Adjuvant Chemotherapy Could Improve Prognosis in Patients With CRC

Although the number of patients who would benefit is likely limited, completing adjuvant chemotherapy was found to improve the prognosis of stage III colorectal cancer (CRC) in patients aged 80 years and older, according to a study published in the International Journal of Clinical Oncology. Disease free survival was affected by the length of time a patient took adjuvant chemotherapy.

CRC is the leading cause of death related to cancer across the world, with an increasing number of people of older age contracting the disease. Although surgical resection is the primary approach to treating CRC, patients of older age have a higher risk of recurrence. Adjuvant chemotherapy is used to limit the recurrence that occurs after the operation but patients aged 80 years and older are not often included in studies evaluating the effectiveness of this treatment. The long-term prognosis of patients aged 80 years and older with CRC who had a surgical resection and took adjuvant chemotherapy was examined in this study.

Older woman taking chemotherapy | Image credit: Monkey Business - stock.adobe.com

A total of 17 institutions that were a part of the Hiroshima Surgical study group of Clinical Oncology were included in the prospective cohort study. Patients were included if they had a diagnosis of stage III CRC, were aged 80 years and older, and had a surgical resection. Data was collected on adjuvant chemotherapy administration, follow-up, and oncological outcomes. The 3-year disease free survival (DFS) was used as the primary endpoint whereas the secondary endpoints included overall survival (OS) and relapse-free survival (RFS).

All patients who met the criteria to receive adjuvant chemotherapy were given information on its adverse events and significance before receiving the treatment. All adjuvant chemotherapy was started within 8 weeks of the resection surgery. Patients who did not meet the requirements to get adjuvant chemotherapy were most often given uracil-tegafur and leucovorin (UFT/LV) in 300 mg/m² and 75 mg per day doses respectively. Follow up in patients with adjuvant chemotherapy included evaluation of tumor markers every 3 months for 2 years, biannual assessments for another year, and annual assessments for up to 5 years. Tomography scans were done for the chest and abdomen every 6 months for 3 years and annually in the subsequent 5 years.

There were 214 patients that were enrolled and included in the study between December 2013 and June 2018, where the median age was 84 (range, 80-101) years and of which 99 were male patients.

There were 41 patients who were not eligible for adjuvant chemotherapy due to performance status, multiple cancers, cognitive dysfunction, organ dysfunction, or an in-hospital death. There were 65 patients who received adjuvant chemotherapy. There were 30 cases where therapy was discontinued due to adverse events, recurrence during treatment, withdrawal of consent before starting treatment, and development of second cancer.

There was 42.5 months (IQR, 0.16-84.04 months) of follow-up time. A total of 36 patients died due to CRC and 30 died due to other causes. Recurrence was found in 27.1% of patients, of which 50% received some treatment. A total of 17 patients had secondary cancers during the follow-up. DFS rate was found to be 63.3% in patients, with the 3-year OS rate being 76.9% and the 3-year RFS rate being 62.9%.

There were 173 patients who took adjuvant chemotherapy who were included in the study. The propensity score method was used to assess the effect of adjuvant chemotherapy on survival. The researchers found that the DFS was significantly longer in patients who had completed adjuvant chemotherapy when compared with non-adjuvant chemotherapy and discontinuation of adjuvant chemotherapy, respectively (80.0% vs 65.5% and 56.3%).

There were some limitations to this study. The prospective, nonrandomized, controlled nature of the study was a major limitation. Indicators and other functional assessments that were specific to older patients did not have data collected.

The researchers concluded that completing adjuvant chemotherapy in patients who were aged 80 years and older who had stage III CRC had a heavy impact in treatment, as discontinuing the treatment was associated with a worse DFS.

Reference

Mochizuki T, Shimomura M, Nakahara M, et al. Survival outcomes of patients with stage III colorectal cancer aged 80 years who underwent curative resection: the HiSCO-04 prospective cohort study. Int J Clin Oncol. Published online December 15, 2023. doi:10.1007/s10147-023-02440-9