Updated Clinical Calculators Guide Treatment Plan for Rectal Cancer

Martin R. Weiser, MD

Physicians from Memorial Sloan Kettering Cancer Center (MSK) have developed and validated clinical calculators to guide patients with colorectal cancer on the probability of survivability and tumor recurrence, and whether to elect for surgery or delay surgery following chemotherapy or chemoradiotherapy (1), (2), (3). In a 2021 study published in JAMA Network Open (2), the calculator proved to be an effective tool in assessing the likelihood of tumor recurrence and patient survival. In a recent study, also published in JAMA Network Open, the team expanded the concept of the calculator to predict if survivability would change based on immediate surgery versus delayed surgery3.

The initial validation study included 1,905 patients with rectal cancer. MSK physicians developed a multiple variable calculator that had superior results compared with the American Joint Committee on Cancer (AJCC) guidelines for treatment of rectal cancer1. Rectal cancer offers difficult and unique challenges, but MSK physicians were able to adapt a colon cancer calculator and make it specific for rectal cancer, resulting in an optimized plan of care.

“We built a calculator based on the paradigm of chemo, radiation, and surgery that predicts the chance of the tumor coming back. This is called recurrence-free survival (RFS),” says Martin R. Weiser, MD, a surgeon at MSK and an academic leader in the field of rectal cancer. “However, over the past few years, there’s a new treatment paradigm in which we closely monitor patients that get chemo and radiation — and determine which treatments or combination of treatments are most effective in getting rid of the tumor.”

The most recent work from MSK and Dr. Weiser in JAMA Network Open (3) included 302 patients who received total neoadjuvant therapy (TNT) from 2009 to 2015 and whose final data was analyzed within the past year. Patient data was entered into the calculator, which accurately computed outcomes of patients’ RFS if surgical intervention was elected immediately or significantly delayed. The calculator mirrored the findings that surgical intervention immediately following TNT does not have better outcomes than delayed surgical intervention.

These calculators are not only a tool for physicians but are also an empowering resource patients can access during their diagnosis and treatment. As an open online resource, patients will be able to get a deeper understanding of whether to have or delay surgery, augmenting the conversations they have with their physicians.

“The information can help patients know what their risk is, which is always helpful. It gives them agency for the rest of their life,” says Dr. Weiser. “The fact that it’s dynamic allows you to check predictions along your pathway of treatment.”

The survivability and recurrence calculator includes multiple clinical variables:

  •  Microsatellite genomic data
  •  AJCC guideline diagnosis category
  • The number of tumor-involved lymph nodes
  • The presence of high-risk pathologic features, including metastasis
  • The presence of tumor-infiltrating lymphocytes
  • The use of chemotherapy

To ensure validity of MSK’s rectal cancer calculator, it was compared to an external cohort of patients from Washington University’s Siteman Cancer Center that yielded analogous outcomes.

“The colon cancer clinical calculator uses molecular factors now, which is very exciting. The treatment of rectal cancer continues to become more and more complicated. So advanced rectal cancer — which is many patients we see — where the tumors grow through the wall or involves lymph nodes, we treat with chemotherapy radiation. Whereas in the past, it was almost always surgery,” says Dr. Weiser.

These calculators represent an important step, not only in colorectal cancer treatment but also in all oncologic calculators as the frontiers on cancer treatment and diagnosis continue to evolve with the incorporation of molecular genetics and other new technologies.

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Dr. Weiser discloses the following relationships and financial interests: Ultimate Opinions in Medicine LLC and UptoDate.

Advancing Research Through Multidisciplinary Collaboration

MSK experts collaborated as part of a multidisciplinary team that included the Departments of Medicine, Radiation Oncology, and Epidemiology and Biostatistics.

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Call our dedicated clinician access number at 833-315-2722 or click the link below, and one of our care advisors will assist you with your referral needs.
  1. Weiser MR, Hsu M, Bauer PS, et al. Clinical Calculator Based on Molecular and Clinicopathologic Characteristics Predicts Recurrence Following Resection of Stage I-III Colon Cancer. J Clin Oncol. 2021;39(8):911-919.
  2. Weiser MR, Chou JF, Keshinro A, et al. Development and Assessment of a Clinical Calculator for Estimating the Likelihood of Recurrence and Survival Among Patients With Locally Advanced Rectal Cancer Treated With Chemotherapy, Radiotherapy, and Surgery [published correction appears in JAMA Netw Open. 2022 Jan 4;5(1):e2147251]. JAMA Netw Open. 2021;4(11):e2133457.
  3. Weiser MR, Chou JF, Kim JK, et al. A Dynamic Clinical Calculator for Estimating Conditional Recurrence-Free Survival After Total Neoadjuvant Therapy for Rectal Cancer and Either Surgery or Watch-and-Wait Management. JAMA Netw Open. 2022;5(9):e2233859. Published 2022 Sep 1.

The additional following authors contributed to this publication: Joanne F. Chou, MPH; Jin K. Kim, MD; Maria Widmar, MD, MPH; Iris H. Wei, MD; Emmanouil P. Pappou, MD, PhD; J. Joshua Smith, MD, PhD; Garrett M. Nash, MD, MPH; Philip B. Paty, MD; Andrea Cercek, MD; Leonard B. Saltz, MD; Paul B. Romesser, MD; Christopher H. Crane, MD; Julio Garcia-Aguilar, MD, PhD; Deborah Schrag, MD, MPH; Mithat Gönen, PhD.