Precise modeling of anatomical structures is key to surgical planning for cancer patients. Because the respiratory function is vital to the survival of all tissues in the human body, surgical strategy takes on even greater significance for lung cancer cases. SPECT/CT imaging can be the answer referring physicians seek for pre-operative assessment and prediction of postoperative lung function.
In 1963, the use of tobacco in the United States averaged more than half a pack per day for every adult.1 Release of the landmark Smoking and Health: Report of the Advisory Committee to the Surgeon General of the Public Health Service from Luther L. Terry, M.D., Surgeon General of the U.S. Public Health Service in 1964, left little doubt of the link to lung cancer as well as other serious health issues. While more than 7,000 articles on the topic have since been released and per capita consumption has declined significantly, lung cancer remains widespread. According to the Centers for Disease Control and Prevention (CDC), "more than 45 million American adults still smoke, more than 8 million are living with a serious illness caused by smoking, and about 438,000 Americans die prematurely each year as a result of tobacco use."2
While research indicates that smoking can impact the likelihood of lung cancer, only 20% are active smokers at the time of diagnosis. Over 60% are former smokers, and approximately 15% have smoked less than 100 cigarettes in their lifetime, or considered "never smokers."3
Further supporting the prevalence of the disease, the American Cancer Society4 cites these estimates for 2019:
- 228,150 new cases of lung cancer (51% men, 49% women)
- 142,670 deaths from lung cancer (54% men, 46% women)
Resective thoracosurgical treatment is often indicated for Stage I and II lung cancers. However, one of the challenges of removing a portion of lung tissue is determining if the patient will be left with sufficient lung capacity for recovery as well as the ongoing quality of life. A KCU Sarajevo study published in 2014 indicated a reduction in forced expiratory volume (FEV), a primary measure of lung function, by up to 44% following such a procedure.5 When greater reduction than that is predicted, an alternative treatment method may be more appropriate than surgery.
Moving beyond SPECT
While a chest X-ray shows what lung structures look like6, aiding in the identification of abnormalities, a single-photon emission computerized tomography (SPECT) scan shows how lungs work – both ventilation and perfusion.7 Presently in this country, SPECT is commonly used to diagnose or monitor disorders of the brain, heart, and bones8. The U.S. lags behind other developed nations in the adoption of SPECT with CT imaging. By expanding to a SPECT/CT platform, a medical facility can provide an enhanced capability for the referring physician in planning lung cancer treatment.9
Quantitative SPECT/CT meticulously models lung anatomy, as well as function – with an additional preoperative planning layer4. The procedure calculates existing lung function; both global (meaning function of the entire lungs), as well as regional (referring to the contribution of each lobe). In this way, it helps the oncologist estimate a variety of "what if" scenarios. If a specific area of the lung was surgically removed, what would the impact be on the patient's post-surgical lung function? By ordering studies that allow the evaluation of post-operative quality of life scenarios, the clinician is better prepared to make decisions about the location and extent of the lung to be removed, or contemplation of alternative therapies.9
Considerations for the clinician
A decade-old study published in the Journal of Thoracic Oncology5 emphasized the physician's critical need for such technology. While that research focused on the value of lung perfusion imaging to predict complications following chemoradiation or radiation therapy for lung cancer patients, the advantages of the then-emerging SPECT/CT imaging capability were obvious and similar to surgical concerns.
In the 2008 study, the authors concluded, "LPS (lung perfusions score) was superior to previous attempts at using lung scintigraphy to predict post-therapy pulmonary function in patients with lung cancer in that it accounted for both localized perfusion defects and the remaining global lung perfusion."5
SPECT/CT has continued to evolve, now with a combination of anatomical and functional images, plus segmentation tools, which aid in quantifying individual lobe function relative to overall ventilation and perfusion. SPECT/CT increases the physician's confidence in accurately selecting patients who will benefit from lobectomy, bilobectomy, or pneumonectomy.9,10
Viability for medical facilities
The introduction of SPECT technology by Kuhl and Edwards in 1963 brought the concept to nuclear medicine and imaging, and subsequently to many medical centers.11 Investment in a SPECT system is undeniably substantial. The combination of SPECT and CT presents remarkable potential for increased referral and number of studies, with a justifiable cost/performance ratio.
An upgrade to the dual-modality imaging technique facilitates clinical utility with established applications, such a lung cancer treatment planning. It provides disease localization (sensitivity) and exclusion of false positives (specificity) superior to SPECT alone, for future potential in oncology studies.
Availability and value of SPECT/CT equates to:
- Increased exams due to physician preference
- Growth in procedure volume
- Increase in resulting surgical services
- Positive impact on patient care
According to the World Health Organization's September 2018 press release, "lung cancer is the most commonly diagnosed cancer in men (14.5% of the total cases in men and 8.4% in women) and the leading cause of cancer death in men (22.0%; i.e., about one in five of all cancer deaths)."12 Imagine the satisfaction in knowing that your organization's diagnostic capabilities will help to reduce those numbers in the coming years.