Background PD-L1 expression (PD-L1) on tumor cells with or without immune cells is widely reported in clinical trials of PD-1 blockade in metastatic non-small cell lung cancer (NSCLC). Various cutpoints have been studied. Methods We performed a systematic search of MEDLINE, EMBASE and conference proceedings up to December 2019 for randomized and non-randomized clinical trials of anti-PD-1 or anti-PD-L1 monotherapy in metastatic NSCLC. We retrieved data on objective response rate (ORR), 1 year (1yr PFS) and 2 year progression-free survival (2yr PFS), and 2 year (2yr OS) and 3 year overall survival (3yr OS) in various PD-L1 subgroups. Results were pooled and analysed based on different cutpoints, with non-randomized comparisons made to pooled chemotherapy outcomes. Results 9,810 patients in twenty-seven studies were included. In treatment-naïve patients, benefits with PD-1 blockade over chemotherapy were seen in ORR in patients having PD-L1 ≥50%, in 2yr OS for PDL1 ≥1%, and in 1yr PFS, 2yr PFS and 3yr OS for unselected patients. First-line PD-1 blockade compared to chemotherapy demonstrated higher ORR, 2yr PFS and 3yr OS if PD-L1 ≥50%; lower ORR, higher 2yr PFS and similar 3yr OS if PD-L1 1-49%; and lower ORR, similar 1yr PFS and lower 2yr OS if PD-L1 <1%. In previously treated patients, PD-1 blockade demonstrated similar or superior outcomes to chemotherapy in all PD-L1 subgroups. Conclusions PD-L1 should guide the choice of PD-1 blockade versus chemotherapy in treatment-naïve patients. In previously treated patients, PD-1 blockade provides a favourable outcome profile to chemotherapy in all PD-L1 subgroups.

Clinical guidelines typically recommend a combination of chemotherapy, radiotherapy and surgery for the management of newly diagnosed rectal cancer. However, standard-of-care treatment may be high risk or not feasible after prior treatment for prostate cancer. Very few case reports describe outcomes or treatment options in this instance. The aim of the present retrospective study was to determine local treatment patterns and outcomes in patients with this diagnosis. The study population consisted of patients with rectal cancer who were treated at Westmead Hospital (Western Sydney, Australia) between January 2008 and January 2020, and had a background of previously treated or synchronous prostate cancer. A review of electronic medical records was conducted and a descriptive analysis was performed. In total, 15 (6.4%) male patients with rectal cancer had a synchronous or previously treated prostate cancer. Stage II, III and IV rectal cancer was recorded in 60.0, 26.7 and 13.3%, respectively. Overall, 8 patients had previously received definitive intent radiotherapy and did not receive neoadjuvant radiotherapy for their rectal cancer. After a median follow-up time of 2.4 years, 25.0% had experienced loco-regional recurrence and the overall survival rate was 87.5%. A total of 3 patients with higher-stage disease underwent neoadjuvant chemotherapy without radiotherapy, resulting in three R0 resections and no recurrences, at the time of data cut-off. At the centre in the present study, prior prostate cancer affected treatment decisions for newly diagnosed rectal cancer. Neoadjuvant chemotherapy was well tolerated and is an option for patients with stage III disease. Outcomes in patients who did not receive neoadjuvant radiotherapy were acceptable but with high rates of loco-regional recurrence. These findings provide some guidance for other clinicians when making decisions regarding treatment of this challenging disease.