Chen, Heidi

Abstract Background: Fluoro-deoxyglucose positron emission tomography (FDG-PET) scans are used for diagnosis and staging of known or suspected non-small cell lung cancer (NSCLC). Single institution studies examining the impact of avidity on survival have reported mixed results. The purpose of this study is to evaluate the association between FDG-PET avidity and survival in the national prospective ACOSOG Z4031 trial in patients with pathological Stage I NSCLC. Methods: Between 2004 and 2006, 1074 patients with known or suspected clinical stage I (cT1-2N0M0) NSCLC were enrolled in the ACOSOG Z4031 trial and underwent surgical resection. FDG-PET results were abstracted from radiology interpretations included in the case report forms. FDG-PET avidity was categorized based on either radiologist description or reported maximum standard uptake value (SUV). The four categories were: 1) not avid and not cancerous (SUV=0), 2) low avidity and likely not cancerous (SUV>0 and <2.5), 3) avid and probably cancerous (SUV≥2.5 and <5) and 4) highly avid and likely cancerous (SUV≥5). The lesion was classified as avid if in categories 3 or 4. The final diagnosis was determined by pathological examination and all cause mortality was reported. Cox proportional hazard regression was used to assess the impact of FDG-PET avidity on survival. The covariates used in the model included pStage, gender, age, race, and preoperative lesion size. Kaplan-Meier survival curves were calculated and the log-rank test was used to determine differences in survival based on FDG-PET avidity. Results: There were 51 enrolling sites in 39 cities with 969 eligible participants. Preoperative FDG-PET results were available for 540 participants with NSCLC and 81% had FDG-PET avid or highly avid lesions. 400 patients had pStage I NSCLC and the 5 year survival was 70% with 95%CI (65%, 75%). FDG-PET avidity, male gender, age, and lesion size negatively impacted survival. FDG-PET avidity in pStage I disease still negatively impacted survival (p=0.03) when controlling for lesion size. The 5 year survival for Stage I disease was 80% with 95%CI (68%, 88%) in FDG-PET negative patients and 67% with 95% CI (61%, 72%) in FDG-PET positive patients (p=0.02). Conclusions: In a national surgical population with pathological stage I NSCLC, FDG-PET avidity negatively impacted five year survival, independently of lesion size. Further work should be done to determine if chemotherapy would be beneficial in patients with PET avid lesions and pStage I NSCLC. Citation Format: Eric L. Grogan, Stephen A. Deppen, Heidi Chen, Karla V. Ballman, Francys C. Verdial, Melinda C. Aldrich, Paul A. Decker, David H. Harpole, Robert J. Cerfolio, Robert J. Keenan, David R. Jones, Thomas A. D'Amico, Joseph B. Shrager, Bryan F. Meyers, Joe B. Putnam. FDG-PET avidity negatively impacts survival in pStage I NSCLC in the ACOSOG Z4031 trial. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-296. doi:10.1158/1538-7445.AM2013-LB-296

Purpose Indications for sentinel lymph node biopsy (SLNB) for thin melanoma are continually evolving. We present a large multi-institutional study to determine factors predictive of sentinel lymph node (SLN) metastasis in thin melanoma. Patients and Methods Retrospective review of the Sentinel Lymph Node Working Group database from 1994 to 2012 identified 1,250 patients who had an SLNB and thin melanomas (≤ 1 mm). Clinicopathologic characteristics were correlated with SLN status and outcome. Results SLN metastases were detected in 65 (5.2%) of 1,250 patients. On univariable analysis, rates of Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, ulceration, and absence of regression differed significantly between positive and negative SLN groups (all P < .05). These four variables and mitotic rate were used in multivariable analysis, which demonstrated that Breslow thickness ≥ 0.75 mm (P = .03), Clark level ≥ IV (P = .05), and ulceration (P = .01) significantly predicted SLN metastasis with 6.3%, 7.0%, and 11.6% of the patients with these respective characteristics having SLN disease. Melanomas < 0.75 mm had positive SLN rates of < 5% regardless of Clark level and ulceration status. Median follow-up was 2.6 years. Melanoma-specific survival was significantly worse for patients with positive versus negative SLNs (P = .001). Conclusion Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, and ulceration significantly predict SLN disease in thin melanoma. Most SLN metastases (86.2%) occur in melanomas ≥ 0.75 mm, with 6.3% of these patients having SLN disease, whereas in melanomas < 0.75 mm, SLN metastasis rates are < 5%. By using a 5% metastasis risk threshold, SLNB is indicated for melanomas ≥ 0.75 mm, but further study is needed to define indications for SLNB in melanomas < 0.75 mm.