Thyroid dysfunction, manifested by primary hypothyroidism, hyperthyroidism, goiter, or nodules, is a common delayed effect of radiation therapy fields that include the thyroid gland incidental to treating Hodgkin lymphoma (HL), brain tumors, head and neck sarcomas, and acute lymphoblastic leukemia. Of children treated with radiation therapy, most develop hypothyroidism within the first 2 to 5 years posttreatment, but new cases can occur later. Reports of thyroid dysfunction...
The oral cavity extends from the skin-vermilion junctions of the anterior lips to the junction of the hard and soft palates above and to the line of circumvallate papillae below and is divided into the following specific areas:
Anterior two thirds of tongue.
Floor of mouth.
The main routes of lymph node drainage are into the first station nodes (i.e., buccinator, jugulodigastric, submandibular, and submental). Sites close to the midline often drain bilaterally. Second station nodes include the parotid, jugular, and the upper and lower posterior cervical nodes.
Early cancers (stage I and stage II) of the lip and oral cavity are highly curable by surgery or by radiation therapy, and the choice of treatment is dictated by the anticipated functional and cosmetic results of treatment and by the availability of the particular expertise required of the surgeon or radiation oncologist for the individual patient.[1,2,3] The presence of a positive margin or a tumor depth of more than 5 mm significantly increases the risk of local recurrence and suggests that combined modality treatment may be beneficial.[4,5]
Advanced cancers (stage III and stage IV) of the lip and oral cavity represent a wide spectrum of challenges for the surgeon and radiation oncologist. Except for patients with small T3 lesions and no regional lymph node and no distant metastases or who have no lymph nodes larger than 2 cm in diameter, for whom treatment by radiation therapy alone or surgery alone might be appropriate, most patients with stage III or stage IV tumors are candidates for treatment by a combination of surgery and radiation therapy. Furthermore, because local recurrence and/or distant metastases are common in this group of patients, they should be considered for clinical trials. Such trials evaluate the potential role of radiation modifiers or combination chemotherapy combined with surgery and/or radiation therapy.
Patients with head and neck cancers have an increased chance of developing a second primary tumor of the upper aerodigestive tract.[6,7] A study has shown that daily treatment of these patients with moderate doses of isotretinoin (13-cis-retinoic acid) for 1 year can significantly reduce the incidence of second tumors. No survival advantage has yet been demonstrated, however, in part due to recurrence and death from the primary malignancy. An additional trial has shown no benefit of retinyl palmitate or retinyl palmitate plus beta-carotene when compared to retinoic acid alone.[Level of evidence: 1iiDii]
The rate of curability of cancers of the lip and oral cavity varies depending on the stage and specific site. Most patients present with early cancers of the lip, which are highly curable by surgery or by radiation therapy with cure rates of 90% to 100%. Small cancers of the retromolar trigone, hard palate, and upper gingiva are highly curable by either radiation therapy or surgery with survival rates of as much as 100%. Local control rates of as much as 90% can be achieved with either radiation therapy or surgery in small cancers of the anterior tongue, the floor of the mouth, and buccal mucosa.