Hypothyroidism as a consequence of intensity-modulated radiotherapy with concurrent taxane-based chemotherapy for locally advanced head-and-neck cancer

PURPOSE

To conduct a retrospective review of 168 consecutively treated locally advanced head-and-neck cancer (LAHNC) patients treated with intensity-modulated radiotherapy (IMRT)/chemotherapy, to determine the rate and risk factors for developing hypothyroidism.

METHODS AND MATERIALS

Intensity-modulated radiotherapy was delivered in 33 daily fractions to 69.3 Gy to gross disease and 56.1 Gy to clinically normal cervical nodes. Dose-volume histograms (DVHs) of IMRT plans were used to determine radiation dose to thyroid and were compared with DVHs using conventional three-dimensional radiotherapy (3D-RT) in 10 of these same patients randomly selected for replanning and with DVHs of 16 patients in whom the thyroid was intentionally avoided during IMRT. Weekly paclitaxel (30 mg/m(2)) and carboplatin area under the curve-1 were given concurrently with IMRT.

RESULTS

Sixty-one of 128 evaluable patients (47.7%) developed hypothyroidism after a median of 1.08 years after IMRT (range, 2.4 months to 3.9 years). Age and volume of irradiated thyroid were associated with hypothyroidism development after IMRT. Compared with 3D-RT, IMRT with no thyroid dose constraints resulted in significantly higher minimum, maximum, and median dose (p < 0.0001) and percentage thyroid volume receiving 10, 20, and 60 Gy (p < 0.05). Compared with 3D-RT, IMRT with thyroid dose constraints resulted in lower median dose and percentage thyroid volume receiving 30, 40, and 50 Gy (p < 0.005) but higher minimum and maximum dose (p < 0.005).

CONCLUSIONS

If not protected, IMRT for LAHNC can result in higher radiation to the thyroid than with conventional 3D-RT. Techniques to reduce dose and volume of radiation to thyroid tissue with IMRT are achievable and recommended.

Taxane-based chemoirradiation for organ preservation with locally advanced head and neck cancer: results of a phase II multi-institutional trial

BACKGROUND

The optimal drug schedule and sequencing of chemotherapy and radiation for organ preservation in head and neck cancer has yet to be determined. We undertook a phase II trial of a taxane-based induction chemotherapy (ICT) followed by a taxane-based concurrent chemoradiation (CCR) regimen in patients with resectable stage III or IV disease to determine the feasibility, toxicity, and overall efficacy.

METHODS

Forty-four patients with laryngeal or tongue base carcinomas were enrolled. All patients received 3 cycles of chemotherapy with paclitaxel 175 mg/m(2) and carboplatin AUC (area under the curve) 6-7.5 over 30 minutes on days 1, 22, and 43. Responding patients went on to receive radiation (70 Gy/7 weeks) with cisplatin 75 mg/m(2) IV on days 1, 22, and 43 and weekly paclitaxel 30 mg/m(2) IV (n = 22). Because of hematologic toxicity, the concurrent regimen was changed to weekly carboplatin AUC 1 plus weekly paclitaxel 30 mg/m(2) (n = 22).

RESULTS

Twenty-three patients with stage III and 21 patients with stage IV disease were enrolled. Median follow-up was 3.7 years. Acute toxicity of concurrent cisplatin and paclitaxel was excessive, with significant hematologic toxicity and 2 toxic deaths. Acute toxicities of concurrent carboplatin and paclitaxel were tolerable. No patients required permanent percutaneous gastrostomy tubes. The organ preservation rate was 83% (toxic deaths considered failures). Of 42 evaluable patients, 20 patients had complete responses (48%), 17 partial responses (41%), 3 minor responses (11%), 1 stable disease (2%), and 1 progressive disease (2%). Two-year local control, relapse-free survival, and overall survival were 82%, 77%, and 71%, respectively.

CONCLUSION

There were no significant differences in relapse-free survival or organ preservation rates between concurrent regimens. Platinum and paclitaxel-based CCR is feasible after ICT and provides a high rate of organ preservation. Substitution of concurrent cisplatin to weekly carboplatin with paclitaxel and radiation has an improved toxicity profile. The ease of administration and low toxicity make this a regimen that is practical for use in the community setting.