Staging of primary malignancies of bone

Tumor necrosis in osteosarcoma: inclusion of the point of greatest metabolic activity from F-18 FDG PET/CT in the histopathologic analysis

OBJECTIVE

To determine if the location of the point of maximum standardized uptake value (SUVmax) being included in or not included in the histopathologic slab section corresponded to tumor necrosis or survival.

MATERIALS AND METHODS

Twenty-nine osteosarcoma patients underwent post-chemotherapy [fluorine-18]-fluoro-2-deoxy-D: -glucose (FDG) positron-emission tomography-computed tomography (PET/CT) prior to resection. PET/CT images were correlated with slab-section location as determined by photographs or knowledge of specimen processing. The location of the point of SUVmax was then assigned as being 'in' or 'out' of the slab section. Cox's proportional hazard regression was used to evaluate relationships between the location and value of SUVmax and survival. Logistic regression was employed to evaluate tumor necrosis.

RESULTS

No correlation was found between the SUVmax location and survival or tumor necrosis. High SUVmax correlated to poor survival.

CONCLUSION

High SUVmax value correlated to poor survival. Minimal viable tumor (> 10%) following chemotherapy is a known indicator of poor survival. No correlation was found between the location of SUVmax and survival or tumor necrosis. Therefore, the SUVmax value either does not correspond to a sufficient number of tumor cells to influence tumor necrosis measurement or it was included in the out-of-slab samples that were directed to viable-appearing areas of the gross specimen. Since high SUVmax has been previously found to correspond to poor tumor necrosis, and tumor necrosis is simply an estimate of the amount of viable tumor, SUVmax likely represents many viable tumor cells. Therefore, when not in the slab section, SUVmax was likely included in the tumor necrosis measurement through directed sampling, validating our current method of osteosarcoma specimen analysis.

Her-2/neu, p-53, and their coexpression in osteosarcoma

BACKGROUND

There is controversy regarding the patterns and prognostic significance of Her-2/neu and p-53 expression in osteosarcoma. Further, their combined expression has not been studied.

PROCEDURE

Prechemotherapy biopsy specimens of 63 osteosarcoma patients from June 2004 to August 2006 were analyzed for Her-2/neu and p-53 using immunohistochemistry and compared with grade, stage, and morphologic subtype of tumor.

RESULTS

There were 59 high-grade tumors; 32 of 63 had metastases. Histopathologic types included 36 of 63 osteoblastic and 18 of 63 chondroblastic subtypes. Male sex (P=0.045) and chondroblastic type (P=0.004) were associated with metastatic disease. Her-2/neu cytoplasmic staining was seen in 30 of 63 (47.1%) cases, 4 of 30 had additional membranous staining, 17 of 30 were metastatic, and 29 of 30 were high-grade tumors. Staining grade was 3+ in 10 of 30 samples whereas staining intensity 3+ was observed in 26 of 30 samples. Her-2/neu 3+ staining grade was significantly associated with chondroblastic subtype (6/18, P=0.026). P-53 staining was seen in 20 of 63 (31.74%) cases (all high grade), of which 11 were metastatic. Staining grades 3+ and 4+ were seen in 16 of 20 samples whereas staining intensity 3+ in 13 of 20 samples. P-53 expression was higher in chondroblastic (7/18, P value was not significant) and fibroblastic (3/3, P<0.05) subtypes. Coexpression of Her-2/neu and p-53 was seen in 10 cases (15.87%); 3 of 10 cases showed Her-2/neu membranous staining (P=0.01).

CONCLUSIONS

Her-2/neu (47.1%), p-53 (31.74%), and their combined expression (15.87%) were not related to grade or stage of tumor. Chondroblastic subtype was associated with staining grade 3+ of Her-2/neu staining whereas coexpression of Her-2/neu and p-53 was significantly associated with membranous Her-2/neu staining.

18F-FDG PET/CT as an indicator of progression-free and overall survival in osteosarcoma

The aim of our study was to retrospectively evaluate whether maximum standardized uptake value (SUV(max)), total lesion glycolysis (TLG), or change therein using (18)F-FDG PET/CT performed before and after initial chemotherapy were indicators of patient outcome.

METHODS

Thirty-one consecutive patients who underwent (18)F-FDG PET/CT before and after chemotherapy, followed by tumor resection, were retrospectively reviewed. Univariate Cox regression was used to analyze for relationships between covariates of interest (SUV(max) before and after chemotherapy, change in SUV(max), TLG before and after chemotherapy, change in TLG, and tumor necrosis) and progression-free and overall survival. Logistic regression was used to evaluate tumor necrosis.

RESULTS

High SUV(max) before and after chemotherapy (P = 0.008 and P = 0.009, respectively) was associated with worse progression-free survival. The cut point for SUV(max) before chemotherapy was greater than 15 g/mL* (P = 0.015), and after chemotherapy it was greater than 5 g/mL* (P = 0.006), as measured at our institution and using lean body mass. Increase in TLG after chemotherapy was associated with worse progression-free survival (P = 0.016). High SUV(max) after chemotherapy was associated with poor overall survival (P = 0.035). The cut point was above the median of 3.3 g/mL* (P = 0.043). High TLG before chemotherapy was associated with poor overall survival (P = 0.021). Good overall and progression-free survival was associated with a tumor necrosis greater than 90% (P = 0.018 and 0.08, respectively). A tumor necrosis greater than 90% was most strongly associated with a decrease in SUV(max) (P = 0.015).

CONCLUSION

(18)F-FDG PET/CT can be used as a prognostic indicator for progression-free survival, overall survival, and tumor necrosis in osteosarcoma.