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Poster presented at:

Olfactory neuroblastoma – 10-year experience with

volumetric modulated arc therapy

Ariyaratne H1, Ward A2, Bhudia P2, Lund V2, Carnell D2

1Royal Free London NHS Foundation Trust, 2University College London Hospitals NHS Foundation Trust

Email: hemal.ariyaratne@nhs.net

Purpose

Olfactory neuroblastoma is an unusual head and neck tumour arising

from neuroectodermal cells. Localized disease is best managed with

combined modality treatment with surgical resection and radiotherapy

(1). Treatment is challenging due to the proximity of organs at risk.

The majority of previously reported series of patients have been treated

with conformal radiotherapy (2,3). We report our experience in using

volumetric modulated arc therapy (VMAT) with concurrent chemotherapy

in the treatment of olfactory neuroblastoma.

Methods

We retrospectively reviewed the records of patients with olfactory

neuroblastoma treated at University College London Hospital from Aug

2006 - June 2016.

Radiotherapy was inverse-planned and delivered using RapidarcTM

VMAT (Varian Medical Systems Inc, CA). A dose of 60 – 65 Gy in 30

fractions was delivered to the planning target volume. The radiotherapy

planning constraints for organs at risk were:

Fig. 1. Dose distribution achieved with VMAT after resection of olfactory

neuroblastoma with positive margins near left orbit.

Induction chemotherapy was used for bulky disease. Concurrent

platinum-based chemotherapy was administered during radiotherapy

using cisplatin 35 mg/m2 weekly. Acute toxicity was assessed using the

CTCAE grading system. Kaplan-Meier survival analysis was used for the

whole group..

Conclusion

VMAT radiotherapy with concurrent chemotherapy for olfactory

neuroblastoma is well-tolerated. Overall survival for patients with

olfactory neuroblastoma is very good after multi-modality treatment.

References

1. Lund VJ, Howard D, Wei W, Spittle M. Olfactory Neuroblastoma: Past, Present, and Future?

The Laryngoscope. 2003;113(3):502-7.

2. Castelnuovo P, Bignami M, Delù G, Battaglia P, Bignardi M, Dallan I. Endonasal endoscopic

resection and radiotherapy in olfactory neuroblastoma: Our experience. Head & Neck.

2007;29(9):845-50.

3. Zappia JJ, Carroll WR, Wolf GT, Thornton AF, Ho L, Krause CJ. Olfactory neuroblastoma:

The results of modern treatment approaches at the University of Michigan. Head & Neck.

1993;15(3):190-6.

4. Kadish S, Goodman M, Wang C. Olfactory neuroblastoma—A clinical analysis of 17 cases.

Cancer. 1976;37(3):1571-6.

Results

17 consecutive patients treated with VMAT radiotherapy were included.

Median follow-up of patients was 43 months. Median age was 57 years

(range 22 – 75 years). 53% were male. The Kadish (4) staging of

patients is shown below:

13 patients had endoscopic surgery and 3 patients had open craniofacial

resection. One patient had unresectable disease. Even with inverse-

planned treatment, there were minor deviations from radiotherapy

constraints for the optic apparatus in some patients, due to the proximity

to the target volume (Fig. 1).

There was no acute grade 3/4 toxicity, and no long-term visual or

neurological toxicity during the period of follow-up. 5-year overall survival

of patients in this series was 83%. (Fig.2 below)

Kadish Stage No. ofpatients

%

A 4 23.5

B 3 17.6

C 7 41.2

D 3 17.6

Total 17 100.0

Organ at risk Parameter Constraint

Spinal cord Max 46 Gy

D0.1cc 44 Gy

Spinal cord PRV Max 50 Gy

D0.1cc 48 Gy

Brainstem Max 55 Gy

D0.1cc 54 Gy

Brainstem PRV Max 59 Gy

D0.1cc 55 Gy

Parotid Mean 24 Gy

Optic nerve PRV Max 50 Gy

Optic chiasm PRV Max 50 Gy

Lens Max 6 Gy

Cochlea Mean 48 Gy

EP-1042Hemal Ariyaratne DOI: 10.3252/pso.eu.ESTRO36.2017

Clinical track: Head and Neck