Older cancer patients need to cope with two major stressful situations simultaneously – age‐related stress and illness‐related stress. The current study aimed to explore whether patients’ quality of life (QoL) and functional limitations have a reciprocal effect over time, and further aimed to assess whether these effects differ by age group.

Data were drawn from the two first waves of the Survey of Health, Ageing and Retirement in Europe. Five hundred ninety‐eight participants reported that they were diagnosed with cancer or malignant tumours. All participants completed self‐report questionnaires tapping personal and medical data, QoL and functional limitations.

By using a two‐wave cross‐lagged design, findings showed a reciprocal relationship between QoL and functional limitations among older cancer patients. This reciprocal relationship was stronger in the direction from QoL to functional limitations, especially among those 75 and older in comparison with younger patients (50–74). This suggests that assessment of QoL may be beneficial to clinicians in predicting deterioration in functional limitations among older patients receiving cancer treatment.