Nuclear Imaging Offers Noninvasive Assessment of Early Stage Cervical Cancer
In patients with cervical cancer who do not have enlarged lymph nodes, SPECT-MRI imaging of their sentinel lymph nodes (SLNs) could assess whether metastases are present, according to a study published in the Journal of Nuclear Medicine.1
An estimated 18.6 women per 100 000 in the United States are affected by cervical cancer, the fourth most common cancer in women worldwide. Early diagnosis is critical. Although surgical resection and examination of the SLNs remains the most accurate way to assess metastasis, SPECT-MRI imaging may reduce false negative MRI findings in patients with early stage disease thereby potentially saving some of them from a need for invasive diagnostic procedures.
"An interesting aspect of this research, and the field in general, is that we are taking more and more steps toward combined technology to minimize invasive diagnostics in patients with cervical cancer," said Jacob P. Hoogendam, MD, of the University Medical Center Utrecht, Netherlands, and corresponding author in the study. "With these methods we aim to reduce morbidity via more tailored and informed selections between radical hysterectomy and chemo/radiation for each patient, instead of solely stage-based treatment selections."
Between March 2011 and February 2015, the research team evaluated 75 cases of stage IA1-IIB1 cervical cancer in patients who presented at the center. Patients with enlarged lymph nodes on MRI were excluded.
The remaining patients underwent an SLN mapping procedure with preoperative Tc-99m-nanocolloid SPECT-CT. In total, 136 SLNs were analyzed, and 13 SLNs (9.6%) were found to contain metastases.
"We need to be aware that a dichotomous lymph node cut-off on MRI, typically a 10 mm short axis diameter to determine whether it is suspicious or not, is relatively crude and certainly does not fit all patients," explained Hoogendam about evaluating patients with stage 1 or 2 cervical cancer. "Our study investigated whether a more individualized, imaging-based assessment is possible for the small metastases that are currently missed on imaging (ie, false negative on MRI)."
"The novelty of our study is the focused review of fewer than 5 sentinel nodes, instead of indiscriminately reviewing the entire pelvic lymphatic chain (up to 100 nodes per patient). Less is more."
Hoogendam also argued for an interdisciplinary approach to both clinical practice and research, stating, "This sentinel node focus requires a combination of preoperative nuclear medicine imaging (SPECT), radiology (MRI), and the gynecological oncology department (intraoperative sentinel node procedure). We should not be islands within a hospital; better interdisciplinary cooperation can synergistically lead to new insights, more relevant research questions, and better patient care."
1. Hoogendam JP, Zweemer RP, Hobbelink MG, et al. 99mTc-nanocolloid SPECT/MRI fusion for the selective assessment of nonenlarged sentinel lymph nodes in patients with early-stage cervical cancer. J Nucl Med. 2016;57(4):551-556.