BMC Cancer Research article Should tumor depth be included in prognostication of soft tissue sarcoma? Anders Rydholm* and Pelle Gustafson Address: Department of Orthopedics, University Hospital, SE-221 85 Lund, Sweden Email: Anders Rydholm* - Anders.Rydholm@ort.lu.se; Pelle Gustafson - Pelle.Gustafson@ort.lu.se * Corresponding author BioMed Central Open Access Published: 26 May 2003 BMC Cancer 2003, 3:17 Received: 10 December 2002 Accepted: 26 May 2003 This article is available from: http://www.biomedcentral.com/1471-2407/3/17 © 2003 Rydholm and Gustafson; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are per- mitted in all media for any purpose, provided this notice is preserved along with the article's original URL. prognosissoft tissue sarcomastagingtumor depth Abstract Background: Most staging systems for soft tissue sarcoma are based on histologic malignancy- grade, tumor size and tumor depth. These factors are generally dichotomized, size at 5 cm. We believe it is unlikely that tumor depth per se should influence a tumor's metastatic capability. Therefore we hypothesized that the unfavourable prognostic importance of depth could be explained by the close association between size and depth, deep-seated tumors on average being larger than the superficial ones. When tumor size is dichotomized, this effect should be most pronounced in the large size (>5 cm) group in which the size span is larger. Methods: We analyzed the associations between tumor size and depth and the prognostic importance of grade, size and depth in a population-based series of 490 adult patients with soft tissue sarcoma of the extremity or trunk wall with complete, 4.5 years minimum, follow-up. Results: Multivariate analysis showed no major prognostic effect of tumor depth when grade and size were taken into account. The mean size of small tumors was the same whether superficial or deep but the mean size of large and deep-seated tumors were one third larger than that of large but superficial tumors. Tumor depth influenced the prognosis in the subset of high-grade and large tumors. In this subset deep-seated tumors had poorer survival rate than superficial tumors, which could be explained by the larger mean size of the deep-seated tumors. Conclusion: Most of the prognostic value of tumor depth in soft tissue sarcomas of the extremity or trunk wall can be explained by the association between tumor size and depth. Background Most staging systems for soft tissue sarcoma are based on histologic malignancy grade, tumor size and tumor depth (the French (FNCLCC) system [1]; the Memorial Sloan Kettering (MSK) system [2]; the American Joint Commit- tee on Cancer/International Union Against Cancer AJCC/ UICC system 5th ed [3]. However, we think it is unlikely that tumor depth per se, all other things being equal, should influence the risk of metastatic spread from a soft tissue sarcoma. One explanation for the prognostic value of tumor depth could be the association between depth and tumor size, deep-seated tumors being larger. Most systems dichotomize size at 5 cm. Prognostic information from tumor depth may be obtained if each size group (1– 5/>5 cm) is divided into superficial and deep-seated tumors if the mean size of the deep-seated tumors is larger Page 1 of 5 (page number not for citation purposes)