Breast cancer is a heterogeneous disease. Liquid biopsy is a novel diagnostic tool and may provide answers to many questions related to unevenness in prognosis and ultimate outcome. Different technologies for CTC isolation, enrichment, detection, and characterization are under evaluation. Various clinical trials and meta-analysis have been conducted to define the role of CTC in early and metastatic breast cancer. CTCs are superior to other serum markers for prognostication. Their role as predictive marker remains elusive.

Context:Lung cancer has been the most common cancer in the world for several decades. Pemetrexed is recommended as an option for the maintenance treatment in metastatic adenocarcinoma lung, if disease has not progressed immediately following platinum-based chemotherapy.Aims:To study efficacy and toxicity profile of pemetrexed as a maintenance chemotherapeutic agent in patients with stage IV adenocarcinoma lung, not progressing after first line chemotherapy. Settings and Design: This was an observational, prospective. We enrolled patients with stage IV adenocarcinoma lung who has not progressed on first line chemotherapy, from September 2013 to August 2014 at a tertiary care cancer institute in North India.Materials and Methods:In all, 108 patients with stage IV adenocarcinoma lung were started on induction pemetrexed/platinum chemotherapy. 60 patients with no disease progression & ECOG PS 0-2 were started on Pemetrexed maintenance. Progression free survival (PFS) and toxicity profile were recorded.Results:The mean number of maintenance cycles was 8.3 (range 2-28). 13 (21.6%) patients took >10 maintenance cycles. Pemetrexed maintenance therapy resulted in progression free survival (PFS) of 5.4 months. PFS on pemetrexed was consistent for all patient subgroups, including induction response: complete/partial responders (n-31) and stable disease (n-29). 14 patients had grade III/IV adverse events with anemia being the most common in 3/60 patients (5%). 3 patients (5%) developed renal dysfunction out of which 1 was grade III.Conclusions:Pemetrexed continuation maintenance chemotherapy is active and well tolerated. Pemetrexed maintenance should be considered in patients with advanced adenocarcinoma lung patients who have not progressed on completion of induction chemotherapy.