Neurotoxic side effects and impact on daily life in patients with colorectal cancer with adjuvant oxaliplatin-based chemotherapy

Abstract: Introduction: Colorectal cancer (CRC) is one of the most common cancers globally. Chemotherapeutic drugs are frequently used in postoperative treatment. The platinum compound oxaliplatin (OXA) is an option for adjuvant treatment of patients with resected CRC, and has been shown to improve survival. OXA-induced neurotoxic side effects are common (e.g. sensitivity to cold, numbness). Neurotoxicity can interfere with the patient’s daily living and affect ability to carry out activities. Because there is no evidence for effective treatment in terms of eliminating neurotoxic side effects, the most successful approaches include early identification, reduction of dose and interruption of treatment. Current research has identified a need for patient-oriented evidence in terms of long-term follow-up of neurotoxicity.Aim: The overall aim of this thesis was to explore OXA-induced neurotoxic side effects in patients with colorectal cancer, and the influence on patients’ daily lives during and post OXA treatment.Methods: The thesis is based on four studies, and includes an analysis of medical records, as well as prospective quantitative and qualitative approaches with longitudinal data collection through a mobile phone-based system. The studies were performed at oncology departments in four hospitals in Sweden. Inclusion criteria were that patients should be at least 18 years of age, and should have been treated with chemotherapy, including OXA (FOLFOX, XELOX), in an adjuvant setting for CRC stages II-III. Study I had a retrospective design, and data involved (n=61) medical records. A structured protocol was used to evaluate the documentation of patients’ neurotoxic side effects. In studies II and III, ten patients were recruited using a strategy of purposeful and consecutive selection according to the inclusion criteria, where OXA-related neurotoxic side effects were assessed. A total of 10 interviews were carried out when neurotoxic side effects appeared (II), and after completed OXA treatment (3, 6 and 12 month’s follow-up) 25 repeated interviews were conducted (III). The prospective longitudinal study IV aimed to identify and assess patient-reported outcomes in terms of neurotoxic side effects, and their impact on patients’ daily activities (n=46). An Oxaliplatin-associated Neurotoxicity Questionnaire (OANQ) was administered in real time to indicate patientreported outcomes. In total, 370 questionnaire responses were available for analysis.Results: The results from the retrospective study (I) showed that a free description of the degree of neurotoxic side effects was given in the patients’ medical records. No formal assessment had been used in the documentation. The findings of the two qualitative studies contribute knowledge about how patients endure neurotoxic side effects early in the treatment phase, and how they learn to live with neurotoxicity in the long-term perspective. Patients coped with their side effects by developing different self-care strategies to restore normality in their daily lives (II-III). Neurotoxic side effects interferes with the patient’s daily activities in a variety of ways. These side effects change in terms of their character and their location in the body over time. The most frequent side effects during treatment were cold-precipitated tingling in the upper extremities and in the mouth/throat. At the end of treatment, neurotoxicity in the lower extremities was considered high and interfered with the patients’ daily activities. The results show significant differences between baseline data, and nine of the patients had not returned to baseline after one year (IV).Conclusion: Neurotoxic side effects affect patients’ daily activities in different ways, with an impact on their physical, psychological, emotional and social life. Patients endured and coped with their side effects in different ways involving self-care strategies to restore normality. The patients’ daily lives were affected by numbness and tingling in the legs and tingling in upper extremity, and they had learned to live with these side effects. The neurotoxic side effects changed character and localisation over time. These results should be taken into account when patients are informed about treatment, and in the dialogue about the benefits and risks.