Abstract 3016
Background
Although dedicated breast PET (DbPET) visualizes sub-centimeter breast cancer lesions and intratumoral heterogeneity, the impact of histology on the detectability of DbPET remains unknown.
Methods
This study included 455 patients with breast cancer, who underwent whole-body PET (WBPET) and ring-type DbPET between January 2016 and March 2018. The relationship of histology and sensitivities of WBPET and DbPET for breast cancer was assessed.
Results
The median patient age was 57 years and histology was as follows: 82 (18.0%) noninvasive carcinoma, 18 (4.0%) microinvasive carcinoma, 305 (67.0%) invasive carcinoma with no special type, 9 (2.0%) invasive lobular carcinoma, and 41 (9.0%) other types. The sensitivity of WBPET and DbPET was 74.5% and 93.2%, respectively. The sensitivities of each histology on WBPET/DbPET were 41.5%/78.0%, 72.2%/100%, 83.9%/96.7%, 44.4%/88.9%, and 78.0%/95.1%, respectively (Table). The sensitivity was low on WBPET in noninvasive, microinvasive, invasive lobular, mucinous and tubular carcinomas. Lobular carcinoma in situ had low sensitivity on both WBPET and DbPET imaging. In the multivariate analysis, undetectable tumor factors on WBPET were sub-centimeter tumor size (Odds ratio [OR] = 6.04, P < 0.001) and histology (OR = 1.69, P = 0.08); for DbPET, Ki-67 labeling index was an undetectable tumor factor (OR = 4.32, P = 0.039).Table: 1343P
Sensitivities of whole-body and dedicated breast PET according to histology
| N | Sensitivity (%) | P | ||
|---|---|---|---|---|
| WbPET | DbPET | |||
| Total | 455 | 339 (74.5) | 424 (93.2) | < 0.001 |
| Noninvasive carcinoma | 82 | 34 (41.5) | 64 (78.0) | < 0.001 |
| Ductal carcinoma in situ | 72 | 32 (44.4) | 61 (84.7) | < 0.001 |
| Lobular carcinoma in situ | 8 | 1 (12.5) | 2 (25.0) | 1 |
| Others | 2 | 1 (50.0) | 1 (50.0) | 1 |
| Microinvasive carcinoma | 18 | 13 (72.2) | 18 (100) | 0.046 |
| Invasive carcinoma of no special type | 305 | 256 (83.9) | 295 (96.7) | < 0.001 |
| Invasive lobular carcinoma | 9 | 4 (44.4) | 8 (88.9) | 0.131 |
| Others | 41 | 32 (78.0) | 39 (95.1) | 0.048 |
| Mucinous carcinoma | 19 | 13 (68.4) | 18 (94.7) | 0.09 |
| Tubular carcinoma | 5 | 3 (60.0) | 4 (80.0) | 0.444 |
| Carcinoma with apocrine differentiation | 5 | 5 (100) | 5 (100) | 1 |
| Invasive micropapillary carcinoma | 5 | 5 (100) | 5 (100) | 1 |
| Others | 7 | 6 (85.7) | 7 (100) | 1 |
Conclusions
Breast cancers with the specific histological subtypes are hard to detect on WBPET. DbPET can overcome the factors for weak WBPET detectability, such as tumor size and histology, and might prevent the overdiagnosis of lobular carcinoma in situ.
Clinical trial identification
Legal entity responsible for the study
Hiroshima University.
Funding
Has not received any funding.
Editorial Acknowledgement
Disclosure
All authors have declared no conflicts of interest.
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