Chest CT shows value during follow-up for head and neck cancer patients

Multislice CT chest studies should be routinely performed, especially during follow-up exams, for some head and neck cancer patients, according to a recent study from Taiwan in the Archives of Otolaryngology -- Head and Neck Surgery.

Chest CT is recommended for newly diagnosed head and neck cancer patients at high risk for developing a malignant neoplasm of the lung during follow-up, according to Dr. Yen-Bin Hsu of the otolaryngology department at Taipei Veterans General Hospital and colleagues.

The researchers retrospectively examined 270 chest CT scans for 192 patients with biopsy-proven head and neck sqaumous cell carcinoma during a 42-month period. Patients with primary tumors originating in the nose, paranasal sinuses, or nasopharynx and patients with carcinomas having an unknown primary site were excluded (Arch Otolaryngol Head Neck Surg 2008;134[10]:1050-1054).

Routine yearly chest radiography has been shown to contribute little to the overall survival in patients with HNSCC (Acta Otolaryngol 2002;122[7]:765-778). Chest CT is superior to radiography in sensitivity and adds little extra time and radiation dose, but it is more expensive. Hsu and colleagues set out to determine the cost-effectiveness of routine screening by chest CT.

They found 79 scans were considered abnormal, with 54 showing a malignant neoplasm of the lung and 25 showing indeterminate lesions. The rate of abnormal scans was significantly higher in the follow-up case group (44.2%) than in the new case group (14.2%). Ten of 15 indeterminate scans (66.7%) with small (<1 cm) solitary pulmonary nodules showed disease progression on subsequent follow-up scans, which changed the patient's diagnoses to a malignant neoplasm of the lung.

Chest CT performed at initial diagnosis of tumors theoretically has the greatest effect on treatment planning, though Hsu and colleagues found a low rate of an abnormal chest CT scans. The follow-up revealed a greater number of abnormal scans, suggesting chest CT is more cost-effective in the follow-up period. The researchers also note follow-up CT scans should be mandatory to accommodate false positives, even on pregnant women.

"The additional risk from radiation exposure of chest CT [for pregnant women] is very low (1/10000)," Hsu said.

Further research is needed to confirm the finding.

Though PET/CT is potentially better than CT alone for treatment response monitoring, it is also more expensive and may not be widely available, Hsu said.

The study is important because it provides a data-driven, evidence-based assessment that chest CT is beneficial for HNSCC patients in finding both metastases and second primary tumors, according to Dr. David S. Mendelson, chief of clinical informatics and director of radiology information systems at Mount Sinai Medical Center.

This is a not a new discovery, however, said Dr. Cris Meyer, an associate professor of radiology at the University of Cincinnati.

Basically, the current study is in line with the published literature, he said.

The study has limitations: It is retrospective, there was selection bias in arranging chest CT, and some patients had a limited follow-up period.

For more information from the Diagnostic Imaging archives:

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