The Current State of Radiotherapy for Pediatric Brain Tumors: An Overview of Post-Radiotherapy Neurocognitive Decline and Outcomes

Tumors of the central nervous system are the most common solid malignancies diagnosed in children. While common, they are also found to have some of the lowest survival rates of all malignancies. Treatment of childhood brain tumors often consists of operative gross total resection with adjuvant chemotherapy or radiotherapy. The current body of literature is largely inconclusive regarding the overall benefit of adjuvant chemo- or radiotherapy. However, it is known that both are associated with conditions that lower the quality of life in children who undergo those treatments. Chemotherapy is often associated with nausea, emesis, significant fatigue, immunosuppression, and alopecia. While radiotherapy can be effective for achieving local control, it is associated with late effects such as endocrine dysfunction, secondary malignancy, and neurocognitive decline. Advancements in radiotherapy grant both an increase in lifetime survival and an increased lifetime for survivors to contend with these late effects. In this review, the authors examined all the published literature, analyzing the results of clinical trials, case series, and technical notes on patients undergoing radiotherapy for the treatment of tumors of the central nervous system with a focus on neurocognitive decline and survival outcomes.

Nomogram for predicting the survival rate of primary pulmonary mucoepidermoid carcinoma patients: a retrospective study based on SEER database

Background

Primary pulmonary mucoepidermoid carcinoma (PMEC) is a rare malignant tumor, and the clinical manifestations lack specificity. The study evaluates the prognostic factors and constructs a practicable nomogram to estimate the individualized survival status for PMEC patients.

Methods

Surveillance, Epidemiology, and End Results (SEER) database was used to selected eligible patients between 1975 and 2016. The baseline characteristics including age, sex, race, marital status, tumor stage, differentiated degree, tumor laterality, primary tumor site, tumor size, lymph node metastases status, distant metastases status, surgery, chemotherapy, and radiation. We identified independent variables to build 3-, 5-, 10-year overall survival (OS) and cancer-specific survival (CSS) nomograms by univariate and multivariate analyses.

Results

A total of 438 PMEC patients met our selection criteria. In multivariate analysis, age, tumor stage, differentiated grade, tumor size, lymph node metastases status, distant metastases status, surgery and radiation were involved in the nomogram. The C-index (0.887 (95% CI: 0.863-0.911), calibrate plots and ROC curves (AUC =0.941, 0.951, 0.935 for 3-, 5-, 10-year OS, respectively) indicated the satisfied accuracy and practicability of our nomograms. Compared to TNM system, our model also showed a superior prediction (IDI =0.167, 0.171, 0.172, P<0.001).

Conclusions

We built OS (CSS) nomograms that can accurately estimate individualized survival time and identify the risk classification of PMEC.

Postoperative radiotherapy for T1/2N0M0 mucoepidermoid carcinoma positive for CRTC1/3-MAML2 fusions

BACKGROUND

The National Comprehensive Cancer Network (NCCN) guidelines recommend considering postoperative radiotherapy (PORT) for completely resected T1/2N0M0 salivary mucoepidermoid carcinomas when they show tumor spillage, perineural invasion, or intermediate/high-grade histology. CRTC1/3-MAML2 fusions have been associated with a favorable clinical outcome.

METHODS

Forty-seven T1/2N0M0 mucoepidermoid carcinoma cases positive for CRTC1/3-MAML2 fusions were completely resected and were not treated with PORT.

RESULTS

Pathologically, none of the cases showed tumor spillage or perineural invasion. Cases with intermediate/high-grade histology numbered 9 (19%) to 26 (55%) with the currently used 3 different grading systems. During the follow-up (median 60 months), locoregional tumor recurrence occurred in 4 cases, which were treated with surgery alone. At the last follow-up (median 60 months; 7-160), all patients were alive with no evidence of disease.

CONCLUSION

An excellent prognosis may be achieved without PORT in T1/2N0M0 mucoepidermoid carcinoma patients positive for CRTC1/3-MAML2 fusions when the tumors are completely resected without tumor spillage.

Childhood and adolescent tracheobronchial mucoepidermoid carcinoma (MEC): a case-series and review of the literature

Tracheobronchial mucoepidermoid carcinomas (MEC) are rare in the pediatric population with literature limited primarily to case reports. Here we present our institutional experience treating MEC in three patients and review the literature of 142 pediatric cases previously published from 1968 to 2013. Although rare, tracheobronchial MEC should be included in the differential diagnosis in a child with recurrent respiratory symptoms. Conservative surgical management is often sufficient to achieve complete resection and good outcomes.

Proton beam therapy for metastatic liver tumors

PURPOSE

The purpose of this study was to investigate the safety and efficacy of proton beam therapy (PBT) for the treatment of metastatic liver tumors.

MATERIAL AND METHODS

A total of 140 patients with liver metastasis who received PBT were retrospectively investigated. The main primary tumor sites were the colorectum (60) and the pancreas (19).

RESULTS

One hundred thirty-three patients (95%) completed treatment. Two patients experienced late adverse effects (rib fracture and cholangitis). The 5-year overall survival (OS) rate was 24%. In the 85 patients with lesions confined to the liver, the 5-year OS rate of was 28%, and in the 55 patients with lesions both inside and outside the liver, it was 16% (P=0.007). Among the patients with lesions confined to the liver, the 5-year OS rate of the 62 patients who received curative treatment was 30%, and that of the 23 patients who received palliative treatment, 23% (P=0.016). Multivariate analysis showed that the treatment strategy (curative and palliative) alone was associated with the OS rate (P=0.02).

CONCLUSION

PBT is a potentially safe and effective treatment for metastatic liver tumors.

Proton beam therapy for pediatric ependymoma

BACKGROUND

The aim of this study was to evaluate the efficacy of proton beam therapy for pediatric patients with ependymoma.

METHODS

Proton beam therapy was conducted for six patients (three boys and three girls; age, 2-6 years; median, 5 years) with ependymoma. The tumors were WHO grades 2 and 3 in two and four patients, respectively. All patients underwent surgery (subtotal and gross total resection in three patients each) and proton beam therapy at doses of 50.4-61.2 GyE (median, 56.7 GyE). The mean doses to normal brain tissue in proton beam therapy and photon radiotherapy were simulated using the same treatment planning computed tomography images.

RESULTS

All patients completed the planned irradiation. The follow-up period was 13-44 months (median, 24.5 months) from completion of proton beam therapy and all patients were alive at the end of this period. Local recurrence in the treatment field occurred in one patient at 4 months after proton beam therapy at 50.4 GyE. Alopecia and mild dermatitis occurred in all patients, but there was no severe toxicity. One patient had a once-off seizure after proton beam therapy and alopecia persisted in another patient for 31 months, but no patients had difficulty with daily life. The simulation showed that proton beam therapy reduces the dose to normal brain tissue by approximately half compared with photon radiotherapy.

CONCLUSIONS

Proton beam therapy for pediatric ependymoma is safe, does not have specific toxicities, and can reduce irradiation of normal brain tissue.

Primary malignant pulmonary tumors in children: a review of the national cancer data base

BACKGROUND

The purpose is to delineate the clinical and pathological characteristics of rare primary malignant pulmonary tumors in children.

METHODS

Utilizing the National Cancer Data Base (NCDB), we analyzed all children (≤ 18 years) with a primary malignant pulmonary tumor from 1998 to 2011 to identify factors associated with better survival.

RESULTS

Of 211 children identified, the most common histology was carcinoid tumor (n=133, 63%) followed by mucoepidermoid carcinoma (MEC) (n=37, 18%), squamous cell carcinoma (SCC) (n=19, 9%), adenocarcinoma (n=16, 8%), bronchoalveolar carcinoma (BAC) (n=4, 2%), and small cell carcinoma (SCLC) (n=2, <1%). Factors that significantly affected survival include histology, race, tumor size, lymph node status, and extent of surgery. Patients with MEC and carcinoid tumors had a better overall survival compared to patients with other histologies (p<0.0001). The 5-year overall survival for MEC and carcinoid tumors was 100% and 95% (95% CI 87-98), respectively, versus 50% (95%CI 1-91) for BAC, 28% (95%CI 9-52) for SCC, and 26% (95%CI 5-55) for adenocarcinoma.

CONCLUSION

The majority of pediatric patients with a primary malignant pulmonary tumor present with carcinoid tumor or MEC and have an excellent prognosis. Lung cancers which are common in adults, but rare in children, have a worse prognosis.