# Radiation Oncology/Head & Neck/Sinonasal/Maxillary sinus

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## Epidemiology

* 3% of aerodigestive tract malignancies
* Peak incidence in age 50-59
* M:F 3:1
* 70-80% of tumors of the paranasal sinuses originate in maxillary sinus.

## Risk Factors

* Medical/occupational exposure (thorotrast, nickel, chromium,hydrocarbons, nitrogen mustard)
* Woodworkers have 500 times greater risk than general population of having carcinoma of maxillary sinus

## Anatomy

* The paranasal sinuses include the frontal, ethmoid, sphenoid, and maxillary sinuses.
Borders of Maxillary Sinus
* Medial border - nasal cavity
* Superior border - orbit
* Anterolateral border - facial bone
* Posteromedial border - infratemporal fossa
Ohngren's line is the oblique plane joining medial canthus of the eye with the angle of the mandible. It divides the maxilla into the infrastructure and superstructure. This line was originally described in the 1930's by Dr. Ohngren to delineate the limits of resectability of a tumor in the maxillary sinus. Tumors that extended into the superstructure (superoposterior to Ohngren's line) were more likely to involve the orbit, ethmoids, and pterygopalatine fossa. This line became the basis of original staging systems.
Nodal drainage of Paranasal sinuses
* Retropharyngeal nodes 1st echelon
* Periparotid nodes
* Submandibular nodes
Clinically involved nodes occur in approximately 15% of pts overall, but has been reported as >20% for SCC histology.

## Staging

see Staging

## Treatment

* Radiation therapy alone can be used as a primary modality for T1-T2 N0 patients, inoperable patients.
* Indications for adjuvant radiation therapy include: T1N0 patients with positive margins, perineural invasion, T3 or T4; consider for T2N0. For any N+, radiation to the neck
* Contraindications of surgery include intracranial invasion, carotid involvement, bilateral cavernous sinus involvement, and distant metastases
NCCN Radiation Therapy Guidelines:
* Definitive xrt for primary and gross adenopathy: >66 Gy
* Treatment of undissected neck: 50 Gy
* Adjuvant xrt for primary tumor bed: >60 Gy
* Adjuvant xrt to dissected neck (high risk nodal stations): >60 Gy
* Adjuvant xrt to dissected neck (low risk nodal stations): >50 Gy

### Surgical Management

* Subtotal Maxillectomy - 2 walls of maxilla removed. Generally indicated only for early (T1-2 lesions) of infrastructure.
* Radical Maxillectomy - The entire maxilla is removed. This is the standard operation for locally advanced carcinoma of maxilla. Resection includes the maxilla, nasal bone, ethmoid sinus, and sometimes the pterygoid plates. The surgery spares the zygoma, orbital periosteum, and palatal mucosa.
* Craniofacial Resection This surgery is indicated when tumor involves the roof of the ethmoid sinus. The posterior line of resection is foramen ovale, foramen rotundum and internal carotid. The inferior line of resection is similar to craniofacial frontoethmoidectomy and radical maxillectomy.
* Orbital Exenteration This surgery was practiced commonly in the 50's and 60's, but has fallen out of favor. It is generally indicated when orbital fat invasion is seen or orbital contents grossly involved.

### Adjuvant Radiation Therapy

* UT Southwestern, 2002 (1980-97) PMID 12439163 -- "Paranasal sinus malignancies: an 18-year single institution experience." (Myers LL et al, Laryngoscope. 2002 Nov;112(11):1964-9.)
** 141 pts w/ paranasal sinus malignancy, 88% w/ locally advanced dz, 70% maxillary sinus, 26% ethmoid sinus
** 62% underwent surgery as part of multimodality tx approach.
** 5yr DSS 52%, 10yr DSS 35%
** Local recurrence rate 56%
* The Netherlands, 2000 (1977-1996) PMID 10924968 -- "Does the combination of radiotherapy and debulking surgery favor survival in paranasal sinus carcinoma?" (Jansen EP et al, Int J Radiat Oncol Biol Phys. 2000 Aug 1;48(1):27-35.)
** 73 pts w/ paranasal sinus carcinoma tx'd w/ either combination therapy (surg + RT) or monotherapy (surg, RT alone)
** 5yr local control 65% w/ combination surg + xrt, 47% w/ xrt alone
** Orbital invasion associated w/ poor local control.
* MDACC, 1991 (1969-85) PMID 1924855 -- "Maxillary sinus carcinomas: natural history and results of postoperative radiotherapy." (Jiang GL et al, Radiother Oncol 1991 Jul;21(3):193-200.)
** 73 pts w/ maxillary sinus CA tx'd w/ surgery and postop xrt (dose of 50-60 Gy via wedged pair or 3-field technique)
** 5yr local control was 78%
** 5yr relapse free survival was 51%
** Overall nodal recurrence rate w/o elective nodal irradiation was 38% for SCC or undifferentiated, 5% for adenoid cystic.

### Elective Nodal Irradiation

* Stanford, 2000 (1959-96) PMID 10701732 -- "Lymph node metastasis in maxillary sinus carcinoma." (Le QT, Int J Radiat Oncol Biol Phys. 2000 Feb 1;46(3):541-9.)
** 97 pts w/ maxillary sinus carcinoma (61 receiving surgery + xrt, 36 pts xrt alone)
** 5yr actuarial survival 34%, 10 yr 31%
** Most common sites of nodal recurrence were levels I and II; 12% nodal relapse at 5yrs; 5yr actuarial risk of nodal relapse was 20% w/o ENI, 0% w/ ENI.
** 5yr actuarial risk of distant relapse 29% w/ neck control, and 81% if neck failure.

### Combined Modality Approach

* Tennessee, 2004 PMID 15313865 -- "Intra-arterial cisplatin and concomitant radiation therapy followed by surgery for advanced paranasal sinus cancer." (Samant S, Arch Otolaryngol Head Neck Surg 2004 Aug;130(8):948-55.)
** 18 pts tx'd w/ preop high dose intra-arterial cisplatin + IV thiosulfate w/ concurrent xrt (50 Gy). 84% T4 lesions. Planned surgery 8 wks post xrt (organ sparing, if possible).
** 2 yr OS 68%, 5 yr OS 53%

## Radiation Techniques and Treatment Planning

* Also please see H&N proton therapy
* Duke, 1999 PMID 10435816 -- "Conformal radiation therapy treatment planning reduces the dose to the optic structures for patients with tumors of the paranasal sinuses." (Brizel, Radiother Oncol. 1999 Jun;51(3):215-8.)
** Comparison of 2D and 3D treatment plans, using Dmax, NTCP and V80
** Conformal plan better: ipsilateral optic nerve 13% NTCP reduction (SS), ipsilateral eye 3% (SS), optic chiasm 0.5% (SS) driven by decreased Dmax and V80