Timing of rectal cancer surgery after short-course radiotherapy: national database study

Efficacy of Neoadjuvant Radiotherapy After Chemotherapy and the Optimal Interval from Radiotherapy to Surgery for Borderline Resectable and Resectable Pancreatic Cancer

BACKGROUND

Benefits of neoadjuvant treatment for pancreatic cancer with major vessel invasion has been demonstrated through randomized controlled trials; however, the optimal neoadjuvant treatment strategy remains controversial, especially for radiotherapy. Therefore, we aimed to evaluate the efficacy and safety of neoadjuvant radiotherapy followed by chemotherapy and the optimal time interval to undergo surgery after radiotherapy in (borderline) resectable pancreatic cancer.

METHODS

Between 2013 and 2022, patients with (borderline) resectable pancreatic cancer with vessel contact who received 5-fluorouracil with leucovorin, oxaliplatin, and irinotecan or gemcitabine and nanoparticle albumin-bound paclitaxel as initial treatment following surgery were included. Patients who received radiotherapy after chemotherapy and those who did not were matched using 1:1 nearest-neighbor propensity scores. Propensity scores were measured using the tumor size at initial image, duration of neoadjuvant chemotherapy, and responsiveness to neoadjuvant chemotherapy.

RESULTS

Of 212 patients, 166 patients were retrieved for the matched cohort. Patients who received radiotherapy had significantly better postoperative survival, local control, and R0 resection rates than those who did not. Furthermore, patients who underwent surgery within 4 weeks after completing radiotherapy had lower intraoperative blood loss and a clinically relevant postoperative pancreatic fistula rate than those who underwent surgery after more than 4 weeks.

CONCLUSIONS

In patients with (borderline) resectable pancreatic cancer with vessel contact who were scheduled for curative-intent surgery after neoadjuvant chemotherapy, additional radiotherapy was associated with better postoperative survival and local control. Furthermore, our findings suggested that scheduling surgery within 4 weeks following radiation therapy might enhance the perioperative outcomes.

Node-sparing modified short-course Radiotherapy Combined with CAPOX and Tislelizumab for locally Advanced MSS of Middle and low rectal Cancer (mRCAT): an open-label, single-arm, prospective, multicentre clinical trial

BACKGROUND

Neoadjuvant chemoradiotherapy followed by total mesorectal excision is a standard treatment for locally advanced rectal cancer. Mismatch repair-deficient locally advanced rectal cancer (LARC) was highly sensitive to PD-1 blockade. However, most rectal cancers are microsatellite stable (MSS) or mismatch repair-proficient (pMMR) subtypes for which PD-1 blockade is ineffective. Radiation can trigger the activation of CD8 + T cells, further enhancing the responses of MSS/pMMR rectal cancer to PD-1 blockade. Radioimmunotherapy offers a promising therapeutic modality for rectal cancer. Progenitor T exhausted cells are abundant in tumour-draining lymph nodes and play an important role in immunotherapy. Conventional irradiation fields include the mesorectum and regional lymph nodes, which might cause considerable damage to T lymphocytes and radiation-induced fibrosis, ultimately leading to a poor response to immunotherapy and rectal fibrosis. This study investigated whether node-sparing modified short-course irradiation combined with chemotherapy and PD-1 blockade could be effective in patients with MSS/ pMMR LARC.

METHODS

This was a open-label, single-arm, multicentre, prospective phase II trial. 32 LARC patients with MSS/pMMR will receive node-sparing modified short-course radiotherapy (the irradiated planned target volume only included the primary tumour bed but not the tumour-draining lymph nodes, 25 Gy/5f, 5 Gy/f) followed by CAPOX and tislelizumab. CAPOX and tislelizumab will be started two days after the completion of radiotherapy: oxaliplatin 130 mg/m2 intravenous infusion, day 1; capecitabine 1000 mg/m2 oral administration, days 1-14; and tislelizumab 200 mg, intravenous infusion, day 1. There will be four 21-day cycles. TME will be performed at weeks 14-15. We will collect blood, tumour, and lymphoid specimens; perform flow cytometry and in situ multiplexed immunofluorescence detection; and analyse the changes in various lymphocyte subsets. The primary endpoint is the rate of pathological complete response. The organ preservation rate, tumour regression grade, local recurrence rate, disease-free survival, overall survival, adverse effects, and quality of life will also be analysed.

DISCUSSION

In our research, node-sparing modified radiotherapy combined with immunotherapy probably increased the responsiveness of immunotherapy for MSS/pMMR rectal cancer patients, reduced the occurrence of postoperative rectal fibrosis, and improved survival and quality of life. This is the first clinical trial to utilize a node-sparing radiation strategy combined with chemotherapy and PD-1 blockade in the neoadjuvant treatment of rectal cancer, which may result in a breakthrough in the treatment of MSS/pMMR rectal cancer.

TRIAL REGISTRATION

This study was registered at www.

CLINICALTRIALS

gov .

TRIAL REGISTRATION NUMBER

NCT05972655. Date of registration: 31 July 2023.

Quality of life and clinical outcomes in rectal cancer patients treated on a 1.5T MR-Linac within the MOMENTUM study

Background and purpose

This study assessed quality of life (QoL) and clinical outcomes in rectal cancer patients treated with magnetic resonance (MR) guided short-course radiation therapy (SCRT) on a 1.5 Tesla (T) MR-Linac during the first 12 months after treatment.

Materials and methods

Rectal cancer patients treated with 25 Gy SCRT in five fractions with curative intent in the Netherlands (2019-2022) were identified in MOMENTUM (NCT04075305). Toxicity (CTCAE v5) and QoL (EORTC QLQ-C30 and -CR29) was primarily analyzed in patients without metastatic disease (M0) and no other therapies after SCRT. Patients who underwent tumor resection were censored from surgery. A generalized linear mixed-model was used to investigate clinically meaningful (≥10) and significant (P < 0.05) QoL changes. Clinical and pathological complete response (cCR and pCR) rates were calculated in patients in whom response was documented.

Results

A total of 172 patients were included, of whom 112 patients were primarily analyzed. Acute and late radiation-induced high-grade toxicity were reported in one patient, respectively. CCR was observed in 8/64 patients (13 %), 14/37 patients (38 %) and 13/16 patients (91 %) at three, six and twelve months; pCR was observed in 3/69 (4 %) patients. After 12 months, diarrhea (mean difference [MD] -17.4 [95 % confidence interval [CI] -31.2 to -3.7]), blood and mucus in stool (MD -31.1 [95 % CI -46.4 to -15.8]), and anxiety (MD -22.4 [95 % CI -34.0 to -10.9]) were improved.

Conclusion

High-field MR-guided SCRT for the treatment of patients with rectal cancer is associated with improved disease-related symptom management and functioning one year after treatment.