Patients with cancer undergoing chemotherapy may have different cancer symptom clusters (CSC) that negatively impact their quality of life (QoL). These symptoms can sometimes arise from the disease itself or as a result of their cancer treatment. This study aimed to: examine the feasibility of longitudinal testing of CSC pattern and QoL in a sample of adult cancer patients undergoing outpatient chemotherapy; to identify the cardiovascular risk of patients with cancer undergoing outpatient chemotherapy; and to investigate the most prevalent CSC and their impact on the QoL of these patients. A longitudinal pilot study was conducted with eleven participants with a mean age of 56.09 years (range: 27–79) diagnosed with malignant neoplasm and undergoing outpatient chemotherapy treatment were evaluated during 6 cycles of chemotherapy. The CSC, cardiovascular risk, and QoL were assessed using the MSAS, FRS, and EQ-5D-3L™, respectively. Descriptive statistical and non-parametric bivariate analyses were performed. Patients who started chemotherapy treatment generally had a low to moderate cardiovascular risk and were likely to have a family history of hypertension, acute myocardial infarction, and stroke. Cardiovascular risk was found to be correlated with patient age (Rho
s
= 0.64; P = .033). In addition, the results showed a reduction in the QoL scoring over the 6 chemotherapy sessions. Regarding the most prevalent CSC, 2 clusters were identified: the neuropsychological symptom cluster (difficulty concentrating-sadness-worry) and the fatigue-difficulty sleeping cluster. Between the first and sixth chemotherapy sessions, there was a decrease in the perception of “mild” severity (P = .004) and an increase in the perception of “severe” and “very severe” (P = .003) for all symptoms. Adequate attention to CSC should be the basis for the accurate planning of effective interventions to manage the symptoms experienced by cancer patients.