Multiple Primary Tumors in Oral Cancer : Patient Characteristics and Survival Patterns

• Author / Creator

  Sawani, Salima Asifali

• Objectives: To identify the risk factors of MPT development in oral cancer patients and to examine the survival rates of oral cancer patients with MPTs and its associated factors.
  Materials and Methods: We retrospectively studied the data of 3,549 patients diagnosed with primary oral cancer using the Alberta Cancer Registry database between 2005 and 2020.
  Results: A total of 513 patients developed MPTs with an overall incidence of 14.5%. Among them, 78% MPTs were metachronous tumors and the average time interval of development of 1st MPT was 4.04±3.67 years. The proportion of comorbid conditions was significantly higher in MPT patients as compared to non-MPT patients (52% vs. 40.02%, p < 0.001). The oral cavity cancer (OCC) as a primary tumor was found to be significantly greater in patients who developed MPTs (53.4%, p = 0.002). The most common MPT site was oral region (31.8%) followed by lungs (19.1%) and digestive system (12.3%). Advanced age, average income, co-morbidities including COPD, diabetes and cardiovascular disease, and increased duration from diagnosis to treatment were found to be potential risk factors for MPT development in POC patients. Survival analysis revealed a sharp decrease in survival rate of oral cancer survivors after developing MPTs (from 70% to 47%, p = 0.004). Multivariate regression analyses indicated that age > 45-year, BMI < 18.5, synchronous tumors, stage III and IV POC, > 2 comorbid conditions and MPT developing in digestive system had a poor disease specific survival.
  Conclusions: Development of MPT is a significant risk in oral cancer patients leading to increase mortality rates. Long-term follow-up is necessary for oral cancer patients to diagnose the occurrence of MPTs to improve the prognosis of the disease.

• Subjects / Keywords

  • oral cancer
  • multiple primary tumors
  • second primary tumors
  • disease specific survival

• Graduation date

  Fall 2022

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-3r3c-gq80

• License

  This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.