Radiofrequency Ablation in the Treatment of Chronic Radiation Enteritis

Abstract

Introduction

Radiation enteritis is the most common complication during radiotherapy for malignant tumors in the abdominal cavity, retroperitoneum, and pelvis. Bleeding is one of the common and severe complications in patients with radiation enteritis (Eur J Med Res 30(1):23, 2025). Endoscopic radiofrequency ablation (RFA) has emerged as a potential treatment, but data on its efficacy and safety are limited. This study conducted a retrospective analysis of the clinical data of patients with radiation enteritis whom we treated, aiming to evaluate the efficacy and safety of radiofrequency ablation (RFA) in the treatment of hemorrhagic chronic radiation proctopathy (CRP).

Method

In this single-center retrospective study, 18 patients with hemorrhagic CRP who underwent endoscopic RFA were included. Patient demographics, clinical variables, endoscopic features, and treatment outcomes were analyzed. Univariate analysis was performed to identify factors associated with treatment failure, and multivariate analysis was not conducted due to the extremely low number of treatment failure events which would lead to statistically unreliable results and high overfitting risk.

Result

The cohort (median age 75 years; 72.2% female) had a median follow-up of 20 months (range: 3–67 months). Hemoglobin levels measured at 6 months post-treatment showed a statistically significant increase compared to pre-treatment levels. Based on the primary endpoint, treatment success was achieved in 15 out of 18 patients (83.3%). Among the 3 patients who did not meet the primary endpoint, 2 required additional endoscopic treatment and 1 continued to experience intermittent hematochezia despite endoscopic improvement. The mean endoscopic score improved from 3.44 to 1.06 (P < 0.001). Given the extremely small number of treatment failure events (n = 2, 11.1%), formal univariate statistical testing for failure-associated factors was not performed; instead, descriptive comparisons were conducted for clinical and endoscopic characteristics of the failed cases. No severe complications (e.g., perforation) occurred; mild to moderate anal pain was the most common adverse event.

Conclusion

In this retrospective series, RFA for hemorrhagic CRP was associated with good tolerability, significant improvements in bleeding, hemoglobin levels, and endoscopic appearance, with a good safety profile over medium-term follow-up.

Introduction

Chronic radiation proctitis (CRP) is a rectal radiation-induced injury resulting from radiotherapy for pelvic malignancies. Although radiotherapy significantly prolongs patients’ survival, its physical damaging effects on normal tissues can lead to injuries in pelvic and abdominal organs, with the rectum being the most commonly and persistently affected site. More than 75% of patients receiving pelvic radiotherapy develop acute radiation proctitis, and approximately 5–20% of them progress to chronic radiation proctitis. Symptoms in CRP patients are prolonged and recurrent, often leading to severe late-stage complications such as massive gastrointestinal bleeding, perforation, obstruction, and intestinal fistula. Clinical management of CRP remains challenging, and the condition significantly impairs patients’ quality of life. Current management strategies for CRP include nutritional support, medication, endoscopic therapy, and surgical intervention. However, pharmacological treatments offer limited efficacy or are associated with numerous adverse effects in controlling rectal bleeding caused by CRP, while surgical procedures entail significant trauma and high risks of adverse events. Endoscopic therapy has gradually become the primary treatment for CRP-related bleeding. Endoscopic radiofrequency ablation (RFA) is a novel treatment method for CRP; however, its safety and long-term efficacy have not been fully understood yet. This study retrospectively reviews RFA for hemorrhagic CRP patients from a single center. Given the exploratory nature of this retrospective design without a control group, the primary aim is to describe our initial experience and generate hypotheses for future comparative studies.

Materials and Methods

Study Population

A retrospective analysis was conducted on the clinical data of 18 patients with CRP and bleeding who underwent endoscopic RFA for hemostasis at Shandong Cancer Hospital from February 2022 to April 2025. Clinical and laboratory assessments were performed before and after treatment, and patient demographics, clinical manifestations, medical history, and Hb levels of the patients were recorded. Gastrointestinal endoscopy was completed preoperatively, and treatment was administered to exclude certain diseases that could cause blood loss, such as gastrointestinal polyps, hemorrhoids, and peptic ulcers. Proctoscopy was performed to evaluate the extent of lesions. Treatment risks were fully explained, and informed consent was obtained from patients and their families.

Inclusion criteria:

1. History of pelvic radiation therapy with a diagnosis of CRP;

2. No use of anticoagulant medications such as aspirin, warfarin, or heparin within the past week;

3. Persistent rectal bleeding despite conservative medical treatment; and

4. Stable vital signs and ability to tolerate colonoscopy under anesthesia and sedation.

Exclusion Criteria:

1. Patients with hemorrhagic radiation proctitis whose primary disease required further surgery, chemotherapy, or radiotherapy;

2. Presence of other causes of rectal bleeding identified during colonoscopy aside from CRP;

3. Patients with major complications of chronic radiation proctitis, such as stenosis, fistula, deep ulcers > 1 cm² in area, or sepsis;

4. Patients with severe coagulation disorders (INR > 2.0) or platelet counts < 50,000/mm³;

5. Patients with severe cardiopulmonary or renal failure, limb movement disorders, and/or cognitive dysfunction; and

6. Patients with recurrence of the primary tumor or lost to follow-up during the follow-up period.

Endoscopic manifestations of CRP patients were recorded, and the severity of CRP was graded based on endoscopic scoring. According to the Zinicola endoscopic scoring system [2], three factors were independently assessed: the distribution of telangiectasias, the affected surface area, and the presence of active bleeding. The cumulative score was calculated to determine the endoscopic severity of CRP: mild (2 points), moderate (3 points), or severe (4–5 points). Endoscopic scoring was performed by the operating endoscopists immediately during the procedure (Table 1).

Table 1.

Zinicola endoscopic score

Factors	Endoscopic Findings	Score
Distribution of telangiectasia Distal rectum	< 10 cm from the anal verge	1 point
	Entire rectum and/or sigmoid colon (≥ 10 cm from the anal verge)	2 points
Surface Area Covered by Telangiectasia	< 50%	1 point
	≥ 50%	2 points
Presence of Fresh Blood	Yes	1 point
	No	0 points

1. Distribution of telangiectasia: The distal rectum (< 10 cm from the edge of the anus) is worth 1 point, the entire rectum or sigmoid colon (≥ 10 cm from the edge of the anus) is worth 2 points

2. If the surface area covered by dilated capillaries is <50%, it is worth 1 point; if it is ≥ 50%, it is worth 2 points

3. Whether there is fresh bleeding: 0 points if none, 1 point if there is

All procedures were performed by a dedicated team. The team was led by a single senior - titled physician who boasted over 20 years of experience in endoscopic interventional surgeries. This senior physician collaborated with an intermediate-level physician having more than 5 years of surgical experience, aiming to minimize technical discrepancies as much as possible. All procedures were completed under non - intubated general anesthesia. The equipment utilized included gastroscopes (Olympus, Japan) and a RFA system (Halo90, BARRx/Covidien, Sunnyvale, USA).

Research Methods

Treatment Approach

Prior to RFA treatment, all patients received standard bowel preparation using compound polyethylene glycol electrolyte powder to minimize fecal contamination and create an optimal operating environment. Prophylactic antibiotics were not administered preoperatively. Radiation proctitis was confirmed, and areas of potential or active bleeding were identified. A gastroscope was used instead of a colonoscope during treatment because the gastroscope is more flexible and easier to manipulate, especially when coupled with the RFA catheter. Additionally, the Halo90 electrode catheter device was specifically designed for use with gastroscopes. A standardized operating protocol was aimed for, utilizing the Halo90 catheter and the energy settings described. All other procedural parameters (bowel prep, anesthesia, power setting, treatment interval) were consistent across the cohort. The Halo90 catheter was precisely positioned at the 6 o’clock position, with the power set at 40 W/cm². For actively bleeding telangiectatic regions located within 8 cm above the dentate line, an energy level of 15 J/cm² was applied. In contrast, for the upper and middle rectum, which were more than 8 cm above the dentate line, an energy setting of 12 J/cm² was used. To prevent sensory damage to the anal mucosa, ablation was carried out approximately 1 mm away from the dentate line. After inserting the device into the patient’s rectum, the operator conducted a thorough inspection to identify bleeding areas caused by telangiectasia. The operator then rotated the gastroscope knob to press the electrode firmly against the targeted rectal wall and initiate energy delivery. The Halo90 system automatically delivered energy and stopped. Typically, 1–2 RFA applications were performed on each telangiectatic site to ensure sufficient ablation and effective hemostasis (Fig. 1). To enhance the hemostatic effect, coagulated tissue at the treatment site was not scraped off. To maintain the electrode surface’s efficacy for subsequent treatment areas, the RFA catheter was withdrawn and cleaned every 8 applications to maintain electrode efficacy. The procedure was repeated as necessary until the affected rectal mucosa was completely ablated, appeared pale white, and showed no signs of fresh bleeding under direct endoscopic observation. For severe bleeding cases where clinical efficacy was difficult to achieve in a single session, two or more treatment sessions were often performed, with at least 4 weeks between each treatment cycle.

Fig. 1.

Endoscopic manifestations of radiation proctitis before and after RFA treatment

Before treatment during treatment after treatment

Definitions

In this study, the primary outcome measure for treatment success was strictly defined as the cessation of hematochezia without the need for any further endoscopic or surgical intervention for rectal bleeding within 6 months following the last RFA treatment. Secondary outcome measures included: Improvement in hemoglobin (Hb) levels, defined as a ≥ 10% increase or normalization from pre-treatment levels; Reduction in the Zinicola endoscopic score; Regression of telangiectasia (defined as eradication or the presence of only a few residual lesions). Complications were defined as clinical conditions that required ongoing intervention, such as the continued need for red blood cell transfusion, the development of refractory rectal ulcers, and/or the formation of rectovaginal fistulas. Recurrence was defined as the exacerbation or re-emergence of symptoms, including diarrhea or hematochezia, within six months after the completion of treatment compared to the pre-treatment state [3, 4].

Observation Indicators and Follow-Up

Antiplatelet drugs and oral anticoagulants were resumed 5–7 days post-procedure. Following RFA treatment, the patient’s condition, complications caused by RFA, the number of medical visits related to rectal bleeding, the need for blood transfusion, and the endoscopic severity score were recorded.

Follow-up was conducted via telephone or outpatient clinic visits at 1, 3, 6, 12 months and annually thereafter. Colonoscopies and Hb level checks were scheduled at these intervals. To assess hemoglobin improvement, the Hb value measured at the 6-month follow-up visit was used as the primary post-treatment time point, as this was considered sufficient to capture the full effect of mucosal healing while minimizing confounding from transient fluctuations. If a patient required blood transfusion within 3 months prior to the 6-month Hb measurement, that Hb value was excluded from the analysis to avoid artificially inflated post-treatment levels; in such cases, the next available Hb measurement after the 6-month time point (but before any subsequent intervention) was used instead. Follow-up assessments included inquiries about anal pain, tenesmus, abdominal pain, diarrhea, hematochezia, changes in bowel habits, as well as reviewing post-treatment Hb levels and recording any transfusions or other interventions that could potentially increase Hb levels. Patients with persistent rectal bleeding and severe anemia were considered for re-treatment.

Statistical Methods

Data analysis was performed using SPSS software (version 25.0). Measurement data conforming to a normal distribution were expressed as mean ± SD and were compared between groups using paired t-tests. Non-normally distributed continuous data were expressed as the median (range). Categorical data are expressed as frequency (%), and comparisons between groups were made using theχ²test. A P-value < 0.05 was considered statistically significant. Non-parametric, two-tailed, paired signed-rank tests were used to assess differences in continuous variables between the two treatment periods (i.e., the 6 months before and after RFA), and exact significance levels were calculated. For hemoglobin analysis, pre-treatment Hb was defined as the value measured closest to the first RFA session (within 30 days prior). Post-treatment Hb was defined as the value measured at the 6-month follow-up visit according to the protocol described above. Due to the extremely low number of treatment failure events (n = 2) among the 18 patients, formal inferential statistical analysis (including univariate testing) for identifying failure-associated factors was deemed inappropriate and abandoned. Instead, a descriptive comparison of clinical, laboratory, and endoscopic characteristics was conducted for the two failed cases to explore potential clinical correlates of treatment failure. Given the limited sample size (n = 18), a formal power calculation was not performed prior to this retrospective analysis. Results of the descriptive comparisons for failure-associated factors should be interpreted with extreme caution as exploratory observations only.

Results

Demographic Characteristics

This retrospective study included 18 patients with bleeding chronic radiation proctitis, comprising 5 males (27.8%) and 13 females (72.2%). Patient characteristics are summarized in Table 2. The mean patient age was 70.5 ± 12.4 years, with a median of 75 years (range: 63–87 years). All patients with pelvic malignancies had undergone pelvic radiotherapy. The primary tumor sites were prostate cancer in 1 case (5.6%), cervical cancer in 10 cases (55.6%), rectal cancer in 5 cases (27.8%), and uterine corpus tumors in 2 cases (11.1%). The median duration from the cessation of radiotherapy to the onset of radiation proctitis was 10.44 ± 7.81 months [Mean (SE) = 10.44 (1.84); Median (IQR) = 8 (6, 11)]. All patients experienced recurrent rectal bleeding, of whom 11 cases (61.1%) having Hb levels < 9 g/dL requiring blood transfusion. Recurrent rectal bleeding not only led to a decreased quality of life but also resulted in life-threatening events in some cases [4]. Detailed radiotherapy parameters such as dose fractionation, technique (e.g., 3D-CRT, IMRT, VMAT, brachytherapy), and rectal dose-volume metrics were not consistently available in this retrospective analysis, which limits the assessment of their potential influence on proctitis severity or treatment response.

Table 2.

Basic information of patients with radiation proctitis enrolled in the group

	Moderate(n = 12)	Severe(n = 6)	P
Gender			0.283
Male	2	3
Female	10	3
Age	61.75 ± 8.32	67.17 ± 7.96	0.172
Hb before treatment	96.83 ± 28.07	65.83 ± 15.73	0.011
Hb after treatment	126.92 ± 15.52	110.83 ± 19.81	0.063
Time of symptoms appear after radiotherapy	9.91 ± 5.05	11.5 ± 12.21	0.681
Complications			0.283
Yes	2	3
No	10	3
Blood transfusion			0.592
Yes	5	3
No	5	1
Radiotherapy dose	79.1 ± 24.74	100.8 ± 20.75	0.079
Ulcer			0.286
Yes	0	1
No	12	5
Lesion length	6.58 ± 2.64	8.83 ± 3.31	0.107
Underlying diseases
Diabetes	1	2	0.529
Hypertension	2	2	1.000
Liver diseases	3	2	1.000
Kidney disease	3	2	1.000
Cardiovascular diseases	3	0	0.529
Therapeutic outcome			0.067
Success	12	4
Failure	0	2

Lesion Characteristics

Before treatment, 7 patients (38.9%) had extensive circumferential telangiectasias, 3 patients (16.7%) had telangiectasia areas exceeding 75%, 5 patients (27.8%) had lesion lengths exceeding 10 cm, 11 patients (61.1%) had lesion lengths between 5 and 10 cm, and only 2 patients (11.1%) had lesion lengths less than 5 cm. Fresh blood was present in the rectal lumen of 14 patients (77.8%). The mean number of RFA sessions was 1.3 (range: 1–3). RFA treatment failed to successfully control bleeding in 2 patients (11.1%). Descriptive comparison of these two failed cases revealed that both had pre-treatment Hb < 9 g/dL and lesion lengths ≥ 10 cm; no formal statistical testing was conducted for these or other potential failure-associated factors due to the small number of events.

Hb and Endoscopic Score

Hemoglobin levels were measured in all 18 patients at the 6-month post-treatment follow-up. Compared to pre-treatment levels (85.6 ± 27.8 g/L), Hb levels at 6 months increased significantly to 121.6 ± 18.9 g/L (P < 0.001) (Fig. 2). Among the 11 patients who required transfusions pre-treatment, 6 (54.5%) completely ceased requiring transfusions within 6 months after RFA. One patient with radiation proctitis had tenesmus prior to endoscopic treatment, which did not improve after the procedure.

Fig. 2.

The changes of Hb in radiation proctitis of different severity before and after RFA treatment. Hb levels were re-examination six months post-treatment, and varying degrees of increase were observed in all patients. The mean Hb level after treatment increased significantly than that before treatment

The treatment significantly reduced the endoscopic score from a mean of 3.44 to 1.06 (mean score changeΔ = 2.39). The Wilcoxon Signed-Rank Test confirmed that this improvement was highly significant (P < 0.001 = 1.22 × 10^−5). This result supports the significant efficacy of the treatment in improving endoscopic appearance.

Number of Treatments and Scores

16 patients (88.9%) received a single RFA treatment. 2 patients received two RFA sessions [5]. All patients underwent colonoscopy and were scored after RFA treatment. The post-treatment endoscopic score (1.33 ± 0.98) was significantly lower than the pre-treatment score (3.47 ± 0.74; Mean ± SD) (p < 0.001), indicating that RFA significantly improved patients’ endoscopic scores statistically (Fig. 3). Representative colonoscopy findings before and after RFA treatment are shown in Fig. 3. Multifocal bleeding telangiectatic sites were treated with RFA immediately after achieving adequate hemostasis. No further bleeding was observed, and there was no evidence of new telangiectasia formation. A dedicated summary of adverse events is presented in Table 3.

Fig. 3.

Endoscopic score comparison before and after treatment. The score decreased significantly after endoscopic treatment (p < 0.001), indicating that the overall treatment was effective and the overall supportive treatment was effective. The extent of score reduction (about 2 points) was clinically significant. The failed cases (red) were mostly concentrated in the high-rating group before treatment (≥ 4 points), suggesting that patients with severe lesions may need to strengthen the treatment plan

Table 3.

Summary of adverse events following RFA treatment (n = 18)

Adverse Event	n (%)	Severity (CTCAE v5.0 Grade)	Median Duration (Range)	Management
Anal/Rectal Pain	16 (88.9%)	Grade 1–2 (Mild-Moderate)	3 weeks (1–6 weeks)	Oral analgesics (n = 14), Spontaneous resolution (n = 2)
Intermittent Hematochezia	3 (16.7%)	Grade 1–2	7.4 weeks (2–24 weeks)	Observation; resolved spontaneously with mucosal healing
Transient Tenesmus	1 (5.6%)	Grade 1	2 weeks	Observation
Perforation	0	-	-	-
Aggravated Bleeding	0	-	-	-
Ulceration/Stricture	0	-	-	-

Adverse Events

All patients attended regular outpatient follow-up visits postoperatively. The median follow-up duration was 20 months (range: 3–67 months). Among all 18 patients, the procedure was well-tolerated by everyone. No complications such as perforation or worsened bleeding occurred during the treatment operation. The most common adverse event was mild to moderate anal pain, occurring in three patients (16.7%). Among them, two patients required oral analgesics, and one patient experienced spontaneous resolution without intervention. Most rectal discomforts subsided after 3 weeks. Three patients (16.7%) presented with significant rectal bleeding two months after RFA. Among them, 2 patients required blood transfusion to treat anemia. The recurrent bleeding was believed to be caused by delayed mucosal re-epithelialization after RFA treatment and would cease spontaneously once complete mucosal re-epithelialization occurred. However, by the time of their last outpatient visit, all patients showed significant improvement in clinical symptoms and did not require further blood transfusions (Table 4).

Table 4.

Descriptive clinical characteristics of RFA treatment failure cases for radiation proctitis

Variables	Correlation analysis
	Correlation coefficient (r)	p
Ulcer	0.52	0.008
Hb before treatment	-0.41	0.032
Radiotherapy dose	0.18	0.210
Blood transfusion	0.31	0.085
Kidney disease	0.38	0.048
Lesion length	0.22	0.230
Pre-treatment score	0.28	0.160
Time of symptoms appear after radiotherapy(months)	0.15	0.310
Diabetes	0.10	0.450
Hypertension	0.12	0.380

Discussion

Radiation therapy is widely applied in the treatment of pelvic cancers, with an incidence rate of 2–20% [6, 7]. Although substantial advances have been made in radiation technology to deliver more targeted therapy, radiation can induce rectal mucosal injury and increase the baseline function of mucosal microvasculature, leading to enhanced telangiectasia density and recurrent rectal bleeding. The average time of symptom onset is approximately 8 to 12 months after radiotherapy, with the earliest and latest presentations in this cohort occurring at 4 months and 24 months, respectively. Although CRP is a relatively uncommon condition, its incidence and severity are increasing with the refinement of radiation techniques. Therefore, optimal management of CRP requires a clear and evidence-based treatment strategy. To date, the American Society of Colon and Rectal Surgeons (ASCRS) considers pharmacological therapy and endoscopic intervention as the preferred approaches for CRP management. Endoscopic treatment, owing to its direct visualization and minimally invasive nature, has been and continues to be a powerful modality for this disease. Among endoscopic therapies, argon plasma coagulation (APC) is generally regarded as the first-line treatment for CRP. Reported success rates of APC range from 70% to 90%, though more than two treatment sessions may be required in cases of extensive disease. However, APC has disadvantages compared to other endoscopic treatments due to the risk of colonic overdistension caused by argon gas flow. Serious complications such as fistula, perforation, explosion, or stenosis occur in approximately 4% of patients, 20% of patients experience anal pain, which typically resolves spontaneously [8]. In contrast to APC, RFA is a contact-based method for treating CRP that delivers consistent energy to the surface through well-defined and reproducible energy increments, resulting in uniform tissue penetration depth (approximately 1000 μm). Moreover, the tightly spaced bipolar array of RFA catheters restricts the penetration of radiofrequency energy, limiting injury to the superficial mucosa and muscularis propria, while avoiding injury to the submucosa. This minimizes the risk of overtreatment that could lead to ulcers or perforation, as well as the likelihood of operator-dependent technical variability.

RFA was initially designed for the ablation of Barrett’s esophagus [9–11], and is approved by the FDA for the treatment of Barrett’s esophagus and gastric hemostasis applications. The squamous re-epithelialization following RFA can reduce bleeding, fibrosis, and stricture formation due to the superficial depth of ablation (0.5–1 mm) [12]. Even when two ablations are performed at the same site, the maximum depth of injury in the colon and rectum is limited to lamina propria, which is significantly shallower and safer (less than 3 mm) and contact thermal methods (variable) [13, 14]. Finally, Based on published reports, RFA is thought to offer advantages such as more uniform energy delivery and a lower risk of deep tissue injury compared to modalities like APC [15]; however, direct comparative studies are needed to confirm these potential benefits. Trunzo et al. first proposed the use of RFA in the colon and rectum and demonstrated its efficacy and safety [16]. McCarty et al. [7] included six studies in a systematic review and meta-analysis to evaluate the efficacy and safety of RFA for CRP. Among the 71 patients included in the six studies, the overall technical and clinical success rates were 100% and 99%, respectively. The studies also indicated that despite performing two ablations at the same site, the deepest injury caused by RFA was limited to the muscularis propria of the colon and rectum. Our study showed that < u > Hb levels increased significantly from (85.6 ± 27.8) g/L before treatment to (121.6 ± 18.9) g/L at 6 months after treatment (P < 0.001), based on analysis at a standardized follow-up time point to ensure robust and unbiased assessment of hematologic improvement. Among the 11 patients who required blood transfusions, 6 (54.5%) completely discontinued transfusions within 6 months after RFA. Of the 5 patients (45.5%) who remained dependent on transfusions after RFA, 3 experienced a reduction in transfusion requirements. Compared to Postoperatively, three patients (16.7%) reported anal pain. Among them, two patients achieved symptom control with oral analgesics, and one patient experienced spontaneous remission without any intervention. No serious complications were observed during follow-up to date. Therefore, RFA is an effective and well-tolerated treatment for CRP. The high hemostasis rate and the cessation of transfusion requirements demonstrate that RFA is an effective therapeutic option for CRP. While the median follow-up of 20 months provides insight into medium-term outcomes, data on very long-term efficacy and safety beyond 5 years remain limited. The recurrence observed in two cases underscores the need for ongoing surveillance even after initial treatment success.

The most prevalent adverse event associated with RFA is intermittent hematochezia, which is widely believed to stem from the mucosal healing process occurring at the RFA site [17]. Previous research has indicated that the duration of hematochezia typically ranges from 12 to 16 weeks [18]. In our study, 3 patients experienced persistent intermittent hematochezia, with the duration spanning from 2 to 24 weeks, with a mean duration of 7.4 weeks. As has been documented in prior studies, squamous re-epithelialization following RFA is likely the principal mechanism that prevents recurrent hemorrhage [19, 20]. The duration of hematochezia after RFA treatment may be intricately linked to the time required for complete mucosal healing and squamous re-epithelialization. In cases where patients continue to suffer from rectal bleeding, we generally opt to perform retreatment 4–12 weeks after the initial treatment. Other adverse events of RFA include mild to moderate anorectal pain [21]. However, the majority of these symptoms can be effectively managed with oral analgesics and tend to resolve spontaneously within a few weeks. Notably, no serious complications have been reported in the literature.

In our cohort of 18 patients, two experienced RFA treatment failure in terms of achieving the primary endpoint. Descriptive characterization of these two failed cases showed that both presented with circumferential telangiectasia, lesion lengths ≥ 10 cm and pre-treatment Hb < 9 g/dL; these findings are presented as exploratory clinical observations only, with no formal statistical testing performed due to the extremely small number of failure events. A Hb level < 7 g/dl was further observed as a notable factor in the two failed cases, though this finding is exploratory due to the small sample size. In a study by Sultania et al. [22], Hb level was reported as the only protective factor against treatment failure (OR 0.59, 95% CI: 0.38–0.89), with no risk factors being identified. Consistent with these findings, the two patients who experienced treatment failure exhibited a certain degree of anemia and required blood transfusion. We did not find a significant correlation between the presence of fresh blood and RFA treatment failure.

According to the Vienna classification system, ulcers represent a severe manifestation of radiation proctitis. Goldner et al. [23] proposed that patients receiving high-dose radiation treatment within a specific volume may develop histopathological changes, such as ulcers, in addition to mucosal congestion or telangiectasia. Descriptive analysis of our cohort showed that ulceration and telangiectasia involving ≥ 50% of the rectal surface area were clinical features associated with treatment failure in the small number of failed cases, but no definitive inferences can be drawn regarding their predictive value due to the lack of formal statistical testing and the extremely low event count. Pre-treatment Hb was associated with treatment failure in univariate analysis, and it may be a consequence of chronic blood loss from extensive lesions or ulcerations, though this hypothesis cannot be verified due to the lack of multivariate analysis.

The study cohort exhibited a marked gender imbalance (72.2% female), primarily reflecting the high prevalence of cervical and uterine cancers in our sample. This limits the generalizability of findings to male-predominant populations (e.g., prostate cancer survivors), where pelvic anatomy, radiation fields, and tissue responses may differ. While our small sample precluded formal sex-based subgroup analysis, no overt qualitative differences in lesion characteristics or treatment tolerance were noted between genders. Future studies should aim for more balanced enrollment or stratified analyses to explore potential gender-related effects on RFA outcomes. This consideration aligns with growing recognition of gender as a biological variable influencing radiotherapy toxicity profiles [24].

This study has several limitations. Firstly, it is a single-center, retrospective, single-arm cohort study, which is subject to patient selection bias, as the population admitted to our hospital may present with more severe diseases compared to other centers not specialized in treating neoplastic diseases and their complications. Consequently, the results may not be fully generalizable to patients with milder forms of radiation proctopathy treated in community settings. and the conclusions are limited by the lack of a control group. Further comparative studies or randomized trials are necessary. In addition, it is inherently subject to patient selection bias and the absence of a comparative control group (e.g., patients treated with argon plasma coagulation). This design limits the strength of causal inferences regarding the relative efficacy of RFA. Therefore, the evidence presented should be considered exploratory and hypothesis-generating rather than confirmatory. Secondly, the endoscopic severity scoring was assessed by the same endoscopists performing the RFA procedures, which introduces potential for observer bias. Future studies would benefit from independent, blinded review of endoscopic images to enhance the objectivity of scoring. Additionally, the lack of objective data on patient satisfaction and symptom improvement may also contribute to potential subjective bias. In fact, the clinical decisions regarding the need for retreatment (RFA or any other treatment) are not standardized, making it difficult to draw relatively uniform conclusions. Thirdly, endoscopic techniques vary significantly among different operators. while a core protocol was followed, minor technical variations existed, such as the use of Halo60 vs. Halo90 catheters or differences in the number of pulses applied by individual operators. Although these variations did not appear to markedly affect safety or efficacy in our cohort, they highlight the need for further technical standardization and evaluation in prospective studies to optimize and unify the RFA procedure for CRP. Other parameters (power, preparation, sedation, time interval between treatments) varied greatly among operators. Fourthly, as a retrospective analysis, we were unable to obtain standardized, detailed radiotherapy parameters for all patients. The reported radiation doses were often the prescribed total doses, which in many cases, particularly for cervical cancer, likely represented an arithmetic sum of external beam radiotherapy and brachytherapy. This sum does not accurately reflect the biologically effective dose delivered to the rectum. This lack of detailed, organ-specific dosimetric data (e.g., EQD2, Dmax, V40) prevents any meaningful analysis of the relationship between radiation exposure and the severity of proctopathy or the response to RFA. Fifth, although we used a standardized 6-month time point for post-treatment hemoglobin assessment to improve methodological rigor, the exclusion of Hb values within 3 months of transfusion in some cases, while necessary to avoid confounding, may still introduce some degree of selection bias. Future prospective studies should incorporate scheduled, protocol-driven Hb measurements at fixed intervals to eliminate this concern. Finally, the small sample size (n = 18) and the low number of treatment failure events (n = 2) precluded any formal inferential statistical analysis for identifying factors associated with treatment failure; only descriptive comparisons of the failed cases were feasible. All observed associations should be regarded as exploratory and hypothesis-generating, requiring validation in larger prospective cohorts. This limitation underscores the need for multi-center studies with adequate sample sizes to reliably identify predictors of treatment outcomes in chronic radiation proctopathy. The technique of RFA for radiation proctitis could be better standardized and evaluated in future prospective studies. Nevertheless, Our retrospective experience suggests that RFA for radiation proctitis is feasible, safe, and effective, and does not appear to be strongly operator-dependent, showing similar efficacy and safety to those reported in the literature.

Conclusion

Our retrospective experience suggests that RFA is an emerging technique with good tolerability, high clinical success rates, favorable long-term outcomes, and no serious complications in the treatment of CRP. It may represent a potential treatment option, possibly as a second-line modality after failed first-line therapies. However, larger, prospective, controlled studies comparing RFA with other endoscopic therapies are needed before it can be routinely recommended for CRP. More experience and longer follow-up periods are required to recommend it as a primary treatment option.

Author Contributions

Conceptualization, Ming Chen, Zengjun Li; Methodology, Xinguang Huang; Investigation, Dongyang Wang; Data curation, Huizhuan Zhai; Writing—original draft preparation, Mingjuan Sun; Writing—review and editing, Haipeng Wang, Hao Zhang; Supervision, Meng Lu; Funding acquisition, Zengjun Li. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Shandong Medical Association (No. YXH2022ZX02018) .

Data Availability

All data generated or analyzed during this study are included in this published article.

Declarations

Competing Interests

The authors declare no competing interests.