Second malignancies in children: the usual suspects?

Pediatric Gastrointestinal Stromal Tumors and Neuroendocrine Tumors: Advances in Surgical Management

Gastrointestinal stromal tumors and neuroendocrine tumors in adult and pediatric populations differ immensely. Despite these established differences, the extreme rarity of gastrointestinal stromal tumors and neuroendocrine tumors in the pediatric population has resulted in the lack of consensus management guidelines, making optimal surgical approaches unclear. Comprehensive management principles to guide surgical approaches in adult literature are extensive. However, these are still lacking for pediatric patients. International cooperation to develop standardized pediatric-specific guidelines is urgently warranted in the future. This article highlights the vast differences between adult and pediatric parameters and provides recommendations on optimal and novel surgical approaches in children.

RILA blood biomarker as a predictor of radiation-induced sarcoma in a matched cohort study

Purpose

Radiation-induced sarcoma (RIS) is a rare but serious event. Its occurrence has been discussed during the implementation of new radiation techniques and justified appropriate radioprotection requirements. New approaches targeting intrinsic radio-sensitivity have been described, such as radiation-induced CD8 T-lymphocyte apoptosis (RILA) able to predict late radio-induced toxicities. We studied the role of RILA as a predisposing factor for RIS as a late adverse event following radiation therapy (RT).

Patients and methods

In this prospective biological study, a total of 120 patients diagnosed with RIS were matched with 240 control patients with cancer other than sarcoma, for age, sex, primary tumor location and delay after radiation. RILA was prospectively assessed from blood samples using flow cytometry.

Results

Three hundred and forty-seven patients were analyzed (118 RIS patients and 229 matched control patients). A majority (74%) were initially treated by RT for breast cancer. The mean RT dose was comparable with a similar mean (± standard deviation) for RIS (53.7 ± 16.0 Gy) and control patients (57.1 ± 15.1 Gy) (p = .053). Median RILA values were significantly lower in RIS than in control patients with respectively 18.5% [5.5–55.7] and 22.3% [3.8–52.2] (p = .0008). Thus, patients with a RILA >21.3% are less likely to develop RIS (p < .0001, OR: 0.358, 95%CI [0.221–0.599].

Conclusion

RILA is a promising indicator to predict an individual risk of developing RIS. Our results should be followed up and compared with molecular and genomic testing in order to better identify patients at risk. A dedicated strategy could be developed to define and inform high-risk patients who require a specific approach for primary tumor treatment and long term follow-up.

Chemotherapy with radiotherapy influences time-to-development of radiation-induced sarcomas: a multicenter study

Background:

An increasing number and proportion of cancer patients with apparently localised disease are treated with chemotherapy and radiation therapy in contemporary oncology practice. In a pilot study of radiation-induced sarcoma (RIS) patients, we demonstrated that chemotherapy was associated with a reduced time to development of RIS. We now present a multi-centre collaborative study to validate this association.

Methods:

This was a retrospective cohort study of RIS cases across five large international sarcoma centres between 1 January 2000 to 31 December 2014. The primary endpoint was time to development of RIS.

Results:

We identified 419 patients with RIS. Chemotherapy for the first malignancy was associated with a shorter time to RIS development (HR 1.37; 95% CI: 1.08–1.72; P=0.009). In the multi-variable model, older age (HR 2.11; 95% CI 1.83–2.43; P<0.001) and chemotherapy for the first malignancy (HR 1.61; 95% CI 1.26–2.05; P<0·001) were independently associated with a shorter time to RIS. Anthracyclines and alkylating agents significantly contribute to the effect.

Conclusions:

This study confirms an association between chemotherapy given for the first malignancy and a shorter time to development of RIS.

[Hereditary bone tumors]

Hereditary bone tumors are rare and result from mutations affecting cell cycle regulation (e.g. retinoblastoma syndrome/RB1 and Li-Fraumeni syndrome/TP53, Gardner syndrome/APC), energy metabolism (enchondromatosis/IDH1/2), complex signaling cascades (multiple hereditary exostoses/EXT1/2) and DNA integrity (Rothmund-Thomson/RECQL4, Werner/WRN and Bloom syndromes/BLM). The majority of syndromes are incompletely understood and can lead to multiple benign tumors, of which some might undergo secondary malignant transformation over time (enchondromatosis: enchondromas, multiple hereditary exostoses: osteochondromas, Gardner syndrome: osteomas) or bone sarcomas, primarily osteosarcomas as primary (Li-Fraumeni, Rothmund-Thomson, Werner and Bloom syndromes) or secondary manifestation (retinoblastoma syndrome) of the disease. Some syndromes additionally predispose to the development of a variety of other malignant tumors during life. Compared to sporadically occurring tumors, syndrome-related neoplasms can differ in the time of manifestation, site and histology, which can help in recognizing a specific tumor predisposition syndrome.

Childhood neuroendocrine tumours: a descriptive study revealing clues for genetic predisposition

BACKGROUND

Neuroendocrine tumours (NETs) are rare in children and limited data are available. We aimed to specify tumour and patient characteristics and to investigate the role of genetic predisposition in the aetiology of paediatric NETs.

METHODS

Using the Dutch Pathology Registry PALGA, we collected patient- and tumour data of paediatric NETs in the Netherlands between 1991 and 2013 (N=483).

RESULTS

The incidence of paediatric NETs in the Netherlands is 5.40 per one million per year. The majority of NETs were appendiceal tumours (N=441;91.3%). Additional surgery in appendiceal NETs was indicated in 89 patients, but performed in only 27 of these patients. Four out of five patients with pancreatic NETs were diagnosed with Von Hippel-Lindau disease (N=2) and Multiple Endocrine Neoplasia type 1 (N=2). In one patient with an appendiceal NET Familial Adenomatous Polyposis was diagnosed. On the basis of second primary tumours or other additional diagnoses, involvement of genetic predisposition was suggestive in several others.

CONCLUSIONS

We identified a significant number of patients with a confirmed or suspected tumour predisposition syndrome and show that paediatric pancreatic NETs in particular are associated with genetic syndromes. In addition, we conclude that treatment guidelines for appendiceal paediatric NETs need revision and improved implementation.

Progress from clinical trials and emerging non-conventional therapies for the treatment of Medulloblastomas

Medulloblastomas are highly aggressive tumors of the cerebellum with an embryonal origin. Despite current treatment modalities which include a combination of surgery, chemotherapy and/or radiation, challenges still exist to effectively treat some patients, especially those within the younger age group. In an effort to find improved therapies, ongoing research led by world-wide teams have explored non-conventional therapeutic strategies, as well as examined the efficacy of several drugs in clinical trials among patients with Medulloblastomas. We outline in this article, recent advances on the efficacy and toxicity of numerous therapeutic agents including those that are DNA damaging agents, microtubules binding compounds, and those that are inhibitors of Topoisomerase and of the Notch and Hedgehog signaling pathway, which were assessed in recent Phase I and II clinical trials. Among these clinical trials, it is unfortunate that the outcomes were dismal with the majority of the patients with Medulloblastomas still succumbing to relapse after conventional therapies. Furthermore, it is yet to be established clearly the clinical efficacy of non-conventional therapies such as immunotherapy and gene therapy. Moreover, there is growing interest in proton therapy as a potential replacement for photon therapy, while high dose chemotherapy and autologous stem cell rescue may improve therapeutic efficacies. However, further research is needed to resolve the inherent toxicity from these novel therapeutic methods. In conclusion, novel therapies based on a better understanding of the biology of Medulloblastomas are pivotal in improving non-conventional therapies in the treatment of this deadly disease.

[Hereditary bone tumors]

Familial diseases leading to bone tumor formation are rare. They are mainly caused by genetic alterations of cell cycle constituent genes, such as retinoblastoma syndrome (RB1) and Li-Fraumeni syndrome (p53), of genes involved in growth-regulating transcriptional cascades, such as enchondromatosis (PTHR1) and multiple hereditary exostoses (EXT1, EXT2) or of genes maintaining chromosomal stability, such as Rothmund-Thomson (RECQL4), Werner (WRN) and Bloom syndromes (BLM). This leads to multiple benign bone tumors, which may undergo secondary malignant transformation (enchondromatosis: enchondromas, multiple hereditary exostoses: osteochondromas) or bone sarcomas, mainly osteosarcomas, such as primary (Li-Fraumeni, Rothmund-Thomson, Werner and Bloom syndromes) or secondary manifestations (retinoblastoma syndrome) of the underlying disease. Some of these lesions also carry an increased risk for developing additional malignant diseases. In contrast to sporadically occurring similar tumors, differences in manifestation in time, topography or histology may be present which can aid in the correct recognition of the underlying syndrome.

The potential of proton beam therapy in paediatric cancer

A group of Swedish oncologists and hospital physicists have estimated the number of patients in Sweden suitable for proton beam therapy. The estimations have been based on current statistics of tumour incidence, number of patients potentially eligible for radiation treatment, scientific support from clinical trials and model dose planning studies and knowledge of the dose-response relations of different tumours and normal tissues. It is estimated that in paediatric cancers, proton beams are of potential importance in 80-100 children annually in Sweden. About 20 of the patients have medulloblastoma. The main purpose is to reduce late sequelae, but these are also increased chances to avoid myelosupression during e.g. concomitant chemo-radiation and to further intensify the chemotherapy.

Radiation-induced sarcoma: 25-year experience from the Norwegian Radium Hospital

BACKGROUND

The aim of this study was to determine the prevalence and outcome of radiation-induced sarcomas (RISs) among sarcoma patients referred to the Norwegian Radium Hospital (NRH).

MATERIAL AND METHODS

Ninety patients were identified from the institutional sarcoma data base. Medical records and histological and cytological material from both primary and secondary tumours were reviewed.

RESULTS

RIS represented 3.0 % of the sarcomas in the data base. The median latency time from radiotherapy of the primary tumour to the diagnosis of RIS was 13.6 years (range 2.5-57.8 years). Gynaecological, breast and testicular cancers were the most common primary diagnoses. For the RISs 13 different histological types were identified including 25 malignant fibrous histiocytomas (28% of all) and 22 osteosarcomas (24%). The sarcoma-related 5-year crude survival was 33% (95 % CI 23-43 %). Unfavourable prognostic factors were metastases at presentation, incomplete surgery and presence of tumour necrosis.

CONCLUSION

Radiation-induced sarcoma is rare and harbours an aggressive clinical behaviour. Complete surgical resection is mandatory for cure.

Secondary osteosarcoma arising after treatment for childhood hematologic malignancies

Secondary osteosarcoma arising after the treatment of hematologic malignancies other than Hodgkin's lymphoma is rare. We report two cases of secondary osteosarcoma arising after treatment for childhood hematologic malignancies (non-Hodgkin's lymphoma and lymphoblastic leukemia). A 10-year-old boy, at the age of 3, was diagnosed with non-Hodgkin's lymphoma. He received chemotherapy, radiation, and bone-marrow transplantation and then was in complete remission. At 6 years, he complained of increasing pain of the right thigh and was diagnosed with osteoblastic osteosarcoma. A 26-year-old man, at the age of 6, was diagnosed as having acute lymphoblastic leukemia (ALL). He received chemotherapy, radiation, and peripheral blood stem cell transplantation (PBSCT). At 11 years after PBSCT, he visited with the complaint of left lumbar swelling. He was diagnosed with chondroblastic osteosarcoma. In both cases alkaline phosphatase (ALP) had already increased prior to the onset of the symptom. We should rule out secondary osteosarcoma at the abnormal elevation of ALP during clinical follow-up of patients after treatment of childhood hematologic malignancies.

Imaging of osteosarcoma after irradiation: self-assessment module

The educational objectives of this self-assessment module on the imaging of postirradiation osteosarcoma are for the participant to exercise, self-assess, and improve his or her understanding of the features used to establish the diagnosis of postirradiation sarcoma.

Primary malignant tumours of bone following previous malignancy

Destructive bone lesions occurring in patients who have previously had a malignancy are generally assumed to be a metastasis from that malignancy. We reviewed 60 patients with a previous history of malignancy, who presented with a solitary bone lesion that was subsequently found to be a new and different primary sarcoma of bone. These second malignancies occurred in three distinct groups of patients: (1) patients with original tumours well known to be associated with second malignancies (5%); (2) patients whose second malignancies were likely to be due to the previous treatment of their primary malignancy (40%); (3) patients in whom there was no clearly defined association between malignancies (55%). The purpose of this study is to emphasise the necessity for caution in assuming the diagnosis of a metastasis when a solitary bone lesion is identified following a prior malignancy. Inappropriate biopsy and treatment of primary bone sarcomas compromises limb salvage surgery and can affect patient mortality.

Conjunctival melanoma 3 years after radiation and chemotherapy for retinoblastoma

An 8-month-old infant with advanced bilateral retinoblastoma was managed with enucleation of the right eye and chemotherapy and radiotherapy of the left eye. Three years after treatment, an ill-defined, nonpigmented mass was noted in the anophthalmic right socket. Excisional biopsy revealed an amelanotic melanoma of the conjunctiva with superficial orbital invasion. There has been no tumor recurrence during 20 months of follow-up.

Survival and late effects in children with Hodgkin's lymphoma treated with MOPP/ABV and low-dose, extended-field irradiation

PURPOSE

Reduced-intensity protocols for pediatric Hodgkin's lymphoma are aimed at preserving excellent relapse-free survival while decreasing the incidence of late effects.

PATIENTS AND METHODS

We retrospectively reviewed the outcome of 123 children treated consecutively for Hodgkin's lymphoma at a single institution. Patients with stages I-IIIB disease received three cycles of mechlorethamine, vincristine, procarbazine, and prednisone (MOPP)/ doxorubicin, bleomycin, and vinblastine (ABV) followed by 15 Gy of extended-field irradiation, while those with stage IV disease were treated with six to eight cycles of MOPP/ABV chemotherapy with or without radiotherapy.

RESULTS

At a median follow-up of 8.5 years (range, 1.4 to 15.5 years), the estimated 10-year overall survival and event-free survival are 94% (SE, 2.2%) and 88% (SE, 3.1%) respectively. There have been 12 treatment failures and six disease-related deaths. A very large mediastinal mass ( 50% of the maximal thoracic diameter) was associated with a 10-year event-free survival of 50% (SE, 14%) compared with 91% (SE, 4.0%) for smaller masses (P < .001). Late cardiopulmonary toxicity is largely absent, and the incidence of hypothyroidism is 14%. There have been no cases of secondary leukemia and four secondary solid malignancies observed to date.

CONCLUSION

MOPP/ABV and low-dose, extended-field radiotherapy is an effective treatment for pediatric Hodgkin's lymphoma. With median follow-up of 8.5 years, late cardiopulmonary effects and secondary malignancies from this treatment regimen are infrequent. Continued longitudinal observations, particularly for breast cancer in female patients and gonadotoxicity, will determine whether the goal of decreasing treatment-related complications while maintaining excellent survival has been achieved.

New malignancies following childhood cancer in the United States, 1973–2002

The objectives of our study were to quantify risks for developing new malignancies among childhood cancer survivors, identify links between particular types of first and subsequent cancer, and evaluate the possible role of treatment. A cohort of 25,965 2-month survivors of childhood cancer diagnosed in the U.S. during 1973-2002 was identified and followed through SEER cancer registries. Observed-to-expected ratios (O/E) were calculated, and Poisson regression was used to compare risks among treatment groups. Childhood cancer survivors were at nearly 6-fold risk of developing a new cancer relative to the general population (O/E = 5.9, 95% CI: 5.4-6.5). Most common were subsequent primary cancers of the female breast, central nervous system, bone, thyroid gland and soft tissue, as well as cutaneous melanoma and acute non-lymphocytic leukemia (ANLL). The greatest risks of subsequent cancers occurred among patients diagnosed previously with Hodgkin lymphoma (HL), Ewing sarcoma, primitive neuroectodermal tumor, or retinoblastoma. Risk of subsequent solid cancers was higher among persons whose initial treatment for childhood cancer included radiotherapy, whereas the excess of subsequent ANLL was strongly related to chemotherapy. The O/E for subsequent ANLL increased with increasing calendar year of initial cancer diagnosis among survivors of cancers other than HL, most likely due to increasing use of leukemogenic drugs for solid cancers and non-Hodgkin lymphoma. Childhood cancer survivors are at markedly increased risk of developing a variety of new cancers relative to the general population, but the magnitude of excess risk and specific types of second cancer vary widely by type of first cancer.

Outcome of secondary high-grade glioma in children previously treated for a malignant condition: A study of the Canadian Pediatric Brain Tumour Consortium

BACKGROUND AND PURPOSE

Reports of secondary high-grade glioma (HGG) in survivors of childhood cancer are scarce. The aim of this study was to review the pattern of diagnosis, the treatment, and outcome of secondary pediatric HGG.

PATIENTS AND METHODS

We performed a multi-center retrospective study among the 17 paediatric institutions participating in the Canadian Pediatric Brain Tumour Consortium (CPBTC).

RESULTS

We report on 18 patients (14 males, 4 females) treated in childhood for a primary cancer, who subsequently developed a HGG as a second malignancy. All patients had previously received radiation therapy +/- chemotherapy for either acute lymphoblastic leukaemia (n=9) or solid tumour (n=9). All HGG occurred within the previous radiation fields. At the last follow-up, 17 patients have died and the median survival time is 9.75 months.

CONCLUSION

Although aggressive treatment seems to provide sustained remissions in some patients, the optimal management is still to be defined. Further documentation of such cases is necessary in order to better understand the pathogenesis, the natural history and the prevention of these tumours.

Primary thyroid cancer after a first tumour in childhood (the Childhood Cancer Survivor Study): a nested case-control study

BACKGROUND

Survivors of malignant disease in childhood who have had radiotherapy to the head, neck, or upper thorax have an increased risk of subsequent primary thyroid cancer, but the magnitude of risk over the therapeutic dose range has not been well established. We aimed to quantify the long-term risk of thyroid cancer after radiotherapy and chemotherapy.

METHODS

In a nested case-control study, 69 cases with pathologically confirmed thyroid cancer and 265 matched controls without thyroid cancer were identified from 14,054 5-year survivors of cancer during childhood from the Childhood Cancer Survivor Study cohort. Childhood cancers were diagnosed between 1970 and 1986 with cohort follow-up to 2000.

FINDINGS

Risk of thyroid cancer increased with radiation doses up to 20-29 Gy (odds ratio 9.8 [95% CI 3.2-34.8]). At doses greater than 30 Gy, a fall in the dose-response relation was seen. Both the increased and decreased risks were more pronounced in those diagnosed with a first primary malignant disease before age 10 years than in those older than 10 years. Furthermore, the fall in risk remained when those diagnosed with Hodgkin's lymphoma were excluded. Chemotherapy for the first cancer was not associated with thyroid-cancer risk, and it did not modify the effect of radiotherapy. 29 (42%) cases had a first diagnosis of Hodgkin's lymphoma compared with 49 (19%) controls. 11 (42%) of those who had Hodgkin's lymphoma had subsequent thyroid cancers smaller than 1 cm compared with six (17%) of those who had other types of childhood cancer (p=0.07).

INTERPRETATION

The reduction in radiation dose-response for risk of thyroid cancer after childhood exposure to thyroid doses higher than 30 Gy is consistent with a cell-killing effect. Standard long-term follow-up of patients who have had Hodgkin's lymphoma for detection of thyroid cancer should also be undertaken for survivors of any cancer during childhood who received radiotherapy to the thorax or head and neck region.

SECONDARY LEIOMYOSARCOMAS: A Report of 4 Cases

Survivors of childhood cancer risk developing second malignant neoplasms (SMN). a small proportion of SMNs is represented by soft tissue sarcoma (STS), including leiomyosarcoma. The files of the STS Italian Cooperative Group (ICG) were reviewed and 4 patients with secondary leiomyosarcoma were identified, only two of them still alive. In 3 cases, the leiomyosarcoma occurred in the radiation field. The authors found no clear differences between primary and secondary leiomyosarcomas, but leiomyosarcoma proved to be the most frequent SMN registered by the ICG, confirming the need for further studies to identify any distinctive features or syndromes.

Minimal 16q Genomic Loss Implicates Cadherin-11 in Retinoblastoma

Retinoblastoma is initiated by loss of both RB1 alleles. Previous studies have shown that retinoblastoma tumors also show further genomic gains and losses. We now define a 2.62 Mbp minimal region of genomic loss of chromosome 16q22, which is likely to contain tumor suppressor gene(s), in 76 retinoblastoma tumors, using loss of heterozygosity (30 of 76 tumors) and quantitative multiplex PCR (71 of 76 tumors). The sequence-tagged site WI-5835 within intron 2 of the cadherin-11 (CDH11) gene showed the highest frequency of loss (54%, 22 of 41 samples tested). A second hotspot for loss (39%, 9 of 23 samples tested) was detected within intron 2 of the cadherin-13 (CDH13) gene. Furthermore, deletion of the exons of CDH11 and/or WI-5835 was shown by quantitative multiplex PCR in 17 of 30 (57%) of previously untested tumors. Immunoblot analyses revealed that 91% (20 of 22) retinoblastoma exhibited either a complete loss or a decrease of the intact form of CDH11 and 8 of 13 showed a prevalent band suggestive of the variant form. Copy number of WI-5835 for these samples correlated with CDH11 protein expression. CDH11 staining was evident in the inner nuclear layer in early mouse retinal development and in small transgenic murine SV40 large T antigen–induced retinoblastoma tumors, but advanced tumors frequently showed loss of CDH11 expression by reverse transcription-PCR, suggestive of a role for CDH11 in tumor progression or metastasis. CDH13 protein and mRNA were consistently expressed in all human and murine retinoblastoma compared with normal adult human retina. Our analyses implicate CDH11, but not CDH13, as a potential tumor suppressor gene in retinoblastoma.

Soft tissue sarcoma as a second malignant neoplasm in the pediatric age group

BACKGROUND

Survivors of childhood malignancies have an increased risk of developing second malignant neoplasms (SMN) due to their prior treatment and/or genetic susceptibility. A small proportion of SMNs are soft tissue sarcomas (STS), whose prognosis is generally thought to be poor, though publications on such patients' treatment and outcome is limited.

METHODS

The authors analyzed 25 patients who were registered for the Italian Cooperative Group protocols for pediatric STS from 1979 to 2000. The primary tumor was STS in five patients; Hodgkin disease in five patients; leukemia in four patients; retinoblastoma, neuroblastoma, and Wilms tumor in two patients each; and other tumor types in five patients. SMNs occurred after a median of 8 years (range, 1.9-15.0 years) and included rhabdomyosarcoma (RMS) in 4 patients, malignant peripheral nerve sheath tumor in 4 patients, extraosseous Ewing family tumor (EFT) in 4 patients, leiomyosarcoma in 3 patients, fibrosarcoma in 2 patients, synovial sarcoma in 2 patients, and other tumor types in 6 patients. Treatment generally was administered according to the guidelines for primary STS.

RESULTS

Seven non-RMS patients with STS underwent surgery alone, whereas 18 patients received chemotherapy and 8 patients received radiotherapy. Retreatment was feasible with acceptable toxicity. Fifteen patients were alive in complete remission of their SMN at the time of last follow-up. Responses to chemotherapy and survival were satisfactory for patients with tumors such as RMS and EFT. Complete tumor resection was correlated with a favorable prognosis in patients with other types of STS and in patients with postirradiation sarcoma. Two patients developed a third malignancy.

CONCLUSIONS

Although prior treatment may hinder the management of these patients, pediatric STS second malignancies can be cured using the same strategies used for de novo pediatric sarcomas. Long-term follow-up is mandatory given the risks of further malignancies and more severe, treatment-related side effects.

Second malignancies in pediatric patients: imaging findings and differential diagnosis

Therapeutic advances in the treatment of pediatric neoplasms have improved the prognosis but have also increased the risk of developing rare second malignant neoplasms (SMNs). Primary neoplasms that are often associated with SMNs include lymphoma, retinoblastoma, medulloblastoma, neuroblastoma, and leukemia. The most common SMNs are central nervous system (CNS) tumors, sarcomas, thyroid and parotid gland carcinomas, and leukemia, particularly acute myeloblastic leukemia. Genetic predisposition, chemotherapy, and especially radiation therapy are implicated as pathogenic factors in SMN. All survivors of childhood cancer should have lifelong follow-up, preferably with magnetic resonance imaging, which does not require ionizing radiation and provides greater anatomic detail and resolution in the head and neck region and the CNS. A new or progressive lesion may represent recurrence of the primitive neoplastic process, late radiation injury, or, more infrequently, an SMN. Differential diagnosis can be very difficult, and outcome is often fatal. Treatment protocols should be modified to reduce the risk for SMN without compromising the effectiveness of initial therapy. Clinicians should individualize treatment for patients who are genetically predisposed to SMN. In addition, radiologists should be familiar with the long-term consequences of antineoplastic therapy to facilitate diagnosis and anticipate adverse outcomes.

Second neoplasms after megavoltage radiation for pediatric tumors

BACKGROUND

Because ionizing radiation is a known carcinogen, diligent long-term follow-up in children exposed to therapeutic radiation is required. The authors updated an earlier study on the nature and risk of second neoplasms (SN) in patients treated with megavoltage radiotherapy as children.

METHODS

The authors followed 446 children who were treated for a primary malignancy with megavoltage radiotherapy between January 16, 1954 and December 31, 1980. These children survived a minimum of 5 years. The nature and incidence of SNs were evaluated in this population. Patients with bilateral retinoblastoma or neurofibromatosis were excluded from the study due to their large genetically based predisposition for developing an SN.

RESULTS

The Kaplan-Meier actuarial survival rate was 80% (95% confidence interval [CI] 74-85%) at 30 years for all patients. Thirty-seven (8.3%) patients developed SNs, most of which occurred within the original radiation treatment field, 3.8-31.8 years (median, 15.5 years) after radiotherapy. The cumulative risk of developing an SN was 13% (95% CI 9-19%) at 30 years and the standardized incidence ratio for the development of any SN was 5.2 (95% CI 3.4-7.6%). The most common SNs were breast carcinoma (n = 8), skin carcinoma (five basal cell carcinomas, two malignant melanomas, and one dermatosarcoma), and meningiomas (n = 6). All eight breast carcinomas occurred after the treatment of childhood Hodgkin disease. Of the 37 patients with SNs, 12 died of either the SN (n = 10) or of recurrent disease (n = 2). Risk factors associated with developing a SN included initial diagnosis of Hodgkin disease (P = 0.0003), female gender (P = 0.008), and an initial diagnosis of acute lymphoblastic leukemia (P = 0.02).

CONCLUSIONS

Patients in the radiation-treated cohort experienced increased mortality, were at an increased risk of developing an SN, and should undergo increased medical surveillance as adults. The cumulative probability of developing an SN has increased substantially at 30 years, largely due to an increase in follow-up time. In addition, the cumulative probability curve does not show evidence of plateau after increased duration of follow-up. Finally, the emergence of secondary breast carcinoma in the current study was not noted in the previous analysis.

Gamma knife radiosurgery and its possible relationship to malignancy: a review

✓ The question has been raised recently whether gamma knife radiosurgery (GKS) can induce secondary neoplasia. Because there is little or no detailed knowledge about this potential complication, background information culled from the radiotherapy literature is reviewed as a guide to the clinical situations in which radiotherapy may induce secondary neoplastic change. Available case reports are then reviewed and discussed against the background of the current knowledge. On the basis of the review, the following suggestions are proposed on how to limiting the extent of this complication, document its frequency, and inform patients. It should be remembered that: the benefits of GKS are great; its alternatives also have risks; there often are no alternatives to GKS; follow-up documentation should be pursued more actively so that, if possible, no patient falls through the net; practitioners should be proactive in defining the problem, and genetic analysis of tumor biopsy specimens obtained in patients who will undergo or have undergone GKS should become routine; the extent of secondary neoplasia is not known; and patient information should be guided by what is known rather than by what is feared.