An evaluation of factors impacting the survival of Manitoba women with ovarian cancer treated with neoadjuvant chemotherapy
Abstract
Prior analyses by the Manitoba Ovarian Cancer Outcomes study group identified that late-stage ovarian cancer
patients receiving neoadjuvant chemotherapy had poorer survival than patients receiving adjuvant chemotherapy. This
is consistent with other observational studies identifying neoadjuvant survival being worse compared to adjuvant
survival. Additional investigations into potential causes behind poorer neoadjuvant survival in Manitoba between the
years 2004-2010 were conducted. In this thesis project, possible predictors of neoadjuvant treatment were examined.
Furthermore, a series of clinical questions were generated to investigate the effects of treatment-related factors on
neoadjuvant patient survival, such as residual tumour post-surgery, chemotherapy-induced toxicities, chemotherapy
dose reduction, delay in chemotherapy treatment, and the number of cycles of chemotherapy. It was determined that
predictors of neoadjuvant treatment included older age, unclassified epithelial tumour histotype, and a short time period
(0-50 days) from suspicion to diagnosis of malignancy. Variables that did not substantially affect neoadjuvant patient
survival included chemotherapy dose reduction, chemotherapy dose interruption, chemotherapy toxicities, and
absence of residual tumour post surgery. However, neoadjuvant patients were more likely to require more than one
line of chemotherapy, which might contribute to their increased risk of death. It appears that neoadjuvant patients likely
present with greater disease severity compared to adjuvant patients. This may lead to clinical selection bias, whereby
sicker patients are appropriately treated with neoadjuvant chemotherapy. This study demonstrated that poor survival in
the neoadjuvant patient population is due to greater disease severity upon presentation, unfavourable tumour
histotype, and later disease stage resulting in treatment with neoadjuvant chemotherapy.