A composition comprising microspheres which comprise a water insoluble, water-swellable polymer and associated with the polymer, in releasable form, a first and second chemotherapeutic agent, for use in the treatment of a pancreatic tumour or cyst, the first chemotherapeutic agent having the general formula I in which R 1 is selected from H, halogen, hydroxyl and lower (C 1-6) alkyl, optionally substituted by a hydroxyl, amine, alkoxy, halogen, acyl and acyloxy groups; A is C O or CH 2; and R is NR 2 R 3 where R 2 and R 2 are the same or different and each represents a hydrogen atom, a substituted or unsubstituted C 1-4 alkyl group or a substituted or unsubstituted carbocyclic or heterocyclic group, or R 2 and R 3 together with the nitrogen atom to which they are attached form an optionally substituted heterocyclic ring which may be interrupted by -O-, -S- or >NR 4 in which R 4 is a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted phenyl group; and wherein the grouping -A-R is bonded to a carbon atom located in any of the positions in the A ring of the camptothecin compound and R 1 is substituted in the A or B ring, including salts thereof; and the second chemotherapeutic agent is selected from rapamycin and its analogues, which analogues are selected from sirolimus, temsirolimus, everolimus, biolimus, ABT-578 and AP23573 and esters and salts thereof; wherein the microspheres, when equilibrated in water at 37°C, comprise at least 40 wt% water based on weight of polymer plus water, wherein the polymer is anionically charged at pH7 and the first chemotherapeutic agent is cationically charged and electrostatically associated with the polymer, and wherein separate particles are, each loaded with one of the drugs or each particle is jointly loaded with both the drugs; and wherein, in the treatment, the composition is injected into the pancreatic tumour or cyst or around its perimeter, preferably under the guidance of endoscopic ultrasound. in which R 1 is selected from H, halogen, hydroxyl and lower (C 1-6) alkyl, optionally substituted by a hydroxyl, amine, alkoxy, halogen, acyl and acyloxy groups; A is C O or CH 2; and R is NR 2 R 3 where R 2 and R 2 are the same or different and each represents a hydrogen atom, a substituted or unsubstituted C 1-4 alkyl group or a substituted or unsubstituted carbocyclic or heterocyclic group, or R 2 and R 3 together with the nitrogen atom to which they are attached form an optionally substituted heterocyclic ring which may be interrupted by -O-, -S- or >NR 4 in which R 4 is a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted phenyl group; and wherein the grouping -A-R is bonded to a carbon atom located in any of the positions in the A ring of the camptothecin compound and R 1 is substituted in the A or B ring, including salts thereof; and the second chemotherapeutic agent is selected from rapamycin and its analogues, which analogues are selected from sirolimus, temsirolimus, everolimus, biolimus, ABT-578 and AP23573 and esters and salts thereof; wherein the microspheres, when equilibrated in water at 37°C, comprise at least 40 wt% water based on weight of polymer plus water, wherein the polymer is anionically charged at pH7 and the first chemotherapeutic agent is cationically charged and electrostatically associated with the polymer, and wherein separate particles are, each loaded with one of the drugs or each particle is jointly loaded with both the drugs; and wherein, in the treatment, the composition is injected into the pancreatic tumour or cyst or around its perimeter, preferably under the guidance of endoscopic ultrasound.