A classification for maxillary sinus cancer was already reported in the first edition of the Manual for Cancer Staging of the American Joint Committee on Cancer (AJCC) in 1977; however, only in 1987, a common classification was adopted from both the AJCC and the Union Internationale Contre le Cancer (UICC). Conversely, even though some independent classification for staging ethmoid cancer had been proposed (Ellingwood and Million 1979; Roux et al. 1991), only in 1997 was an official staging system specific for the ethmoid site published. Approximately at the same time, an original classification for ethmoid cancer was developed by Cantu et al. (1997) (Table 9.1), with the intent to better stratify patients survival according to the extent of the tumor to adjacent anatomic areas. By analyzing a cohort of 123 patients undergoing craniofacial resection, they demonstrated with their classification a progressive worsening of the prognosis from T2 to T4 categories, a finding which was not observed when using 1997 AJCC-UICC classification (Cantu et al. 1999b).
The most recent update of AICC and UICC (Sobin and Witteking 2002) (Table 9.2-9.3) classification has introduced some important modifications. First of all, the second site of paranasal sinuses (the first one being the maxillary sinus) has been defined as "naso-ethmoidal complex", which includes two different regions, the ethmoid sinuses and the nasal cav-
Table 9.1. Classification of malignant ethmoid tumors at the Istituto Nazionale per lo Studio e la Cura dei Tumori
T1 Tumor involving the ethmoid and nasal cavity, sparing the most superior ethmoid cells T2 Tumor with an extension to or erosion of the cribriform plate, with or without erosion of the lamina papyracea and without extension into the orbit T3 Tumor extending into the anterior cranial fossa extra-durally and/or into the anterior two thirds of the orbit, with or without erosion of the anteroinferior wall of the sphenoid sinus, and/or involvement of the maxillary and/or frontal sinus T4 Tumor with intradural extension, and/or involving the orbital apex, the sphenoid sinus, the pterygoid plate, the infratemporal fossa, or the skin
Table 9.2. AJCC-UICC staging system for maxillary sinus tumors (2002)
T1 Tumor limited to maxillary sinus mucosa with no erosion or destruction of bone T2 Tumor causing bone erosion or destruction including extension into the hard palate and/or middle nasal meatus, except extension to posterior wall of maxillary sinus and pterygoid plates T3 Tumor invades any of the following: bone of the posterior wall of the maxillary sinus, subcutaneous tissues, floor or medial wall of orbit, pterygoid fossa, ethmoid sinuses
T4a Tumor invades anterior orbital contents, skin of cheek, pterygoid plates, infratemporal fossa, cribriform plate, sphenoid or frontal sinuses T4b Tumor invades any of the following: orbital apex, dura, brain, middle cranial fossa, cranial nerves other than maxillary division of trigeminal nerve (V2), nasopharynx, or clivus
Table 9.3. AJCC-UICC staging system for nasal cavity and ethmoid sinus tumors (2002)
T1 Tumor restricted to any one subsite, with or without bony invasion
T2 Tumor invading two subsites in a single region or extending to involve an adjacent region within the naso-ethmoidal complex, with or without bony invasion T3 Tumor extends to invade the medial wall or floor of the orbit, maxillary sinus, palate, or cribriform plate T4a Tumor invades any of the following: anterior orbital contents, skin of nose or cheek, minimal extension to anterior cranial fossa, pterygoid plates, sphenoid or frontal sinuses
T4b Tumor invades any of the following: orbital apex, dura, brain, middle cranial fossa, cranial nerves other than (V2), nasopharynx, or clivus ity. The former is divided in right and left, while four subsites (septum, floor, lateral wall, and vestibule) made up the latter. Secondarily, a better stratification of patients in regards to invasion of the orbit (anterior part vs. apex) and of the anterior skull base (bone, dura, and brain) has been provided. This has led to the division of T4 lesions into two different sub-categories (T4a and T4b), with the aim to separate resectable from unresectable tumors.
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