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Brachytherapy in the Treatment of Head and Neck Cancer

Brachytherapy in the Treatment of Head and Neck Cancer

Quon and Harrison have performed a considerable service
to patients with head and neck cancers by reminding the oncology community that
a state-of-the-art treatment team must include state-of-the-art brachytherapy.

A fundamental adage in radiotherapy is "If you don’t hit it, you can’t
cure it." Modern tools of external-beam radiotherapy, such as
intensity-modulated radiation therapy, allow us to tailor radiation dose
distributions (at least on the computer screen) to conform almost as tightly to
the shape of the cancer as brachytherapy. In the head and neck region, however,
ensuring that radiation always hits its target is not easy: Accurately
repositioning and immobilizing inherently mobile structures such as the tongue,
the mandible, and the cervical spine—day after day, week after week—can be
quite difficult.

Advantages of Brachytherapy

With brachytherapy, one has the confidence that radiation is always hitting
its target because the source of irradiation is located within the target, or
right on it, rather than several feet away. Furthermore, the duration of the
treatment, instead of weeks and months, is measured in days (and now, with high-dose-rate
brachytherapy, in minutes). Brachytherapy is, therefore, quite appropriately
described as the ultimate conformal radiotherapy and belongs in the
armamentarium of physicians dealing with patients suffering from head and neck
cancers.

Among the frustrations of being a head and neck brachytherapist is seeing
patients after local recurrence and knowing that, if brachytherapy had been
employed as part of the original planned treatment, the outcome would probably
have been better. I shall, therefore, take this opportunity to amplify three of
the issues discussed by Quon and Harrison in their comprehensive review, namely,
(1) the role of brachytherapy in nasopharyngeal carcinoma, (2) the role of
brachytherapy in the postoperative patient, and (3) the role of high-dose-rate
brachytherapy.

Brachytherapy in
Nasopharyngeal Carcinoma

Adequate external-beam irradiation to the nasopharynx and the retropharyngeal
lymph nodes is constrained, even in the modern era, by the proximity of these
sites to critical structures such as the brainstem, the optic chiasm, and the
spinal cord. In the recent Intergroup study 0099, no brachytherapy was allowed,
and as a result, one in three patients (23/69) treated by radiotherapy suffered
local recurrence.[1] This was in striking contrast to several reports from the
United States,[2-4] Europe,[5] and Asia,[6,7] suggesting that adding a planned
brachytherapy boost to external irradiation led to local recurrences in fewer
than 1 in 10 patients, and was quite safe.

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