Intensity modulated radiation therapy with dose painting to treat rhabdomyosarcoma

Intensity-Modulated Radiation Therapy With Dose Painting: A Brain-Sparing Technique for Intracranial Germ Cell Tumors

BACKGROUND

We sought to assess patterns of failure in pediatric patients with intracranial germ cell tumors (GCT) treated with intensity-modulated radiation therapy with dose painting (DP-IMRT).

PROCEDURE

Between July 2007 and October 2013, 11 patients with localized GCT-five germinomas and six nongerminoma GCT (NGGCT)-received definitive treatment with DP-IMRT. Three representative patients were selected for replanning with (i) whole ventricular irradiation (WVI) with opposed lateral beams plus IMRT to the primary tumor and (ii) sequential IMRT. These plans were compared to the patients' original DP-IMRT plans for dosimetric analyses.

RESULTS

Four patients with germinoma received radiation therapy alone: 45 Gy in 1.8 Gy fractions to the primary tumor and 25 Gy in 1.0 Gy fractions to whole ventricles using a dose-painting plan. One patient with germinoma received a reduced dose of 30.6 Gy to the primary tumor after neoadjuvant chemotherapy. Patients with NGGCT (n = 6) underwent multimodality treatment including chemotherapy (n = 6) and surgery (n = 3). These patients received 54 Gy to the primary tumor and 32.4-36 Gy to the whole ventricles. Dosimetric analyses showed DP-IMRT delivered decreased mean dose to whole brain, temporal lobes, hippocampi, cochleae, and optic nerves. With median follow-up of 4 years, 3-year failure-free survival was 100% for patients with germinoma and 67% for patients with NGGCT. One patient with a pineal NGGCT experienced a local recurrence within the high dose-volume while another experienced an isolated biochemical failure.

CONCLUSIONS

DP-IMRT is dosimetrically superior to standard IMRT techniques for sparing of normal tissues. Disease control in this small series appears at least comparable to published results.

Postoperative intensity-modulated radiation therapy provides favorable local control and low toxicities in patients with soft tissue sarcomas in the extremities and trunk wall

Purpose

To investigate the efficacy and toxicity of postoperative intensity-modulated radiation therapy (IMRT) for patients with soft tissue sarcomas (STSs) in the extremities and trunk wall.

Patients and methods

Eighty patients with localized STSs in the extremities and trunk wall treated with function-conserving surgery and postoperative IMRT were analyzed. The primary locations were in the extremities in 51 patients and in the trunk wall in 29 patients. The margins were positive in nine patients and negative in 71 patients. The median dose of IMRT was 64 Gy.

Results

At a median follow-up time of 38 months, eight patients developed local recurrences. The 5-year local control (LC) rate was 88.1%. The patients with negative margins exhibited much better LC than did those with positive margins (90% vs 64.8%, P=0.023). Multivariate analysis revealed that positive margin was an independent risk factor for LC. The 5-year distant metastasis-free survival, disease-free survival, and overall survival rates were 75.2%, 72.6%, and 83.6%, respectively. Large tumor size (>5 cm) was significantly associated with poor overall survival. Edema and joint stiffness were observed in 17.6% and 9.8% of patients with extremity STSs, respectively.

Conclusion

IMRT provides excellent LC and low toxicity for patients with STSs in the extremities and trunk wall.

Ethical analysis as a tool for addressing treatment controversies: radiotherapy timing in children with orbital rhabdomyosarcoma as a case example

PURPOSE

The treatment of orbital rhabdomyosarcoma is a topic of debate between North American and European clinicians, with the utility of radiation therapy as part of initial management in question. Despite differences in philosophy, the dominant North American approach of upfront radiation and the dominant European approach of radiation only in the event of recurrence yield a similar rate of overall survival. We sought to identify the ethical arguments for each approach.

METHODS

Established moral principles and appeals in contemporary medical ethics were utilized to identify the ethical arguments supporting each treatment approach. The potential for technologic advances to alter the analysis was considered.

RESULTS

Emphasizing the principle of beneficence, the North American approach seeks to reduce recurrence rates. In contrast, the European approach seeks to avoid radiation-induced sequelae, emphasizing the principle of nonmaleficence. Both approaches are based on well-established ethical principles, evidence, and clinical experience. Thus, both approaches currently appear to have legitimacy and should be included in the informed consent process. However, if treatment-related toxicity is reduced through improvements in radiation delivery, the North American approach could emerge as ethically superior.

CONCLUSIONS

Ethical analysis can aid in addressing challenges that arise when professional practices and perspectives differ in the management of cancer patients.

Brachytherapy in children with rhabdomyosarcomas of the nasolabial fold

BACKGROUND

Rhabdomyosarcomas (RMS) of the nasolabial fold can be difficult to manage surgically due to functional and cosmetic limitations. Therefore, brachytherapy (BT) has been proposed to improve local control while limiting the volume of irradiation as well as the extent of the surgical excision.

MATERIALS AND METHODS

Sixteen pediatric cases with RMS of the nasolabial fold treated from 1971 to 2005 were retrospectively reviewed.

RESULTS

Median follow-up was 4.4 years (1.7-33). Half of the patients were male and their age at diagnosis ranged from 4 months to 13.5 years. Histological subtypes included 10 embryonal and 6 alveolar RMS. Initial treatment consisted of induction multi-agent chemotherapy in all cases. In 12 patients, BT was combined with local excision (4 complete resections, 1 with macroscopic residual disease, and 7 with microscopic disease). Low dose-rate brachytherapy was performed in all cases according to the Paris system, using plastic catheters implanted per-operatively. The doses delivered ranged from 50 to 70 Gy, depending on chemotherapy response, and surgical margin status. 10 patients relapsed: 4 local, 6 regional, and 2 metastatic failures were reported. The median time to relapse was 6.5 months. At the time of analysis eight patients were alive and four had died. Four cases, under palliative care at last check-up, were lost to follow-up.

CONCLUSION

BT provided an acceptable local control rate, but the poor regional control of these cases may suggest a need for more aggressive management of cervical regional lymph node regions in RMS of the nasolabial fold.

Patterns of failure for rhabdomyosarcoma of the perineal and perianal region

PURPOSE

To analyze prognostic factors and patterns of failure for rhabdomyosarcoma of the perineal and perianal region (PRMS), with an emphasis on radiation therapy for locoregional control.

METHODS AND MATERIALS

Detailed records of all 14 patients treated for PRMS at Memorial Sloan-Kettering Cancer Center between 1998 and 2012 were reviewed. The Kaplan-Meier method was used to assess the event-free survival (EFS) and overall survival (OS), and a competing-risks analysis was used to assess the cumulative incidence of local, regional, and distant failures.

RESULTS

Median age was 15.8 years (range, 1.1-31.9 years). High-risk features were identified: 9 of 14 patients (64%) had group 3 disease and 3 of 14 (21%) had group 4; 11 of 14 tumors (78%) were alveolar; 12 of 14 tumors (86%) were ≥5 cm; and 9 of 14 patients (64%) had involved lymph nodes (N1). Of those aged ≥10 years at diagnosis, 9 of 10 (90%) had alveolar histology, all had tumors ≥5 cm, and 8 of 10 (80%) presented with N1 disease. The rates of local, regional, and distant failure at 5 years were 17%, 31%, and 52%, respectively. Although 3 of the 4 patients with regional failure received nodal irradiation, only one of the nodal failures occurred in the radiation therapy field. The 5-year EFS was 33%, and OS was 39%. Age ≥10 years was associated with poor outcomes: EFS was 13% in patients aged ≥10 years, compared with 75% in those aged <10 years (P=.04); the OS was 13% in patients aged ≥10 years, compared with 100% in those aged <10 years (P=.04).

CONCLUSIONS

Patients with PRMS, especially those aged ≥10 years, present with poor prognostic features and continue to have poor outcomes. Given the high incidence of regional node recurrence, we recommend prophylactic ilioinguinal lymph node irradiation for all patients aged ≥10 years. For children aged <10 years, nodal evaluation is essential to determine the role for lymph node irradiation.

Intensity-modulated radiotherapy (IMRT) in pediatric low-grade glioma

BACKGROUND

The objective of this study was to evaluate local control and patterns of failure in pediatric patients with low-grade glioma (LGG) who received treatment with intensity-modulated radiation therapy (IMRT).

METHODS

In total, 39 children received IMRT after incomplete resection or disease progression. Three methods of target delineation were used. The first was to delineate the gross tumor volume (GTV) and add a 1-cm margin to create the clinical target volume (CTV) (Method 1; n = 19). The second was to add a 0.5-cm margin around the GTV to create the CTV (Method 2; n = 6). The prescribed dose to the GTV was the same as dose to the CTV for both Methods 1 and 2 (median, 50.4 grays [Gy]). The final method was dose painting, in which a GTV was delineated with a second target volume (2TV) created by adding 1 cm to the GTV (Method 3; n = 14). Different doses were prescribed to the GTV (median, 50.4 Gy) and the 2TV (median, 41.4 Gy).

RESULTS

The 8-year progression-free and overall survival rates were 78.2% and 93.7%, respectively. Seven failures occurred, all of which were local in the high-dose (≥95%) region of the IMRT field. On multivariate analysis, age ≤5 years at time of IMRT had a detrimental impact on progression-free survival.

CONCLUSIONS

IMRT provided local control rates comparable to those provided by 2-dimensional and 3-dimensional radiotherapy. Margins ≥1 cm added to the GTV may not be necessary, because excellent local control was achieved by adding a 0.5-cm margin (Method 2) and by dose painting (Method 3).