Durable Complete Responses in Metastatic Colorectal Cancer Treated with Chemotherapy Alone

Background/Purpose: The median survival for patients with metastatic colorectal cancer (mCRC) has progressively increased over the past decades. Since the introduction of 5-fluorouracil (5-FU)-based chemotherapy, followed by hepatic resection of metastases, and more recently the adoption of newer chemotherapeutic regimens associated with targeted therapy, the gains are getting more substantial. Despite the recognition of the potential for long-term survival after surgical resection of metastatic disease, long-term survival data to determine the potential curative role of chemotherapy alone is lacking. Methods: We performed a retrospective review of 2751 patients who presented with mCRC at The MD Anderson Cancer Center from 1990 through 2003. Patients alive at 5 years who achieved complete response with chemotherapy and were not submitted to any surgical or interventional procedures directed to the metastatic sites were included in the analysis. Results: The 5-year overall survival rate for all patients with mCRC during this period was 10.8%. Among these long-term survivors, 2.2% achieved a sustained complete response after chemotherapy (all 6 with fluoropyrimidines and 2 with irinotecan) as the only treatment modality and were without evidence of disease until the last follow-up visit (median of 10.3 years). This number corresponds to 0.24% (6 of 2541) of all patients with mCRC included in this review. Conclusion: Cure with chemotherapy alone is possible for a very small number of patients with metastatic colorectal cancer. Improved therapies are increasing complete response rates, but the impact of modern chemotherapy on durable complete responses will require additional follow up.

A Sustained Virologic Response Is Durable in Patients With Chronic Hepatitis C Treated With Peginterferon Alfa-2a and Ribavirin

BACKGROUND & AIMS: A sustained virologic response (SVR) to therapy for hepatitis C virus (HCV) infection is defined as the inability to detect HCV RNA 24 weeks after completion of treatment. Although small studies have reported that the SVR is durable and lasts for long periods, it has not been conclusively shown. METHODS: The durability of treatment responses was examined in patients originally enrolled in one of 9 randomized multicenter trials (n = 1343). The study included patients who received pegylated interferon (peginterferon) alfa-2a alone (n = 166) or in combination with ribavirin (n = 1077, including 79 patients with normal alanine aminotransferase levels and 100 patients who were coinfected with human immunodeficiency virus and HCV) and whose serum samples were negative for HCV RNA (<50 IU/mL) at their final assessment. Patients were assessed annually, from the date of last treatment, for a mean of 3.9 years (range, 0.8-7.1 years). RESULTS: Most patients (99.1%) who achieved an SVR had undetectable levels of HCV RNA in serum samples throughout the follow-up period. Serum samples from 0.9% of the patients contained HCV RNA a mean of 1.8 years (range, 1.1-2.9 years) after treatment ended. It is not clear if these patients were reinfected or experienced a relapse. CONCLUSIONS: In a large cohort of patients monitored for the durability of an SVR, the SVR was maintained for almost 4 years after treatment with peginterferon alfa-2a alone or in combination with ribavirin. In patients with chronic hepatitis C infection, the SVR is durable and these patients should be considered as cured.