MBBS Enrichment Year 2018-19

Centre for Applied Anatomy, Centre for Health Science Education www.bristol.ac.uk • Four malignancies, namely ovarian carcinoma, pancreatic carcinoma, nasopharyngeal carcinoma and piriform sinus cancer and their corresponding body spaces would be assessed. • By reviewing literature concerning malignancies and their associated body spaces, the effect of body space on cancer diagnosis, prognosis and metastasis is evaluated. • This study aims at providing practitioner with more understanding about the clinical significance of body spaces on cancer. By summarizing the impact of different spaces on cancer diagnosis, prognosis and pattern of spread, it is aimed that factors could be found and thus result in easier diagnosis and better prognosis, as well as practitioner would be aware of and better appreciate the importance of spaces in malignancy. Background and Aims • The prognosis is worse in piriform sinus cancer and the differences in body spaces involved could be a reason leading to this pattern. NPC spread in an predictable manner to parapharyngeal space which skip metastasis is less likely. On the contrary, due to retropharyngeal space involvement in piriform sinus cancer which is a space with no anatomical barrier facilitating vertical spread of cancer cell, skip metastasis is more common. • Also, nasopharyngeal carcinoma typically primarily involve parapharyngeal space due to the close proximity to the sinus of Morgagni at the common origin fossa of Rosenmuller, but piriform sinus could perform local invasion in different directions. • While in pancreatic and ovarian cancer, they are both prognositically bad due to late presentation partly because of their corresponding body spaces. They could extend through ligaments and peritoneal fluid to invade into peritoneal cavity which is a large space without any anatomical barrier resulting in extensive metastasis. These affect their prognosis significantly as well. Findings Definition and Methodology Body spaces and cancer diagnosis, prognosis and metastasis Functional and Clinical Anatomy, University of Bristol Chue Brian • Content of the space e.g. fluid, vessels and lymphatics could act as facilitator for cancer spreading. In peritoneal spread of ovarian cancer, ascitic fluid provides cancer cell with the receptors for attachment on omentum and abdominal wall. It also acts as a transport medium for cancer cell to travel to distant organs. Body space and cancer prognosis • Delayed presentation and tendency of distant metastasis • Specific anatomical structures involved in body spaces which varies across different malignancies especially in surgical approaches Discussion Limitations and Future Research Directions • The major research methodology is literature review of cancer and their corresponding body spaces. 1. Ovarian cancer à Ovarian fossa and peritoneal cavity 2. Pancreatic cancer à Retroperitoneal space 3. Nasopharyngeal carcinoma à Fossa of Rosenmuller and parapharyngeal space 4. Piriform sinus cancer à Piriform sinus and retropharyngeal space • For body spaces, the area of study will include spaces which is mesothelium- lined and could be created without tissue damage, which includes body cavities e.g. peritoneal cavity, spaces which are potential space would be included too which usually consist of two structures compressing against each other e.g. retroperitoneal, parapharyngeal and retropharyngeal space, space that is indirectly communicated with the atmosphere e.g. piriform sinus in hypopharynx and depression in body structure e.g. ovarian fossa and Rosenmuller fossa. Body space and cancer diagnosis • Unoccupied space and flexibility of body space boundary could delay diagnosis as they provide tumor space to extend into. • Content of the space could affect imaging efficacy e.g. the effect of bowel gas on traditional transabdominal ultrasonography in pancreatic and ovarian cancer in peritoneal cavity. • Accessibility of the space by routine physical examination, digital examination and endoscopic study would affect diagnostic difficulty e.g. pancreatic cancer which locates deep in trunk where skin changes and lump are not found. Body space and cancer metastasis • Nearby constraints and passage e.g. sinus/ ligament can predict route of direct invasion. • Time and resources constraints à more combinations of cancers and corresponding body space could be included in the future • Not all confounding factors are eliminated e.g. nature of tumor and condition of patient groups à different types of research can be conducted and more control groups could be used to improve the significance of the study in future Table 1: Similarities and differences of nasopharyngeal carcinoma and piriform sinus cancer Chue Brian 62