS histological subtypes are unknown. We quantified the risk of STS histological subtypes after specific types of childhood cancer.

Methods

We pooled data from 13 European cohorts, yielding a cohort of 69 460 five-year survivors of childhood cancer. Standardized incidence ratios (SIRs) and absolute excess risks (AERs) were calculated.

Results

Overall, 301 STS developed compared with 19 expected (SIR = 15.7, 95% confidence interval [CI] = 14.0 to 17.6). The highest standardized incidence ratios were for malignant peripheral nerve sheath tumors (MPNST; SIR = 40.6, 95% CI = 29.6 to 54.3), leiomyosarcomas (SIR = 29.9, 95% CI = 23.7 to 37.2), and fibromatous neoplasms (SIR = 12.3, 95% CI = 9.3 to 16.0). SIRs for MPNST were highest following central nervous system tumors (SIR = 80.5, 95% CI = 48.4 to 125.7), Hodgkin lymphoma (SIR = 81.3, 95% CI = 35.1 to 160.1), and Wilms tumor (SIR = 76.0, 95% CI = 27.9 to 165.4). Standardized incidence ratios for leiomyosarcoma were highest following retinoblastoma (SIR = 342.9, 95% CI = 245.0 to 466.9) and Wilms tumor (SIR = 74.2, 95% CI = 37.1 to 132.8). AERs for all STS subtypes were generally low at all years from diagnosis (AER < 1 per 10 000 person-years), except for leiomyosarcoma following retinoblastoma, for which the AER reached 52.7 (95% CI = 20.0 to 85.5) per 10 000 person-years among patients who had survived at least 45 years from diagnosis of retinoblastoma.

Conclusions

For the first time, we provide risk estimates of specific STS subtypes following childhood cancers and give evidence that risks of MPNSTs, leiomyosarcomas, and fibromatous neoplasms are particularly increased. While the multiplicative excess risks relative to the general population are substantial, the absolute excess risk of developing any STS subtype is low, except for leiomyosarcoma after retinoblastoma. These results are likely to be informative for both survivors and health care providers.

Retinoblastoma: diagnosis and management--the UK perspective

In the developed world, retinoblastoma is an uncommon yet highly curable ocular malignancy of childhood affecting 40-50 children in the UK each year. The presenting signs, most commonly leukocoria and squint, should alert the primary care physician or secondary care physician to examine for the red reflex, the absence of which is an indication for urgent ophthalmology assessment. Diagnosis is made by clinical examination and staging may include bone marrow sampling, lumbar puncture and MRI scanning. CT should be avoided to reduce radiation exposure in a population of whom a proportion are at considerable risk of second malignancies. Although enucleation is necessary for many children, over recent years there has been a growing emphasis on conservative management in an attempt to reduce the need for enucleation and avoid the adverse late effects associated with external beam radiotherapy. This review will describe approaches to treatment in the UK and how the stage, laterality and position of the tumour within the eye influence treatment choices.

Risk of subsequent malignant neoplasms in long-term hereditary retinoblastoma survivors after chemotherapy and radiotherapy

PURPOSE

Hereditary retinoblastoma (Rb) survivors have increased risk of subsequent malignant neoplasms (SMNs). Previous studies reported elevated radiotherapy (RT) -related SMN risks, but less is known about chemotherapy-related risks.

PATIENTS AND METHODS

In a long-term follow-up study of 906 5-year hereditary Rb survivors diagnosed from 1914 to 1996 and observed through 2009, treatment-related SMN risks were quantified using cumulative incidence analyses and multivariable Cox proportional hazards regression models with age as the underlying time scale.

RESULTS

Nearly 90% of Rb survivors were treated with RT, and almost 40% received alkylating agent (AA) -containing chemotherapy (predominantly triethylenemelamine). Median follow-up time to first SMN diagnosis was 26.3 years. Overall SMN risk was not significantly elevated among survivors receiving AA plus RT versus RT without chemotherapy (hazard ratio [HR], 1.27; 95% CI, 0.99 to 1.63). AA-related risks were significantly increased for subsequent bone tumors (HR, 1.60; 95% CI, 1.03 to 2.49) and leiomyosarcoma (HR, 2.67; 95% CI, 1.22 to 5.85) but not for melanoma (HR, 0.74; 95% CI, 0.36 to 1.55) or epithelial tumors (HR, 0.89; 95% CI, 0.48 to 1.64). Leiomyosarcoma risk was significantly increased for survivors who received AAs at age < 1 (HR, 5.17; 95% CI, 1.76 to 15.17) but not for those receiving AAs at age ≥ 1 year (HR, 1.75; 95% CI, 0.68 to 4.51). Development of leiomyosarcoma was significantly more common after AA plus RT versus RT (5.8% v 1.6% at age 40 years; P = .01).

CONCLUSION

This comprehensive quantification of SMN risk after chemotherapy and RT among hereditary Rb survivors also demonstrates an AA-related contribution to risk. Although triethylenemelamine is no longer prescribed, our findings warrant further follow-up to investigate potential SMN risks associated with current chemotherapies used for Rb.

Solid tumors after chemotherapy or surgery for testicular nonseminoma: a population-based study

PURPOSE

Increased risks of solid tumors after older radiotherapy strategies for testicular cancer (TC) are well established. Few population-based studies, however, focus on solid cancer risk among survivors of TC managed with nonradiotherapy approaches. We quantified the site-specific risk of solid cancers among testicular nonseminoma patients treated in the modern era of cisplatin-based chemotherapy, without radiotherapy.

PATIENTS AND METHODS

Standardized incidence ratios (SIRs) for solid tumors were calculated for 12,691 patients with testicular nonseminoma reported to the population-based Surveillance, Epidemiology, and End Results program (1980 to 2008) and treated initially with either chemotherapy (n = 6,013) or surgery (n = 6,678) without radiotherapy. Patients accrued 116,073 person-years of follow-up.

RESULTS

Two hundred ten second solid cancers were observed. No increased risk followed surgery alone (SIR, 0.93; 95% CI, 0.76 to 1.14; n = 99 solid cancers), whereas significantly increased 40% excesses (SIR, 1.43; 95% CI, 1.18 to 1.73; n = 111 solid cancers) occurred after chemotherapy. Increased risks of solid cancers after chemotherapy were observed in most follow-up periods (median latency, 12.5 years), including more than 20 years after treatment (SIR, 1.54; 95% CI, 0.96 to 2.33); significantly increased three- to seven-fold risks occurred for cancers of the kidney (SIR, 3.37; 95% CI, 1.79 to 5.77), thyroid (SIR, 4.40; 95% CI, 2.19 to 7.88), and soft tissue (SIR, 7.49; 95% CI, 3.59 to 13.78).

CONCLUSION

To our knowledge, this is the first large population-based series reporting significantly increased risks of solid cancers among patients with testicular nonseminoma treated in the modern era of cisplatin-based chemotherapy. Subsequent analytic studies should focus on the evaluation of dose-response relationships, types of solid cancers, latency patterns, and interactions with other possible factors, including genetic susceptibility.

Sarcoma risk after radiation exposure

Sarcomas were one of the first solid cancers to be linked to ionizing radiation exposure. We reviewed the current evidence on this relationship, focusing particularly on the studies that had individual estimates of radiation doses. There is clear evidence of an increased risk of both bone and soft tissue sarcomas after high-dose fractionated radiation exposure (10 + Gy) in childhood, and the risk increases approximately linearly in dose, at least up to 40 Gy. There are few studies available of sarcoma after radiotherapy in adulthood for cancer, but data from cancer registries and studies of treatment for benign conditions confirm that the risk of sarcoma is also increased in this age-group after fractionated high-dose exposure. New findings from the long-term follow-up of the Japanese atomic bomb survivors suggest, for the first time, that sarcomas can be induced by acute lower-doses of radiation (<5 Gy) at any age, and the magnitude of the risk is similar to that observed for other solid cancers. While there is evidence that individuals with certain rare familial genetic syndromes predisposing to sarcoma, particularly Nijmegen Breakage Syndrome, are particularly sensitive to the effects of high dose radiation, it is unclear whether this is also true in very low-dose settings (<0.1 Gy). The effects of common low-penetrance alleles on radiosensitivity in the general population have not been well-characterized. Some evidence suggests that it may be possible to identify radiation-induced sarcomas by a distinct molecular signature, but this work needs to be replicated in several dose settings, and the potential role of chemotherapy and tumor heterogeneity needs to be examined in more detail. In summary, radiation exposure remains one of the few established risk factors for both bone and soft tissue sarcomas. Similar to many other cancers children have the highest risks of developing a radiation-related sarcoma. Efforts to limit unnecessary high-dose radiation exposure, particularly in children, therefore remain important given the high fatality rates associated with this disease.

Sarcomas in hereditary retinoblastoma

Children diagnosed with the hereditary form of retinoblastoma (Rb), a rare eye cancer caused by a germline mutation in the RB1 tumor suppressor gene, have excellent survival, but face an increased risk of bone and soft tissue sarcomas. This predisposition to sarcomas has been attributed to genetic susceptibility due to inactivation of the RB1 gene as well as past radiotherapy for Rb. The majority of bone and soft tissue sarcomas among hereditary Rb survivors occur in the head, within the radiation field, but they also occur outside the radiation field. Sarcomas account for almost half of the second primary cancers in hereditary Rb survivors, but they are very rare following non-hereditary Rb. Sarcomas among hereditary Rb survivors arise at ages similar to the pattern of occurrence in the general population. There has been a trend over the past two decades to replace radiotherapy with chemotherapy and other focal therapies (laser or cryosurgery), and most recently, chemosurgery in order to reduce the incidence of sarcomas and other second cancers in Rb survivors. Given the excellent survival of most Rb patients treated in the past, it is important for survivors, their families and health care providers to be aware of the heightened risk for sarcomas in hereditary patients.

Risk factors associated with secondary sarcomas in childhood cancer survivors: a report from the childhood cancer survivor study

PURPOSE

Childhood cancer survivors have an increased risk of secondary sarcomas. To better identify those at risk, the relationship between therapeutic dose of chemotherapy and radiation and secondary sarcoma should be quantified.

METHODS AND MATERIALS

We conducted a nested case-control study of secondary sarcomas (105 cases, 422 matched controls) in a cohort of 14,372 childhood cancer survivors. Radiation dose at the second malignant neoplasm (SMN) site and use of chemotherapy were estimated from detailed review of medical records. Odds ratios (ORs) and 95% confidence intervals were estimated by conditional logistic regression. Excess odds ratio (EOR) was modeled as a function of radiation dose, chemotherapy, and host factors.

RESULTS

Sarcomas occurred a median of 11.8 years (range, 5.3-31.3 years) from original diagnosis. Any exposure to radiation was associated with increased risk of secondary sarcoma (OR = 4.1, 95% CI = 1.8-9.5). A dose-response relation was observed, with elevated risks at doses between 10 and 29.9 Gy (OR = 15.6, 95% CI = 4.5-53.9), 30-49.9 Gy (OR = 16.0, 95% CI 3.8-67.8) and >50 Gy (OR = 114.1, 95% CI 13.5-964.8). Anthracycline exposure was associated with sarcoma risk (OR = 3.5, 95% CI = 1.6-7.7) adjusting for radiation dose, other chemotherapy, and primary cancer. Adjusting for treatment, survivors with a first diagnosis of Hodgkin lymphoma (OR = 10.7, 95% CI = 3.1-37.4) or primary sarcoma (OR = 8.4, 95% CI = 3.2-22.3) were more likely to develop a sarcoma.

CONCLUSIONS

Of the risk factors evaluated, radiation exposure was the most important for secondary sarcoma development in childhood cancer survivors; anthracycline chemotherapy exposure was also associated with increased risk.

Soft tissue sarcoma diagnosed subsequent to lymphoma is associated with prior radiotherapy and decreased survival

BACKGROUND

Cancer survivors are at increased risk for second malignancies, and vigilance is thus required. The authors sought to determine whether there was an association among lymphoma, sarcoma, and the associated treatments for these diseases.

METHODS

From the authors' prospective soft tissue sarcoma (STS) database of 8240 patients, they identified 112 patients with STS and lymphoma treated from 1982 to 2009 who had complete follow-up data. They examined the importance of the initial diagnosis in patients with both STS and lymphoma, in addition to determining the role of radiation therapy, a known inducer of sarcoma.

RESULTS

Review of their sarcoma, gastric, urology, breast, and gynecology databases revealed that lymphoma (95%) or leukemia (5%) occurred in 1.6% of STS patients in comparison to 0.5% of patients in the other databases (P < .01; odds ratio, 3.1; 95% confidence interval, 2.6-3.8). Patients diagnosed with STS only were more likely to die of disease at 10 years compared with those with STS and lymphoma (P = .006), but this difference was not significant when patients presenting with recurrence or metastases were excluded. Among patients with lymphoma and STS, lymphoma was the first diagnosis in 71% of patients. Median survival after STS diagnosis was shorter when lymphoma was the initial diagnosis (67 vs 170 months, P = .002), and these patients were more likely to have radiation-associated STS (44% vs 3%, P < .001).

CONCLUSIONS

There was a 3-fold higher incidence of lymphoma in STS patients compared with other solid tumors. The poor prognosis of those diagnosed with both STS and lymphoma was most likely a consequence of prior irradiation.

Solid cancers after allogeneic hematopoietic cell transplantation

Transplant recipients have been reported to have an increased risk of solid cancers but most studies are small and have limited ability to evaluate the interaction of host, disease, and treatment-related factors. In the largest study to date to evaluate risk factors for solid cancers, we studied a multi-institutional cohort of 28 874 allogeneic transplant recipients with 189 solid malignancies. Overall, patients developed new solid cancers at twice the rate expected based on general population rates (observed-to-expected ratio 2.1; 95% confidence interval 1.8-2.5), with the risk increasing over time (P trend < .001); the risk reached 3-fold among patients followed for 15 years or more after transplantation. New findings showed that the risk of developing a non-squamous cell carcinoma (non-SCC) following conditioning radiation was highly dependent on age at exposure. Among patients irradiated at ages under 30 years, the relative risk of non-SCC was 9 times that of nonirradiated patients, while the comparable risk for older patients was 1.1 (P interaction < .01). Chronic graft-versus-host disease and male sex were the main determinants for risk of SCC. These data indicate that allogeneic transplant survivors, particularly those irradiated at young ages, face increased risks of solid cancers, supporting strategies to promote lifelong surveillance among these patients.

The British Childhood Cancer Survivor Study: Objectives, methods, population structure, response rates and initial descriptive information

BACKGROUND

In Britain 75% of individuals diagnosed with childhood cancer survive at least 5 years. The British Childhood Cancer Survivor Study was established to determine the risks of adverse health and social outcomes among survivors. To be eligible individuals were diagnosed with childhood cancer in Britain between 1940 and 1991 and survived at least 5 years. The entire cohort of 17,981 form the basis of population-based studies of late mortality and the risks/causes of second malignant neoplasms using national registration systems.

METHODS

A postal questionnaire was sent to survivors who were alive and aged at least 16 years via their primary care physician.

RESULTS

Of the 14,836 survivors eligible to receive a questionnaire, 10,483 (71%) returned it completed. Of the 13,211 who were mailed a questionnaire by their primary care physician 10,483 (79%) returned it completed. Outline treatment information concerning initial radiotherapy, chemotherapy and surgery is available.

CONCLUSIONS

This is the largest available population-based cohort of childhood cancer survivors to have included investigation of a wide spectrum of adverse outcomes (the risk of which might be increased as a result of childhood cancer or its treatment). The study should provide useful information for counselling survivors, planning long-term clinical follow-up and evaluating the long-term risks likely to be associated with proposed treatment strategies.