PREATREATMENT PET FOR HEAD AND NECK CANCER

March 3, 2010 — In patients with head and neck squamous cell carcinoma, a pretreatment measure obtained on a positron emission tomography (PET) scan is a strong predictor of disease-free survival. Specifically, the measure is the maximal standardized uptake value (SUV_max) obtained from [¹⁸F]-fluorodeoxyglucose (FDG) PET scans.

Researchers found that pretreatment SUV_max of the primary tumor was significantly associated with disease-specific survival and overall survival, and that pretreatment SUV_max for lymphodenopathy was significantly associated with distant metastasis.

These new results were presented at the 2010 Multidisciplinary Head and Neck Cancer Symposium, sponsored by the American Head and Neck Society, the American Society of Clinical Oncology, and the American Society for Radiation Oncology.

The findings of this study show that measuring SUV before treatment can help guide treatment selection, explained lead author Min Yao, MD, PhD, a radiation oncologist at University Hospitals Case Medical Center in Cleveland, Ohio.

"For higher SUV in either the primary tumor or lymph node, more aggressive treatment is needed," said Dr. Yao during a press briefing.

In their study, Dr. Yao and colleagues sought to determine the prognostic significance of SUV_max measured with FDG PET that was obtained prior to treatment in patients with head and neck squamous cell carcinoma.

The retrospective study examined 295 patients who were treated with intensity-modulated radiation therapy (IMRT). Of this group, 177 had FDG PET before treatment and a record of SUV_max for their primary tumor (SUV_p) and/or lymphadenopathy (SUV_ln). Within the cohort, 125 patients received definitive IMRT (99 also received concurrent chemotherapy) and 52 received postoperative IMRT (10 with concurrent chemotherapy).

The primary tumor sites were oropharynx (n = 87), oral cavity (n = 32), larynx (n = 32), hypopharynx (n = 8), nasopharynx (n = 6), unknown primary (n = 8), and nasal cavity/sinus (n = 4).

The median follow-up for all patients was 22.6 months (range, 1.03 - 75.43 months); for living patients it was 29.1 months (range, 5.5 - 75.43 months).

Three-Year Survival Rates

Survival	3-year rates (%)
Overall	67.40
Local recurrence-free	95.00
Regional recurrence-free	95.00
Local-regional recurrence-free	92.60
Distant metastasis-free	78.80
Disease-specific	78.80
Disease-free survival	63.95

Strong Predictor of Outcomes

In multivariate analysis adjusted for factors such as age, sex, disease site, and stage of disease, SUV_p was significantly associated with disease-specific survival (P = .038) and overall survival (P = .042). It was also strongly associated with disease-free survival (P = .068). However, in univariate analysis, SUV_p was not associated with any measure of survival.

In univariate analysis, SUV_ln was only associated with distant metastasis-free survival (P = .026), and that association was significant. Upon multivariate analysis, that significant association with distant metastasis-free survival remained (P = .05).

When SUV_ln was less than 11.3, the 3-year distant metastasis-free survival was 82.1%. In contrast, when SUV_ln was higher than 11.3, distant metastasis-free survival was 63.4% (P = .018).

"The important point of this study is that by doing imaging before treatment, you not only gain the information about the cancer, you also learn how metabolically active it is," said Michael Graham, MD, PhD, who moderated the briefing.

"Then you can make decisions about how aggressively to treat it," said Dr. Graham, who is director of nuclear medicine at the University of Iowa in Iowa City.

2010 Multidisciplinary Head and Neck Cancer Symposium (MHNCS): Abstract 11. Presented February 26, 2010.