Clinical guidelines can sometimes be slow to respond to epidemiology.
Take the case of oropharyngeal cancers that are associated with human papillomavirus (HPV) infection. They are increasingly common in the United States and, as several studies have demonstrated, have better survival than cancers of this type that are not HPV-positive.
Nonetheless, one of the beacons in oncology care, the National Comprehensive Cancer Network (NCCN), recommends the same follow-up care guidance for oropharynx squamous cell carcinoma whether it is associated with HPV or not, according to two experts.
For post-treatment follow-up, including recurrence detection, “the NCCN guidelines are one-size-fits-all,” said Jessica Frakes, MD, a radiation oncologist at the Moffitt Cancer Center and Research Institute in Tampa, Florida.
She spoke during a press briefing at the Multidisciplinary Head and Neck Cancer Symposium 2016 in Scottsdale, Arizona.
“You are exactly right: the NCCN is fairly vague about when to perform imaging,” said Christine Gourin, MD, an otolaryngologist at Johns Hopkins University in Baltimore, who moderated the press briefing.
Dr Frakes and her colleagues have stepped into this informational breach with a new study that might help clinicians gain clarity on the use of surveillance imaging in HPV-positive oropharyngeal cancer and reduce its frequency.
“The purpose of our study is to determine when these patients fail and when they have side effects so we know how to guide optimal follow-up,” Dr Frakes explained.
The study authors examined 246 cases of nonmetastatic HPV-positive oropharynx squamous cell carcinoma treated with radiation therapy at Moffitt from 2006 to 2014. Most patients (84.6%) received radiation therapy and a concurrent systemic therapy; a minority (15.4%) received radiation alone. Most patients had locally advanced disease.
The team’s major finding was that the great majority of recurrences and toxicities can be detected with imaging 3 months after treatment with definitive radiation therapy and physical exams during the 6 months after treatment.
Specifically, all six local failures were detected by sight or with flexible laryngoscopy conducted during physical exams in that 6-month period.
Eight of the nine regional recurrences (89%), 12 of the 13 locoregional failures (92%), and 15 of the 21 distant recurrences (71%) were detected from symptoms or with a PET/CT scan 3 months after treatment
“For most patients with HPV-associated oropharynx cancer, after a negative 3-month PET scan, physical exams with history and direct visualization are sufficient to find recurrences,” said Dr Frakes in a press statement.
The findings — and the suggestion that PET scans can be suspended after 3 months — are akin to what happens in clinical practice at Johns Hopkins, Dr Gourin reported.
“We have stopped routinely imaging patients after 3 months if a PET is negative, and it’s true that we do pick up more recurrences clinically than radiologically,” she said.
Cutting down on PET scans in this patient population is a good thing, suggested Dr Gourin. “I think we probably do too much post-treatment surveillance imaging,” she said.
There are multiple benefits to suspending imaging, including potentially lowering patient stress because they know their recurrence risk is low and don’t have anxiety related to test results.
Plus, there is a cost reduction.
“A PET scan costs $1500 [for the patient],” said Dr Frakes. Dr Gourin noted that the test is even more expensive in her geographic region.
Factors That Increase Recurrence Risk
The study authors also identified disease characteristics that increase the likelihood of recurrence.
Both regional and distant failures were more common in patients who presented with five or more positive lymph nodes or who had level IV lymph nodes (P < .05).
And the risk of developing distant metastases was greater in patients with a lymph node larger than 6 cm or with bilateral lymphadenopathy (P < .05).
But overall, the results are “excellent,” said Dr Frakes. Within 3 years, the rate of local control was 97.8%, of regional control was 95.3%, of locoregional control was 94.0%, and of freedom from distant metastases was 91.4%. The rate of 3-year overall survival was 91.0%.
Toxicities were also low, which is an endorsement of the multidisciplinary care, said Dr Frakes.
Only 9% of patients experienced severe late toxicities, including 19 grade 3 toxicities and two grade 4 toxicities. These were resolved in 16 of 21 toxicities (76%) at the time of last follow-up.
Most of the toxicities and/or recurrences (64%) occurred in the first 6 months after treatment; only four events occurred more than 2 years after treatment.
Dr Gourin questioned the low rate of serious late toxicities seen with this nonsurgical management of patients. Such a low rate “has not been our experience” at Johns Hopkins, she said.
Dr Frakes and Dr Gourin have disclosed no relevant financial relationships.
Multidisciplinary Head and Neck Cancer Symposium (MHNCS) 2016: Abstract 6. Presented February 19, 2016.
*This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.