Comparison of Topical Photodynamic Therapy With Topical Calcipotriol in Management of Oral Leukoplakia

Objectives

Primary Objectives:

3.1 To compare the effect of 2.5% Toluidine blue mediated topical photodynamic therapy and topical calcipotriol (0.005%) on clinical response after completion of treatment at 4 weeks from baseline during management of Oral leukoplakia

Secondary Objectives:

3.2 To compare the effect of 2.5% Toluidine blue mediated topical photodynamic therapy with topical Calcipotriol (0.005%) on lesion size, lesion roughness/ whiteness, and oral health quality of life after completion of treatment at 4 weeks and 12 weeks from baseline during management of Oral leukoplakia 3.3 To compare the effect of 2.5% Toluidine blue mediated topical photodynamic therapy with topical Calcipotriol (0.005%) on salivary molecular markers ( IL6, TNF-α, PCNA, Survivin and VEGF) after completion of treatment at 4 weeks from baseline 3.4 To compare the adverse events, time to complete response and recurrence rates between the two groups

Rationale:

Nearly two thirds of Oral Cancers are preceded by oral potentially malignant disorders like OL, caused by tobacco, alcohol and areca nut habits. OL has a high prevalence and malignant transformation rate ( 0.13%- 40.8%).There are no universal management protocols for OL. Preventive, conservative, medical and surgical interventions have several limitations and high recurrence rates. Non homogenous, dysplastic, large, mutifocal, proliferative recurrent and recalcitrant OL in subjects with co morbidities pose even more serious challenges in management for the oral physician who often resort to conservative measures with watchful observation. Patients with OL have to deal with unaesthetic appearance of lesion and fear of malignancy which affects their oral and psychological health.

Removal of the pathological OL lesions is believed to reduce the risk of malignancy. There are surgical, laser ablation, electrocautery, cryotherapy options available but they are associated with post operative complications like pain, swelling, infections, neuropathy, scarring and adversely affect oral function with high recurrence rates. These methods only address the physical abnormal area where instituted and do not bring about any beneficial change in the biology of the affected area. There is a need for non invasive methods of removing OL without the current limitations and which also bring about favourable molecular changes in the underlying and adjacent tissues to mitigate the risk of malignant transformation.

Photodynamic therapy (PDT) is a non invasive method of removing abnormal tissue using a Photosensitizer (PS) and approprite light activation which selectively targets abnormal cells and causes cytotoxicity and death. PDT also causes apoptosis, vascular disruption and has immuno modulatory effects to decrease the risk of malignancy. The most widely used and studied PS is 5 -aminolevulinic acid (5-ALA). 5 ALA has several limitations as it is very expensive, photosensitive, causes swelling, pain , burning sensation, allergic reaction on adjacent tissue , requires a dark room for application and long incubation hours ( 2 hours). Toludine Blue (TB) is a metachromatic dye which has been used as a vital stain in oral cancer screening as it preferentially stains mitotic and dysplastic cells. It can also be used as a PS as it gets activated by red light ( 620- 660nm) and has been used in PDT in a single case series of 15 OL lesions with 40% complete response. It is cheap, safe , less toxic and photosensitive, targets abnormal cells, simple application, requires less incubation time, no dark room required and no reported side effects. PDT has usually been tried with 5ALA as photosensitizer (Ps) and Laser light as activator. PDT with LED light source as activator is cheaper and more feasible in resource limited settings.

Topical Retinoids have been used as a non invasive method to remove lesions of OL due to their antikeratinocyte activity but have high recurrence rates, risk of systemic toxicity and development of resistance. Topical calcipotriol is a synthetic Vit D analogue which has been used in Psoriasis for its antiproliferative anti inflammatory anti angiogenic and immunomodulatory effects. There are only two studies that have used Calcipotriol in OL with complete response from 25%-80% with no side effects.

There is no RCT that have compared the effects of TB mediated PDT and topical calcipotriol in OL at present.

The levels of Pro- oncogenic cytokines ( IL6, TNF-α, PCNA, Survivin and VEGF) that promote inflammation, proliferation and angiogenesis are important prognostic biomarkers that can help to evaluate the benefits of any intervention in OL. There are no studies that have evaluated these cytokines after topical PDT or Calcipotriol therapy in OL.

Number of Patients:

Sample Size:In a systematic review and meta-analysis on PDT for Oral Leukoplakia by Zhang et al(2023) overall complete response was seen in 50% of patients.

While only 2 studies, mention results of topical Calcipotriol(0.005%) in oral leukoplakia with sample size of 20 in both study groups. In one RCT (Femanio et al 2001) which found a CR of 80% in OL after topical calcipotriol at 5 weeks. In another study(Galwash et al 2017) in which total response was 25% at 4weeks.

Due to lack and variability of data in available studies on response of topical calcipotriol(0.005%) in Oral Leukoplakia We can anticipate CR in 25% of patients in our study. Estimated sample size for two-sample comparison of proportions Test H0:P1=P2, where p1 is the proportion in population 1 and p2 is the proportion in population 2.

Assumption:

alpha=0.0500(two-sided) power=0.8000 p1=0.2500 p2=0.5000 n2/n1=1.00 Estimated required sample sizes: n1=66, n2=66 Final sample size was 83/ group considering 20% of patients as lost to follow up.

Total sample size: 166

Group A (n=83):Non-invasive PDT using LED of wavelength ranging from 630-660nm( Fluence 15 J/cm2) as light source and 2.5% TB as photosensitizer will be used in oral leukoplakia once a week for 4 weeks along with preventive and conventional therapy.

Group B (n=83):Topical application of Calcipotriol ointment 0.005% twice a day for 4 weeks along with preventive and conventional therapy

5.5 Study design An open label Randomized clinical trial

Block Randomization:

Block randomization with varying block size will be done using computer generated random numbers. Allocation ratio (1:1)

Allocation concealment:

Participants will be randomized using sequentially numbered, opaque sealed envelopes (SNOSE): the randomization group will be written on a paper and is kept in an opaque sealed envelope prepared with aluminium foil sheet and carbon sheet in each. The envelope will be labelled with a serial number and randomization code and will have an identifier of trial on its front. The intervention will be written on a paper inside the envelope and sealed by technician. Envelopes will be opened sequentially by the operator, and patients will be allotted a study arm as per the intervention mentioned inside the envelope. Used envelopes will be stored separately until the completion of trial.

Intervention

Conventional non-invasive management (Usual care):

All subjects in the two groups will receive the same standard conventional non- invasive management advised for OL as per current scientific evidence.

* Brief behavioral Tobacco, areca nut and alcohol habit cessation counseling as per WHO 5As and 5Rs technique at baseline and each follow up. * Oral prophylaxis * Removal of oral irritational factors like sharp teeth, appliances or prosthesis, impacted buccoverted third molars, parafunctional habits * Oral hygiene maintenance instructions * Control of systemic conditions (Anemia, Diabetes, hypertension, thyroid disorders) by specialist referral * Removal of all predisposing factors for oral candida infection * Advocacy for safe sexual practices * Nutrition and diet counseling( seasonal and regional food rich in nutrients, vitamins, antioxidants avoidance of spicy /sour/ hot foods and drinks) * Regular surveillance for malignant transformation Investigations: Orthopantomogram, Complete hemogram, Liver function tests, Renal Function tests, Lipid profile, Parathyroid hormone, Serum Ca2+, Serum Vit D3 level, Serum electrolytes level Site selection of Oral leukoplakia in trial In subjects with multiple areas of involvement, the non homogeneous and larger lesions will be selected for treatment and assessment.

Photodynamic Therapy Protocol:

Protocol for preparation and application of 2.5% TB as Ps:

The protocol foresees the application of 2.5% TB, prepared following standard procedures and adapting the proportions as stated by Epstein et al., on the lesions, using a cotton applicator tips, with a margin of 3mm from the surrounding normal tissue and leaving it to sit for 5min, avoiding any contact with the saliva using cotton rolls, cheek retractor and suction apparatus Protocol for LED Photodynamic therapy in Oral Leukoplakia patients Equipment LED light source Wavelength 630-660nm Peak Power 0.04 W/cm2 Fluence 15 J/cm 2 Spot size 0.66cm2 Distance Intraorally: At oral mucosal surface(Contact mode) Mode Continuous, circular motion, overlapping, in clockwise concentric manner with LED handpiece perpendicular to surface Duration of cycle 360 seconds over 1 cm2 area of diagnosed OL lesion. Cycles per sitting One cycle per sitting No. of sittings Four, One sitting / week ( @ Day 0, 1 week, 2 week, 3 week Area of intervention Intraoral over OL lesion ( non homogenous and larger lesion given preference in subjects with multiple site involvement ) Treatment time 360sec/6 minutes for OL lesion of size 1cm2/12 min for 2cm2 Dosimetry and calibration of LED device Every month using power meter and spectrometer

Protocol for application of topical Calcipotriol(0.005%) ointment in Oral Leukoplakia patients:

All patients will be shown the site of OL lesion and demonstration for application of topical Calcipotriol ointment(0.005%) will be given to them. Patients are advised to apply Cal ointment twice daily for 4 weeks after meals.

Steps in application of topical Calcipotriol(0.005%) ointment:

Dry the lesion site with sterile gauze Apply the agent as a ointment with a cotton bud Leave the ointment for at least 30 minutes Avoid swallowing the drug Avoid drinking/ eating/ spitting for at least 30 minutes after drug application Reiteration of the protocol to subject with physical demonstation at each follow-up visit

Training of operators:

The operator and the assistant, giving and assisting intraoral PDT therapy will be trained in the protocol as per study.

Therapeutic monitoring of PDT:

• Lesion size [Срок оценки: Baseline, 4 weeks, 12 weeks]
• Lesion roughness/ whiteness: Number of patients with total resolution/ Moderate resolution/ Minimal change/ No visible change [Срок оценки: Baseline, 4 weeks, 12 weeks]
• Oral Health quality of Life: Number of patients with OHIP-14 scores 0-8 [Срок оценки: baseline, 4 weeks, 12 weeks]
• Concentration of salivary molecular markers ( IL6, TNF-α, PCNA, Survivin and VEGF) [Срок оценки: Baseline, 4 weeks]