This is a prospective study to evaluate in-field disease control, survival and late toxicity in patients with cervical cancer or pelvic recurrence treated with spatially fractionated RT.

The study will include patients with primary cervical cancer or pelvic recurrence not suitable for brachytherapy in view of anticipated or actual suboptimal target coverage due to aberrant anatomy or large residual disease at the time of brachytherapy.

Patients will be treated with spatially fractionated radiation therapy (SFRT) after EBRT completion to a dose of 25-30 Gy in 5-6 fractions in the primary setting. For patients receiving re-irradiation, 20-25 Gy in 4-5 fractions will be delivered with SFRT, which however may be individualised to match with clinical practice in the re-RT setting. Total EQD2 Gy for organs at risk will be matched to brachytherapy.

The study will be conducted at Tata Memorial Hospital, Mumbai and Advanced Centre for Treatment, Research and Education In Cancer (ACTREC), Navi Mumbai.

Inclusion Criteria:

1. Patients with cervical cancer post EBRT, with expected suboptimal brachytherapy dose coverage due to-

   1. Aberrant uterine or pelvic anatomy leading to difficulty in localization of the cervical OS or negotiation of the uterine canal accurately by two independent clinicians in up to two procedures.
   2. Large residual disease at the time of brachytherapy with anticipated suboptimal target coverage either determined in clinic based on pre-brachytherapy imaging or at dose planning (e.g. figure 2).
   3. Very narrow vaginal canal not accommodating even the smallest intracavitary or vaginal cylinder applicators.

2. Patients with inoperable endometrial cancer not suitable for anaesthesia or have anticipated suboptimal coverage of target volume at brachytherapy as identified on pre-brachytherapy imaging obtained after EBRT.

3. Patients with large pelvic recurrences after surgery and/or (chemo) radiation, not amenable to surgical salvage or brachytherapy after salvage EBRT due to reasons specified in item 1.

4. Patients with contraindications to anaesthesia for brachytherapy with sufficient risk of on-table or post procedure adverse events.

Exclusion Criteria:

1. Any pre-existing fistula in bladder or rectum.
2. Pelvic prosthesis.
3. Refusal to provide consent.