Rate of Distant Metastases on ¹⁸F-FDG PET/CT at Initial Staging of Breast Cancer: Comparison of Women Younger and Older Than 40 Years

Abstract

Women who have breast cancer and are younger than 40 y have a poorer outcome than older women. A higher rate of undetected metastases at the time of diagnosis in younger women has been proposed to account for this difference. Our main objective was to test this hypothesis by comparing the distant metastasis rate (DMR) on initial 18 F-FDG PET/CT in a group of breast cancer patients younger than 40 y (,40 y group) with that in a group of breast cancer patients older than 40 y ($40 y group). An assessment of associations between distant metastases and tumor characteristics was a second objective of the present study. Methods: A retrospective single-institution study was performed on women who had breast cancer and no prior malignancy, who were asymptomatic for metastatic lesions on initial clinical examination, and who had initial 18 F-FDG PET/CT within 3 mo after pathologic breast cancer diagnosis and before initial treatment. On the basis of these criteria, data for 2 groups of women differing only in age (,40 y and $40 y) were extracted from the hospital information system of Curie Institute-Paris. 18 F-FDG PET/CT examinations were reviewed, and the DMR was recorded for each clinical stage subgroup (stages I-III). Results: For each group (,40 y and $40 y), 107 patients were included, with the same number of patients in each clinical stage subgroup (12 stage I patients, 32 stage IIA patients, 30 stage IIB patients, and 33 stage III patients). The ages of the patients (mean 6 SD) were 34.5 6 4.0 y (,40 y group) and 56.0 6 10.7 y ($40 y group). No significant difference in DMRs was observed between the ,40 y group and the $40 y group (DMRs, 21% and 22%, respectively; P 5 1). The DMRs in patients not selected for age were 8% for stage I, 11% for stage IIA, 15% for stage IIB, and 44% for stage III. Conclusion: The DMR was not significantly higher in younger breast cancer patients (,40 y) than in older breast cancer patients ($40 y), ruling out the assumption that undetected metastases at diagnosis explain the poorer outcome of younger women. However, our results highlight the high yield of 18 F-FDG PET/CT for initial breast cancer staging, even in stage II patients, whatever their age. Br east cancers affect women younger than 40 y at rates of 5%-7% (1). Women in this age category have lower breast cancer-specific survival than older women (2). In a large epidemiological study, Gnerlich et al. showed that specific mortality was higher in women younger than 40 y and diagnosed with stage I or II disease than in older women diagnosed with stage I or II disease (3).One possible hypothesis for this higher specific mortality is that initial staging could underestimate distant metastases in low stages more often in women younger than 40 y than in older women. In a recent study, Riedl et al. took advantage of the superiority of 18 F-FDG PET/CT over conventional imaging for the detection of breast cancer metastases (4-8) to examine this hypothesis; they reported relatively high distant metastasis rates (DMRs) in patients youn...

Overuse of Chest CT in Patients With Stage I and II Breast Cancer: An Opportunity to Increase Guidelines Compliance at an NCCN Member Institution

“…13 Other authors have published similar results. 26,27 The rate of pulmonary nodule detection in this study was 27.7%, which is higher than that reported in the radiation oncology literature, but consistent with other large-volume studies. 28,29 The high detection rate of incidental pulmonary nodules has led to recommendations for additional follow-up from the Fleischner Society and the American College of Chest Physicians.…”

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“…Age: Two studies reported the influence of age on DM rate[27,33]. In the first study, among 134 young patients (< 40-year-old), the DM rate was 5% and 10.9% for clinical stage I and stage II, respectively[27].…”

“…In the first study, among 134 young patients (< 40-year-old), the DM rate was 5% and 10.9% for clinical stage I and stage II, respectively[27]. In the second study, among 214 stage I-III patients, the DM rates did not differ significantly between the age groups of < 40-year-old and ≥ 40-year-old[33]. However, the DM rates in the younger age group were 8% in stage I, 9% in stage IIA and 17% in stage IIB, equating to 2x’s higher than those found in the first study.…”

“…Among 141 patients with moderate to poorly differentiated invasive breast cancers, the rate of DM was 30% for stage II patients[22]. However, correlation between tumor histologic grade and DM risk was not investigated in other studies[17-21,23,24,26-33]. …”

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