Evaluation and Predictive Factors of Complete Response in Rectal Cancer after Neoadjuvant Chemoradiation Therapy

The response to neoadjuvant chemoradiation therapy is an important prognostic factor for locally advanced rectal cancer. Although the majority of the patients after neoadjuvant therapy are referred to following surgery, the clinical data show that complete clinical or pathological response is found in a significant proportion of the patients. Diagnostic accuracy of confirming the complete response has a crucial role in further management of a rectal cancer patient. As the rate of clinical complete response, unfortunately, is not always consistent with pathological complete response, accurate diagnostic parameters and predictive markers of tumor response may help to guide more personalized treatment strategies and identify potential candidates for nonoperative management more safely. The management of complete response demands interdisciplinary collaboration including oncologists, radiotherapists, radiologists, pathologists, endoscopists and surgeons, because the absence of a multidisciplinary approach may compromise the oncological outcome. Prediction and improvement of rectal cancer response to neoadjuvant therapy is still an active and challenging field of further research. This literature review is summarizing the main, currently known clinical information about the complete response that could be useful in case if encountering such condition in rectal cancer patients after neoadjuvant chemoradiation therapy, using as a source PubMed publications from 2010–2021 matching the search terms “rectal cancer”, “neoadjuvant therapy” and “response”.

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A Retrospective Analysis Comparing Outcomes Following Total Neoadjuvant Therapy and Following Neoadjuvant Chemoradiation Therapy in Patients with Locally Advanced Rectal Cancer

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2019.06.2074 ◽

2019 ◽

Vol 105 (1) ◽

pp. E179

Author(s):

S. Zhu ◽

P. Brodin ◽

K. English ◽

N. Ohri ◽

J.W. Chuy ◽

...

Keyword(s):

Rectal Cancer ◽

Neoadjuvant Therapy ◽

Retrospective Analysis ◽

Locally Advanced ◽

Advanced Rectal Cancer ◽

Locally Advanced Rectal Cancer ◽

Neoadjuvant Chemoradiation ◽

Chemoradiation Therapy ◽

Neoadjuvant Chemoradiation Therapy ◽

Total Neoadjuvant Therapy

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Assessment of macroscopic features in relation to tumor response to neoadjuvant chemoradiation therapy in rectal cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.4_suppl.507 ◽

2013 ◽

Vol 31 (4_suppl) ◽

pp. 507-507

Author(s):

Amanda Kathleen Arrington ◽

Julio Garcia-Aguilar ◽

Marjun Philip Duldulao ◽

Carrie Luu ◽

Julian Sanchez ◽

...

Keyword(s):

Rectal Cancer ◽

Tumor Response ◽

Locally Advanced ◽

Pathologic Complete Response ◽

Complete Response ◽

Neoadjuvant Chemoradiation ◽

Chemoradiation Therapy ◽

Oncologic Outcomes ◽

Neoadjuvant Chemoradiation Therapy ◽

Pathologic Features

507 Background: Several studies show locally advanced rectal cancer patients with clinical complete response (cCR) have comparable oncologic outcomes to pathologic complete response (pCR) to neoadjuvant chemoradiation therapy (NCRT). Thus, total mesorectal excision (TME) could potentially be avoided. Our objective was to validate macroscopic features of cCR. Methods: 164 patients with stage II/III rectal cancer were previously enrolled in a phase II trial and treated by NCRT and TME. Tumor response in the surgical specimens was assessed according to AJCC guidelines. A pCR was defined as absence of viable tumor cells. Gross macroscopic features by the pathologist were tabulated and our cohort was applied to previously published cCR criteria. Results: 25.0% (n = 41) had pCR; 75.0% (n = 123) had non-pCR. Descriptors were condensed into 14 macroscopic features by combining terms and excluding those rarely mentioned. Several reports affirm that scarring signifies cCR, while others suggest that fibrosis, edema, ulceration and nonpalpable tumor to be consistent with cCR. In our study, scarring was found in 6.1% of patients, 16.7% of which had pCR. We found that hyperemia, scarring, flat, smooth, and tan-pink mucosa were significantly associated with pCR (p < 0.05). In contrast, a firm lesion and ulceration were frequently observed in patients with non-pCR (p = 0.02 and 0.05 respectively). Conclusions: Our study suggests that macroscopic pathologic features do correlate with pCR. Although cCR has comparable oncologic outcomes as pCR with favorable outcomes, standard criteria of cCR should first be defined so NCRT patients can safely be selected for observation only. [Table: see text]

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Totally neoadjuvant chemoradiation therapy with mFOLFOX6 in locally advanced rectal cancer: A single arm phase II study (FOTAC).

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.4_suppl.tps816 ◽

2017 ◽

Vol 35 (4_suppl) ◽

pp. TPS816-TPS816

Author(s):

Jianwei Zhang ◽

Yue Cai ◽

Huabin Hu ◽

Jian Xiao ◽

Dianke Chen ◽

...

Keyword(s):

Rectal Cancer ◽

Phase Ii Study ◽

Locally Advanced ◽

Pathologic Complete Response ◽

Complete Response ◽

Advanced Rectal Cancer ◽

Locally Advanced Rectal Cancer ◽

Neoadjuvant Chemoradiation ◽

Chemoradiation Therapy ◽

Neoadjuvant Chemoradiation Therapy

TPS816 Background: Preoperative 5-Fluorouracil based chemoradiotherapy is the standard of treatment for locally advanced rectal cancer. About 15% to 18% of patients would achieve pathologic complete response (pCR) after 5-Fluorouracil based chemoradiation. And the survival outcome of patients with pCR was much better than that of non-pCR. In our previous FOWARC study, in the group of preoperative systemic chemotherapy with mFOLFOX6 combined with radiation, the pCR rate was up to 27.5%. In another study, adding mFOLFOX6 after neoadjuvant chemo radiation in locally advanced rectal cancer improve the pCR rate to 38%. This phase II study aimed to explore whether totally neoadjuvant chemoradiation therapy with mFOLFOX6 could further improve the pCR rate in locally advanced rectal cancer. Methods: The primary endpoint is the pathologic complete response rate (pCR).The secondary endpoint included 3-year disease free survival rate, 3-year local recurrence rate, and safety. We hypothesized that totally neoadjuvant chemoradiation therapy with mFOLFOX6 could improve the pCR rate from 18% to 45% with 5% type I error and 80% power. Fifty patients met inclusion criteria will be enrolled in the trial. All patients will receive long term radiation for 25 times and 50Gy before surgery. Four cycles of mFOLFOX6 would be performed every 2 weeks during radiotherapy, and another 4-6 cycles would be added after radiotherapy and before operation. Totally, the patients will receive 8-10 cycles of chemotherapy before surgery. MRI of the pelvic will be performed every 4 cycles of the therapy to assess clinical response. Then the patient will receive total mesorectal excision at least 8 weeks after radiotherapy. The post-operative chemotherapy will be omitted and all the patients go to surveillance. Clinical trial information: NCT02887313.

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