Using thallium-201 SPECT to detect recurrent or residual nasopharyngeal carcinoma after radiotherapy in patients with indeterminate CT findings

Surveillance tools for detection of recurrent nasopharyngeal carcinoma: An evidence-based review and recommendations

Objective

Nasopharyngeal carcinomas (NPC) are tumors arising from epithelium of the nasopharynx. The 5-year survival rate of primary NPC is 80% with significant risks of recurrence. The objective here is to provide an evidence-based systemic review of the diagnostic value of different modalities in detecting local, regional, and distal recurrent NPC, as well as the associated costs with these modalities.

Methods

MEDLINE, EMBASE, and the Cochrane review database were queried. Two hundred and twenty-three abstracts were generated using the inclusion criteria: patients >18 years of age; histopathological reference standard; and modalities pertaining to imaging or microbiology.

Results

Twenty-four manuscripts fulfilled the inclusion criteria and 5 surveillance tools identified: endoscopy, MR, FDG-PET, Tc-99m MIBI and ²⁰¹TI SPECT, and EBV DNA.

Conclusions

For local surveillance, endoscopy is the gold standard recommendation, with increased efficacy if Narrow Band Imaging or contact endoscopy are utilized. MRI and FDG-PET is also recommended to help with local to distal spread; however, Tc-99m MIBI and ²⁰¹TI SPECT are options as well. EBV DNA is recommended as a cheap and accessible adjunct surveillance tool if an available as an option.

Evaluation of Undifferentiated Carcinoma of Nasopharyngeal Type with Thallium-201 and Technetium-99m MIBI SPECT

OBJECTIVE: To determine the value of 201-thallium (201-Tl) and technetium-99m sestamibi (Tc-99m MIBI) single photon emission computed tomography (SPECT) for detecting primary undifferentiated carcinoma of nasopharyngeal type (UCNT), residual/recurrent tissue, and lymph node involvement.

STUDY DESIGN AND SETTING: SPECT of head and neck was prospectively performed in 46 patients with a history of UCNT (201-Tl in 24 patients, Tc-99m MIBI in 22). CT/MRI findings, clinical follow-up, and pathohistological verification served as a gold standard for calculating sensitivity, specificity, and accuracy of each scintigraphic technique. Tumor-to-background index (T/Bg) was derived when SPECT findings were positive.

RESULTS: Sensitivity of 201-Tl SPECT was 87 percent, with 78 percent specificity, 83 percent accuracy, and T/Bg of 4.05 ± 1.50. Tc-99m MIBI SPECT had 85 percent sensitivity, 78 percent specificity, 82 percent accuracy, and T/Bg of 4.45 ± 1.27.

CONCLUSION AND SIGNIFICANCE: 201-Tl SPECT and Tc-99m MIBI SPECT are useful for detecting primary UCNT, residual/recurrent disease, and lymph node involvement. This use is particularly valuable after chemoradiotherapy when CT/MRI may be ambiguous.

Comparison of201Tl-chloride SPECT with99mTc-MIBI SPECT in the depiction of malignant head and neck tumors

OBJECTIVE

Comparison of 201Tl chloride SPECT (TI-SPECT) with 99mTc-MIBI SPECT (MIBI-SPECT) in the depiction of malignant head and neck tumors was prospectively studied.

METHODS

Forty-one patients with various tumors of the head and neck were included in this prospective study. Histologically, 36 patients had squamous cell carcinomas, 3 undifferentiated carcinomas, 1 transitional cell carcinoma, and 1 MALT lymphoma. All patients underwent a simultaneous dual-isotope SPECT of the head and neck with 201Tl and 99mTc-MIBI. Dual-isotope SPECT for early (n=41) and delayed acquisition (n=21) was performed. Qualitatively, 3 observers evaluated both TI-SPECT and MIBI-SPECT individually. The interpretation criteria were graded as grade 1 (no abnormal increased uptake) to 5 (definitely increased uptake of a degree equal to or greater than that of normal salivary gland). Statistical analysis of the comparison of Tl-SPECT and MIBI-SPECT was performed. The interobserver difference was evaluated using the kappa-coefficient. Quantitatively, T/N ratio (the ratio of the counts in the tumor divided by that in the normal nuchal muscles) and retention index were compared between TI-SPECT and MIBI-SPECT.

RESULTS

On both the early and delayed images, the grades of uptake of the tumor in TI-SPECT were significantly higher than those in MIBI-SPECT by three observers. The grade of Tl-uptake of the tumor on the delayed images was 5 for all observers (kappa-coefficient=1); however, the kappa-coefficient varied from 0.39 to 0.84 in early T1-SPECT, and in early and delayed MIBI-SPECT. Statistical differences in T/N ratio were noted between early TI-SPECT (2.87 +/- 1.19) and MIBI-SPECT (2.48 +/- 1.06), and between delayed Tl-SPECT (2.11 +/- 0.70) and MIBI-SPECT (1.20 +/- 0.48). The retention index or Tl-SPECT (0.81 +/- 0.24) was significantly higher than that of MIBI-SPECT (0.52 +/- 0.15).

CONCLUSIONS

The present study qualitatively and quantitatively showed that 201Tl had higher accumulation in the tumor than 99mTc-MIBI in both early and delayed images.