CT lung screening may have added value in cancer detection beyond the chest, say researchers from New York. CT screening could replace routine CT surveillance for detecting the recurrence of head and neck squamous cell carcinoma (HNSCC), according to findings published in the November issue of Oral Oncology.
The researchers examined hundreds of patients with HNSCC at Roswell Park Comprehensive Cancer Center in Buffalo who underwent radiation therapy or chemoradiation followed by a series of routine CT scans. They found no cases of recurrent cancer on the patients' head and neck CT scans, but they did discover more than 50% of all cases of salvageable recurrent cancer on chest CT scans of patients who were also eligible for lung cancer screening (Oral Oncol, November 2018, Vol. 86, pp. 273-277).
"Routine surveillance for HNSCC patients with lung CT imaging had value but head and neck CT scans failed to identify any successfully salvaged patients," senior author Dr. Anurag Singh and colleagues wrote. "Given this finding, routine CT imaging surveillance in HNSCC patients should be restricted to annual lung screening with low-dose chest CT."
Routine CT surveillance
The most common malignant cancer of the head and neck, HNSCC is often treatable with radiation therapy or chemoradiation if it's diagnosed in its early stages. Post-treatment care usually involves a follow-up imaging exam such as PET/CT to assess a patient's response to therapy and to confirm that there is no cancer recurrence -- ultimately removing the need for additional surgery.
However, recent research has shown that post-treatment detection of cancer recurrence with PET/CT does not improve patient survival any more than standard clinical detection without imaging, according to the authors. PET/CT was particularly limited in detecting recurrent cancers that could be managed with salvage surgery.
In light of such reports, the National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO) have stated in their guidelines that there is no benefit to routine surveillance imaging for most cancers including HNSCC.
But could post-treatment surveillance of HNSCC with conventional CT prove more effective?
Exploring the possible utility of CT for routine surveillance imaging, Singh and colleagues examined the medical records and imaging data of 534 patients with squamous cell carcinoma of the head and neck who underwent radiation therapy or chemoradiation between 2008 and 2017 at their institution.
The mean age of the patient cohort was 60.9 years, 81.5% were male, 80% were current or former smokers, and 49% met the NCCN eligibility criteria for CT lung cancer screening.
Approximately 83.5% of the patients responded to treatment, based on results from a PET/CT exam, and these patients subsequently underwent surveillance CT scanning every three months in the first year following treatment, every six months in the second year, and annually starting from the third year onward.
Chest or head and neck CT?
Among those who responded to initial treatment, 84 (15.7%) had cancer recurrence and needed to undergo additional salvage treatment. Only 15 of these patients survived surgery with no evidence of cancer.
The physicians failed to detect any of the successfully salvaged patients on the surveillance head and neck CT scans. In contrast, they retrospectively identified eight of the 15 patients who had successful salvage treatment on CT lung screening exams.
| Predicting HNSCC recurrence with head and neck CT vs. lung screening CT | ||
| Head and neck CT | Lung screening CT | |
| Detection rate of patients who survived salvage treatment | 0/15 | 8/15 |
Overall, 53.3% of patients with cancer recurrence who were eligible for lifesaving salvage treatment would have been found on a CT lung screening exam, highlighting the test's potential value in head and neck cancer survival.
"In successfully treated HNSCC patients we recommend follow-up with PET/CT at 13 weeks, CT neck/maxillofacial/chest at six months, and low-dose chest CT annually," the authors wrote. "Surveillance head and neck CT imaging is not recommended until better salvage treatment is available to treat locoregional recurrence."
CT lung screening for HNSCC
For the most part, the findings support the guidelines set forth by the NCCN and ASCO, which indicate that there is no benefit to routine CT surveillance imaging for nearly all cancer patients, the authors noted. Although it is not frequently discussed in the context of head and neck cancer surveillance, chest CT scanning for eligible smokers may be an exception to this rule.
The researchers acknowledged several limitations of the study, including the small number of patients with cancer recurrence evaluated and the low percentage of patients (roughly half) who met the National Lung Screening Trial (NLST) criteria for lung cancer screening eligibility.
Recently, new immunotherapy drugs have shown promising antitumor activity in recurrent and metastatic HNSCC, the authors wrote. "[These] future agents may eventually allow for more aggressive surveillance of HNSCC survivors to catch failures early and treat with immunotherapy. Until then, we recommend only annual low-dose screening CT for HNSCC survivors."
