Current Landscape and Potential Challenges of Immune Checkpoint Inhibitors in Microsatellite Stable Metastatic Colorectal Carcinoma

Colorectal cancer (CRC) is the third most frequent cancer and the second most common cause of cancer-related death in Europe. High microsatellite instability (MSI-H) due to a deficient DNA mismatch repair (dMMR) system can be found in 5% of metastatic CRC (mCRC) and has been established as a biomarker of response to immunotherapy in these tumors. Therefore, immune checkpoint inhibitors (ICIs) in mCRC with these characteristics were evaluated with results showing remarkable response rates and durations of response. The majority of mCRC cases have high levels of DNA mismatch repair proteins (pMMR) with consequent microsatellite stability or low instability (MSS or MSI-low), associated with an inherent resistance to ICIs. This review aims to provide a comprehensive analysis of the possible approaches to overcome the mechanisms of resistance and evaluates potential biomarkers to establish the role of ICIs in pMMR/MSS/MSI-L (MSS) mCRC.

Albumin-bound paclitaxel as new treatment for metastatic cholangiocarcinoma: A case report

BACKGROUND

Cholangiocarcinomas are rare and very aggressive tumors. Most patients have advanced-stage or unresectable disease at presentation, and the systemic therapies have limited efficacy. Albumin-bound paclitaxel (nab-paclitaxel) is a solvent-free taxane that has been approved for the treatment of some cancers such as breast, non-small cell lung and pancreatic cancer, however it has not been applied to treat cholangiocarcinoma. We have both preclinical and clinical evidence of the efficacy of nab-paclitaxel in cholangiocarcinoma, yet no phase 3 trials have been made.

CASE SUMMARY

A 63-year-old man was diagnosed in December 2016 with stage III B intrahepatic cholangiocarcinoma. Surgery was performed, followed by adjuvant chemotherapy treatment with capecitabine and gemcitabine; although, the gemcitabine was suspended due to allergic reaction after two cycles. In April 2019, metastatic cholangiocarcinoma relapse was diagnosed, and a first-line treatment with FOLFOX scheme was started. Eight cycles were administered, producing an initial clinical improvement and decrease in blood tumor marker levels. Radiological and serological progression was noted in September 2019. As a second-line treatment, FOLFIRI was not recommended due to risk of worsening the patient’s tumor-related diarrhea. A combination therapy with gemcitabine was not feasible, as the patient had previously suffered from an allergic reaction to this treatment. We decided to use nab-paclitaxel as a second-line treatment, and four cycles were administered. Both clinical and serological responses were observed, and a radiological mixed response was also noted.

CONCLUSION

Advanced cholangiocarcinoma could be treated with nab-paclitaxel monotherapy, which should be studied in combination with other types of treatment (chemotherapy, fibroblast growth factor receptor inhibitors).

Watch and wait approach in rectal cancer: Current controversies and future directions

According to the main international clinical guidelines, the recommended treatment for locally-advanced rectal cancer is neoadjuvant chemoradiotherapy followed by surgery. However, doubts have been raised about the appropriate definition of clinical complete response (cCR) after neoadjuvant therapy and the role of surgery in patients who achieve a cCR. Surgical resection is associated with significant morbidity and decreased quality of life (QoL), which is especially relevant given the favourable prognosis in this patient subset. Accordingly, there has been a growing interest in alternative approaches with less morbidity, including the organ-preserving watch and wait strategy, in which surgery is omitted in patients who have achieved a cCR. These patients are managed with a specific follow-up protocol to ensure adequate cancer control, including the early identification of recurrent disease. However, there are several open questions about this strategy, including patient selection, the clinical and radiological criteria to accurately determine cCR, the duration of neoadjuvant treatment, the role of dose intensification (chemotherapy and/or radiotherapy), optimal follow-up protocols, and the future perspectives of this approach. In the present review, we summarize the available evidence on the watch and wait strategy in this clinical scenario, including ongoing clinical trials, QoL in these patients, and the controversies surrounding this treatment approach.