There is absolutely no doubt that long-term follow-up with computed tomography (CT) should be the standard of care for survivors of early-stage non-small cell lung cancer (NSCLC). In the following argument, I will present the logical reasoning, overwhelming evidence and solid consensus guidelines that mandate CT surveillance as the highest standard of care that we can offer to our patients.
The risk of survivors
Survivors of early-stage NSCLC are among the highest-risk patients for developing another lung cancer; either a new metachronous primary tumor (1-2% per-year risk) or recurrent disease (10-38% overall risk) (1). It has been consistently demonstrated that, although the risk of recurrent lung cancer decreases with time, the risk of a new metachronous primary cancer continues to increase to as high as 6% person-years (2). When compared to the high-risk population of smokers in the National Lung Cancer Screening Trial (NLST), who had a cumulative lung cancer risk of 0.6% person-years, survivors of NSCLC have 10 times that risk (3). Based on this fact alone, it is logical to extrapolate that survivors of lung cancer will derive a much higher benefit from CT surveillance than the 20% relative reduction in mortality that was reported in the NLST (3).
Overwhelming evidence for early detection and survival
The high-quality evidence supporting CT surveillance after curative treatment for NSCLC is very hard to refute. A recent study evaluating low dose CT surveillance after NSCLC resection found that 8.1% of patients will be diagnosed with a second lung cancer at a median follow-up of 4.3 years. In 87% of those patients, CT was able to detect the cancer at Stage I, and those patients were offered a second round of curative treatment with an overall 5-year survival of 69% (4). Another prospective study, comparing surveillance with minimal dose CT to surveillance with chest X-ray after curative resection of early-stage NSCLC, demonstrated that CT is more sensitive (94% vs. 21%; P<0.0001) and has a higher negative predictive value (99% vs. 96%; P=0.007) than chest X-ray for the diagnosis of new or recurrent cancer (5). In that study, the prevalence of new or recurrent disease was 23.2%, and the majority of patients (78%) had asymptomatic Stage I cancer that was only detected on CT. These patients were treated for a second round with curative intent and had a median survival of 69 months. A multitude of other series in NSCLC survivors have consistently reproduced this data, confirming the excellent sensitivity of CT in the early detection of asymptomatic new NSCLC, the potential for offering curative treatment for a second time, and the positive effect on prolonged survival (6-8). A recent meta-analysis of pooled data from 1,669 patients who underwent resection of NSCLC has demonstrated that CT surveillance is associated with a statistically significant improvement in survival when disease is detected at the asymptomatic stage (9).
Adherence to guidelines
Clinicians who treat NSCLC in an evidence-based manner are guided by a combination of clinical judgment, multidisciplinary tumor board discussions, and recommendations from practice guidelines. Agencies advocating for surveillance after resection of early-stage NSCLC include the National Cancer Centre Network (NCCN) (10), American Association for Thoracic Surgery (AATS) (11), American College of Radiology (ACR) (12), American College of Chest Physicians (6), American Society of Clinical Oncology (13), and the European Society of Medical Oncology (14). Although these recommendations differ on the imaging modalities and intervals for surveillance, the most widely followed guidelines of the NCCN, AATS, and ACR mandate for the use of CT in surveillance. Intensive surveillance with CT every 6 months is recommended for the first 2-4 years after resection of early-stage NSCLC, when the chance of cancer recurrence is highest. Beyond 5 years after treatment, most guidelines recommend yearly low dose CT screening to detect new metachronous primary lung cancer.
There should be no doubt in anybody’s mind that CT surveillance is the standard of care for patients who are curatively treated for early-stage NSCLC. These are the patients at highest risk for developing another lung cancer in the future, and there is high-quality evidence and unequivocal guidelines to support their surveillance.
Conflicts of Interest: The author has no conflicts of interest to declare.
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- Lou F, Huang J, Sima CS, et al. Patterns of recurrence and second primary lung cancer in early-stage lung cancer survivors followed with routine computed tomography surveillance. J Thorac Cardiovasc Surg 2013;145:75-81; discussion 81-2. [PubMed]
- National Lung Screening Trial Research Team, Aberle DR, Adams AM, et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med 2011;365:395-409. [PubMed]
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- National Comprehensive Cancer Network. NCCN Clinical practice guidelines in oncology (NCCN Guidelines®): non-small cell lung cancer, version 2.2013. Available online: http://www.respiratory-thessaly.gr/assets/nscl%202.%202013.pdf, accessed on Jul 16, 2014.
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