Clinical outcomes among patients with head and neck cancer treated by intensity-modulated radiotherapy with and without adaptive replanning.

The purpose of this study was to determine the effect of adaptive replanning on clinical outcome among patients treated by intensity-modulated radiotherapy (IMRT) for head and neck cancer. Three hundred seventeen patients underwent IMRT with daily image-guidance for newly diagnosed squamous cell carcinoma of the head and neck to a median dose of 66 Gy (range, 60-74 Gy). Of these 317 patients, 51 (16%) underwent adaptive radiotherapy with modification of the original IMRT midway during treatment. The 2-year local-regional control was 88% for patients treated with adaptive replanning compared with 79% for patients treated without (p = .01). The median time to local-regional recurrence for the 4 patients treated by adaptive radiotherapy was 7 months (range, 3-15 months) with all failures occurring within the high-dose planning target volume (PTV). Although the use of routine replanning is probably not necessary, our findings do suggest a significant benefit in appropriately selected patients.

Chen AM ，Daly ME ，Cui J ，Mathai M ，Benedict S ，Purdy JA ... -  《-》

Hypothyroidism after 3-dimensional conformal radiotherapy and intensity-modulated radiotherapy for head and neck cancers: prospective data from 2 randomized controlled trials.

The purpose of this study was to determine the incidence of hypothyroidism after chemoradiation in head and neck squamous cell cancer (HNSCC). One hundred twenty-two patients treated with 3-dimensional conformal radiotherapy (3DCRT; 70 Gy/35#) or intensity-modulated radiation therapy (IMRT; 66 Gy/30#) in 2 identical simultaneous randomized trials were studied. Thyroid function was assessed at baseline and every 3 to 6 monthly thereafter. Development of subclinical (thyroid-stimulating hormone [TSH] >4.67 μIU/mL) or biochemical (T4 <4.5 μg/dL) hypothyroidism was noted. Multivariate analyses were done to determine the factors associated with hypothyroidism. At a median of 41 months, 55.1% of the patients developed hypothyroidism (39.3% subclinical, 15.7% biochemical). The IMRT arm had higher subclinical hypothyroidism (51.1% vs 27.3%; p = .021) peaking around 1 year postradiotherapy in both arms. Younger age, hypopharynx/larynx primary, node positivity, higher dose/fraction (IMRT arm), and D100 were statistically significant factors for developing hypothyroidism. Postradiotherapy hypothyroidism peaks at 1 year. Higher dose per fraction possibly led to greater incidence of hypothyroidism in the IMRT cohort.

Murthy V ，Narang K ，Ghosh-Laskar S ，Gupta T ，Budrukkar A ，Agrawal JP ... -  《-》

Initial clinical experience with helical tomotherapy for head and neck cancer.

Chen AM ，Jennelle RL ，Sreeraman R ，Yang CC ，Liu T ，Vijayakumar S ，Purdy JA ... -  《-》

Evaluation of the planning target volume in the treatment of head and neck cancer with intensity-modulated radiotherapy: what is the appropriate expansion margin in the setting of daily image guidance?

To compare patterns of disease failure among patients treated with intensity-modulated radiotherapy (IMRT) in conjunction with daily image-guided radiotherapy (IGRT) for head and neck cancer, according to the margins used to expand the clinical target volume (CTV) to create a planning target volume (PTV). Two-hundred and twenty-five patients were treated with IMRT for squamous cell carcinoma of the head and neck. Daily IGRT scans were acquired using either kilovoltage or megavoltage volumetric imaging prior to each delivered fraction. The first 95 patients were treated with IMRT with 5-mm CTV-to-PTV margins. The subsequent 130 patients were treated using 3-mm PTV expansion margins. Two-year estimates of overall survival, local-regional control, and distant metastasis-free survival were 76%, 78%, and 81%, respectively. There were no differences with respect to any of these endpoints among patients treated with 5-mm and 3-mm PTV expansion margins (p > 0.05, all). The 2-year local-regional control rate for patients treated with IMRT with 5-mm and 3-mm PTV margins was 78% and 78%, respectively (p = 0.96). Spatial evaluation revealed no differences in the incidences of marginal failures among those treated with 5-mm and 3-mm PTV margins. The use of 3-mm PTV expansion margins appears adequate and did not increase local-regional failures among patients treated with IMRT for head and neck cancer. These data demonstrate the safety of PTV reduction of less than 5 mm and support current protocols recommending this approach in the setting of daily IGRT.

Chen AM ，Farwell DG ，Luu Q ，Donald PJ ，Perks J ，Purdy JA ... -  《-》

Adaptive Radiotherapy for Head and Neck Cancer.

Surucu M ，Shah KK ，Roeske JC ，Choi M ，Small W Jr ，Emami B ... -  《-》