**3. Evidence supporting the role of PC in patients with lung cancer**

A growing body of evidence supports using PC in patients with lung cancer. Temel et al. (2010) performed a study on early referral to PC specialists for patients newly diagnosed with advanced NSCLC [2], which is probably the most formative study on PC to date. The findings of this study showed that patients assigned to early PC combined with routine oncologic therapy had a better QoL, lower depression levels, less aggressive end-of-life care, and a significant albeit moderate improvement in overall survival. The advantages of early PC involvement in advanced lung cancer care attracted substantial research interest after this trial.

Numerous studies have found that early PC can have a positive impact on survival and QoL. For example, in the ENABLE randomized control trial, four educational sessions were held with advanced practice nurses trained in PC over the course of a week, which was followed up with monthly phone consultations. The findings showed that patients with advanced cancer undergoing PC had improved QoL [11]. Furthermore, the survival rates were found to be improved in patients with advanced cancer who were given access to a PC specialist at an early stage with monthly followups [12]. Early PC was also found to reduce caregiver depression scores and stress burden [3]. In another randomized controlled trial, medical oncology clinics were randomized into PC team consultation and monthly follow-up groups [13]. The findings indicated significant improvements in end-of-life care and patient satisfaction at the primary 3-month endpoint, as well as vast improvements in the additional QoL metrics at 4 months (secondary endpoint) [13]. A recent retrospective analysis including a large cohort of patients diagnosed with advanced lung cancer who had been referred to a PC provider following their diagnosis found that survival rates were improved (i.e., the likelihood of death was reduced) in acute care settings [14]. Notably, this positive relationship with improved survival was only evident in patients who were seen by a PC specialist more than 1 month after diagnosis (but within a year). Contrarily, a negative relationship was observed among patients who were seen within the first month. Interestingly, patients referred within a month of diagnosis were seen in inpatient settings, which indicates that such appointments may have been in the end-of-life setting. The higher chances of death in such patients may be due to poor functional status, extensive disease burden, and*/*or poor prognosis, which may have ultimately hastened the PC referral process.

Researchers have investigated the different components involved in a PC visit to determine the optimal ways to achieve the benefits listed above. Many different patient outcomes are impacted by a PC provider's area of focus during each appointment. For instance, outpatient PC consultations can help with symptom management, prognostic information, psychosocial support, and elucidating patients' end-of-life care objectives. A prior study revealed that patients who had more

consultations focusing on coping with symptoms reported better QoL and depression scores, whereas those who had more consultations focusing on treatment decisions were less likely to receive aggressive end-of-life care. Furthermore, patients with more consultations focusing on advance care planning were more likely to relocate to a hospice [15]. Studies have also shown that early PC referral improves prognostic understanding in patients with advanced lung cancer [16].

The above evidence confirms the advantages of early PC introduction. Consequently, there has been a significant increase in the number of patients referred to PC within 1 year of diagnosis of metastatic lung cancer [17]. Nevertheless, despite the increase in the proportion of patients referred to PC from 3% in 2001 to over 30% in 2013, most patients did not receive a PC referral at all, and only one-fifth of those who did, received outpatient PC services [17]. Thus, research indicates that most people with advanced lung cancer are not able to see a PC practitioner regularly, despite the well-documented advantages of this treatment approach.
