Current guidelines recommend home parenteral nutrition (HPN) for cancer patients with chronic deficiencies of dietary intake or absorption when enteral nutrition is not adequate or feasible in suitable patients. HPN has been shown to slow down progressive weight loss and improve nutritional status, but limited information is available on the monitoring practice of cancer patients on HPN. Clinical management of these patients based only on nutritional status is incomplete. Moreover, some commonly used clinical parameters to monitor patients (weight loss, body weight, body mass index, and oral food intake) do not accurately reflect patient's body composition, while bioelectrical impedance analysis (BIA) is a validated tool to properly assess nutritional status on a regular basis. Therefore, patient's monitoring should rely on other affordable indicators such as Karnofsky Performance Status (KPS) and modified Glasgow Prognostic Score (mGPS) to also assess patient's functional status and prognosis. Finally, catheter-related complications and quality of life represent crucial issues to be monitored over time. The purpose of this narrative review is to describe the role and relevance of monitoring cancer patients on HPN, regardless of whether they are receiving anticancer treatments. These practical tips may be clinically useful to better guide healthcare providers in the nutritional care of these patients.