High rates of tumor growth and disease progression detected on serial pretreatment fluorodeoxyglucose‐positron emission tomography/computed tomography scans in radical radiotherapy candidates with nonsmall cell lung cancer

Abstract

BACKGROUND:The authors studied growth and progression of untreated nonsmall cell lung cancer (NSCLC) by comparing diagnostic and radiotherapy (RT) planning fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) scans before proposed radical chemo-RT. METHODS: Patients enrolled on a prospective clinical trial were eligible for this analysis if they underwent 2 pretreatment whole body FDG-PET/CT scans, >7 days apart. Scan 1 was performed for diagnosis/disease staging and scan 2 for RT planning. Interscan comparisons included disease stage, metabolic characteristics, tumor doubling times, and change in treatment intent. RESULTS: Eighty-two patients underwent planning PET/CT scans between October 2004 and February 2007. Of these, 28 patients (61% stage III, 18% stage II) had undergone prior staging PET/CT scans. The median interscan period was 24 days (range, 8-176 days). Interscan disease progression (TNM stage) was detected in 11 (39%) patients. The probability of upstaging within 24 days was calculated to be 32% (95% confidence interval [CI], 18%-49%). Treatment intent changed from curative to palliative in 8 (29%) cases, in 7 because of PET. For 17 patients who underwent serial PET/CT scans under standardized conditions, there was a mean relative interscan increase of 19% in tumor maximum standardized uptake value (SUV) (P ¼ .022), 16% in average SUV (P ¼ .004), and 116% in percentage injected dose (P ¼ .002). Estimated doubling time of FDG avid tumor was 66 days (95% CI, 51-95 days). CONCLUSIONS: Rapid tumor progression was detected in patients with untreated, predominantly stage III, NSCLC on serial FDG-PET/CT imaging, highlighting the need for prompt diagnosis, staging, and initiation of therapy in patients who are candidates for potentially curative therapy. Cancer 2010;116:5030-7.

Effect of PET/CT on Management of Patients with Non–Small Cell Lung Cancer: Results of a Prospective Study with 5-Year Survival Data

“…By preventing futile and morbid attempts at cure, PET/CT can spare scarce and expensive surgical and RT resources, allowing patients to receive more appropriate palliative therapies or supportive care. By reducing the time to definitive diagnosis and staging, PET/CT may improve the chances of cure by reducing the likelihood of progression before therapy (17). It is encouraging that the patients who had the most expensive and potentially morbid therapy or surgery had the longest OS, whereas those with the worst outcome had the least aggressive treatment.…”

An assessment of cone beam CT in the adaptive radiotherapy planning process for non-small-cell lung cancer patients

“…24,25 Disease progression cannot be ruled out as a contributing factor when explaining the increase in volume from planning CT to Day 1 of treatment. In the UK, there is now a greater focus on working to 31-day targets where the patients' "ready-to-start" date to "start-of-treatment" should not exceed this time with the hope that the opportunity for progression is minimized.…”

18F-FDG PET as a Surrogate Biomarker in Non–Small Cell Lung Cancer Treated with Erlotinib: Newly Identified Lesions Are More Informative Than Standardized Uptake Value

“…Although the development of new lesions within 2 wk of starting therapy may seem to be an unlikely event, recent work demonstrates that rapid progression can occur in NSCLC (19). Hence, it is plausible that new lesions on 18 F-FDG PET reflect aggressive biology, with new metastasis or growth of small lesions overcoming partial-volume effects within the steep component of the count-recovery curve leading to a significant increase in standardized uptake value (SUV) (20).…”