Chemo beneficial in node-positive appendix adenocarcinoma

Chemotherapy appears to confer survival advantage in patients with appendix adenocarcinoma who have node-positive tumours, according to a study presented at ESMO Sarcoma 2023.

Analysis involving 216 patients (median age 59 years, 58 percent women, 68 percent had metastatic disease) showed that systemic chemotherapy was associated with a lower risk of death among patients with positive nodes as compared with no chemotherapy.

The protective effect in node-positive tumours was seen across all chemotherapy subgroups: neoadjuvant or adjuvant (median overall survival [OS], not reached vs 27 months; p=0.005), prior (median OS, 81 vs 27 months; p=0.011), and palliative chemotherapy (median OS, 28 vs 27 months; p<0.001). [ESMO Sarcoma, abstract 8O]

The finding “confirms that positive lymph node status identifies a subgroup of patients with appendix adenocarcinoma who derive the most benefit from systemic chemotherapy,” according to lead study investigator Dr Madeleine Strach from the Christie NHS Foundation Trust, Manchester, UK.

Of the patients included, 141 (69 percent) had mucinous adenocarcinomas, 71 had unspecified adenocarcinomas, and four had signet ring adenocarcinomas. Some 182 patients (84 percent) underwent cytoreductive surgery and heated intraperitoneal chemotherapy, and 97 patients received systemic chemotherapy (neoadjuvant n=12, adjuvant n=16, prior=18, palliative n=51). Oxaliplatin plus fluoropyrimidine was the most common chemotherapy regimen used (29 percent).

After a median follow-up of 56 months, median OS in the entire cohort was 122 months, with 5- and 10-year OS rates of 63 percent and 51 percent, respectively. Median progression-free survival (PFS) was 41 months, with 5- and 10-year PFS rates of 43 percent and 40 percent, respectively.

Patients with signet ring cell adenocarcinoma (hazard ratio [HR], 20.7; p<0.001), those with high-burden residual disease (CC2/3; HR, 29.2; p<0.001), and those with lymph node involvement (N1/2; HR, 19.1; p<0.001) had the poorest outcomes, Stach said, adding that these groups should be the focus for clinical trials and development of novel therapies.

However, she acknowledged that despite the large number of patients included in the study, the groups were small in number. Also, the retrospective nature of the data was subject to selection bias.

Stach ended her presentation by calling for a prospective study of chemotherapy in appendix adenocarcinoma patients with node-positive disease.

According to an expert who was not involved in the study, appendix adenocarcinoma is studied less than colon cancer due to being rare, “and the use of chemotherapy in [appendix adenocarcinoma] is controversial.”

“Therefore, it is striking that the results from this study show systemic chemotherapy based on fluoropyrimidine and oxaliplatin to be associated with improved survival, albeit in a small and selected group of patients presenting with positive lymph nodes,” Dr Alvaro Arjona-Sánchez from Hospital Universitario Reina Sofía in Córdoba, Spain, said in a statement.