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ViewAttendees 5

Session: Rectal Cancer Super Session: Abstract Session

SS06 - Correlation Between Grade of Clinical Response to Neoadjuvant Therapy for Rectal Cancer and Oncologic Outcomes in the Era of Watch-and-Wait

Sunday, June 2, 2024
11:13 AM – 11:21 AM ET, USA
Location: Hall A

    Abstract Podium Presenter(s)

  • Roni Rosen, MD

    Research Fellow
    Memorial Sloan Kettering Cancer Center
    Memorial Sloan Kettering Cancer Center
    New York, NY, United States

    All relevant financial disclosures have been managed and will be listed below.
    This individual has no financial relationships with ineligible companies.

    • Author(s)

  • Aron P. Bercz, MD (he/him/his)

    Research Resident
    Memorial Sloan Kettering Cancer Center
    Memorial Sloan Kettering Cancer Center
    New York, NY, United States

    All of the relevant financial relationships listed below have been mitigated.
    This individual has no financial relationships with ineligible companies.

  • Hannah Williams, MD

    Research Fellow
    Memorial Sloan Kettering Cancer Center
    Memorial Sloan Kettering Cancer Center
    New York, NY, United States

    All relevant financial disclosures have been managed and will be listed below.
    This individual has no financial relationships with ineligible companies.

  • PM

    Parisa Malekzadeh, MD

    Surgical Oncology Fellow
    Memorial Sloan Kettering Cancer Center
    504 E 63rd street APT 36L, New York, United States

    Disclosure information not submitted.

  • LS

    Leonard Saltz, MD

    Attending Physician
    Department of Medical Oncology, Memorial Sloan Kettering Cancer Center
    New York, New York, United States

    Disclosure information not submitted.

  • IW

    Iris Wei, MD

    Surgeon
    Memorial Sloan Kettering Cancer Center
    New York City, New York, United States

    Disclosure information not submitted.

  • Maria Widmar, MD, MPH, FACS (she/her/hers)

    Assistant Attending
    Memorial Sloan Kettering Cancer Center
    Weill Cornell Medical Center
    New York, New York, United States

    All relevant financial disclosures have been managed and will be listed below.
    This individual has no financial relationships with ineligible companies.

  • Garrett M. Nash, MD, MPH

    Vice Chair, Department of Surgery
    Memorial Sloan Kettering
    New York, New York, United States

    Disclosure information not submitted.

  • Emmanouil Pappou, MD, PhD

    Assistant Attending
    Memorial Sloan Kettering Cancer Center
    new York, New York, United States

    All relevant financial disclosures have been managed and will be listed below.
    This individual has no financial relationships with ineligible companies.

  • PR

    Paul Romesser, MD

    Assistant Attending
    Memorial Sloan Kettering Cancer Center
    New York, New York, United States

    Disclosure information not submitted.

  • Martin Weiser, MD

    Attending Surgeon and Professor
    Memorial Sloan Kettering Cancer Center
    Cornell Medical College
    New York, New York, United States

    All relevant financial disclosures have been managed and will be listed below.
    This individual has no financial relationships with ineligible companies.

  • MG

    Mithat Gonen, PhD

    Attending Biostatistician
    Memorial Sloan Kettering Cancer Center
    New York, New York, United States

    Disclosure information not submitted.

  • Philip B. Paty, FASCRS, FACS

    Attending Surgeon, Colorectal Surgery Service
    Memorial Sloan Kettering Cancer Center
    New York, New York, United States

    Disclosure information not submitted.

  • Julio Garcia-Aguilar, MD, PhD (he/him/his)

    Chief Attending
    Memorial Sloan Kettering Cancer Center
    Memorial Sloan Kettering Cancer Center
    New York, New York, United States

    Disclosure information not submitted.

    • Senior Author(s)

  • J. Joshua Smith, MD, PhD

    Associate Attending
    Memorial Sloan Kettering Cancer Center
    MSKCC, Weill Cornell Medical College
    New York, New York, United States

    Disclosure information not submitted.

Purpose/Background: Background: The watch-and-wait (WW) strategy provides an opportunity to avoid unnecessary resection in rectal cancer patients who achieve a clinical complete response (cCR) after neoadjuvant therapy (NAT), yet the management of those with a near complete response (nCR) who evolve to a cCR remains controversial. Herein we assessed the oncologic outcomes of patients managed by WW (sustained cCR and nCR that developed into cCR) and those with an incomplete response (iCR) to NAT treated with a total mesorectal excision (TME).

Methods/Interventions:

Methods: A retrospective analysis was conducted at a comprehensive cancer center that included patients diagnosed with rectal adenocarcinoma between January 1, 2006, and December 31, 2020. None of these patients were enrolled in the OPRA study. Included patients either achieved cCR, nCR or iCR as determined and noted by the treating clinicians after receiving NAT. Patients agreed to a WW strategy of active surveillance if they achieved a cCR. Salvage surgery was utilized for patients managed by WW in the case of local regrowth. Patients with iCR underwent total mesorectal excision (TME). Rates of local and distant recurrence were calculated for each cohort. Kaplan-Meier estimates were used to assess 3- and 5-year rates of local regrowth, TME-free, overall and disease-free survival.

Results/Outcomes:

Results: A total of 1245 patients with rectal adenocarcinoma were identified and divided into 3 cohorts—iCR (n=647), nCR (n=203) and cCR (n=395)—according to clinician-determined response to NAT. The median follow-up was 4.3 years. The three groups were similar in median age [iCR (IQR) 56 (47-66), nCR 56 (48-67), cCR 59 (49-70)] and distance from the anal verge [iCR (IQR) 7 cm (5-9), nCR 6 cm (4-9), cCR 6 cm (4-8)]. The cCR group consisted of 395 patients, of whom 351 entered WW (89%) and 44 opted for surgery due to patient preference (11%). Within the nCR cohort, 89 (44%) patients achieved cCR and continued to WW, 5 (2%) patients achieved a cCR but elected to undergo surgery, while 109 (54%) patients had an iCR and were recommended TME. For those managed by WW, the 3- and 5-year local regrowth rates (95% CI) were 24% (20-29) and 27% (22-32) in the cCR cohort, and 44% (34-55) and 46% (36-57) in the nCR cohort. The TME-free survival rate at 3- and 5-years (95% CI) was 78% (74-83) and 73% (68-79) in the cCR group, and 59% (50-71) and 49% (37-65) in the nCR group. The local recurrence rates in the iCR, nCR and cCR groups were 7% (n=46), 4% (n=9), and 2% (n=7) respectively; while the distant recurrence rates for each group were 24% (n=156), 21% (n=42), and 12% (n=49). The 3- and 5-year disease-free and overall survival improved with greater clinical response to neoadjuvant therapy with intermediate outcomes noted for patients with nCR compared to iCR or cCR (table 1).

Conclusion/Discussion:

Conclusion: Higher rates of organ preservation and lower rates of local regrowth were noted for patients who achieved a cCR after NAT using a WW strategy compared to nCR patients. While greater clinical response to neoadjuvant therapy reflects improved oncologic outcomes, patients with a nCR experienced associated intermediate oncologic outcomes compared to iCR patients. Ongoing prospective trials integrating WW after cCR as determined by prospectively evaluated, uniform criteria will bolster the work to better select sustained complete responders.