Submandibular gland-sparing intensity modulated radiotherapy in the treatment of head and neck cancer: Sites of locoregional relapse and survival

Figures & data

Table I. Patient and tumor characteristics.

Characteristic	n	%
Gender
Female	22	28*
Male	58	73
Age
Median	60
Range	30–79
Tumor site
Larynx	15	19*
Oropharynx	50	63
Hypopharynx	11	14
Nasopharynx	4	5
T category**
T1	25	31
T2	31	39
T3	16	20
T4	8	10
N category**
N0	32	40
N1	8	10
N2a	15	19
N2b	23	29
N3	2	3*
Stage
I	5	6
II	15	19
III	19	24
IV	41	51
Radiotherapy
Definitive	39	49
Postoperative	41	51

*The percentages do not add up to 100 due to rounding.

**According to the International Union Against Cancer (UICC) Tumour-Node Metastasis (TNM) classification [5].

Figure 1. The mean cumulative total radiation doses to the contralateral parotid gland (cPG), contralateral submandibular gland (cSMG), ipsilateral parotid gland (iPG) and ipsilateral submandibular gland (iSMG).

Table II. The numbers of spared parotid and submandibular glands by the primary tumor site.

		Numbers of spared salivary glands
Primary tumor site	Patients n	Ipsilateral parotid gland n (%)	Contralateral parotid gland n (%)	Ipsilateral submandibular gland n (%)	Contralateral submandibular gland n (%)
Larynx	15	14 (93)	15 (100)	12 (80)	15 (100)
Oropharynx	50	25 (50)	50 (100)	1 (2)*	50 (100)
Hypopharynx	11	9 (82)	11 (100)	1 (9)	11 (100)
Nasopharynx	4	1 (25)	4 (100)	0 (0)	4 (100)

*Removed at neck dissection in 37 (90%) of 41 patients who received postoperative radiotherapy.

Table III. Mean doses to the spared salivary glands by the primary tumor site.

		Cumulative radiation dose to the salivary gland
Tumor site	Patients n	Ipsilateral parotid gland Mean (range) Gy	Contralateral parotid gland Mean (range) Gy	Ipsilateral submandibular gland Mean (range) Gy	Contralateral submandibular gland Mean (range) Gy
Larynx	15	17.0 (8.0–25.4)	13.8 (7.7–20.0)	29.2 (20.7–44.1)	28.6 (18.6–40.9)
Oropharynx	50	27.9 (19.3–44.3)	22.4 (14.8–28.2)	32.4 (32.4)	27.8 (16.7–43.7)
Hypopharynx	11	23.8 (15.8–42.8)	20.9 (13.8–27.7)	33.6 (33.6)	29.0 (23.2–35.3)
Nasopharynx	4	28.0 (28.0)	25.1 (23.8–26.4)	–	26.2 (24.0–29.1)

Figure 1. Local control following submandibular gland sparing intensity modulated radiotherapy (IMRT).

Sobin LH, Wittekind C. TNM classification of malignant tumours. 6th ed. UICC, Wiley-LISS: New York; 2002.

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