All patients present with unclear masses both in the ambulant setting as well as in specialized musculoskeletal centers. After appropriate imaging and finding of a suspected diagnosis, a biopsy is often necessary for confirmation to plan the further procedure. Prompt referral for further diagnostics is particularly important if a malignant disease is the possible cause of the mass. Although many biopsy-techniques have been described, there is currently no standardized procedure.
For example, Errani et al. described the current concepts in the biopsy of musculoskeletal tumors, which primarily include fine needle aspiration, core needle biopsy, or incisional biopsy and came to the conclusion that there is still no clarity about the optimal biopsy acquisition (Errani, et al. 2013).
Due to the low risk of complications and the lower costs, they recommended CNB to be preferred, but if this remains without a result, an incisional biopsy should be performed (Errani, et al. 2013).
Once more, this shows the discordance about the validation of the different methods, especially CNB versus incisional biopsy. While some centers prefer CNB as the method of choice and publish good results in the available literature, primarily IB is used in our center with also very good results. The division of the histopathological findings into the individual tumor types makes it clear that IB shows the same sensitivity not only in soft tissue, but also in bone tissue, and has a high diagnostic confidence in solid tumors as well as in the malignancies of the hematopoietic system and metastases. From our point of view, what is important is the uncomplicated acquisition of a biopsy without a high risk of complications, the rapid availability, and the correct diagnosis. The purpose of this study was to investigate the accuracy of incisional biopsy in cases of existing suspicion of a malignant tumor of the musculoskeletal system. Especially in the case of malignant tumors, the most precise, timely and complication-free biopsy possible is of elementary importance for the correct diagnosis and appropriate planning of further therapy (Traina, et al. 2015).
Recently, Birgin et al. reported in a systematic review about diagnosing the correct soft-tissue-tumor-type. The conclusion of their meta-analysis demonstrated that CNB is not inferior to IB. Sensitivity was calculated as 97% in the CNB group and 96 in the IB group for malignancy. For soft-tissue-tumors: CNB 88% and IB 93%. It is debatable whether CNB may provide higher diagnostic confidence in bone sarcoma due to its fixed position in solid tissue, whereas in soft tissue sarcomas, the displaceability of the mass, patient positioning, or the biopsy itself may significantly reduce sensitivity. In this case, open biopsy is clearly superior, as it is possible for the experienced surgeon to assess the local findings intraoperatively and still isolate and biopsy the possibly displaced soft tissue sarcoma. In conclusion and with focus on a simple technique, a high diagnostic accuracy while having less complications the meta-analysis found CNB to be the superior method (Birgin, et al. 2020).
In this study, all biopsies were performed in general anesthesia and by means of surgically incisional biopsy. The incisional biopsies were highly accurate with a sensitivity of 97.6% for malignancy. In the 2.4% cases, in which a reliable histopathological diagnosis could not be made, re-biopsy was performed with evidence of malignancy. Compared to the results in literature, this can be rated as at least equal, if not even superior (Birgin, et al. 2020), (Piya Kiatisevi, et al. 2013), (Issakov, et al. 2003).
Hau et al. studied the diagnostic accuracy of computed tomography (CT)-guided biopsies and fine needle aspirates of musculoskeletal lesions. They figured 359 cases out, the overall accuracy was 71%. The accuracy for 101 fine needle aspirations was 63% and for 258 CT-guided core biopsies was 74% (Hau, et al. 2002).
Other studies also described that IB can have an advantage over CNB, especially in the biopsy of soft tissue tumors. Pohling et al. described in the case of soft tissue tumors a sensitivity of 100% vs. 81.8% in the comparison of CNB vs IB (Pohlig, et al. 2012). Regarding to the accuracy of the respective biopsy technique in soft tissue mass diagnosis, there are correspondingly controversial results in the literature: Sina et al describe a sensitivity of 100% for surgical biopsies while CNBs only reach 79.17% (Kasraeian, et al. 2010). Another important point in addition to the accuracy of the biopsy is the complication rate of the respective biopsy technique. Many studies recommend CNB because of the supposedly lower risk of complications (Issakov, et al. 2003), (Birgin, et al. 2020), (Mitsuyoshi, et al. 2006).
Surgery-specific risks are hematoma and surgical site infection and in relation to CNB – more pain. One also needs to consider the need for re-biopsy in the case of incorrect or unevaluable histopathology as a relevant complication and rated it as such in our study. Many authors recommend CNB over IB precisely because of the supposedly lower complication rate as well as the lower costs (Birgin, et al. 2020; Issakov, et al. 2003), (Errani, et al. 2013).
In all IB performed in this study, 8 complications occurred, of which 2 were secondary bleeding that required another operation and 6 were re-biopsies because there was no histopathological valid result. In the analyzed collectivity at the UCC was a very low risk of complications of 2.4%. The number of necessary re-biopsies with 0.6% it is to be highlighted here, since from our point of view these must also be evaluated as a complication. Klein et al. showed in their study that the number of necessary re-biopsies was significantly higher in the case of CNB compared to IB (50 vs. 5; p = 0.003) (Klein, et al. 2021).
The need of re-biopsy must be taken to account, especially in the case of malignant tumors since these delays further therapy. Also, in the Adams et al study, 6% of the diagnostic biopsies yielded no result (= re-biopsy necessary). Even more critical for patient´s welfare was a 3% rate of false diagnosis. In these cases, the biopsy described a benign tumor, which turned out to be a malignant tumor after complete resection. Patient´s survival of cancerous disease related directly to the speed of treatment (Adams, et al. 2010).
Thus, an appointment for biopsy and consecutive discussion of the patient in the multidisciplinary tumor conference must be available in short time. (Ballhause, et al. 2022).
A biopsy could be carried out just 8,8 days after the first presentation in the UCC and the final histopathological result was available after a further 10.6 days. Accordingly, the diagnosis was already available 19.4 days after the first presentation. The biopsies of this study obtained by IB further corresponded histopathological in 100% with the histopathology of the resected material, correspondingly there was a sensitivity of 100% for malignancy and a specificity of 97.6% for the tumor type. This also shows how accurate correctly performed IBs are.
Although there is not much detailed data for comparison in the current literature, we see this as a respectable time course that enables patients to be referred quickly to the appropriate individual further treatment.
Aside from the already described necessity for re-biopsies, there were 2 postoperative bleedings in our collective that required another surgical treatment. Interestingly, these cases were not associated with a significantly longer operation time in comparison: 15 min and 24 min. All biopsies showed an average operation time of 23.5 minutes. There were no further complications with the general anesthesia in any case. The extended operation time of the complication courses can be best explained by a more invasive surgical procedure because of a more complex location of the tumor.
As already described, due to the extremely large heterogeneity of possible bone and soft tissue tumors of the musculoskeletal system, the type of biopsy is possible in different ways and, as already discussed leads to different results especially regarding the precision of a CNB compared to an IB. Accordingly, there are different recommendations in the literature. In the analysis of patient age performed, the validity of the data is evident. On average, the malignant bone tumors are more than 20 years younger than the patients in whom a metastasis of a malignant primaries was secured. This statement agrees with the literature due to osteosarcomas and Ewing's sarcomas occurring most frequently in young adulthood (Henze, et al. 2019). The frequency of metastases especially of gender-specific osseous metastasis is more evident in the advanced age of the patients. Interestingly, the sensitivity of our IB is independent of tumor location. Comparable to the literature, soft tissue sarcomas were clearly more frequent in the lower extremities, which can be explained by the greater amount of muscle and connective tissue.
Ultimately, an individual indication for each patient must be carefully examined. In the case of easily accessible tumors, the incision biopsy is usually a harmless method to perform with low complication and high accuracy. In the case of deeper-lying masses that may require complex and more invasive access due to their location, with corresponding soft tissue damage to be expected the possibility of a minimal invasive CNB should be examined. In case of increased risk of postoperative bleeding, CNB can be advantageous.
The overall aim should be to guarantee the respective patient the fastest and safest possible diagnostic method and thus promptly supply a definitive therapy, after thorough discussion of the patient in a multidisciplinary tumor board.
All limitations of retrospective studies apply to this analysis. A heterogenous group of surgeons performed the IBs. The malignant specimen was resected only by three experienced musculoskeletal surgeons.