Overview
Definition:
Radiation proctitis is a spectrum of injury to the rectal mucosa and submucosa caused by pelvic radiotherapy, typically for pelvic malignancies like prostate, cervical, uterine, or anal cancers
It can manifest acutely during or shortly after treatment, or chronically, often months to years later.
Epidemiology:
The incidence of radiation proctitis varies significantly, with estimates ranging from 5% to over 95% depending on radiation dose, fractionation, treatment techniques, and duration of follow-up
Chronic radiation proctitis affects approximately 5-20% of patients treated with pelvic radiotherapy
Factors increasing risk include higher doses, larger treatment volumes, and concurrent chemotherapy.
Clinical Significance:
Chronic radiation proctitis can lead to debilitating symptoms such as rectal bleeding, tenesmus, fecal incontinence, pain, and stricture formation, significantly impacting a patient's quality of life
Surgical intervention is often considered for refractory or severe cases that do not respond to conservative medical management, posing significant challenges for surgeons due to the irradiated tissues.
Clinical Presentation
Symptoms:
Acute symptoms may include urgency, tenesmus, diarrhea, and mucus discharge
Chronic symptoms are more commonly characterized by intermittent or persistent hematochezia, often bright red blood, which can be severe
Rectal pain, feeling of incomplete evacuation, fecal urgency, and incontinence can also occur
Strictures may present with obstipation or altered stool caliber.
Signs:
Digital rectal examination may reveal mucosal friability, edema, telangiectasias, ulcerations, or a palpable stricture
Proctoscopy or sigmoidoscopy is essential to visualize the extent of mucosal damage, telangiectasias, ulcerations, and pinpoint bleeding points
Advanced strictures might be evident on imaging or physical examination.
Diagnostic Criteria:
Diagnosis is primarily clinical and endoscopic, based on a history of pelvic radiotherapy and characteristic findings on sigmoidoscopy
Histopathology can confirm changes but is often not required unless malignancy is suspected
Grading of severity (e.g., using the Radiation Therapy Oncology Group (RTOG) scale or the LENT-SOMA scale) helps guide management.
Diagnostic Approach
History Taking:
A detailed history of radiation therapy is crucial, including radiation dose, fractionation, target volume, and treatment dates
Inquire about the onset and nature of symptoms: frequency, severity, triggers, and response to prior treatments
Evaluate for red flags such as significant weight loss, change in bowel habits suggestive of malignancy, or signs of systemic illness.
Physical Examination:
Begin with general assessment and vital signs
Perform a digital rectal examination to assess for masses, tenderness, and the presence of blood or stool
Perform a proctosigmoidoscopy to directly visualize the rectal mucosa up to at least 30 cm, noting the presence and extent of telangiectasias, friability, ulcerations, and strictures.
Investigations:
Laboratory tests may include complete blood count (to assess for anemia from bleeding), electrolytes, and renal function
Endoscopy (flexible sigmoidoscopy or colonoscopy) is paramount to assess mucosal damage, exclude other pathologies (e.g., malignancy, infection), and guide treatment
Biopsies may be taken to rule out recurrent malignancy or other conditions
Imaging such as MRI pelvis or CT abdomen/pelvis might be useful to assess for strictures, fistulas, or abscesses, especially if surgical intervention is contemplated.
Differential Diagnosis:
Differential diagnoses include inflammatory bowel disease (ulcerative colitis, Crohn's disease), infectious proctitis (CMV, HSV), ischemic colitis, hemorrhoids, anal fissures, sexually transmitted infections, and colorectal malignancy
Endoscopic findings and history are key to distinguishing these.
Management
Initial Management:
For acute radiation proctitis, conservative measures include dietary modifications (low-residue diet), antidiarrheal agents (loperamide), and topical treatments
For chronic radiation proctitis, initial management focuses on symptom control with topical agents, such as sucralfate enemas, mesalamine suppositories or enemas, or short-chain fatty acid (SCFA) enemas.
Medical Management:
Medical management strategies aim to reduce inflammation and promote healing
Topical treatments are preferred to minimize systemic absorption
Options include sucralfate enemas (1g in 30mL saline, TDS), mesalamine enemas or suppositories (e.g., 500mg BD), short-chain fatty acid enemas (to restore colonic health), and topical steroids (e.g., hydrocortisone enemas) for short durations
Oral pentoxifylline and vitamin E have shown some efficacy in improving symptoms and reducing bleeding by improving microcirculation.
Surgical Management:
Surgical options are reserved for patients with severe, refractory symptoms (significant bleeding, pain, obstruction, or fistula) unresponsive to medical management
Indications include intractable bleeding, symptomatic strictures causing obstruction, recto-vaginal or recto-vesical fistulas, and severe pain or tenesmus impacting quality of life
Procedures include: Endoscopic thermal coagulation (argon plasma coagulation) for bleeding telangiectasias
Strictureplasty or dilation for short, benign strictures
Diverting stoma (colostomy) to decompress the bowel and allow healing
Rectal resection with abdominoperineal resection (APR) or low anterior resection (LAR) with diversion for extensive disease, severe strictures, or fistulas
Sacral nerve stimulation for refractory fecal incontinence
Rectal augmentation or reconstruction procedures are less common due to poor tissue healing in irradiated fields.
Supportive Care:
Nutritional support, fluid and electrolyte balance are crucial, especially in patients with significant bleeding or diarrhea
Pain management should be optimized
Wound care is important for patients undergoing surgery
Psychosocial support is also vital given the chronic nature of the condition and its impact on quality of life.
Complications
Early Complications:
Early complications of radiation injury can include acute proctitis symptoms, radiation-induced cystitis, and proctitis-related diarrhea
Severe bleeding or perforation is rare but possible during acute phases.
Late Complications:
Late complications include chronic radiation proctitis with persistent bleeding, ulceration, and friability
Rectal strictures, entero-rectal or recto-vaginal fistulas, radiation-induced fibrosis, incontinence, and chronic pain are significant long-term sequelae
Malignant transformation within the irradiated field, though rare, is a concern.
Prevention Strategies:
Optimal radiotherapy planning to limit radiation dose to the rectum is paramount
Modern techniques like Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) aim to spare rectal tissue
Prophylactic measures like rectal spacers can further reduce rectal dose
Prompt management of acute radiation proctitis may prevent progression to chronic disease.
Prognosis
Factors Affecting Prognosis:
Prognosis depends on the severity of radiation damage, the extent of disease, the presence of complications (strictures, fistulas), patient comorbidities, and response to treatment
Patients with milder forms of chronic radiation proctitis can often achieve symptom control with medical management
Those requiring surgery generally have more severe disease.
Outcomes:
Medical management can control symptoms in a majority of patients
For those requiring surgery, outcomes vary
Diversion with stoma can provide significant relief, allowing healing
Resection provides definitive treatment for severe disease but carries morbidity
The functional outcome after complex reconstructive surgery in irradiated fields can be challenging.
Follow Up:
Regular follow-up with gastroenterologists or colorectal surgeons is essential for patients with chronic radiation proctitis, even those managed medically
Follow-up includes monitoring for symptom recurrence, progression of disease, and the need for endoscopic surveillance, especially to rule out malignancy
For surgical patients, post-operative follow-up is critical for wound healing and stoma care.
Key Points
Exam Focus:
DNB/NEET SS exams often test understanding of the timing of radiation proctitis (acute vs
chronic), the role of conservative management, specific topical therapies (sucralfate, mesalamine, SCFA), systemic agents (pentoxifylline), and surgical indications/options for refractory cases
Understanding stricture management and fistula treatment in irradiated bowel is key.
Clinical Pearls:
Always ask about prior pelvic radiation in patients presenting with rectal bleeding
Use topical treatments preferentially for chronic proctitis to minimize systemic effects
Argon plasma coagulation is effective for bleeding telangiectasias
Consider stenting for benign strictures prior to definitive surgery if feasible and indicated
Always rule out malignancy in any new or worsening symptoms in a previously irradiated field.
Common Mistakes:
Over-reliance on systemic steroids or oral medications for chronic radiation proctitis without adequate topical therapy
Failing to adequately investigate for malignancy in patients with a history of pelvic radiation and rectal bleeding
Performing extensive resections without considering the poor healing potential of irradiated tissues and the benefits of diversion
Underestimating the impact of radiation on tissue integrity when planning surgery.