<PAGE>

                                                                    EXHIBIT 2.11

                          MID-AMERICA CRYOTHERAPY, L.P.
                              SERVICE FEE AGREEMENT


         THIS SERVICE FEE AGREEMENT (the "Agreement") is made and entered into
effective as of February 26, 2004, by and among Endocare, Inc. ("Endocare"), a
Delaware corporation and General Partner of Mid-America Cryotherapy, L.P., a
Texas limited partnership ("Mid-America Cryotherapy"), and the Limited Partners
of Mid-America Cryotherapy.

                               W I T N E S S E T H

         WHEREAS, the parties hereby acknowledge that healthcare reimbursements
for cryosurgical therapy for prostate cancer and therapies for benign prostate
hyperplasia have been reduced;

         WHEREAS, Endocare, a medical device company concentrated on developing
minimally invasive devices for the treatment of prostate cancer, has made
significant improvements in its proprietary cryosurgical technologies resulting
in more efficient and effective therapies for prostate cancer and benign
prostate hyperplasia;

         WHEREAS, the parties desire to better align their respective economic
interests under the Mid-America Cryotherapy Limited Partnership Agreement, dated
April 1, 2001, as amended on September 30, 2002;

         WHEREAS, Endocare proposes to reduce the service fee received by
Mid-America Cryotherapy from $2,500 to a maximum of $2,000, such reduction to be
effective January 1, 2004, and further reduce such service fee effective
January 1, 2005, to a maximum of 90% of the rate that will be received by other
third parties, for similar services, during 2005;

         WHEREAS, the Limited Partners of Mid-America Cryotherapy acknowledge
that Endocare, a provider of certain proprietary cryosurgical technologies to
Mid-America Cryotherapy, is a General Partner of Mid-America Cryotherapy; and

         WHEREAS, the Limited Partners of Mid-America Cryotherapy further
acknowledge that the proposed service fee reduction under this Agreement creates
a conflict of interest for Endocare and that the material facts (i) as to
Endocare's relationship to or interest in Mid-America Cryotherapy and (ii) as to
the proposed service fee reduction have been adequately disclosed and discussed
with the Limited Partners of Mid-America Cryotherapy.

         NOW, THEREFORE, in consideration of the foregoing and for other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, intending to be legally bound hereby, the parties hereto agree as
follows:

<PAGE>

                                    ARTICLE I
                              SERVICE FEE AGREEMENT

         SECTION 1.01 Service Fee Reduction. The Limited Partners of Mid-America
Cryotherapy (the "Mid-America Cryotherapy Physicians") hereby agree to reduce
the service fee received by Mid-America Cryotherapy (the "Service Fee"), from
$2,500 to a maximum of $2,000, such reduction to be effective as of January 1,
2004, and shall further reduce the Service Fee effective January 1, 2005 to a
maximum of 90% of the rate that will be received by other third parties, for
similar services, during 2005. In addition, Mid-America Cryotherapy and the
Mid-America Cryotherapy Physicians covenant and agree to support Endocare in the
restructuring of any and all agreements necessary to effectuate the Service Fee
reduction.


                                   ARTICLE II
                                  MISCELLANEOUS

         SECTION 2.01 This Amendment shall be governed by and construed in
accordance with the laws of the State of Delaware applicable to contracts
executed and performed in such State, without giving effect to the conflicts of
laws principles.

         SECTION 2.02 This Amendment may be executed in counterparts, each of
which shall be deemed an original, but all of which shall be taken together and
constitute one and the same instrument.

         SECTION 2.03 The parties hereto hereby ratify and approve the Purchase
Agreement, as amended hereby, and the parties hereto acknowledge that all of the
terms and provisions of the Purchase Agreement as amended hereby, are and remain
in full force and effect



                  [Remainder of page intentionally left blank.]


                                       2

<PAGE>

         IN WITNESS WHEREOF, this Agreement has been duly executed and delivered
by the parties hereto, or their duly authorized officer, as of the date first
above written.

                                         MID-AMERICA CRYOTHERAPY, L.P.,
                                         a Texas limited partnership

                                         By: Endocare, Inc., its General Partner


                                         By:    /s/ William J. Nydam
                                                --------------------------------
                                         Name: William J. Nydam
                                         Title: President


                                         By: its Limited Partners:


                                         By:    /s/ Dr. Wade L. Lowry
                                                --------------------------------
                                         Name: Dr. Wade L. Lowry


                                         By:    /s/ Dr. John House
                                                --------------------------------
                                         Name: Dr. John House


                                         By:    /s/ Dr. David Ellis
                                                --------------------------------
                                         Name: Dr. David Ellis


                                         By:    /s/ Dr. Michael Collini
                                                --------------------------------
                                         Name: Dr. Michael Collini


                                         By:    /s/ Dr. H. Patterson Hezmall
                                                --------------------------------
                                         Name: Dr. H. Patterson Hezmall


                                         By:    /s/ Dr. James Saalfield
                                                --------------------------------
                                         Name: Dr. James Saalfield


                                         By:    /s/ Dr. Richard Scriven
                                                --------------------------------
                                         Name: Dr. Richard Scriven


                    [SIGNATURE PAGE TO SERVICE FEE AGREEMENT]


<PAGE>

                                         By:    /s/ Dr. John Jaderlund
                                                --------------------------------
                                         Name: Dr. John Jaderlund


                                         By:    /s/ Dr. Lawrence Alter
                                                --------------------------------
                                         Name: Dr. Lawrence Alter


                                         By:    /s/ Dr. James Vestal
                                                --------------------------------
                                         Name: Dr. James Vestal


                                         By:    /s/ Dr. Gordon S. Brody
                                                --------------------------------
                                         Name: Dr. Gordon S. Brody


                                         By:    /s/ Dr. Robert A. Dowling
                                                --------------------------------
                                         Name: Dr. Robert A. Dowling


                                         By:    /s/ Dr. V. Gary Price
                                                --------------------------------
                                         Name: Dr. V. Gary Price


                                         By:    /s/ Dr. Kirk Pinto
                                                --------------------------------
                                         Name: Dr. Kirk Pinto


                                         By:    /s/ Dr. Kenneth Licker
                                                --------------------------------
                                         Name: Dr. Kenneth Licker


                    [SIGNATURE PAGE TO SERVICE FEE AGREEMENT]