The effects of cancer treatment-induced bone loss on morphological sex assessment
Jasny, Kalan Leigh
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Cancer is currently the second most common cause of death in the U.S. with over 600,000 people expected to die from cancer this year alone. The diagnosis of cancer steadily increased through most of the 20th century due to a rise in tobacco usage, causing a relatively recent growth in cancer research. In the past several decades, treatments for cancer have been rapidly changing and advancing, and it is vital to understand how these medications affect the human skeleton. Presently, little research has been conducted on how medications alter the human skeleton and impact the biological profile. One of the primary side effects of drug and radiation-based treatments for a neoplasm is cancer treatment-induced bone loss (CTIBL), which may impact the expression of sexual dimorphism in morphological traits. It is hypothesized that CTIBL would decrease the robusticity of sexually dimorphic nonmetric traits and skew the ordinal scores towards gracile. A total of 178 individuals with documented cancer and/or treatment and 178 individuals without documented cancer from the William M. Bass Donated Skeletal Collection at the University of Tennessee, Knoxville, were assessed following conventional sex assessment standards for the skull and os coxa. These methods presented by Buikstra and Ubelaker (1994), Klales et al. (2012), and Walker (2005) were applied to the os coxa and Walker’s (2008) method for the skull. The individuals ranged in age from 26 to 97 years and included 350 European Americans, two African Americans, one Asian/Polynesian, and three Native Americans. The control group was designed to parallel the experimental group by demographic information including sex, ancestry, and age-at-death. The experimental group was also subdivided into two groups that included individuals that underwent chemotherapy and/or radiation (drug subgroup) and individuals who only underwent surgery as a form of treatment (surgery subgroup). Thirty-six randomly selected individuals were also rescored to test for intraobserver agreement. IBM’s Statistical Package for Social Sciences (SPSS) was used to calculate Chi-Square, ANOVA, ANCOVA, and Cohen’s Kappa analyses. The Chi-Square and ANOVA analyses were used to determine if there was any statistically significant relationship between cancer treatment status and the scores of the morphological traits. The results indicated no significant relationship between cancer treatment status and the trait scores (p > 0.05) for all analyses except for the Chi-square analysis of the glabella for females in the pooled sample (p=0.047) and the ANOVA analysis of the ventral arc in the surgery group when sex was not considered (p=0.010). It is possible that these traits are affected by cancer treatment status. However, it is more likely that these results were due to natural variation between the control and experimental groups. Intraobserver agreement was calculated using Cohen’s Kappa analysis. Intraobserver agreement ranged from fair to substantial with most traits indicating moderate intraobserver agreement. Some possible confounders of the study include the unknown duration of cancer treatments, the use of a history of cancer as a proxy for cancer treatment, not knowing when the individual underwent cancer treatment before death, and the assumption that the individuals included in the sample were accurately documented. Cancer Treatment-Induced Bone Loss may only affect bone mineral density as opposed to the expression of sexually dimorphic traits as many of these visually assessed traits are sites of muscle attachments. Though CTIBL does not appear to affect morphological sex assessment, further research should be conducted on the possible effects of CTIBL for other components of the biological profile.