IMRT for Head and Neck Cancer: Updated Clinical Results
S. Jack Wei, MD
Abramson Cancer Center of the University of Pennsylvania
Last Modified: October 22, 2003
Moderator: Theodore L. Phillips, MD., University of California, San Francisco
Nancy Lee, MD, Memorial Sloan-Kettering Cancer Center, New York
- Approximately 150 papers have reported on the outcomes of H&N cancer patients treated with IMRT.
- The primary endpoints for these trials usually are rates of xerostomia and local control.
- It is important to keep in mind that GTV delineation is a multidisciplinary approach requiring the input of the radiation oncologist, neuroradiologist, and the H&N surgeon.
- CTV delineation requires knowledge of H&N anatomy and patterns of spread.
- In terms of xerostomia, mean parotid doses of <26 Gy has resulted in objective and subjective salivary function preservation and improved quality of life.
- IMRT has resulted in 82% improvement in xerostomia at 12 months compared to 40% improvement with 3DCRT.
- In terms of local control (LC) in nasopharyngeal cancer, comparison to historical controls have shown the following:
- For T1-2 lesions, IMRT 92-100% vs. 3DCRT 64-95%
- For T3-4 lesions, IMRT 92-94% vs. 44-68%
- For oropharyngeal CA, comparison to historical controls for LC have shown:
- For T1-2 lesions, IMRT 92% vs. 3DCRT 70-90%
- For T3-4 lesions, IMRT 87-94% vs. 3DCRT 30-70%
- Similar high rates of LC are seen for other H&N sites.
- In conclusion, IMRT has been shown to decrease xerostomia rates and possibly increase local control compared to historical controls, particularly in patients with more advanced disease.
- These patients may experience higher acute toxicity and likely have an increased risk of second malignancy (from 1% to 1.75%) due to the higher integral dose delivered with IMRT.
- Although randomized trials would be beneficial, it would be difficult to enroll patients into these studies given the existing, non-randomized data.
- Two ongoing European trials are currently examining these questions, and the results are eagerly anticipated.