Survival for Advanced Head, Neck Cancer Improvements May Be Related to PET

Clinical Question

Does positron emission tomography (PET) impact staging and survival in head and neck cancer?

Background: PET imaging has been widely adopted because of the increased sensitivity of PET in detecting occult nodal and distant metastases. It has been suggested that PET may lead to improvements in stage-specific survival by upstaging patients through detection of occult disease.

Study design: Retrospective chart review of adult patients diagnosed from 2008-2010 with head and neck carcinoma of the nasopharynx, oropharynx, oral cavity, larynx, hypopharynx, salivary gland, and sinus for whom stage was known. PET was not used at these institutions prior to 2005. Multivariate and survival analysis of PET use were confined to the years between 2005 and 2008.

Setting: Four large nonprofit integrated health systems (Seattle, Detroit, Denver, and Portland, Ore.).

Synopsis: There were 958 patients who met study criteria, with 436 patients in the PET era group, of which 33% underwent PET. The majority of patients had oral cavity disease (45%). There was no difference in primary site, age, sex, or comorbidity between the groups treated in the time range of 2000-2004 and those treated in 2005-2008, but advanced stage disease was more common (48%) in the 2005-2008 time period compared with 2000-2004 (38%). Tobacco use and HPV status were not known. In the charts from the 2005-2008 period, patients with oropharyngeal cancer were significantly more likely to undergo PET (29%) than not (8%). PET use was associated with significantly higher stage of disease, with a greater proportion of patients staged III or IV (63%) compared with the patients who did not undergo PET (35%). Distant metastatic disease was more common when PET was used (5.6%) than not (2.7%). On multivariate analysis, male patients and patients with oropharyngeal cancer, nasopharyngeal cancer, and sinus cancer were more likely to have stage III or IV disease. Two-year survival for all patients did not significantly differ by PET status (56% vs 53%). A significant increase in two-year stage-specific survival was found for stage III and IV disease when PET was used (52%) than when it was not (32%); however, multivariate analysis showed no association between the use of PET and survival in patients with stage III or IV disease.

Bottom line: These data suggest that improvements in survival for advanced stage disease in recent years may be due to radiologic upstaging with PET; however, major limitations to this study are the positive association between oropharyngeal cancer and advanced stage and the absence of HPV status, which may account for the improved survival seen in advanced stage disease.