ASCO has released a new guideline providing recommendations to practicing clinicians on radiographic imaging and biomarker surveillance strategies after definitive, curative-intent therapy in patients with stage I to III non–small cell lung cancer or small cell lung cancer. These guideline recommendations were published in the Journal of Clinical Oncology.1
Bryan J. Schneider, MD
Nasser Altorki, MBBCh
“This is a controversial topic without a lot of high-level data to guide our practicing clinicians,” said guideline co-chair Bryan J. Schneider, MD, of the University of Michigan. “As we have more and more patients [who] undergo potentially curative therapy, it is difficult to map out how best to follow these patients, and we see a lot of varying approaches in practice.”
To fully inform clinicians, the guideline was authored by an expert panel that included representatives from medical oncology, thoracic surgery, radiation oncology, pulmonology, radiology, primary care, and advocacy experts.
It is important to note that the guideline addresses imaging related only to routine surveillance, an area that has seen an explosion of modalities in recent years, according to guideline co-chair Nasser Altorki, MBBCh, of Weill Cornell Medicine. “This technology has sprinted forward at an incredible speed,” he added. “We now have CT [computed tomography] scans at varying doses, PET [positron-emission tomography]/CT, fusion PET/CT, and a lot of other modalities that people can use, with no clear consensus on what is best.”
The expert panel conducted a literature search and identified 14 relevant studies to inform the recommendations. Areas lacking in evidence were informed by consensus expert opinion of the panel.
Surveillance Imaging: Frequency and Type
The guideline recommends a surveillance frequency of every 6 months for the first 2 years to screen for recurrence. “Frequency is very important, and the use of diagnostic CT scans every 6 months for the first 2 years is a reasonable middle-of-the-road position, where recurrence rates are particularly high,” Dr. Altorki said.
During this surveillance period, chest CT is considered the optimal imaging modality. These scans should include the adrenals, with (preferred) or without contrast. There is currently no evidence of an added benefit from imaging the abdomen and pelvis. FDG-PET/CT should not be used.
“During this period, we are looking for local recurrence that may have curative treatment options,” Dr. Schneider said. “We do not have good data to support that the identification of asymptomatic metastatic disease leads to a clear improvement in treatment outcomes. That is why we are not in favor of routine PET/CT imaging.”
PET/CT scans come at a greater cost to the patient and health-care system, expose the patient to higher radiation, and result in a lot of false-positive results, Dr. Altorki added. “We see patients getting surveillance PET scans presumably because it is touted as a superior imaging modality for cancer over CT alone,” Dr. Schneider said. “By doing this, they could potentially miss smaller nodules that may be curative if found on CT.”
Any patient who is not clinically suitable for or willing to accept additional treatment should not be offered surveillance imaging. However, age should not preclude surveillance imaging. In addition, circulating biomarkers should not be used as a surveillance strategy.
After the initial 2-year period, surveillance imaging with low-dose chest CT should occur once a year to screen for new primary lung cancers. “Although patients can certainly develop recurrent disease after the 2-year mark, chances are dramatically diminished, and often times there is a higher risk of developing a new primary that would potentially be amenable to curative therapy,” Dr. Schneider said.
Brain MRI
Finally, the guideline specified that, for stage I to III non–small cell lung cancer, brain magnetic resonance imaging (MRI) should not be used in routine surveillance for recurrence in patients who have undergone curative-intent treatment. However, in patients with stage I to III small cell lung cancer, brain MRI should be offered every 3 months for the first year and every 6 months for the second year of surveillance, if patients have not received prophylactic cranial irradiation; patients who have undergone irradiation may be offered the same schedule.
“We hope these guidelines will give clinicians assurance that it is reasonable to surveil patients at 6-month intervals with CT and not go down the rabbit hole of ordering scans every couple of months or every time a patient calls requesting another scan,” Dr. Schneider said. “Often times, the best reassurance for a patient is being seen in the office, where the clinician can perform a good physical examination and history and then decide if imaging may help the workup of new or progressive symptoms.”
Dr. Altorki also mentioned the lack of evidence in the literature on surveillance imaging after treatment with curative intent. “We definitely need more effective level-1 research studies that could guide surveillance of these patients,” Dr. Altorki said.
DISCLOSURE: For full disclosures of all study authors, visit ascopubs.org.
REFERENCE
1. Schneider BJ, Ismaila N, Aerts J, et al: Lung cancer surveillance after definitive curative-intent therapy: ASCO guideline. J Clin Oncol. December 12, 2019 (early release online).
Originally published in ASCO Daily News. © American Society of Clinical Oncology. ASCO Daily News, December 18, 2019. All rights reserved.
