DURHAM, NC — The standard of care for locoregionally advanced rectal cancer (LARC) in the United States usually involves adjuvant chemotherapy (AC) following chemoradiation (CRT) and total mesorectal excision (TME).
The concern raised by a new study in the Journal of Clinical Oncology, however, is that data proving benefits have been lacking.1
Researchers from the Durham, NC, VAMC and Duke University Medical Center sought to remedy that, by examining the role, optimal regimen and duration of AC in the mandatory, prospectively collected cancer registry of the largest integrated health system in the United States.
To accomplish that, the study team used the VA Central Cancer Registry, including Stage II-III rectal cancer patients diagnosed between January 2001 and April 2011, if they received neoadjuvant CRT, followed by TME, with or without AC.
At least four months of therapy was defined as “adequate chemotherapy,” and survival outcomes were compared. Overall, 649 patients were identified, with 323 receiving AC, while 326 did not (OBS). For the mostly white and male group, mean age 63, median follow-up was 66 months. Almost half of the patients, 49.2% had Stage II disease.
Results indicated that median overall survival (OS) for all patients was 92 months, with six-year OS at 56.8%. Median OS was 72 months for the OBS group and not reached (NR) for the AC group (p < 0.001).
Six-year OS was 49.5% for OBS and 64.1% for AC (p < 0.0001). On PS matched analysis, OS was improved, favoring AC (p < 0.0001).
The researchers reported that median disease-specific survival (DSS) was NR for the whole group and NR for the OBS and AC groups. At six years, DSS was 73.6% for the whole group and 67.9% for OBS vs. 79.2% for AC (p < 0.001). The study team concluded that PS matched analysis for DSS favored AC (p = 0.0004).
No significant difference was detected in OS (p = 0.554) or DSS (p = 0.680) when comparing single vs. multiagent chemotherapy and no significant difference in OS (p = 0.766) or DSS (p = 0.271) when comparing adequate vs. inadequate chemotherapy.
“In this VA population of LARC patients treated with neoadjuvant CRT followed by TME, the addition of AC was found to improve both OS and DSS compared to OBS,” the study authors concluded. “There was no improvement in OS or DSS with the addition of a multi-agent over single-agent chemotherapy.”
1Spiegel D, Boyer M, Hong JC, Williams CD, e. al. Role of adjuvant chemotherapy following chemoradiation and surgery for locoregionally advanced rectal cancer: A Veterans Health Administration analysis. Journal of Clinical Oncology 2018 36:4_suppl, 741-741.