The effect of abdominal radiation on spleen function: a study in children with Wilms' tumor

The Value of IgM Memory B-Cells in the Assessment of Splenic Function in Childhood Cancer Survivors at Risk for Splenic Dysfunction: A DCCSS-LATER Study

Background

Childhood cancer survivors (CCS) who received radiotherapy involving the spleen or total body irradiation (TBI) might be at risk for splenic dysfunction. A comprehensive screening test for examining splenic dysfunction is lacking.

Objective

We investigated whether IgM memory B-cells could be used to assess splenic dysfunction in CCS who received a splenectomy, radiotherapy involving the spleen, or TBI.

Methods

All CCS were enrolled from the DCCSS-LATER cohort. We analyzed differences in IgM memory B-cells and Howell-Jolly bodies (HJB) in CCS who had a splenectomy (n = 9), received radiotherapy involving the spleen (n = 36), or TBI (n = 15). IgM memory B-cells < 9 cells/µL was defined as abnormal.

Results

We observed a higher median number of IgM memory B-cells in CCS who received radiotherapy involving the spleen (31 cells/µL, p=0.06) or TBI (55 cells/µL, p = 0.03) compared to CCS who received splenectomy (20 cells/µL). However, only two CCS had IgM memory B-cells below the lower limit of normal. No difference in IgM memory B-cells was observed between CCS with HJB present and absent (35 cells/µL vs. 44 cells/µL).

Conclusion

Although the number of IgM memory B-cells differed between splenectomized CCS and CCS who received radiotherapy involving the spleen or TBI, only two CCS showed abnormal values. Therefore, this assessment cannot be used to screen for splenic dysfunction.

Coincidental splenic irradiation and risk of functional hyposplenism in oesophageal cancer treatment

INTRODUCTION

Definitive chemoradiotherapy (dCRT) and radical radiotherapy are central to the management of distal oesophageal carcinoma. This study sought to establish whether the spleen receives a significant incidental radiation dose when treating distal oesophageal carcinoma with the standardised dCRT or radical radiotherapy doses.

METHODS

In this single-centre retrospective study, all patients (n = 34) with distal oesophageal cancer, treated with either dCRT or radical radiotherapy over an 18-month period using a volumetric modulated arc therapy (VMAT) planning technique, were included. The median age was 74 years old: 56% were male; 50% (n = 17) had adenocarcinoma and 41% (n = 14) had squamous carcinoma. The majority (79%) received dCRT with a prescribed dose of 50 Gy in 25 fractions while the other 21% of patients were treated with radical radiotherapy alone (55 Gy in 20 fractions). The spleen was retrospectively contoured by one physician, and the V_{10 Gy} and mean splenic dose (MSD) were calculated using Eclipse planning software.

RESULTS

The median MSD was 14.4 Gy with a range of 0.75-28.3 Gy. The median V_{10 Gy} was 62.7%. Of the cohort, 67.6% received an MSD of more than 10 Gy.

CONCLUSIONS

Two-thirds of the patients received a dose of more than the 10 Gy. A review of the literature suggests that higher splenic radiation doses may increase the long-term risk of infection and impact on other outcomes. This study provides important evidence that the spleen receives a significant dose of radiation when treating distal oesophageal cancer and should be considered as an organ at risk.

Supportive care for toxicities in children undergoing radiation therapy

Radiation therapy (RT) is an integral part of the management of many pediatric tumors; however, it is associated with both acute and permanent adverse events that can significantly impact a child's quality of life, lead to treatment delays, and potentially affect outcomes of cancer therapy. Prevention, early detection, and optimal management of these adverse effects will help reduce their impact on the patients' quality of life and overall well-being. Unfortunately, there has not been a coordinated effort to study the etiology, evaluate risk factors, and explore novel treatments for these conditions. Studies of supportive care for children undergoing RT are often small and uncontrolled. This review will focus on the impact of irradiation on the different organ systems and their current management. Further studies are required to improve our understanding of the contributing factors and explore novel treatment options for these adverse effects and to enable children and their families to better cope with some of the unavoidable toxicities following multimodality therapy.

The spleen as an organ at risk in paediatric radiotherapy: A SIOP-Europe Radiation Oncology Working Group report

BACKGROUND

Radiation may cause long-term splenic dysfunction, risking potentially fatal late sepsis. We aimed to review this complication's magnitude in paediatric radiotherapy and gauge the level of awareness of the spleen as an organ at risk.

METHODS

Clinical trial protocols and radiotherapy guidelines, patient/parent information sheets, and professional guidance documents were reviewed to assess the perceived risk of radiotherapy-related splenic dysfunction. Paediatric oncologists and paediatric radiation oncologists across Europe were surveyed to estimate the level of understanding of this risk and to ascertain current practice. Spleen doses received in practice were examined. A systematic review of relevant publications was undertaken.

RESULTS

The risk is not mentioned in most clinical trials, patient information leaflets, or professional guidance documents. When mentioned, a threshold dose of 40 Gy is cited. The survey showed only limited awareness. More than half of patients assessed received spleen doses in excess of 10 Gy. The systematic review identified one paper reporting a relative mortality risk of 5.5 with spleen doses in the 10-20 Gy range.

CONCLUSIONS

The risk of mortality from overwhelming infection is poorly recognised. We therefore recommend routine delineation of the spleen. Protocols and guidelines should give a spleen dose objective as low as reasonably achievable, ideally mean <10 Gy without compromise to target volumes. Revised evidence-based guidelines and continuing professional development activities should inform oncologists. Patient/parent information should mention the risk and the dose received be communicated to colleagues. Antibiotic prophylaxis and/or (re)vaccination should be considered if the mean spleen dose is ≥10 Gy.

Late Infection-Related Mortality in Asplenic Survivors of Childhood Cancer: A Report From the Childhood Cancer Survivor Study

Purpose Infection-related outcomes associated with asplenia or impaired splenic function in survivors of childhood cancer remains understudied. Methods Late infection-related mortality was evaluated in 20,026 5-year survivors of childhood cancer (diagnosed < 21 years of age from 1970 to 1999; median age at diagnosis, 7.0 years [range, 0 to 20 years]; median follow-up, 26 years [range, 5 to 44 years]) using cumulative incidence and piecewise-exponential regression models to estimate adjusted relative rates (RRs). Splenic radiation was approximated using average dose (direct and/or indirect) to the left upper quadrant of the abdomen (hereafter, referred to as splenic radiation). Results Within 5 years of diagnosis, 1,354 survivors (6.8%) had a splenectomy and 9,442 (46%) had splenic radiation without splenectomy. With 62 deaths, the cumulative incidence of infection-related late mortality was 1.5% (95% CI, 0.7% to 2.2%) at 35 years after splenectomy and 0.6% (95% CI, 0.4% to 0.8%) after splenic radiation. Splenectomy (RR, 7.7; 95% CI, 3.1 to 19.1) was independently associated with late infection-related mortality. Splenic radiation was associated with increasing risk for late infection-related mortality in a dose-response relationship (0.1 to 9.9 Gy: RR, 2.0; 95% CI, 0.9 to 4.5; 10 to 19.9 Gy: RR, 5.5; 95% CI, 1.9 to 15.4; ≥ 20 Gy: RR, 6.0; 95% CI, 1.8 to 20.2). High-dose alkylator chemotherapy exposure was also independently associated with an increased risk of infection-related mortality (RR, 1.9; 95% CI, 1.1 to 3.4). Conclusion Splenectomy and splenic radiation significantly increase risk for late infection-related mortality. Even low- to intermediate-dose radiation exposure confers increased risk, suggesting that the spleen is highly radiosensitive. These findings should inform long-term follow-up guidelines for survivors of childhood cancer and should lead clinicians to avoid or reduce radiation exposure involving the spleen whenever possible.

Functional hyposplenism after hematopoietic stem cell transplantation

Functional hyposplenism is associated with chronic GvHD (cGvHD) following hematopoietic stem cell transplantation (HSCT). We hypothesized that hyposplenism measured by pitted red cell counts in cGvHD was transient and related to the severity of disease. We performed a serial, retrospective review of 36 pediatric post-HSCT patients' pit counts at BC Children's Hospital from 2005 to 2013 and compared those counts with the clinical course of patients with late acute GvHD (aGvHD)/cGvHD. Of the 36 patients, 22 had late aGvHD/cGvHD based on National Institutes of Health consensus criteria. Fourteen of 22 GvHD patients had an abnormal pitted red cell count. Ten of 14 abnormal patients had late acute or overlap GvHD syndrome, primarily gastrointestinal disease. A second cohort was prospectively evaluated in a multicenter adult HSCT biomarker trial. We identified 3 out of 10 control patients who had an abnormal pitted red cell count, 3 out of 10 with classic cGvHD and 5 out of 9 patients with overlap syndrome were abnormal. In both the retrospective and prospective studies, hyposplenism was present in patients without late aGvHD/cGvHD suggesting current guidelines regarding antibiotic prophylaxis against encapsulated bacteria after HSCT need to be re-addressed and abnormal pit counts could be used to guide prophylaxis in all HSCT patients.

Splenic Volume Change and Nodal Tumor Response in Non-Hodgkin's Lymphoma Patients after Radioimmunotherapy Using Radiolabeled Lym-1 Antibody

Splenomegaly is frequently found in non-Hodgkin's lymphoma (NHL) patients. This study evaluated the implications of splenic volume change in response to radioimmunotherapy (RIT) using radiolabeled Lym- 1 antibody.

METHODS

Twenty-nine NHL patients treated with radiolabeled-Lym-1 and 9 breast cancer patients, the reference group, treated with radiolabeled ChL6, BrE-3, or m170, were analyzed using X-ray computer tomography (CT) splenic images obtained before and after RIT. Patient-specific radiation doses to the spleen were determined using actual splenic volume determined by CT and body weight.

RESULTS

Of 29 NHL patients, 13 that had splenic volumes equal or less than 310 mL, there was little or no change in splenic volume after RIT, despite splenic radiation doses as high as 23.1 Gy (median 8.0 Gy). Similarly, in a reference group of 9 breast cancer patients, there was little or no change in splenic volume after RIT, despite doses as high as 14.4 Gy (median 11.5 Gy). In the remaining 16 NHL patients, splenic volumes decreased in 13 patients, with initial volumes of 380-1,400 mL, by 68-548 mL despite splenic radiation doses as low as 1.1 Gy (median 3.2 Gy); splenic volumes increased in the other 3 patients after RIT. Although not statistically significant in this small series, therapeutic remission, defined conventionally by nodal tumor response, was more likely when splenic volume decreased after RIT. All 10 NHL patients with greater than a 15% decrease in their splenic volumes after RIT had nodal tumor response (5 complete response, 5 partial response). There were 12 responders (5 complete response and 7 partial response) in 19 NHL patients with less than a 15% decrease in splenic volume after RIT.

CONCLUSIONS

Splenic volume decreased in NHL patients with splenomegaly, despite splenic radiation dose as low as 1.1 Gy. In the absence of splenomegaly, splenic volume did not decrease, even after much higher radiation doses. RIT with radiolabeled-Lym-1 may benefit NHL patients with splenomegaly, with reduction in splenic volume likely owing to a therapeutic effect on malignant lymphocytes.

Initial chemotherapy and low-dose radiation in limited fields in childhood Hodgkin's disease: results of a joint cooperative study by the French Society of Pediatric Oncology (SFOP) and Hôpital Saint-Louis, Paris

To minimize the drawbacks of treatment we had shown in a previous study that it was possible after chemotherapy to limit the radiation fields to the involved areas only. Pursuing our policy of deescalation, we started in January 1982 a study in 29 French pediatric and hematologic centers, with two aims: (1) To compare the efficacy of 4 cycles of two different chemotherapeutic regimens (4 ABVD vs 2 MOPP + ABVD) in early stages (CSIA and II A) while other stages would receive 6 cycles of the same regimen (3 MOPP + 3 ABVD); (2) To evaluate the efficacy of irradiation given at a low dose (20 Gy) in the patients who had a minimum 70% reduction of the size of their nodes (good responders). From January 1982 to March 1987, 174 patients were entered in this study, of whom 157 completed their treatment program at the time of analysis. On completion of chemotherapy, 94% were considered as good responders and were irradiated to 20 Gy. Only 6 patients received a mediastinal boost (up to 40 Gy). Of the 6% (10/157) poor responders a complete remission was obtained in 6 after 40 Gy. Among the good responders, 5 patients relapsed, with only 3 within an area irradiated to 20 Gy. So that 4 nodal relapses occurred among 364 involved lymph areas. The actuarial survival at 42 months (median 30 months) is 95% (IA + IIA = 100%, IB + IIB + III = 94% and IV = 80%) and the disease-free survival 88% (respectively 94, 93 and 54). Until now there is no statistically significant difference between the 2 randomized arms. This study shows that it is possible to achieve a durable remission in most children treated with a less toxic protocol eliminating or reducing Nitrogen Mustard and reducing the dose of irradiation. Less late complications and sequelae are expected with a longer follow-up.